Neuroscience of Behavior - Week 7

Voyager 1

1977 US space probe; flew past Jupiter and Saturn - 722 kg - robotic American space probe launched in September of 1977 - designed to study the outer solar system and interstellar space - operational for 44 years - still transmits data and is the first and farthest probe to leave the solar system - Voyager 1 was developed in 1977 thus its function depends on the mechanical gadgets that were implemented in 1977 - we have re-programmed gadgets on the probe for new functions and it is still giving us VERY useful info about space - metaphor for human evolution - evolutionary pressures are not the same as the ones today so we use the bodily evolutions and brain regions differently than we would have years ago

Non-functional acts of Rituals

Rituals contain many non-functional acts - Rituals have a lot of similarities to OCD compulsions - rituals are soothing - help increase grounded feeling and connection -Both OCD and rituals may be triggered by uncertainty and unpredictability - Rituals and compulsions help the person regain control - Culture may provide the templates of the ritual that our brains can easily assimilate - across the animal kingdom - similar behaviors in birds, rodents, and monkeys show that basal ganglia circuits are important and appear over-expressed in disorders producing repetitive thoughts and behaviors - striatum (caudate nucleus, putamen, nucleus accumbens) - globus pallidus - subthalamic nucleus - all regions increase activity in ritualistic behavior and OCD-like disorders

Social Modules/Mechanisms

The Brain requires a lot of energy--second only to the heart - The part of the brain not involved in controlling the body's homeostatic functions has been increasing over time, relative to the other part - in birds and mammals - areas not involved with basic regulatory function has increases in size faster than those involved in regulatory functions - not in fish and reptiles - NO evolution - the neocortex has been growing at a faster rate than other brain areas - Dunbar (1992)—the complexity of social life is related to the neocortex ratio - increased ability to function in a social setting

Rituals

Thoughtful, habitual behaviors - Common across animal species (bird songs, mating dances, etc.) - A constant tendency of every culture and persistent through the history of humans Why have them? - Precautionary behavior (taught or learned behavior that can help us avoid something (disease, environmental disaster) if we do this ritual over and over it can help increase chance of survival - Reduce anxiety (decrease uncertainty and calm members of the group) - Help delay gratification (rituals can help us cope with delayed gratification before food of payment is given) - Provide social synchrony (syncs members of the group - heavily involved in religion) - Bind groups of individuals together (increases the strength of the group)

Multi-Level Selection

To appreciate this, let's contrast genotype and phenotype Genotype = someone's genetic makeup Phenotype = the traits observable to the outside world produced by that genotype - Suppose there's a gene that influences whether your eyebrows come in two separate halves or form a continuous unibrow - You've noted that unibrow prevalence is decreasing in a population - Which is the more important level for understanding why—the gene variant or the eyebrow phenotype? - Genotype and phenotype are not synonymous, because of gene/environment interactions - Maybe some prenatal environmental effect silences one version of the gene but not the other - Maybe a subset of the population belongs to a religion where you must cover your eyebrows when around the opposite sex, and thus eyebrow phenotype is untouched by sexual selection You're a grad student researching unibrow decline, and you must choose whether to study things at the genotypic or phenotypic level - Genotypic: sequencing eyebrow gene variants, trying to understand their regulation - Phenotypic: examining, say, eyebrow appearance and mate choice, or whether unibrows absorb more heat from sunlight, thereby damaging the frontal cortex, producing inappropriate social behavior and decreased reproductive success - This was the debate—is evolution best understood by focusing on genotype or phenotype? - The most visible proponent of the gene-centered view has long been Dawkins, with his iconic "selfish gene" meme—it is the gene that is passed to the next generation, the thing whose variants spread or decline over time - Moreover, a gene is a clear and distinctive sequence of letters, reductive and irrefutable, while phenotypic traits are much fuzzier and less distinct - This is the core of the concept of "achicken is just an egg's way of making another egg"—the organism is just avehicle for the genome to be replicated in the next generation, and behavior is just this wispy epiphenomenon that facilitates the replication. - This gene-centered view can be divided in two One is that the genome (i.e., the collection of all the genes, regulatory elements, and so on) is the best level to think about things - The more radical view, held by Dawkins, is that the most appropriate level is that of individual genes—i.e., selfish genes, rather than selfish genomes - Amid some evidence for single-gene selection (an obscure phenomenon called intragenomic conflict, which we won't go into), most people who vote for the importance of gene(s) over phenotype view single-gene selfishness as a bit of a sideshow and vote for the genome level of selection being most important phenotype trumps genotype - something championed by Ernst Mayr, Stephen Jay Gould, and others - The core of their argument is that it's phenotypes rather than genotypes that are selected for - As Gould wrote, "No matter how much power Dawkins wishes to assign to genes, there is one thing he cannot give them—direct visibility to natural selection." - In that view, genes and the frequencies of their variants are merely the record of what arose from phenotypic selection - Dawkins introduced a great metaphor: a cake recipe is a genotype, and how the cake tastes is the phenotype - Genotype chauvinists emphasize that the recipe is what is passed on, the sequence of words that make for a stable replicator - But people select for taste, not recipe, say the phenotypists, and taste reflects more than just the recipe—after all, there are recipe/environment interactions where bakers differ in their skill levels, cakes bake differently at various altitudes - The recipe-versus-taste question can be framed practically: Your cake company isn't selling enough cakes. Do you change the recipe or the baker? Can't we all get along? - There's the obvious bleeding-heart answer, namely that there's room for a range of views and mechanisms in our rainbow-colored tent of evolutionary diversity - Different circumstances bring different levels of selection to the forefront - Sometimes the most informative level is the single gene, sometimes the genome, sometimes a single phenotypic trait, sometimes the collection of all the organism's phenotypic traits - We've just arrived at the reasonable idea of multilevel selection

Hobbes or Rousseau

To invoke some estimates, anatomically modern humans emerged about 200,000 years ago, and behaviorally modern ones about 40,000 to 50,000 years ago; animal domestication is 10,000 to 20,000 years old, agriculture around 12,000 - After plant domestication, it was roughly 5,000 more years until "history" began with civilizations in Egypt, the Mideast, China, and the New World When in this arc of history was war invented? - Does material culture lessen or worsen tendencies toward war? - Do successful warriors leave more copies of their genes? - Has the centralization of authority by civilization actually civilized us, providing a veneer of socially contractual restraint? - Have humans become more or less decent to one another over the course of history? - Yes, it's short/nasty/brutish versus noble savage - In contrast to the centuries of food fights among philosophers, contemporary Hobbes-versus-Rousseau is about actual data - Some of it is archaeological, where researchers have sought to determine the prevalence and antiquity of warfare from the archaeological record - Predictably, half of each conference on the subject consists of definitional squabbles - Is "war" solely organized and sustained violence between groups? Does it require weapons? A standing army (even if only seasonally)? - An army with hierarchy and chain of command - If fighting is mostly along lines of relatedness, is it a vendetta or clan feud instead of a war? Fractured Bones - For most archaeologists the operational definition has been streamlined to numerous people simultaneously meeting violent deaths - In 1996 the archaeologist Lawrence Keeley of the University of Illinois synthesized the existing literature in his highly influential War Before Civilization: The Myth of the Peaceful Savage - showing that the archaeological evidence for war is broad and ancient - A similar conclusion comes in the 2011 book The Better Angels of Our Nature: Why Violence Has Declined, by Harvard's Steven Pinker - Cliché police be damned, you can't mention this book without calling it "monumental." - In this monumental work Pinker argued that - (a) violence and the worst horrors of inhumanity have been declining for the last half millennium, thanks to the constraining forces of civilization - (b) the warfare and barbarity preceding that transition are as old as the human species - Keeley and Pinker document savagery galore in prehistoric tribal societies— mass graves filled with skeletons bearing multiple fractures, caved-in skulls, "parrying" fractures (which arise from raising your arm to fend off a blow), stone projectiles embedded in bone - Some sites suggest the outcome of battle—a preponderance of young adult male skeletons - Others suggest indiscriminate massacre—butchered skeletons of both sexes and all ages - Other sites suggest cannibalism of the vanquished In their separate surveys of the literature, Keeley and Pinker present evidence of prestate tribal violence comes from sites in Ukraine, France, Sweden, Niger, India, and numerous precontact American locations - This collection of sites includes the oldest such massacre, the 12,000- to 14,000-year-old Jebel Sahaba site along the Nile in northern Sudan, a cemetery of fifty-nine men, women, and children, nearly half of whom have stone projectiles embedded in their bones - And it includes the largest massacre site, the 700-year-old Crow Creek in South Dakota, a mass grave of more than four hundred skeletons, with 60 percent showing evidence of violent deaths - Across the twenty-one sites surveyed, about 15 percent of skeletons showed evidence of "death in warfare." - One can, of course, be killed in war in a way that doesn't leave fractures or projectiles embedded in bone, suggesting that the percentage of deaths due to warfare was higher - Otzi, in his current state (left), and in an artist's reconstruction (right) - Note: his killer, still at large, probably looked pretty much the same - Keeley and Pinker also document how prehistoric settlements frequently protected themselves with defensive palisades and fortifications - And, of course, as the poster child for prehistoric violence, there is Otzi, the 5,300-year-old Tyrolean "iceman" found in a melting glacier in 1991 on the Italian/Austrian border - In his shoulder was a freshly embedded arrowhead - Thus, Keeley and Pinker document mass casualties of warfare long predating civilization. Just as important, both (starting with Keeley's subtitle) suggest a hidden agenda among archaeologists to ignore that evidence. Why had there been, to use Keeley's phrase, "pacification of the past"? - World War II produced a generation of social scientists trying to understand the roots of fascism - In Keeley's view, the post-World War II generations of archaeologists recoiled from the trauma of the war by recoiling from the evidence that humans had been prepping a long time for World War II - For Pinker, writing from a younger generation's perspective, the current whitewashing of prehistoric violence has the flavor of today's archaeological graybeards being nostalgic about getting stoned in high school and listening to John Lennon's "Imagine." - Keeley and Pinker generated a strong backlash among many notable archaeologists, who charged them with "war-ifying the past." - Most vocal has been R. Brian Ferguson of Rutgers University, with publications with titles like "Pinker's List: Exaggerating Prehistoric War Mortality." Keeley and Pinker are criticized for numerous reasons: - Some of the sites supposedly presenting evidence for warfare actually contain only a single case of violent death, suggesting homicide, not war. - The criteria for inferring violent death include skeletons inclose proximity to arrowheads. However, many such artifacts were actually tools used for other purposes, or simply chips and flakes - For example, Fred Wendorf, who excavated Jebel Sahaba, considered most of the projectiles associated with skeletons to have been mere debris - Many fractured bones were actually healed. Instead of reflecting war, they might indicate the ritualized club fighting seen in many tribal societies - Proving that a human bone was gnawed on by a fellow human instead of another carnivore is tough. One tour-de-force paper demonstrated cannibalism in a Pueblo village from around the year 1100—human feces there contained the human version of the muscle-specific protein myoglobin - In other words, those humans had been eating human meat. Nonetheless, even when cannibalism is clearly documented, it doesn't indicate whether there was exo- or endocannibalism (i.e., eating vanquished enemies versus deceased relatives, as is done in some tribal cultures) - Most important, Keeley and Pinker are accused of cherry- picking their data, discussing only sites of putative war deaths, rather than the entire literature - When you survey the thousands of prehistoric skeletal remains from hundreds of sites worldwide, rates of violent deaths are far lower than 15 percent. - Moreover, there are regions and periods lacking any evidence of warlike violence - The glee in refuting the broadest conclusions of Keeley and Pinker is unmistakable (e.g., Ferguson in the previously cited work: "For 10,000 years in the Southern Levant, there is not one single instance where it can be said with confidence, 'war was there.' [his emphasis] Am I wrong? Name the place.") - Thus these critics conclude that wars were rare prior to human civilizations - Supporters of Keeley and Pinker retort that you can't ignore bloodbaths like Crow Creek or Jebel Sahaba and that the absence of proof (of early war in so many of these sites) is not proof of absence - This suggests a second strategy for contemporary Hobbes-versus-Rousseau debates, namely to study contemporary humans in prestate tribal societies - How frequently do they war? Prehistorians in the Flesh - Well, if researchers endlessly argue about who or what gnawed on a ten- thousand-year-old human bone, imagine the disagreements about actual living humans. - Keeley and Pinker, along with Samuel Bowles of the Santa Fe Institute, conclude that warfare is nearly universal in contemporary nonstate societies - This is the world of headhunters in New Guinea and Borneo, Maasai and Zulu warriors in Africa, Amazonians on raiding parties in the rain forest - Keeley estimates that, in the absence of pacification enforced by outside forces such as a government, 90 to 95 percent of tribal societies engage in warfare, many constantly, and a much higher percentage are at war at any time than is the case for state societies - For Keeley the rare peaceful tribal societies are usually so because they have been defeated and dominated by a neighboring tribe - Keeley charges that there has been systematic underreporting of violence by contemporary anthropologists intent on pacifying living relics of the past Keeley also tries to debunk the view that tribal violence is mostly ritualistic —an arrow in someone's thigh, a head or two bashed with a war club, and time to call it a day - Instead violence in nonstate cultures is lethal. Keeley seems to take pride in this, documenting how various cultures use weapons designed for warfare, meant to cause festering damage - He often has an almost testy, offended tone about those pacifying anthropologists who think indigenous groups lack the organization, self-discipline, and Puritan work ethic to inflict bloodbaths - He writes about the superiority of tribal warriors to Westernized armies, e.g., describing how in the Anglo-Zulu War, Zulu spears were more accurate than nineteenth-century British guns, and how the Brits won the war not because they were superior fighters but because their logistical sophistication allowed them to fight prolonged wars - Like Keeley, Pinker concludes that warfare is nearly ubiquitous in traditional cultures, reporting 10 to 30 percent of deaths as being war related in New Guinea tribes such as the Gebusi and Mae Enga, and a 35 to 60 percent range for Waorani and Jivaro tribes in the Amazon - Pinker estimates rates of death due to violence - Europe currently is in the range of 1 death per 100,000 people per year. During the crime waves of the 1970s and 1980s, the United States approached 10; Detroit was around 45 - Germany and Russia, during their twentieth-century wars, averaged 144 and 135, respectively. In contrast, the twenty-seven nonstate societies surveyed by Pinker average 524 deaths - There are the Grand Valley Dani of New Guinea, the Piegan Blackfoot of the American Great Plains, and the Dinka of Sudan, all of whom in their prime approached 1,000 deaths, roughly equivalent to losing one acquaintance per year - Taking the gold are the Kato, a California tribe that in the 1840s crossed the finish line near 1,500 deaths per 100,000 people per year Yanomamö - No tour of violence in indigenous cultures is complete without the Yanomamö, a tribe living in the Brazilian and Venezuelan Amazon - According to dogma, there is almost always raiding between villages; 30 percent of adult male deaths are due to violence; nearly 70 percent of adults have had a close relative killed by violence; 44 percent of men have murdered - The Yanomamö are renowned because of Napoleon Chagnon, one of the most famous and controversial anthropologists, a tough, pugnacious, no-holds- barred academic brawler who first studied them in the 1960s - He established the Yanomamös' street cred with his 1967 monograph Yanomamo: The Fierce People, an anthropology classic - Thanks to his publications and his ethnographic films about Yanomamö violence, both their fierceness and his are well-known tropes in anthropology - A central concept in the next chapter is that evolution is about passing copies of your genes into the next generation - In 1988 Chagnon published the remarkable report that Yanomamö men who were killers had more wives and offspring than average—thus passing on more copies of their genes - This suggested that if you excel at waging it, war can do wonders for your genetic legacy - Thus, among these nonstate tribal cultures standing in for our prehistoric past, nearly all have histories of lethal warfare, some virtually nonstop, and those who excel at killing are more evolutionarily successful Caveats - And numerous anthropologists object strenuously to every aspect of that picture: - Again with the cherry-picking - In Pinker's analysis of violence among hunter-horticulturalists and other tribal groups, all but one of his examples come from the Amazon or the New Guinea highlands - Global surveys yield much lower rates of warfare and violence - Pinker had foreseen this criticism by playing the Keeley pacification-of-the-past card, questioning those lower rates. In particular he has leveled this charge against the anthropologists (whom he somewhat pejoratively calls "anthropologists of peace," somewhat akin to "believers in the Easter Bunny") who have reported on the remarkably nonviolent Semai people of Malaysia - This produced a testy letter to Science from this group that, in addition to saying that they are "peace anthropologists," not "anthropologists of peace,"stated that they are objective scientists who studied the Semai without preconceived notions, rather than a gaggle of hippies (they even felt obliged to declare that most of them are not pacifists) - Pinker's response was "It is encouraging that 'anthropologists of peace' now see their discipline as empirical rather than ideological, a welcome change from the days when many anthropologists signed manifestos on which their position on violence was 'correct,' and censured, shut down, or spread libelous rumors about colleagues who disagreed." - Pinked was accusing academic adversaries of signing manifestos is like a sharp knee to the groin - Other anthropologists have studied the Yanomamö, and no one else reports violence like Chagnon has - Moreover, his report of increased reproductive success among more murderous Yanomamö has been demolished by the anthropologist Douglas Fry of the University of Alabama at Birmingham, who showed that Chagnon's finding is an artifact of poor data analysis: - Chagnon compared the number of descendants of older men who had killed people in battle with those who had not, finding significantly more kids among the former - However: - (a) Chagnon did not control for age differences—the killers happened to be an average of more than a decade older than the nonkillers, meaning more than a decade more time to accumulate descendants - (b) More important, this was the wrong analysis to answer the question posed—the issue isn't the reproductive success of elderly men who had been killers in their youth - You need to consider the reproductive success of all killers, including the many who were themselves killed as young warriors, distinctly curtailing their reproductive success - Not doing so is like concluding that war is not lethal, based solely on studies of war veterans - Chagnon's finding does not generalize—at least three studies of other cultures fail to find a violence/reproductive success link Nomadic pastoralist tribe study - EX. a study by Luke Glowacki and Richard Wrangham of Harvard examined a nomadic pastoralist tribe, the Nyangatom of southern Ethiopia. Like other pastoralists in their region, the Nyangatom regularly raid one another for cattle - The authors found that frequent participation in large, open battle raiding did not predict increased lifelong reproductive success - Instead such success was predicted by frequent participation in "stealth raiding," where a small group furtively steals cows from the enemy at night. In other words, in this culture being a warrior on 'roids does not predict amply passing on your genes - being a low-down sneaky varmint of a cattle rustler does - These indigenous groups are not stand-ins for our prehistoric past - For one thing, many have obtained weapons more lethal than those of prehistory (a damning criticism of Chagnon is that he often traded axes, machetes, and shotguns to Yanomamö for their cooperation in his studies) - For another, these groups often live in degraded habitats that increase resource competition, thanks to being increasingly hemmed in by the outside world - Outside contact can be catastrophic - Pinker cites research showing high rates of violence among the Amazonian Aché and Hiwi tribes - However, in examining the original reports, Fry found that all of the Aché and Hiwi deaths were due to killings by frontier ranchers intent on forcing them off their land - This tells nothing about our prehistoric past Both sides in these debates see much at stake. - Near the end of his book, Keeley airs a pretty weird worry: "The doctrines of the pacified past unequivocally imply that the only answer to the 'mighty scourge of war' is a return to tribal conditions and the destruction of all civilization." - In other words, unless this tomfoolery of archaeologists pacifying the past stops, people will throw away their antibiotics and microwaves, do some scarification rituals, and switch to loincloths—and where will that leave us? - Critics on the other side of these debates have deeper worries - For one thing, the false picture of Amazonian tribes as ceaselessly violent has been used to justify stealing their land - According to Stephen Corry of Survival International, a human-rights organization that advocates for indigenous tribal peoples, "Pinker is promoting a fictitious, colonialist image of a backward 'Brutal Savage', which pushes the debate back over a century and is still used to destroy tribes A behavior has occurred that is good, bad, or ambiguous - How have cultural factors stretching back to the origins of humans contributed to that behavior - And rustling cattle on a moonless night; or setting aside tending your cassava garden to raid your Amazonian neighbors; or building fortifications; or butchering every man, woman, and child in a village is irrelevant to that question - That's because all these study subjects are pastoralists, agriculturalists, or horticulturalists, lifestyles that emerged only in the last ten thousand to fourteen thousand years, after the domestication of plants and animals. In the context of hominin history stretching back hundreds of thousands of years, being a camel herder or farmer is nearly as newfangled as being a lobbyist advocating for legal rights for robots - For most of history, humans have been hunter- gatherers

Sorry Business

'Sorry business' is an English expression mostly adopted by mainland Aboriginal people in Australia to refer to rituals associated with death or loss - Many responsibilities and obligations to attend funerals and participate in Sorry business or bereavement protocols: - Not using the name of a person who has passed away - Not broadcasting the voice of a person who has passed away - Family members remain in the homes for a period of time - Restrictions on participating in non-bereavement related activities - (Sometimes) prohibition against depicting the image of the deceased person - rituals around how you behave after a person has passed - elaborate protocols that underlie the ritual - help people deal with the emotions of the death

Math Scores and Gender

A remarkably consistent finding, starting with elementary school students, is that males are better at math than females - The difference is minor when it comes to considering average scores, BUT there is a huge difference when it comes to math stars at the upper extreme of the distribution - EX in 1983, for every girl scoring in the highest percentile on the math SAT, there were eleven boys. Why the difference? - There have always been suggestions that testosterone is central - During development, testosterone fuels the growth of a brain region involved in mathematical thinking, and giving adults testosterone enhances some math skills - paper published in Science in 2008 - The authors examined the relationship between math scores and sexual equality in forty countries (based on economic, educational, and political indices of gender equality; the worst was Turkey, the United States was middling, and, naturally, the Scandinavians were tops) - The more gender equal the country, the less of a discrepancy in math scores - By the time you get to the Scandinavian countries, it's statistically insignificant. And by the time you examine the most gender-equal country on earth at the time, Iceland, girls are better at math than boys - he Afghan girl seated next to her husband, is less likely than the Swedish girl to solve the Erdös-Hajnal conjecture in graph theory - culture matters - we carry it with us wherever we go - EX - the level of corruption—a government's lack of transparency regarding use of power and finances—in UN diplomats' home countries predicts their likelihood of racking up unpaid parking tickets in Manhattan. Culture leaves long-lasting residues—Shiites and Sunnis slaughter each other over a succession issue fourteen centuries old - across thirty-three countries population density in the year 1500 significantly predicts how authoritarian the government was in 2000; over the course of millennia, earlier adoption of the hoe over the plow predicts gender equality today - when we contemplate our iconic acts—the pulling of a trigger, the touching of an arm—and want to explain why they happened using a biological framework, culture better be on our list of explanatory factors

Evolution Summary

Evolution theory can be used to develop hypotheses about the brain basis of social behavior - Humans (and other primates) have an exceptionally large neocortex, which has been explained by the social brain hypothesis - Human evolution suggests many possible brain modules for social behavior

Evolution 101

Evolution rests on three steps: - (a) certain biological traits are inherited by genetic means - (b) mutations and gene recombination produce variation in those traits - (c) some of those variants confer more "fitness" than others - Given those conditions, over time the frequency of more "fit" gene variants increases in a population. We start by trashing some common misconceptions - First, that evolution favors survival of the fittest. Instead evolution is about reproduction, passing on copies of genes - An organism living centuries but not reproducing is evolutionarily invisible - The difference between survival and reproduction is shown with "antagonistic pleiotropy," referring to traits that increase reproductive fitness early in life yet decrease life span - For example, primates' prostates have high metabolic rates, enhancing sperm motility - Upside: enhanced fertility; downside: increased risk of prostate cancer - Antagonistic pleiotropy occurs dramatically in salmon, who epically journey to their spawning grounds to reproduce and then die - If evolution were about survival rather than passing on copies of genes, there'd be no antagonistic pleiotropy - Another misconception is that evolution can select for preadaptations— neutral traits that prove useful in the future - This doesn't happen; selection is for traits pertinent to the present - Related to this is the misconception that living species are somehow better adapted than extinct species - Instead, the latter were just as well adapted, until environmental conditions changed sufficiently to do them in; the same awaits us - Finally, there's the misconception that evolution directionally selects for greater complexity - Yes, if once there were only single- celled organisms and there are multicellular ones now, average complexity has increased - Nonetheless, evolution doesn't necessarily select for greater complexity—just consider bacteria decimating humans with some plague. The final misconception is that evolution is "just a theory." I will boldly assume that readers who have gotten this far believe in evolution. Opponents inevitably bring up that irritating canard that evolution is unproven, because (following an unuseful convention in the field) it is a "theory" (like, say, germ theory). Evidence for the reality of evolution includes: Numerous examples where changing selective pressures have changed gene frequencies in populations within generations (e.g., bacteria evolving antibiotic resistance) - Moreover, there are also examples (mostly insects, given their short generation times) of a species in the process of splitting into two - Voluminous fossil evidence of intermediate forms in numerous taxonomic lineages - Molecular evidence - We share ~98 percent of our genes with the other apes, ~96 percent with monkeys, ~75 percent with dogs, ~20 percent with fruit flies - Indicates that our last common ancestor with other apes lived more recently than our last common ancestor with monkeys, and so on Geographic evidence - To use Richard Dawkins's suggestion for dealing with a fundamentalist insisting that all species emerged in their current forms from Noah's ark—how come all thirty- seven species of lemurs that made landfall on Mt. Ararat in the Armenian highlands hiked over to Madagascar, none dying and leaving fossils in transit? Unintelligent design - oddities explained only by evolution - Why do whales and dolphins have vestigial leg bones? Because they descend from a four-legged terrestrial mammal - Why should we have arrector pili muscles in our skin that produce thoroughly useless gooseflesh? - Because of our recent speciation from other apes whose arrector pili muscles were attached to hair, and whose hair stands up during emotional arousal. Evolution sculpts the traits of an organism in two broad ways "Sexual selection" - selects for traits that attract members of the opposite sex "natural selection" - for traits that enhance the passing on of copies of genes through any other route— e.g., good health, foraging skills, predator avoidance. - The two processes can work in opposition - For example, among wild sheep one gene influences the size of horns in males - One variant produces large horns, improving social dominance, a plus for sexual selection - The other produces small horns, which are metabolically cheaper, allowing males to live and mate (albeit at low rates) longer - Which wins—transient but major reproductive success, or persistent but minor success? - An intermediate form - Or consider male peacocks paying a price, in terms of natural selection, for their garish plumage—it costs a fortune metabolically to grow, restricts mobility, and is conspicuous to predators. But it sure boosts fitness via sexual selection. - Importantly, neither type of selection necessarily selects for "the" most adaptive version of a trait, which replaces all others - There can be frequency- dependent selection, where the rarer version of two traits is preferable, or balanced selection, where multiple versions of traits are maintained in equilibrium

Darwin's Theory of Natural Selection

How do new species emerge? Three essential elements for natural selection to operate: 1.Variation in the expression of a trait among members of a species 2. Variation must be heritable (genetically transmitted) 3. A struggle for existence among members of a species, idea promoted by Malthus, an economist / political scientist - Result: individuals will have differential reproductive success and gradual changes will occur in a population - Gradual changes will shift the characteristics of populations and new species will form from ancestral species - occurs over LONG periods of time

Residuals of Cultural Crisis

In times of crisis—the London Blitz, New York after 9/11, San Francisco after the 1989 Loma Prieta earthquake—people pull together - In contrast, chronic, pervasive, corrosive menace doesn't necessarily do the same to people or cultures - The primal menace of hunger has left historical marks - Back to that study of differences between countries' tightness (where "tight" countries were characterized by autocracy, suppression of dissent, and omnipresence and enforcement of behavior norms) - What sorts of countries are tighter? - In addition to the high population-density correlates mentioned earlier, there are also more historical food shortages, lower food intake, and lower levels of protein and fat in the diet - In other words, these are cultures chronically menaced by empty stomachs - Cultural tightness was also predicted by environmental degradation—less available farmland or clean water, more pollution - Similarly, habitat degradation and depletion of animal populations worsens conflict in cultures dependent on bush meat - And a major theme of Jared Diamond's magisterial Collapse: How Societies Choose to Fail or Succeed is how environmental degradation explains the violent collapse of many civilizations Disease - behavioral immunity - the ability of numerous species to detect cues of illness in other individuals; as we'll see, implicit cues about infectious disease make people more xenophobic - Similarly, historical prevalence of infectious disease predicts a culture's openness to outsiders - Moreover, other predictors of cultural tightness include having high historical incidence of pandemics, of high infant and child mortality rates, and of higher cumulative average number of years lost to communicable disease - Obviously, weather influences the incidence of organized violence—consider the centuries of European wars taking a hiatus during the worst of winter and the growing season - Even broader is the capacity of weather and climate to shape culture - The Kenyan historian Ali Mazrui has suggested that one reason for Europe's historical success, relative to Africa, has been the weather—Western- style planning ahead arose from the annual reality of winter coming - Larger- scale changes in weather are known to be consequential - In the tightness study, cultural tightness was also predicted by a history of floods, droughts, and cyclones - Another pertinent aspect of weather concerns the Southern Oscillation, known as El Niño, the multiyear fluctuation of average water temperatures in the equatorial Pacific Ocean - El Niños, occurring about every dozen years, involve warmer, drier weather (with the opposite during La Niña years) and are associated in many developing countries with droughts and food shortages - Over the last fifty years El Niños have roughly doubled the likelihood of civil conflict, mostly by stoking the fires of preexisting conflicts - The relationship between drought and violence is tricky - The civil conflict referred to in the previous paragraph concerned deaths caused by battle between governmental and nongovernmental forces (i.e., civil wars or insurgencies) -Thus, rather than fighting over a watering hole or a field for grazing, this was fighting for modern perks of power. But in traditional settings drought may mean spending more time foraging or hauling water for your crops - Raiding to steal the other group's women isn't a high priority, and why rustle someone else's cows when you can't even feed your own? Conflict declines. - Interestingly, something similar occurs in baboons - Normally, baboons in rich ecosystems like the Serengeti need forage only a few hours a day - Part of what endears baboons to primatologists is that this leaves them about nine hours daily to devote to social machinations—trysting and jousting and backbiting - In 1984 there was a devastating drought in East Africa. Among baboons, while there was still sufficient food, it took every waking moment to get enough calories; aggression decreased - So ecological duress can increase or decrease aggression Global Warming - Raises the key issue of what global warming will do to our best and worst behaviors - There will definitely be some upsides. Some regions will have longer growing seasons, increasing the food supply and reducing tensions. Some people will eschew conflict, being preoccupied with saving their homes from the encroaching ocean or growing pineapples in the Arctic - But amid squabbling about the details in predictive models, the consensus is that global warming won't do good things to global conflict - For starters, warmer temperatures rile people up—in cities during the summers, for every three degree increase in temperature, there was a 4 percent increase in interpersonal violence and 14 percent in group violence - But global warming's bad news is more global—desertification, loss of arable land due to rising seas, more droughts - One influential meta-analysis projected 16 percent and 50 percent increases in interpersonal and group violence, respectively, in some regions by 2050

War and Hunter-Gatherers, Past and Present

Roughly 95 to 99 percent of hominin history has been spent in small, nomadic bands that foraged for edible plants and hunted cooperatively - What is known about hunter-gatherer (for sanity's sake, henceforth HG) violence? - Given that prehistoric HGs didn't have lots of material possessions that have lasted tens of thousands of years, they haven't left much of an archaeological record - Insight into their minds and lifestyle comes from cave paintings dating back as much as forty thousand years - Though paintings from around the world show humans hunting, hardly any unambiguously depict interhuman violence - The paleontological record is even sparser - To date, there has been discovered one site of an HG massacre, dating back ten thousand years in northern Kenya - One approach is comparative, inferring the nature of our distant ancestors by comparing them with extant nonhuman primates - Early versions of this approach were the writings of Konrad Lorenz and of Robert Ardrey, who argued in his 1966 best seller The Territorial Imperative that human origins are rooted in violent territoriality - The most influential modern incarnation comes from Richard Wrangham, particularly in his 1997 book (with Dale Peterson) Demonic Males: Apes and the Origins of Human Violence - For Wrangham chimps provide the clearest guide to the behavior of earliest humans, and the picture is a bloody one - He essentially leapfrogs HGs entirely: "So we come back to the Yanomamo. Do they suggest to us that chimpanzee violence is linked to human war? Clearly they do." - Wrangham summarizes his stance: The mysterious history before history, the blank slate of knowledge about ourselves before Jericho, has licensed our collective imagination and authorized the creation of primitive Edens for some, forgotten matriarchies for others - It is good to dream, but a sober, waking rationality suggests that if we start with ancestors like chimpanzees and end up with modern humans building walls and fighting platforms, the 5- million-year-long trail to our modern selves was lined, along its full stretch, by a male aggression that structured our ancestors' social lives and technology and minds - It's Hobbes all the way down, plus Keeley-esque contempt for pacification- of-the-past dreamers. - This view has been strongly criticized: - (a) We're neither chimps nor their descendants; they've been evolving at nearly the same pace as humans since our ancestral split - (b) Wrangham picks and chooses in his cross-species linkages - for example, he argues that the human evolutionary legacy of violence is rooted not only in our close relationship to chimps but also in our nearly-as-close kinship with gorillas, who practice competitive infanticide - The problem is that, overall, gorillas display minimal aggression, something Wrangham ignores in linking human violence to gorillas - (c) As the most significant species cherry- picking, Wrangham pretty much ignores bonobos, with their far lower levels of violence than chimps, female social dominance, and absence of hostile territoriality - Crucially, humans share as much of their genes with bonobos as with chimps, something unknown when Demonic Males was published (and, notably, Wrangham has since softened his views). - For most in the field, most insights into the behavior of our HG ancestors come from study of contemporary HGs - Once, the world of humans consisted of nothing but HGs; today the remnants of that world are in the few remaining pockets of peoples who live pure HG lives - These include the Hadza of northern Tanzania, Mbuti "Pygmies" in the Congo, Batwa in Rwanda, Gunwinggu of the Australian outback, Andaman Islanders in India, Batak in the Philippines, Semang in Malaysia, and various Inuit cultures in northern Canada - To start, it was once assumed that among HGs, women do the gathering while men supply most of the calories by hunting - In actuality, the majority of calories come from foraging; men spend lots of time talking about how awesome they were in the last hunt and how much awesomer they'll be in the next— among some Hadza, maternal grandmothers supply more calories to families than do the Man the Hunter men - The arc of human history is readily equated with an arc of progress, and key to the latter is the view that agriculture was the best thing humans ever invented - A cornerstone of the agriculture lobby is the idea that primordial HGs were half starved. In reality, HGs typically work fewer hours for their daily bread than do traditional farmers and are longer-lived and healthier. In the words of anthropologist Marshall Sahlins, HGs were the original affluent society - There are some demographic themes shared among contemporary HGs - Dogma used to be that HG bands had fairly stable group membership, producing considerable in-group relatedness - More recent work suggests less relatedness than thought, reflecting fluid fusion/fission groupings in nomadic HGs - The Hadza show one consequence of such fluidity, namely that particularly cooperative hunters find one another and work together What about our best and worst behaviors in contemporary HGs? - Up into the 1970s, the clear answer was that HGs are peaceful, cooperative, and egalitarian. Interband fluidity serves as a safety valve preventing individual violence (i.e., when people are at each other's throats, someone moves to another group), and nomadicism as a safety valve preventing intergroup violence (i.e., rather than warring with the neighboring band, just hunt in a different valley from them) - The standard-bearers for HG grooviness were the Kalahari !Kung - The title of an early monograph about them—Elizabeth Marshall Thomas's 1959 The Harmless People—says it all - !Kung are to the Yanomamö as Joan Baez is to Sid Vicious and the Sex Pistols - Naturally, this picture of the !Kung in particular and HGs in general was ripe for revisionism - This occurred when field studies were sufficiently long term to document HGs killing one another, as summarized in an influential 1978 publication by Carol Ember of Yale - Basically, if you're observing a band of thirty people, it will take a long time to see that, on a per-capita basis, they have murder rates approximating Detroit's (the standard comparison always made) - Admitting that HGs were violent was seen as a purging of sixties anthropological romanticism, a bracing slap in the face for anthropologists who had jettisoned objectivity in order to dance with wolves -By the time of Pinker's synthesis, HG violence was established, and the percentage of their deaths attributed to warfare averaged around 15 percent, way more than in modern Western societies - Contemporary HG violence constitutes a big vote for the Hobbesian view of warfare and violence permeating all of human history

What is NOT Natural Selection

The Progress Myth: "The Ascent of Man" - NOT linear - not directly from chimps to humans - linear fashion is the wrong approach entirely

Social Media

The human brain is really only able to keep track of the relationships of about 150 people - you may follow or know more people but you can only really know things or keep track of 150 people

Continuous or Gradual Change

The term "evolution" carries context-dependent baggage - If you're in the Bible Belt, evolution is leftist besmirching of God, morality, and human exceptionalism. But to extreme leftists, "evolution" is a reactionary term, the slow change that impedes real change—"All reform undermines revolution." - This next challenge addresses whether evolution is actually more about rapid revolution than about slow reform. - A basic sociobiological premise is that evolutionary change is gradual, incremental - As a selective pressure gradually changes, a useful gene variant grows more common in a population's gene pool. As enough changes accrue, the population may even constitute a new species ("phyletic gradualism") - Over millions of years, dinosaurs gradually turn into chickens, organisms emerge that qualify as mammals as glandular secretions slowly evolve into milk, thumbs increasingly oppose in proto-primates - Evolution is gradual, continuous In 1972 Stephen Jay Gould and paleontologist Niles Eldredge of the American Museum of Natural History proposed an idea that simmered and then caught fire in the 1980s - They argued that evolution isn't gradual; instead, most of the time nothing happens, and evolution occurs in intermittent rapid, dramatic lurches Punctuated Equilibrium Their idea, which they called punctuated equilibrium, was anchored in paleontology - Fossil records, we all know, show gradualism—human ancestors show progressively larger skulls, more upright posture, and so on - And if two fossils in chronological progression differ a lot, a jump in the gradualism, there must be an intermediate form that is the "missing link" from a time between those two fossils - With enough fossils in a lineage, things will look gradualist. Eldredge and Gould focused on there being plenty of fossil records that were complete chronologically (for example, trilobites and snails, Eldredge's and Gould's specialties, respectively) and didn't show gradualism - Instead there were long periods of stasis, of unchanged fossils, and then, in a paleontological blink of an eye, there'd be a rapid transition to a very different form - Maybe evolution is mostly like this, they argued. What triggers punctuated events of sudden change? - A sudden, massive selective factor that kills most of a species, the only survivors being ones with some obscure genetic trait that turned out to be vital— an "evolutionary bottleneck - Why does punctuated equilibrium challenge sociobiological thinking? - Sociobiological gradualism implies that every smidgen of difference in fitness counts, that every slight advantage of one individual over another at leaving copies of genes in future generations translates into evolutionary change - At every juncture, optimizing competition, cooperation, aggression, parental investment, all of it, is evolutionarily consequential - And if instead there is mostly evolutionary stasis, much of this chapter becomes mostly irrelevant - The sociobiologists were not amused - They called the punctuated equilibrium people "jerks" (while the punctuated equilibrium people called them "creeps"—get it? PE = evolution in a series of jerks; sociobiology = evolution as a gradual, creeping process) - Gradualist sociobiologists responded with strong rebuttals, taking a number of forms: They're just snail shells - First, there are some very complete fossil lineages that are gradualist - And don't forget, said the gradualists, these punctuated equilibrium guys are talking about trilobite and snail fossils - The fossil record we're most interested in—primates, hominins—is too spotty to tell if it is gradualist or punctuated. How fast do their eyes blink? - Next, said the gradualists, remember, these punctuated equilibrium fans are paleontologists - They see long periods of stasis and then extremely rapid blink-of-the-eye changes in the fossil record. But with fossils the blink of an eye, a stretch of time unresolvably short in the fossil record, could be 50,000 to 100,000 years - That's plenty of time for evolution bloody in tooth and claw to happen - This is only a partial refutation, since if a paleontological blink of the eye is so long, paleontological stasis is humongously long - They're missing the important stuff - A key rebuttal is to remind everyone that paleontologists study things that are fossilized. Bones, shells, bugs in amber. Not organs—brains, pituitaries, ovaries. Not cells—neurons, endocrine cells, eggs, sperm - Not molecules—neurotransmitters, hormones, enzymes. In other words, none of the interesting stuff. Those punctuated equilibrium nudniks spend their careers measuring zillions of snail shells and, based on that, say we're wrong about the evolution of behavior? - This opens the way for some compromise - Maybe the hominin pelvis did indeed evolve in a punctuated manner, with long periods of stasis and bursts of rapid change - And maybe the pituitary's evolution was punctuated as well, but with punctuations at different times - And maybe steroid hormone receptors and the organization of frontocortical neurons and the inventions of oxytocin and vasopressin all evolved that way also, but each undergoing punctuated change at a different time - Overlap and average these punctuated patterns, and it will be gradualist - This only gets you so far, though, since it assumes the occurrence of numerous evolutionary bottlenecks - Where's the molecular biology? - One of the strongest gradualist retorts was a molecular one Micromutation, consisting of point, insertion, and deletion mutations that subtly change the function of preexisting proteins, is all about gradualism - But what mechanisms of molecular evolution explain rapid, dramatic change and long periods of stasis? - recent decades have provided many possible molecular mechanisms for rapid change - This is the world of macromutations: - (a) traditional point, insertion, and deletion mutations in genes whose proteins have amplifying network effects (transcription factors, splicing enzymes, transposes) in an exon expressed in multiple proteins in genes for enzymes involved in epigenetics - (b) traditional mutations in promoters, transforming the when/where/how-much of gene expression (remember that promoter change that makes polygamous voles monogamous) - (c) untraditional mutations such as the duplication or deletion of entire genes. - All means for big, rapid changes. But what about a molecular mechanism for the stasis? - Plunk a random mutation into a transcription-factor gene, thereby creating a new cluster of genes never before expressed simultaneously - What are the odds that it won't be a disaster? Randomly mutate a gene for an enzyme that mediates epigenetic changes, thereby producing randomly different patterns of gene silencing - Parachute a transposable genetic element into the middle of some gene, change a splicing enzyme so that it mixes and matches different exons in multiple proteins - Both asking for major trouble - Implicit in this is stasis, a conservatism about evolutionary change—it takes very unique macro changes during times of very unique challenge to luck out. - Show us some actual rapid change - A final rebuttal from gradualists was to demand real-time evidence of rapid evolutionary change in species - And plenty exist - One example was wonderful research by the Russian geneticist Dmitry Belyaev, who in the 1950s domesticated Siberian silver foxes - He bred captive ones for their willingness to be in proximity to humans, and within thirty-five generations he'd generated tame foxes who'd cuddle in your arms. Pretty punctuated, I'd say - The problem here is that this is artificial rather than natural selection - Interestingly, the opposite has occurred in Moscow, which has a population of thirty thousand feral dogs dating back to the nineteenth century (and where some contemporary dogs have famously mastered riding the Moscow subway system) - Most Moscow dogs are now descendants of generations of feral dogs, and over that time they have evolved to have a unique pack structure, avoid humans, and no longer wag their tails - In other words, they're evolving into something wolflike - Most likely, the first generations of these feral populations were subject to fierce selection for these traits, and it's their descendants who comprise the current population Rapid change in the human gene pool has occurred as well with the spread of lactase persistence—a change in the gene for the enzyme lactase, which digests lactose, such that it persists into adulthood, allowing adults to consume dairy - The new variant is common in populations that subsist on dairy—pastoralists like Mongolian nomads or East African Maasai—and is virtually nonexistent in populations that don't use dairy after weaning—Chinese and Southeast Asians - Lactase persistence evolved and spread in a fraction of a geologic blink of an eye —in the last ten thousand years or so, coevolving with domestication of dairy animals - Other genes have spread in humans even faster. For example, a variant of a gene called ASPM, which is involved in cell division during brain development, has emerged and spread to about 20 percent of humans in the last 5,800 years - And genes that confer resistance to malaria (at the cost of other diseases, such as sickle-cell disease or the thalassemias) are even younger - Still, thousands of years counts as fast only for snail shell obsessives - However, evolution has been observed in real time - A classic example is the work of the Princeton evolutionary biologists Peter and Rosemary Grant, who, over the course of decades of work in the Galapagos, demonstrated substantial evolutionary change in Darwin's finches - Evolutionary change in humans has occurred in genes related to metabolism, when populations transition from traditional to Westernized diets (e.g., Pacific Islanders from Nauru, Native Americans of the Pima tribe in Arizona). The first generations with Westernized diets develop catastrophically high rates of obesity, hypertension, adult-onset diabetes, and death at early ages, thanks to "thrifty" genotypes that are great at storing nutrients, honed by millennia of sparser diets - But within a few generations diabetes rates begin to subside, as there is an increased prevalence in the population of "sloppier" metabolic genotypes - Thus, there are examples of rapid changes in gene frequencies in real time - Are there examples of gradualism? - That's hard to show because gradual change is, er, gradual - A great example, however, comes from decades of work by Richard Lenski of Michigan State University. He has cultured E. coli bacteria colonies under constant conditions for 58,000 generations, roughly equivalent to a million years of human evolution. Over that time, different colonies have gradually evolved in distinctive ways, becoming more adapted - Thus, both gradualism and punctuated change occur in evolution, probably depending upon the genes involved—for example, there has been faster evolution of genes expressed in some brain regions than others - And no matter how rapid the changes, there's always some degree of gradualism—no female has ever given birth to a member of a new species

Population size, density and heterogeneity

The year 2008 marked a human milestone, a transition point nine thousand years in the making: for the first time, the majority of humans lived in cities - The human trajectory from semipermanent settlements to the megalopolis has been beneficial - In the developed world, when compared with rural populations, city dwellers are typically healthier and wealthier; larger social networks facilitate innovation; because of economies of scale, cities leave a smaller per-capita ecological footprint - Urban living makes for a different sort of brain - This was shown in a 2011 study of subjects from a range of cities, towns, and rural settings who underwent an experimental social stressor while being brain-scanned - The key finding was that the larger the population where someone lived, the more reactive their amygdala was during that stressor - Most important for our purposes, urbanized humans do something completely unprecedented among primates—regularly encountering strangers who are never seen again, fostering the invention of the anonymous act - After all, it wasn't until nineteenth-century urbanization that crime fiction was invented, typically set in cities—in traditional settings there's no whodunit, since everyone knows what everyone dun - Growing cultures had to invent mechanisms for norm enforcement among strangers - For example, across numerous traditional cultures, the larger the group, the greater the punishment for norm violations and the more cultural emphases on equitable treatment of strangers - Moreover, larger groups evolved "third-party punishment" (stay tuned for more in the next chapter)—rather than victims punishing norm violators, punishment is meted out by objective third parties, such as police and courts - At an extreme, a crime not only victimizes its victim but also is an affront to the collective population—hence "The People Versus Joe Blow - Finally, life in larger populations fosters the ultimate third-party punisher - As documented by Ara Norenzayan of the University of British Columbia, it is only when societies grow large enough that people regularly encounter strangers that "Big Gods" emerge—deities who are concerned with human morality and punish our transgressions - Societies with frequent anonymous interactions tend to outsource punishment to gods - In contrast, hunter-gatherers' gods are less likely than chance to care whether we've been naughty or nice - Moreover, in further work across a range of traditional cultures, Norenzayan has shown that the more informed and punitive people consider their moralistic gods to be, the more generous they are to coreligionist strangers in a financial allocation game - Separate from the size of a population, how about its density? - One study surveying thirty-three developed countries characterized each nation's "tightness"—the extent to which the government is autocratic, dissent suppressed, behavior monitored, transgressions punished, life regulated by religious orthodoxy, citizens viewing various behaviors as inappropriate (e.g., singing in an elevator, cursing at a job interview) - Higher population density predicted tighter cultures—both high density in the present and, remarkably, historically, in the year 1500. - The issue of population density's effects on behavior gave rise to a well- known phenomenon, mostly well known incorrectly. Calhoun's Rats - In the 1950s John Calhoun at the National Institute of Mental Health asked what happens to rat behavior at higher population densities, research prompted by America's ever-growing cities - And in papers for both scientists and the lay public, Calhoun gave a clear answer: high-density living produced "deviant" behavior and "social pathology." - Rats became violent; adults killed and cannibalized one another; females were aggressive to their infants; there was indiscriminate hypersexuality among males (e.g., trying to mate with females who weren't in estrus). - The writing about the subject, starting with Calhoun, was colorful - The bloodless description of "high-density living" was replaced with "crowding." - Aggressive males were described as "going berserk," aggressive females as "Amazons." - Rats living in these "rat slums" became "social dropouts," "autistic," or "juvenile delinquents." - One expert on rat behavior, A. S. Parkes, described Calhoun's rats as "unmaternal mothers, homosexuals and zombies" (quite the trio you'd invite to dinner in the 1950s) - The work was hugely influential, taught to psychologists, architects, and urban planners; more than a million reprints were requested of Calhoun's original Scientific American report; sociologists, journalists, and politicians explicitly compared residents of particular housing projects and Calhoun's rats. - The take-home message sent ripples through the American heartland destined for the chaotic sixties: inner cities breed violence, pathology, and social deviance. - Calhoun's rats were more complicated than this (something underemphasized in his lay writing) - High-density living doesn't make rats more aggressive. Instead it makes aggressive rats more aggressive. (make violent individuals more sensitive to violence-evoking social cues.) - In contrast, crowding makes unaggressive individuals more timid - In other words, high density-living exaggerates preexisting social tendencies. - Calhoun's erroneous conclusions about rats don't even hold for humans - In some cities—Chicago, for example, circa 1970—higher population density in neighborhoods does indeed predict more violence - Nevertheless, some of the highest-density places on earth—Hong Kong, Singapore, and Tokyo—have miniscule rates of violence - High-density living is not synonymous with aggression in rats or humans. How about the effects of living with different kinds of people? Diversity. Heterogeneity. Admixture. Mosaicism. Two opposite narratives come to mind: Mister Rogers' neighborhood: When people of differing ethnicities, races, or religions live together, they experience the similarities rather than the differences and view one another as individuals, transcending stereotypes. - Trade flows, fostering fairness and mutuality. Inevitably, dichotomies dissolve with intermarriage, and soon you're happily watching your grandkid in the school play on "their" side of town. Just visualize whirled peas. Sharks versus the Jets: Differing sorts of people living in close proximity rub, and thus abrade, elbows regularly. - One side's act of proud cultural identification feels like a hostile dig to the other side, public spaces become proving grounds for turf battles, commons become tragedies - Surprise: both outcomes occur; the final chapter explores circumstances where intergroup contact leads to one rather than the other - Most interesting at this juncture is the importance of the spatial qualities of the heterogeneity - Consider a region filled with people from Elbonia and Kerplakistan, two hostile groups, each providing half the population - At one extreme, the land is split down the middle, each group occupying one side, producing a single boundary between the two - At the other extreme is a microcheckerboard of alternating ethnicities, where each square on the grid is one person large, producing a vast quantity of boundaries between Elbonians and Kerplakis - Intuitively, both scenarios should bias against conflict - In the condition of maximal separation, each group has a critical mass to be locally sovereign, and the total length of border, and thus of the amount of intergroup elbow rubbing, is minimized - In the scenario of maximal mixing, no patch of ethnic homogeneity is big enough to foster a self-identity that can dominate a public space—big deal if someone raises a flag between their feet and declares their square meter to be the Elbonian Empire or a Kerplakistani Republic - But in the real world things are always in between the two extremes, and with variation in the average size of each "ethnic patch." - Does patch size, and thus amount of border, influence relations? - This was explored in a fascinating paper from the aptly named New England Complex Systems Institute, down the block from MIT - The authors first constructed an Elbonian/Kerplaki mixture, with individuals randomly distributed as pixels on a grid - Pixels were given a certain degree of mobility plus a tendency to assort with other pixels of the same type - As self-assortment progresses, something emerges—islands and peninsulas of Elbonians amid a sea of Kerplakis, or the reverse, a condition that intuitively seems rife with potential intergroup violence - As self-assortment continues, the number of such isolated islands and peninsulas declines - The intermediate stage that maximizes the number of islands and peninsulas maximizes the number of people living within a surrounded enclave - The authors then considered a balkanized region, namely the Balkans, ex- Yugoslavia, in 1990 - This was just before Serbians, Bosnians, Croatians, and Albanians commenced Europe's worst war since World War II, the war that taught us the names of places like Srebrenica and people like Slobodan Milošević - Using a similar analysis, with ethnic island size varying from roughly twenty to sixty kilometers in diameter, they identified the spots theoretically most rife for violence; remarkably, this predicted the sites of major fighting and massacres in the war - In the words of the authors, violence can arise "due to the structure of boundaries between groups rather than as a result of inherent conflicts between the groups themselves." - They then showed that the clarity of borders matters as well - Good, clear-cut fences—e.g., mountain ranges or rivers between groups— make for good neighbor - "Peace does not depend on integrated coexistence, but rather on well defined topographical and political boundaries separating groups, allowing for partial autonomy within a single country," the authors concluded - Thus, not only do size, density, and heterogeneity of populations help explain intergroup violence, but patterns and clarity of fragmentation do as well

Before Darwin

William Paley (1802), Natural Theology - great scholar who combines understanding of nature and god - The watch is complex and has a purpose to keep time - It had a designer - The human eye is even more remarkable than the watch and it has a purpose - Absurd to imagine that something more complex than a pocket watch could occur in nature without some 'guiding hand - Who designed the human eye?

Demise of Group Selection

We start by grappling with an entrenched misconception about the evolution of behavior - This is because Americans were taught about the subject in the 1960s by Marlin Perkins on the TV program Mutual of Omaha's Wild Kingdom - Perkins would host. Jim, his sidekick, did dangerous things with snakes - And there were always seamless segues from the program to ads from Mutual of Omaha—"Just as lions mate for hours, you'll want fire insurance for your home. - Perkins espoused wildly wrong evolutionary thinking. - It's dawn on the savanna; there's a herd of wildebeest on a river's edge. The grass is greener on the other side, and everyone wants some, but the river teems with predatory crocodiles. The wildebeest are hemming and hawing in agitation when suddenly an elderly wildebeest pushes to the front, says, "I sacrifice myself for you, my children," and leaps in. And while the crocs are busy with him, the other wildebeest cross the river. - Why would the old wildebeest do that? - because animals behave For the Good of the Species. - Yes, behavior evolves by "group selection" for the good of the species - This idea was championed in the early 1960s by V. C. Wynne-Edwards, whose wrongness made him modern evolutionary biology's Lamarck - Animals don't behave for the good of the species - But what about that wildebeest? - Look closely and you'll see what really happens. Why did he wind up saving the day? - Because he was old and weak they pushed the old guy in. - Group selection was done in by theoretical and empirical studies showing patterns of behavior incompatible with it. - Key work was done by two gods of evolutionary biology, George Williams of SUNY Stony Brook and Oxford's Bill ("W.D.") Hamilton - Consider "eusocial insects," where most individuals are nonreproductive workers - Why forgo reproduction to aid the queen? Group selection, obviously - Hamilton showed that eusocial insects' unique genetic system makes a colony of ants, bees, or termites a single superorganism - askingwhy worker ants forgo reproduction is like asking why your nose cells forgo reproduction - In other words, eusocial insects constitute a unique type of "group." Williams then elaborated on how the more standard genetic system, in species from noneusocial insects to us, was incompatible with group selection - Animals don't behave for the good of the species - They behave to maximize the number of copies of their genes passed into the next generation - This is the cornerstone of sociobiology and was summarized in Dawkins's famed sound bite that evolution is about "selfish genes."

Kin Selection

What it means to be related to someone and to pass on copies of "your" genes - Suppose you have an identical twin, with the same genome as you - As a startling, irrefutable fact, in terms of the genes being passed on to the next generation, it doesn't matter if you reproduce or sacrifice yourself so that your twin reproduces - What about a full sibling who isn't an identical twin? Recall from chapter 8 that you'd share 50 percent of your genes with him - Thus reproducing once and dying so that he reproduces twice are evolutionarily identical - Half sibling, 25 percent of genes in common, calculate accordingly - The geneticist J. B. S. Haldane, who, when asked if he'd sacrifice his life for a brother, is credited to have quipped, "I'll gladly lay down my life for two brothers or eight cousins." - You can leave copies of your genes in the next generation by reproducing, but also by helping relatives reproduce, especially closer relatives - Hamilton formalized this with an equation factoring in the costs and benefits of helping someone, weighted by their degree of relatedness to you - The essence of kin selection - This explains the crucial fact that in countless species, whom you cooperate with, compete with, or mate with depends on their degree of relatedness to you - Mammals first encounter kin selection soon after birth, reflecting something monumentally obvious: females rarely nurse someone else's infants - Next, among numerous primates the mother of a newborn and an adolescent female may commence a relationship fraught with pluses and minuses—the mother occasionally lets the adolescent care for her offspring - For the mother the plus is getting time to forage without baby on board; the minus is that the babysitter may be incompetent - For the adolescent the plus is getting mothering experience; the minus, the effort of child care Lynn Fairbanks of UCLA has quantified the pluses and minuses of such "allomothering" (including that adolescents who practiced mothering have a better survival rate for their own kids) And who is a frequent "allomother"? - The female's kid sister An extension of allomothering is the cooperative breeding of New World monkeys like marmosets - In their social groups only one female breeds, while the others—typically younger relatives—help with child care - The extent to which a male primate cares for infants reflects his certainty of paternity - Among marmosets, who form stable pair-bonds, males do most of the child care - In contrast, among baboons, where a female mates with multiple males during her estrus cycle, it's only the likely fathers (i.e., males who mated on the female's most fertile day, when she had her most conspicuous estrus swelling) who invest in the well-being of the child, aiding him in a fight - Among many primates, how often you groom someone depends on how closely related they are to you - Among baboons, females spend their whole life in their natal troop (whereas males migrate to a new troop at puberty); as a result, adult females have complex cooperative kinship relations and inherit their dominance rank from their mother - Among chimps it's the opposite; females leave home at puberty, and kin-based adult cooperation occurs only among males (for example, where groups of related males attack solitary males from neighboring groups) - Among langurs, when a female defends her infant against a new male, she most often is helped by elderly female relatives. Primates understand kinship Dorothy Cheney and Robert Seyfarth of the University of Pennsylvania, studying wild vervet monkeys, have shown that if animal A is crummy to animal B, afterward, B is more likely to be crummy to A's relatives. And if A is lousy to B, B's relatives are more likely to be crummy to A. Furthermore, if A is lousy to B, B's relatives are more likely to be crummy to A's relatives - In beautiful "playback" experiments, Cheney and Seyfarth first recorded vocalizations from each vervet in a group. - They'd place a speaker in some bushes, and when everyone was sitting around, they'd play a recording of some kid giving a distress call - And the females would all look at the kid's mother —"Hey, that's Madge's kid. What's she going to do?" (Note that this also shows that monkeys recognize voices.) - In a study of wild baboons, Cheney and Seyfarth would wait for two unrelated females to sit near the bush with the speaker and then play one of three vocalizations: - (a) sounds of the two females' relatives fighting with each other -(b) a relative of one fighting with a third party - (c) two other random females fighting - If a female's relative was involved in the fighting, she'd look toward the speaker longer than if there were no relatives involved - And if it was relatives of the two females fighting each other, the higher-ranking one would remind the subordinate of her place by supplanting her from her spot. Another playback study created some baboon virtual reality.18 Baboon A dominates baboon B - Thanks to cutting and splicing of recordings of vocalizations, baboon A is heard making a dominance vocalization, B making a subordination one - When this happens, no baboons looked at the bushes—A > B, boring status quo - But if baboon A is heard making a subordination vocalization after B makes a dominance one—a rank reversal—everyone orients to the bushes ("Did you hear what I just heard?") - Then a third scenario—a dominance reversal between two members of the same family. And no one looks, because it's uninteresting. ("Families, they're crazy. You should see mine—we have these huge dominance reversals and are hugging an hour later.") Baboons "classify others simultaneously according to both individual rank and kinship." - Thus other primates contemplate kinship with remarkable sophistication, with kinship determining patterns of cooperation and competition Nonprimates are also into kin selection - Consider this—sperm in a female's vaginal tract can aggregate, allowing them to swim faster. Among a deer mouse species where females mate with multiple males, sperm aggregate only with sperm from the same individual or a close relative - As behavioral examples, squirrels and prairie dogs give alarm vocalizations when spotting a predator - It's risky, calling attention to the caller, and such altruism is more common when in the proximity of relatives - Social groups built around female relatives occur in numerous species (e.g., lion prides, where related females nurse one another's cubs) - Moreover, while prides typically contain a single breeding male, on those occasions when it's two males, better than chance that they're brothers There is a striking similarity in humans - Most cultures have historically allowed polygyny, with monogamy as the rarer beast - Even rarer is polyandry—multiple men married to one woman - occurs in northern India, Tibet, and Nepal, where the polyandry is "adelphic" (aka "fraternal")—a woman marries all the brothers of one family, from the strapping young man to his infant brother - A challenging implication of kin selection arises - If one accrues fitness benefits by helping relatives pass on copies of their genes, why not help them do that by mating with them? - inbreeding produces decreased fertility and those genetic unpleasantnesses in European royalty - So the dangers of inbreeding counter the kin-selection advantages - Theoretical models suggest that the optimal balance is third-cousin matings. And indeed, numerous species prefer to mate with between a first and a third cousin - This occurs in insects, lizards, and fish, where, on top of that, cousin-mating pairs invest more in the rearing of their offspring than do unrelated parents - A preference for cousin matings occurs in quail, frigate birds, and zebra finches, while among pair-bonded barn swallows and ground tits, females sneak out on their partner to mate with cousins. Similar preferences occur in some rodents (including the Malagasy giant jumping rat, a species that sounds disturbing even without cousins shacking up with each other) - And what about humans? Something similar. Women prefer the smell of moderately related over unrelated men - And in a study of 160 years of data concerning every couple in Iceland (which is a mecca for human geneticists, given its genetic and socioeconomic homogeneity), the highest reproductive success arose from third- and fourth-cousin marriages

Humans and Evolution

Where do humans fit into all this? - Our behavior closely matches the predictions of these evolutionary models - Until you look more closely - Let's start by clearing up some misconceptions. First, we are not descended from chimps - Or from any extant animal - We and chimps share a common ancestor from roughly five million years ago (and genomics show that chimps have been as busy evolving since then as we have) - And there are misconceptions as to which ape is our "closest relative." - In my experience, someone who is fond of duck hunting and country music usually votes chimp, but if you eat organic food and know about oxytocin, it's bonobo - The reality is that we're equally related to both, sharing roughly 98 to 99 percent of our DNA with each - Svante Pääbo of the Max Planck Institutes in Germany has shown that 1.6 percent of the human genome is more related to bonobos than to chimps; 1.7 percent more to chimps than to bonobos - Despite the combination of some of our most fervent wishes and excuses, we're neither bonobos nor chimps - On to how the conceptual building blocks of behavioral evolution apply to humans Promiscuous Tournament or Monogamous Pair- Bonded? - are we a pair-bonded or tournament species? - Western civilization doesn't give a clear answer. We praise stable, devoted relationships yet are titillated, tempted, and succumb to alternatives at a high rate - Once divorces are legalized, a large percentage of marriages end in them, yet a smaller percentage of married people get divorced—i.e., the high divorce rate arises from serial divorcers - Anthropology doesn't help either - Most cultures have allowed polygyny. But within such cultures most people are (socially) monogamous. But most of those men would presumably be polygamous if they could buy more wives.What about human sexual dimorphism? Men are roughly 10 percent taller and 20 percent heavier than women, need 20 percent more calories, and have life spans 6 percent shorter—more dimorphic than monogamous species, less than polygamous ones - Likewise with subtle secondary sexual characteristics like canine length, where men average slightly longer canines than women - Moreover, compared with, say, monogamous gibbons, human males have proportionately bigger testes and higher sperm counts . . . but pale in comparison with polygamous chimps - And back to imprinted genes, reflecting intersexual genetic competition, which are numerous in tournament species and nonexistent in pair-bonders - What about humans? Some such genes, but not many. Measure after measure, it's the same - We aren't classically monogamous or polygamous - As everyone from poets to divorce attorneys can attest, we are by nature profoundly confused—mildly polygynous, floating somewhere in between Individual Selection - At first pass we seem like a great example of a species where the driving force on behavior is maximizing reproductive success, where a person can be an egg's way of making another egg, where selfish genes triumph - Just consider the traditional perk of powerful men: being polygamous - Pharaoh Ramses II, incongruously now associated with a brand of condoms, had 160 children and probably couldn't tell any of them from Moses. Within half a century of his death in 1953, Ibn Saud, the founder of the Saudi dynasty, had more than three thousand descendants - Genetic studies suggest that around sixteen million people today are descended from Genghis Khan - And in recent decades more than one hundred children each were fathered by King Sobhuza II of Swaziland, Ibn Saud's son King Saud, the dictator Jean-Bédel Bokassa of the Central African Republic, plus various fundamentalist Mormon leaders - The human male drive to maximize reproductive success is shown by a key fact—the most common cause of individual human violence is male-male competition for direct or indirect reproductive access to females - And then there is the dizzyingly common male violence against females for coercive sex or as a response to rejection - So plenty of human behaviors would make sense to a baboon or elephant seal. But that's only half the story. Despite Ramses, Ibn Saud, and Bokassa, numerous people forgo reproducing, often because of theology or ideology - And an entire sect—the United Society of Believers in Christ's Second Appearing, aka the Shakers, will soon be extinct because of its adherents' celibacy. And finally, the supposed selfishness of human genes driving individual selection must accommodate individuals sacrificing themselves for strangers - Competitive infanticide as stark evidence of the importance of individual selection - Does anything like that occur in humans? The psychologists Martin Daly and (the late) Margo Wilson of McMaster University in Canada looked at patterns of child abuse and made a striking observation—a child is far more likely to be abused or killed by a stepparent than by a parent - This is readily framed as parallel to competitive infanticide "Cinderella effect," - while embraced by human sociobiologists, has also been robustly criticized - Some charge that socioeconomic status was not sufficiently controlled for (homes with a stepparent, rather than two biological parents, generally have less income and more economic stress, known causes of displacement aggression) - Others think there's a detection bias—the same degree of abuse is more likely to be identified by authorities when it's committed by a stepparent - And the finding has been independently replicated in some but not all studies. I think the jury is still out on the subject Kin Selection - Where do humans fit in terms of kin selection? - We've already seen examples that fit well—e.g., the fraternal polyandry in Tibet, the weirdness of women liking the smell of their male cousins, the universality of nepotism - Moreover, humans are obsessed with kin relations in culture after culture, with elaborate systems of kinship terms (just go into a store and look at the Hallmark cards organized by kinship category—for a sister, a brother, an uncle, and so on) - And in contrast to other primates who leave their natal group around adolescence, when humans in traditional society marry someone from another group and go live with them, they maintain contact with their family of origin - Moreover, from New Guinea highlanders to the Hatfields and McCoys, feuds and vendettas occur along clan lines of relatedness - We typically bequeath our money and land among our descendants rather than among strangers - From ancient Egypt to North Korea and on to the Kennedys and Bushes, we have dynastic rule - How's this for a display of human kin selection: Subjects were given a scenario of a bus hurtling toward a human and a nondescript dog, and they could only save one - Whom would they pick? - It depended on degree of relatedness, as one progressed from sibling (1 percent chose the dog over the sibling) to grandparent (2 percent) to distant cousin (16 percent) to foreigner (26 percent) - As another measure of the importance of kinship in human interactions, people can't be compelled to testify in court against a first-degree relative in many countries and American states - And when humans have damage to the (emotional) vmPFC, they become so unemotionally utilitarian that they would choose to harm family members in order to save strangers - There's a fascinating historical example of how wrong it feels when someone chooses strangers over kin - This is the story of Pavlik Morozov, a boy in Stalin's Soviet Union.57 Young Pavlik, according to the official story, was a model citizen, an ardent flag-waving patriot - In 1932 he chose the state over his kin, denouncing his father (for supposed black marketeering), who was promptly arrested and executed - Soon afterward the boy was killed, allegedly by relatives who felt more strongly about kin selection than he did - The regime's propagandists embraced the story - Statues of the young martyr to the revolution were erected - Poems and songs were written; schools were named for him - An opera was composed, a hagiographic movie made. As the story emerged, Stalin was told about the boy. And what was the response of the man most benefiting from such fealty to the state? Was it "If only all my citizens were that righteous; this lad gives me hope for our future"? No. According to historian Vejas Liulevicius of the University of Tennessee, when told about Pavlik, Stalin snorted derisively and said, "What a little pig, to have done such a thing to his own family." - And then he turned the propagandists loose. - Thus even Stalin was of the same opinion as most mammals: something's wrong with that kid - Human social interactions are profoundly organized around kin selection; with the rare exception of a Pavlik Morozov, blood is thicker than water. - Naturally, until you look more closely. - For starters, yes, across cultures we are obsessed with kinship terms, but the terms often don't overlap with actual biological relatedness - We certainly have clan vendettas, but we also have wars where combatants on opposing sides have higher degrees of relatedness than do fighters on the same side - Brothers fought on opposing sides in the Battle of Gettysburg - Relatives and their armies battle over royal succession; the cousins George V of England, Nicholas II of Russia, and Wilhelm II of Germany happily oversaw and sponsored World War I - And intrafamily individual violence occurs (although at extremely low rates when corrected for amount of time spent together) - There's patricide, often an act of revenge for a long history of abuse, and fratricide - Rarely due to conflicts over issues of economic or reproductive importance—stolen birthrights of biblical proportion, someone sleeping with their sibling's spouse—fratricide is most often about long-standing irritants and disagreements that just happen to boil over into lethality (in early May 2016, for example, a Florida man was charged with second-degree murder in the killing of his brother—during a dispute over a cheeseburger) - And then there is the hideous commonness of honor killings in parts of the world, as we've seen - The most puzzling cases of intrafamily violence, in terms of kin selection, are of parents killing children, a phenomenon most commonly arising from combined homicide/suicide, profound mental illness, or abuse that unintentionally proves fatal - And then there are cases where a mother kills an unwanted child who is viewed as a hindrance—parent/offspring conflict flecked with the spittle of madness - While we bequeath money to our descendants, we also give charitably to strangers on the other side of the planet (thank you, Bill and Melinda Gates) and adopt orphans from other continents - (Being charitable is tinged with self-interest, and most people who adopt kids do so because they cannot have biological offspring—but the occurrence of either act violates strict kin selection.) - And in the primogeniture system of land inheritance, birth order trumps degree of relatedness. Thus we have textbook examples of kin selection, but also dramatic exceptions. - Why do humans have such marked deviations from kin selection? - I think this often reflects how humans go about recognizing relatives. We don't do it with certainty, by innate recognition of MHC-derived pheromones, the way rodents do (despite our being able to distinguish degrees of relatedness to some extent by smell) - Nor do we do it by imprinting on sensory cues, deciding, "This person is my mother because I remember that her voice was the loudest when I was a fetus." Instead we do kin recognition cognitively, by thinking about it - But crucially, not always rationally—as a general rule, we treat people like relatives when they feel like relatives - One fascinating example is the Westermarck effect, demonstrated by marriage patterns among people raised in the Israeli kibbutz system - Communal child rearing is central to the ethos of the traditional socialist agricultural kibbutz approach - Children know who their parents are and interact with them a few hours a day - But otherwise they live, learn, play, eat, and sleep with the cohort of kids their age in communal quarters staffed by nurses and teachers - In the 1970s anthropologist Joseph Shepher examined records of all the marriages that had ever occurred between people from the same kibbutz - And out of the nearly three thousand occurrences, there was no instance of two individuals marrying who had been in the same age group during their first six years of life - Oh, people from the same peer group typically had loving, close, lifelong relationships - But no sexual attraction. "I love him/her to pieces, but am I attracted? Yech—he/she feels like my sibling." Who feels like a relative (and thus not like a potential mate)? Someone with whom you took a lot of baths when you both were kids. How's this for irrationality? - Back to people deciding whether to save the person or the dog. The decision depended not only on who the person was (sibling, cousin, stranger) but also on who the dog was—a strange dog or your own - Remarkably, 46 percent of women would save their dog over a foreign tourist. What would any rational baboon, pika, or lion conclude? - That those women believe they are more related to a neotenized wolf than to another human. Why else act that way? "I'll gladly lay down my life for eight cousins or my awesome labradoodle, Sadie." Human irrationality in distinguishing kin from nonkin takes us to the heart of our best and worst behaviors - This is because of something crucial—we can be manipulated into feeling more or less related to someone than we actually are - When it is the former, wonderful things happen—we adopt, donate, advocate for, empathize with - We look at someone very different from us and see similarities. It is called pseudokinship - And the converse? One of the tools of the propagandist and ideologue drumming up hatred of the out-group—blacks, Jews, Muslims, Tutsis, Armenians, Roma—is to characterize them as animals, vermin, cockroaches, pathogens - So different that they hardly count as human - It's called pseudospeciation and it underpins many of our worst moments.

Gigantic Question #1: What Strategy for Cooperating Is Optimal?

While biologists were formulating these questions, other scientists were already starting to answer them - In the 1940s "game theory" was founded by the polymath John von Neumann, one of the fathers of computer science. Game theory is the study of strategic decision making. Framed slightly differently, it's the mathematical study of when to cooperate and when to cheat - The topic was already being explored with respect to economics, diplomacy, and warfare. What was needed was for game theorists and biologists to start talking - This occurred around 1980 concerning the Prisoner's Dilemma (PD), introduced in chapter 3. Time to see its parameters in detail. - Two members of a gang, A and B, are arrested. Prosecutors lack evidence to convict them of a major crime but can get them on a lesser charge, for which they'll serve a year in prison - A and B can't communicate with each other. Prosecutors offer each a deal—inform on the other and your sentence is reduced There are four possible outcomes: 1. Both A and B refuse to inform on each other: each serves one year 2. Both A and B inform on each other: each serves two years 3. A informs on B, who remains silent: A walks free and B serves three years. 4. B informs on A, who remains silent: B walks and A serves three years. Thus, each prisoner's dilemma is whether to be loyal to your partner ("cooperate") or betray him ("defect") - The thinking might go, "Best to cooperate. This is my partner; he'll also cooperate, and we'll each serve only a year. But what if I cooperate and he stabs me in the back? He walks, and I'm in for three years. Better defect. But what if we both defect—that's two years. But maybe defect, in case he cooperates - If you play PD once, there is a rational solution. If you, prisoner A, defect, your sentence averages out to one year (zero years if B cooperates, two years if B defects); if you cooperate, the average is two years (one year if B cooperates, three years if B defects) - Thus you should defect. In single-round versions of PD, it's always optimal to defect. Not very encouraging for the state of the world. - Suppose there are two rounds of PD - The optimal strategy for the second round is just like in a single-round version—always defect. Given that, the first- round defaults into being like a single-round game—and thus, defect during it also. - What about a three-round game? - Defect in the third, meaning that things default into a two-round game - In which case, defect in the second, meaning defect in the first. - It's always optimal to defect in round Z, the final round. And thus it's always optimal to defect in round Z−1, and thus round Z−2 - In other words, when two individuals play for a known number of rounds, the optimal strategy precludes cooperation. - But what if the number of rounds is unknown (an "iterated" PD)? Things get interesting. Which is when the game theorists and biologists met. - The catalyst was political scientist Robert Axelrod of the University of Michigan. He explained to his colleagues how PD works and asked them what strategy they'd use in a game with an unknown number of rounds. The strategies offered varied enormously, with some being hair-raisingly complicated - Axelrod then programmed the various strategies and pitted them against each other in a simulated massive round-robin tournament Tit for Tat - Which strategy won, was most optimal? It was provided by a mathematician at the University of Toronto, Anatol Rapoport; as the mythic path-of-the-hero story goes, it was the simplest strategy - Cooperate in the first round. After that, you do whatever the other player did in the previous round. It was called Tit for Tat More details: You cooperate (C) in the first round, and if the other player always cooperates (C), you both happily cooperate into the sunset: Example 1: You: C C C C C C C C C C. . . . Her: C C C C C C C C C C. . . . Suppose the other player starts cooperating but then, tempted by Satan, defects (D) in round 10. You cooperated, and thus you take a hit: Example 2: You: C C C C C C C C C C Her: C C C C C C C C C D Thus, you Tit for Tat her, punishing her in the next round: Example 3: You: C C C C C C C C C C D Her: C C C C C C C C C D ? If by then she's resumed cooperating, you do as well; peace returns: Example 4: You: C C C C C C C C C C D C C C. . . . Her: C C C C C C C C C D C C C C. . . . If she continues defecting, you do as well: Example 5: You: C C C C C C C C C C D D D D D. . . . Her: C C C C C C C C C D D D D D D. . . . Suppose you play against someone who always defects. Things look like this: Example 6: You: C D D D D D D D D D. . . . Her: D D D D D D D D D D. . . . This is the Tit for Tat strategy - Note that it can never win - Best case is a draw, if playing against another person using Tit for Tat or someone using an "always cooperate" strategy. Otherwise it loses by a small margin - Every other strategy would always beat Tit for Tat by a small margin - However, other strategies playing against each other can produce catastrophic losses - And when everything is summed, Tit for Tat wins. It lost nearly every battle but won the war. Or rather, the peace - In other words, Tit for Tat drives other strategies to extinction. Tit for Tat has four things going for it: - Its proclivity is to cooperate (i.e., that's its starting state) - But it isn't a sucker and punishes defectors - It's forgiving —if the defector resumes cooperating, so will Tit for Tat. And the strategy is simple. Axelrod's tournament launched a zillion papers about Tit for Tat in PD and related games (more later) Then something crucial occurred—Axelrod and Hamilton hooked up - Biologists studying the evolution of behavior longed to be as quantitative as those studying the evolution of kidneys in desert rats - And here was this world of social scientists studying this very topic, even if they didn't know it - PD provided a framework for thinking about the strategic evolution of cooperation and competition, as Axelrod and Hamilton explored in a 1981 paper (famous enough that it's a buzz phrase—e.g., "How'd your lecture go today?" "Terrible, way behind schedule; I didn't even get to Axelrod and Hamilton") - As the evolutionary biologists started hanging with the political scientists, they inserted real-world possibilities into game scenarios Flaws - One addressed a flaw in Tit for Tat. - Let's introduce signal errors—a message is misunderstood, someone forgets to tell someone something, or there's a hiccup of noise in the system - Like in the real world. There has been a signal error in round 5, with two individuals using a Tit for Tat strategy. This is what everyone means: Example 7: You: C C C C C Her: C C C C C But thanks to a signal error, this is what you think happened: Example 8: You: C C C C C Her: C C C C D You think, "What a creep, defecting like that." You defect in the next round. Thus, what you think has happened: Example 9: You: C C C C C D Her: C C C C D C What she thinks is happening, being unaware of the signal error: Example 10: You: C C C C C D Her: C C C C C C She thinks, "What a creep, defecting like that." Thus she defects the next round. "Oh, so you want more? I'll give you more," you think, and defect. "Oh, so you want more? I'll give you more," she thinks: Example 11: You: C C C C C D C D C D C D C D C D. . . . Her: C C C C D C D C D C D C D C D C. . . . When signal errors are possible, a pair of Tit for Tat players are vulnerable to being locked forever in this seesawing of defection. The discovery of this vulnerability prompted evolutionary biologists Martin Nowak of Harvard, Karl Sigmund of the University of Vienna, and Robert Boyd of UCLA to provide two solutions - "Contrite Tit for Tat" retaliates only if the other side has defected twice in a row - "Forgiving Tit for Tat" automatically forgives one third of defections - Both avoid doomsday signal-error scenarios but are vulnerable to exploitation - A solution to this vulnerability is to shift the frequency of forgiveness in accordance with the likelihood of signal error ("Sorry I'm late again; the train was delayed" being assessed as more plausible and forgivable than "Sorry I'm late again; a meteorite hit my driveway again"). Another solution to Tit for Tat's signal-error vulnerability is to use a shifting strategy - At the beginning, in an ocean of heterogeneous strategies, many heavily biased toward defection, start with Tit for Tat - Once they've become extinct, switch to Forgiving Tit for Tat, which outcompetes Tit for Tat when signal errors occur. What is this transition from hard-assed, punitive Tit for Tat to incorporating forgiveness? Establishing trust. Other elaborations simulate living systems - The computer scientist John Holland of the University of Michigan introduced "genetic algorithms"— strategies that mutate over time - Another real-world elaboration was to factor in the "cost" of certain strategies—for example, with Tit for Tat, the costs of monitoring for and then punishing cheating—costly alarm systems, police salaries, and jail construction - These are superfluous in a world of no signal errors and nothing but Tit for Tat- ers, and Tit for Tat can be replaced by the cheaper Always Cooperate. - Thus, when there are signal errors, differing costs to different strategies, and the existence of mutations, a cycle emerges: a heterogeneous population of strategies, including exploitative, noncooperative ones, are replaced by Tit for Tat, then replaced by Forgiving Tit for Tat, then by Always Cooperate—until a mutation reintroduces an exploitative strategy that spreads like wildfire, a wolf amon Always Cooperate sheep, starting the cycle all over again - More and more modifications made the models closer to the real world - Soon the computerized game strategies were having sex with each other, which must have been the most exciting thing ever for the mathematicians involved - The evolutionary biologists were delighted to generate increasingly sophisticated models with the theoretical economists and theoretical diplomats and theoretical war strategists. The real question was whether animal behavior actually fits any of these models One bizarre animal system suggests Tit for Tat enforcement of cooperation involving the black hamlet fish, which form stable pair-bonds - Nothing strange there - The fish can change sex (something that occurs in some fish species) - As per usual, reproduction is more metabolically costly for the female than the male - So the fish in a pair take turns being the more expensive female - Say fish A and fish B have been doing their sex-change tango, and most recently A was the expensive female and B the cheap male - Suppose B cheats by staying male, forcing A to continue as female; A switches to male and stays that way until B regains his social conscience and becomes female. Another widely cited study suggested a Tit for Tat strategy among stickleback fish - The fish is in a tank, and on the other side of a glass partition is something scary—a bigger cichlid fish. The stickleback tentatively darts forward and back, investigating. Now put a mirror in its tank, perpendicular to the axis of the two fish. In other words, thanks to the mirror, there appears to be a second cichlid next to the first - Terrifying, except from out of nowhere there's this mysterious second stickleback who checks out the second cichlid every time our hero checks out the first—"I have no idea who this guy is, but we're an amazing, coordinated team." - Now convince the stickleback his partner is defecting. Angle the mirror so that the stickleback's reflection is deflected backward - Now when the fish darts forward, his reflection does as well, but—that jerk!—it looks like he's hanging back safely (lagging back even half a body length decreases the likelihood of a fish being predated). When the fish believes his partner is defecting, he stops darting forward - Greater complexity in Tit for Tat-ing is suggested by some animals having multiple roles in their social groups.39 Back to the playback technique with lions, where the roar of a strange male emanated from a speaker in the bushes (or from a life-sized model of a lion) - Lions tentatively came forward to investigate, a risky proposition - Consistently, certain lions hung back - The toleration of these habitual scaredy-cats seemed to violate the demands of reciprocity, until it was recognized that such animals took the lead in other domains (e.g., in hunts) - A similar punch line emerges concerning the Damaraland mole rat - The social groups of it and its relative, the naked mole rat, resemble those of social insects, with nonreproductive workers and a single breeding queen - Researchers noted some workers who never worked and were considerably fatter than the rest - It turns out that they have two specialized jobs—during the rains, they dig through flooded, collapsed tunnels of the burrows, and when necessary, they disperse with the risky task of starting a new colony - I'm not convinced that a Tit for Tat reciprocity has been clearly demonstrated in other species - But evidence of its strict use would be hard for Martian zoologists to document in humans—after all, there are frequently pairs where one human does all the labor, the other doing nothing other than intermittently handing him some green pieces of paper - The point is that animals have systems of reciprocity with sensitivity to cheating

Culture in different parts of the world

Why should people in one part of the globe have developed collectivist cultures, while others went individualist? The US - The United States is the individualism poster child for at least two reasons 1. immigration - Currently, 12 percent of Americans are immigrants, another 12 percent are children of immigrants, and everyone else except for the 0.9 percent pure Native Americans descend from people who emigrated within the last five hundred years - And who were the immigrants? Those in the settled world who were cranks, malcontents, restless, heretical, black sheep, hyperactive, hypomanic, misanthropic, itchy, unconventional, yearning to be free, yearning to be rich, yearning to be out of their damn boring repressive little hamlet, yearning 2. for the majority of its colonial and independent history, America has had a moving frontier luring those whose extreme prickly optimism made merely booking passage to the New World insufficiently novel— and you've got America the individualistic East Asia - Why has East Asia provided textbook examples of collectivism? - The key is how culture is shaped by the way people traditionally made a living, which in turn is shaped by ecology - East Asia it's all about rice - Rice, which was domesticated there roughly ten thousand years ago, requires massive amounts of communal work - Not just backbreaking planting and harvesting, which are done in rotation because the entire village is needed to harvest each family's rice - Collective labor is first needed to transform the ecosystem—terracing mountains and building and maintaining irrigation systems for controlled flooding of paddies - And there's the issue of dividing up water fairly—in Bali, religious authority regulates water access, symbolized by iconic water temples - How's this for amazing—the Dujiuangyan irrigation system irrigates more than five thousand square kilometers of rice farms near Changdu, China, and it is more than two thousand years old - The roots of collectivism, like those of rice, run deep in East Asia Northern China - A fascinating 2014 Science paper strengthens the rice/collectivism connection by exploring an exception - In parts of northern China it's difficult to grow rice, and instead people have grown wheat for millennia; this involves individual rather than collective farming - And by the standard tests of individualist versus collectivist cultures (e.g., draw a sociogram, which two are most similar of a rabbit, dog, and carrot?)—they look like Westerners. The region has two other markers of individualism, namely higher rates of divorce and of inventiveness—patent filings—than in rice-growing regions - The roots of individualism, likes those of wheat, run deep in northern China Turkish People The links between ecology, mode of production, and culture are shown in a rare collectivist/individualist study not comparing Asians and Westerners - The authors studied a Turkish region on the Black Sea, where mountains hug the coastline - There, in close proximity, people live by fishing, by farming the narrow ribbon of land between the sea and the mountains, or as mountain shepherds - All three groups had the same language, religion, and gene stock. - Herding is solitary; while Turkish farmers and fishermen (and women) were no Chinese rice farmers, they at least worked their fields in groups and manned their fishing boats in crews - Herders thought less holistically than farmers or fishermen—the former were better at judging absolute length of lines, the other two at relative judgments; when shown a glove, a scarf, and a hand, herders grouped gloves and scarves categorically, while the others grouped relationally, pairing gloves and hands - In the authors' words, "social interdependence fosters holistic thinking." Jewish V. Orthodox Homes - This theme appears in another study, comparing Jewish boys from either observant Orthodox homes (dominated by endless shared rules about beliefs and behaviors) with ones from far more individualist secular homes - Visual processing was more holistic in the Orthodox, more focused in the secular

Collectivist V. Individualistic Cultures

a large percentage of cross-cultural psychology studies compare collectivist with individualist cultures - This almost always means comparisons between subjects from collectivist East Asian cultures and Americans, coming from that mother of all individualist cultures - As defined, collectivist cultures are about harmony, interdependence, conformity, and having the needs of the group guiding behavior - individualist cultures are about autonomy, personal achievement, uniqueness, and the needs and rights of the individual. Just to be a wee bit caustic, individualist culture can be summarized by that classic American concept of "looking out for number one"; - collectivist culture can be summarized by the archetypical experience of American Peace Corps teachers in such countries— pose your students a math question, and no one will volunteer the correct answer because they don't want to stand out and shame their classmates. - Individualist/collectivist contrasts are striking Individualist - In individualist cultures, people more frequently seek uniqueness and personal accomplishment, use first- person singular pronouns more often, define themselves in terms that are personal ("I'm a contractor") rather than relational ("I'm a parent"), attribute their successes to intrinsic attributes ("I'm really good at X") rather than to situational ones ("I was in the right place at the right time") - The past is more likely to be remembered via events ("That's the summer I learned to swim") rather than social interactions ("That's the summer we became friends") - Motivation and satisfaction are gained from self- rather than group-derived effort (reflecting the extent to which American individualism is about noncooperation, rather than nonconformity) - Competitive drive is about getting ahead of everyone else - When asked to draw a "sociogram"—a diagram of their social network, with circles representing themselves and their friends, connected by lines—Americans tend to place the circle representing themselves in the middle of the page and make it the largest Collectivist - collectivist cultures show more social comprehension; some reports suggest that they are better at Theory of Mind tasks, more accurate in understanding someone else's perspective—with "perspective" ranging from the other person's abstract thoughts to how objects appear from where she is sitting - There is more blame of the group when someone violates a norm due to peer pressure, and a greater tendency to give situational explanations for behavior - Competitive drive is about not falling behind everyone else - when drawing sociograms, the circle representing "yourself" is far from the center, and far from the biggest - Naturally, these cultural differences have biological correlates - subjects from individualist cultures strongly activate the (emotional) mPFC when looking at a picture of themselves, compared to looking at a picture of a relative or friend - in contrast, the activation is far less for East Asian subjects - Another example is a favorite demonstration of mine of cross-cultural differences in psychological stress—when asked in free recall, Americans are more likely than East Asians to remember times in which they influenced someone; conversely, East Asians are more likely to remember times when someone influenced them - Force Americans to talk at length about a time someone influenced them, or force East Asians to detail their influencing someone, and both secrete glucocorticoids from the stressfulness of having to recount this discomfiting event - by my Stanford colleagues and friends Jeanne Tsai and Brian Knutson shows that mesolimbic dopamine systems activate in European Americans when looking at excited facial expressions; in Chinese, when looking at calm expressions. - cultural differences produce different moral systems. In the most traditional of collectivist societies, conformity and morality are virtually synonymous and norm enforcement is more about shame ("What will people think if I did that?") than guilt ("How could I live with myself?") - Collectivist cultures foster more utilitarian and consequentialist moral stances (for example, a greater willingness for an innocent person to be jailed in order to prevent a riot) - The tremendous collectivist emphasis on the group produces a greater degree of in-group bias than among individualist culture members - In one study, for example, Korean and European American subjects observed pictures of either in- or out-group members in pain - All subjects reported more subjective empathy and showed more activation of Theory of Mind brain regions (i.e., the temporoparietal junction) when observing in-group members, but the bias was significantly greater among Korean subjects - In addition, subjects from both individualist and collectivist cultures denigrate out- group members, but only the former inflate assessments of their own group - East Asians, unlike Americans, don't have to puff up their own group to view others as inferior - What is fascinating is the direction that some of these differences take, as shown in approaches pioneered by one of the giants in this field, Richard Nisbett of the University of Michigan - Westerners problem-solve in a more linear fashion, with more reliance on linguistic rather than spatial coding. When asked to explain the movement of a ball - East Asians are more likely to invoke relational explanations built around the interactions of the ball with its environment—friction—while Westerners focus on intrinsic properties like weight and density - Westerners are more accurate at estimating length in absolute terms ("How long is that line?") while East Asians are better with relational estimates ("How much longer is this line than that?") - Consider a monkey, a bear, and a banana. Which two go together? Westerners think categorically and choose the monkey and bear—they're both animals - East Asians think relationally and link the monkey and banana—if you're thinking of a monkey, also think of food it will need - Remarkably, the cultural differences extend to sensory processing, where Westerners process information in a more focused manner, East Asians in a more holistic one - Show a picture of a person standing in the middle of a complex scene; East Asians will be more accurate at remembering the scene, the context, while Westerners remember the person in the middle - Remarkably, this is even observed on the level of eye tracking—typically Westerners' eyes first look at a picture's center, while East Asians scan the overall scene - force Westerners to focus on the holistic context of a picture, or East Asians on the central subject, and the frontal cortex works harder, activating more - cultural values are first inculcated early in life - culture shapes our attitudes about success, morality, happiness, love, and so on - But what is startling to me is how these cultural differences also shape where your eyes focus on a picture or how you think about monkeys and bananas or the physics of a ball's trajectory - Culture's impact is enormous.

Framework for Cultural Neuroscience - Chiao

culture < --Cultural Psychology--> mind <--social-cognitive-affective neuroscience--> brain <-- neurogenetics-->genes (situation-ontogeny-phylongy)

Sexual Dimorphism in the Male and Female Brain

ex. is the empirical finding of math in men and women biological, cultural or an interaction? - Humans do not have large sexual dimorphisms in brain anatomy - But this is not what most people think because many books have been written that spew lies about dimorphisms - one writes that males and females have different CC sizes MYTH: - The claim: Women's corpus callosum is larger than men's and that difference is important - Women use both sides of their brain more symmetrically than men. The larger corpus callosum in women explains female intuition and the ability to "multitask" and tune in to emotions (This is BULL SHIT) - FACT - Studies using MRI, taking into account such things as differences in brain sizes, do not support any CC difference in men and women - A meta-analysis of 49 studies found no significant sex differences in the size or shape of the corpus callosum (Bishop & Wahlsten). - there is a significant myth used to attempt to explain differences in male and female info processing

Failure to accept evolution until the late 19th century

people aggressively rejected it - time since creation - only a few thousand years from what the Bible said - thus no time for evolution but the Bible is WRONG - insufficient evidence - doctrines opposed to the Bible - people were stupid and overly religious

Methods of Cultural Study

- Collective vs. Individualistic Cultures - Stratified vs. Egalitarian Cultures - Cultures of Honor (all over the globe - US culture of honor is quick to defend honor with increased physicality and aggression, also has honor killings and revenge) - Population Size, Population Density, Population Heterogeneity - Gender Roles and Equality (biological differences between XX and YY)

Fossile Record

- Fossils were discovered and creatures were dead that were not in the Bible

Antecedents to Darwin's Evolution

- Gottfried Liebniz (1646-1716) - theory for evolution - Immanuel Kant (1724-1804) - theory for evolution - Erasmus Darwin (1731-1802) - Darwin's grandfather, outlined a theory for evolution and an early attempt at explaining evolution - James Burnett, Lord Monboddo (1714-1799) - interested in origin of language and where it came from

DRD4 and Culture

- The East Asian/Western collectivist/individualist dichotomy has a fascinating genetic correlate - Recall from the last chapter dopamine and DRD4, the gene for the D4 receptor - It's extraordinarily variable, with at least twenty-five human variants (with lesser variability in other primates) - Moreover, the variation isn't random, inconsequential drift of DNA sequences; instead there has been strong positive selection for variants - Most common is the 4R variant, occurring in about half of East Asians and European Americans - There's also the 7R variant, producing a receptor less responsive to dopamine in the cortex, associated with novelty seeking, extroversion, and impulsivity - It predates modern humans but became dramatically more common ten to twenty thousand years ago - The 7R variant occurs in about 23 percent of Europeans and European Americans - And in East Asians only 1 percent - increased 7R shows increased incidence of great migration - So which came first, 7R frequency or cultural style? - The 4R and 7R variants, along with the 2R, occur worldwide, implying they already existed when humans radiated out of Africa 60,000 to 130,000 years ago - Classic work by Kenneth Kidd of Yale, examining the distribution of 7R, shows something remarkable - Starting at the left of the figure above, there's roughly a 10 to 25 percent incidence of 7R in various African, European, and Middle Eastern populations - Jumping to the right side of the figure, there's a slightly higher incidence among the descendants of those who started island-hopping from mainland Asia to Malaysia and New Guinea - The same for folks whose ancestors migrated to North America via the Bering land bridge about fifteen thousand years ago—the Muskoke, Cheyenne, and Pima tribes of Native Americans - Then the Maya in Central America—up to around 40 percent. Then the Guihiba and Quechua of the northern parts of South America, at around 55 percent - Finally there are the descendants of folks who made it all the way to the Amazon basin—the Ticuna, Surui, and Karitiana—with a roughly 70 percent incidence of 7R, the highest in the world - In other words, the descendants of people who, having made it to the future downtown Anchorage, decided to just keep going for another six thousand miles - A high incidence of 7R, associated with impulsivity and novelty seeking, is the legacy of humans who made the greatest migrations in human history - And then in the middle of the chart is the near-zero incidence of 7R in China, Cambodia, Japan, and Taiwan (among the Ami and Atayal) - When East Asians domesticated rice and invented collectivist society, there was massive selection against the 7R variant; in Kidd's words, it was "nearly lost" in these populations - Maybe the bearers of 7R broke their necks inventing hang gliding or got antsy and tried to walk to Alaska but drowned because there was no longer a Bering land bridge. Maybe they were less desirable mates. Regardless of the cause, East Asian cultural collectivism coevolved with selection against the 7R variant - Thus, in this most studied of cultural contrasts, we see clustering of ecological factors, modes of production, cultural differences, and differences in endocrinology, neurobiology, and gene frequencies - The cultural contrasts appear in likely ways—e.g., morality, empathy, child-rearing practices, competition, cooperation, definitions of happiness—but also in unexpected ones —e.g., where, within milliseconds, your eyes look at a picture, or you're thinking about bunnies and carrots.

Spandrel examples

- dreams - no meaning just a by-product of restoring the brain and making memories - art - no good of art for genetic evolution - no function for an evolutionary goal - music - same ad art - See Mehr and diagram in powerpoint - However, it could be seen that music enhances social bonding and increases social connectivity - stronger bonds and increased survival when times are tough - these things co-evolved with humans

Charles Lyell (1729-1875)

- geologist - showed layers in the Earth and that it was older than the Bible Publishes Principles of Geology in 3 volumes in 1830-1833 - "the present is the key to the past" - See time from the rocks and sediment in the Earth - evidence against the Bible

The Primate Neocortex

- increased social life = increased neocortex size - shown across multiple animal species - The Social Brain Hypothesis - Neocortex size as a constraint on group size in primates - for Humans our brains seem best equipped for a group of 150 individuals - larger neocortex = larger group size - see lecture for picture

Methods to Study Culture

- mix of cultural psychology & anthropology - Collective vs. Individualistic Cultures - some countries may have more people in one trait or the other, but there are individual differences in every country/nation - Affects behaviour but also self-construals - Collectivist - focus on the group and how to better society - Japan - individualist - focus on the individual and how to better oneself - USA - self-construals - defines how you act and think of yourself - defined by culture --- Collectivist - relationships with people, groups you are apart of and the workplace --- individualist cultures - emphasize where you went to school, how much money you make and occupation

How Culture and Biology are Interrelated

1. Culture can affect biological processes - culture affects biology 2. Biological processes can shape culture - culture affects bio and bio affects culture - culture (phenotype of novelty seeking could increase the migration - passage along of how we can move to new locations, people move frequently in certain cultures) - biology (dopamine genotypes that could increase the likelihood to seek reward behavior due to genotype) 3. Culture X Biology Interactions - culture affects bio, bio affects culture and both can interact (culture X biology interaction) - genetic variation moderates the link between racial discrimination & the development of conduct problems - the racially discriminated group has conduct issues ONLY of they have the genetic variation - can predict criminal issues and law abiding nature 4. Culture X Biology X Environment Interactions - culture affects bio, bio affects culture and both can interact (culture X biology interaction) and then environment causes a culture X biology X environment interaction - 3 way niche contribution with environment, genetics, ethnic heterogeneity and neighborhoods can shape aggression among adolescents - NEED combo of all these things to get the affect

Culture Study - Ciao et al. 2009

12 young adults living in Nagoya, Japan, and 12 young adults living in Chicago, USA - While in the scanner, they read 72 statements and were asked whether the statement (a) was written in italics (control task), (b) describes themselves when talking to their mother, or (c) describes themselves generally - measured self-construls of people living in the US v. Japan so they could look at cultural values and see if that is related to brain activity - All participants completed the Self-Construal Scale that measured how individual vs. collectivist they personally were (how they view their attachment to individual v. collective) The anterior rostral MPFC activity varied by the stimulus condition but this depended on the person's self-construal - determined mPFC activity - interaction of stim context and self construl to brain activity -Degree of individualism v. collectivism was related to MPFC activity during contextual judgments - Collectivist cultures showed increased mPFC activity if they think about statements relating to their mother - Individualists show increased mPFC activity if they think about the statement that related to how they see themselves - If a person tended to be more collectivist regardless of country they were from they showed increased mPFC activity in the mother task statement - the relationship between individualistic v. cultural task interacts with a persons self-construls and their mPFC activity - regardless of self-construl style and culture there are not strict country differences and it changes per person based on their beliefs

Innate Psychological Gadgets

If you were predicting innate psychological gadgets: spoken language vs. reading - Spoken language - hunter-gatherer - highly important - reading - more recent evolution - not in the older human brain - repurpose language regions and shape then into recognition regions

Complexity of Social Behavior in Groups

According to Dunbar & Schultz (2007), it was cognitive demands of reproductive pair-bonding that triggered the initial evolution of large brains across vertebrates - pair-bonding is more taxing than mating and moving on - keeping a relationship increases social pressure to keep track of this person - In primates, social bonds are formed with others who are not our mates as well

Spandrels

Adaptations vs. By-Products - Spandrels-triangular space at top of an arch and the frame - became decorative not functional - Gould & Lewontin (1979): a spandrel is a phenotypic trait that is a by-product of evolution rather than a direct product of adaptive selection - trait is NOT evolutionarily functional - some traits are not a real of useful adaptations but a by product of helpful adaptations - How do we know what's an evolutionary spandrel? • Tests of adaptive hypotheses: 1. specify the goal 2. characterize the environment - in which behavior would have evolved - help people in that environment to reach goals 3. lay out the engineering specs that would attain the goal in that environment - how would traits have helped with behavior 4. see if the organism has those specs - evidence in modern behavior that reflects these traits? - underlies evolutionary psych experiments - Obvious Psychological Adaptations - regulation of thirst - adaption to know when the body needs water - size constancy in vision - better depth perception - concepts and categories - how we group things together - fear of heights (and spiders?) - help with survival and avoiding danger Less Obvious Ones - empathy - beauty - has goal that tells things about mate and potential offspring - jealousy - warning sign to shift relationship or behavior - disgust - warning to ward off harmful or gross things - feeling lonely - adverse signal that warns of exclusion from the group - we change behavior to increase acceptance and inclusion

Parent-Offspring Conflict

Another feature of behavior turns kin selection on its head. The emphasis until now has been on the fact that relatives share many genes and evolutionary goals - Nonetheless, except for identical twins, just as pertinent is relatives not sharing all their genes or goals. Which can cause conflict - There's parent-offspring conflict One classic example is whether a female should give her child great nutrition, guaranteeing his survival, but at the cost of nutrition for her other children (either current or future). This is weaning conflict - This causes endless primate tantrums - Some female baboon looks frazzled and cranky - Three steps behind is her toddler, making the most pitiful whimpering and whining sounds imaginable - Every few minutes the kid tries to nurse; Mom irritably pushes him away, even slaps him - More wailing - It's parent-offspring weaning conflict - as long as Mom nurses, she's unlikely to ovulate, curtailing her future reproductive potential - Baboon moms evolved to wean their kids at the age where they can feed themselves, and baboon kids evolved to try to delay that day - Interestingly, as females age, with decreasing likelihood of a future child, they become less forceful in weaning There's also mother-fetus conflict. You're a fetus with an evolutionary agenda - What do you want? Maximal nutrition from Mom, and who cares if that impacts her future reproductive potential? - Meanwhile, Mom wants to balance current and future reproductive prospects - Remarkably, fetus and Mom have a metabolic struggle involving insulin, the pancreatic hormone secreted when blood glucose levels rise, which triggers glucose entry into target cells - The fetus releases a hormone that makes Mom's cells unresponsive to insulin (i.e., "insulin resistant"), as well as an enzyme that degrades Mom's insulin - Thus Mom absorbs less glucose from her bloodstream, leaving more for the fetus

Pastoralists ans Southerners

Another important link among ecology, mode of production, and culture is seen in dry, hardscrabble, wide-open environments too tough for agriculture - This is the world of nomadic pastoralism—people wandering the desert, steppes, or tundra with their herds - There are Bedouins in Arabia, Tuareg in North Africa, Somalis and Maasai in East Africa, Sami of northern Scandinavia, Gujjars in India, Yörük in Turkey, Tuvans of Mongolia, Aymara in the Andes - There are herds of sheep, goats, cows, llamas, camels, yaks, horses, or reindeer, with the pastoralists living off their animals' meat, milk, and blood and trading their wool and hides - Anthropologists have long noted similarities in pastoralist cultures born of their tough environments and the typically minimal impact of centralized government and the rule of law. In that isolated toughness stands a central fact of pastoralism: thieves can't steal the crops on someone's farm or the hundreds of edible plants eaten by hunter-gatherers, but they can steal someone's herd - This is the vulnerability of pastoralism, a world of rustlers and raiders - This generates various correlates of pastoralism: Militarism abounds - Pastoralists, particularly in deserts, with their far- flung members tending the herds, are a spawning ground for warrior classes - And with them typically come (a) military trophies as stepping- stones to societal status; (b) death in battle as a guarantee of a glorious afterlife; (c) high rates of economic polygamy and mistreatment of women; and (d) authoritarian parenting. It is rare for pastoralists to be pastoral, in the sense of Beethoven's Sixth Symphony - Worldwide, monotheism is relatively rare; to the extent that it does occur, it is disproportionately likely among desert pastoralists (while rain forest dwellers are atypically likely to be polytheistic). This makes sense - Deserts teach tough, singular things, a world reduced to simple, desiccated, furnace-blasted basics that are approached with a deep fatalism. "I am the Lord your God" and "There is but one god and his name is Allah" and "There will be no gods before me"—dictates like these proliferate - As implied in the final quote, desert monotheism does not always come with only one supernatural being—monotheistic religions are replete with angels and djinns and devils - But they sure come with a hierarchy, minor deities paling before the Omnipotent One, who tends to be highly interventionist both in the heavens and on earth. In contrast, think of tropical rain forest, teeming with life, where you can find more species of ants on a single tree than in all of Britain. Letting a hundred deities bloom in equilibrium must seem the most natural thing in the world - Pastoralism fosters cultures of honor - these are about rules of civility, courtesy, and hospitality, especially to the weary traveler because, after all, aren't all herders often weary travelers? - Even more so, cultures of honor are about taking retribution after affronts to self, family, or clan, and repetitional consequences for failing to do so - If they take your camel today and you do nothing, tomorrow they will take the rest of your herd, plus your wives and daughters - Few of humanity's low or high points are due to the culturally based actions of, say, Sami wandering the north of Finland with their reindeer, or Maasai cow herders in the Serengeti - Instead the most pertinent cultures of honor are ones in more Westernized settings. "Culture of honor" has been used to describe the workings of the Mafia in Sicily, the patterns of violence in rural nineteenth- century Ireland, and the causes and consequences of retributive killings by inner- city gangs - All occur in circumstances of resource competition (including the singular resource of being the last side to do a retributive killing in a vendetta), of a power vacuum provided by the minimal presence of the rule of law, and where prestige is ruinously lost if challenges are left unanswered and where the answer is typically a violent one - Amid those, the most famous example of a Westernized culture of honor is the American South, the subject of books, academic journals, conferences, and Southern studies majors in universities - Much of this work was pioneered by Nisbett - Hospitality, chivalry toward women, and emphasis on social decorum and etiquette are long associated with the South - In addition, the South traditionally emphasizes legacy, long cultural memory, and continuity of family—in rural Kentucky in the 1940s, for example, 70 percent of men had the same first name as their father, far more than in the North - When coupled with lesser mobility in the South, honor in need of defense readily extends to family, clan, and place. For example, by the time the Hatfields and McCoys famously began their nearly thirty-year feud in 1863, they had lived in the same region of the West Virginia/Kentucky border for nearly a century - The Southern sense of honor in place is also seen in Robert E. Lee; he opposed Southern secession, even made some ambiguous statements that could be viewed as opposed to slavery - Yet when offered the command of the Union Army by Lincoln, Lee wrote, "I wish to live under no other government and there is no sacrifice I am not ready to make for the preservation of the Union save that of honor." - When Virginia chose secession, he regretfully fulfilled his sense of honor to his home and led the Confederate Army of Northern Virginia - In the South, defense of honor was, above all, an act of self-reliance - The Southerner Andrew Jackson was advised by his dying mother to never seek redress from the law for any grievances, to instead be a man and take things into his own hands - That he certainly did, with a history of dueling (even fatally) and brawling; on his final day as president, he articulated two regrets in leaving office—that he "had been unable to shoot Henry Clay or to hang John C. Calhoun." Carrying out justice personally was viewed as a requirement in the absence of a functional legal system - At best, legal justice and individual justice were in uneasy equilibrium in the nineteenth-century South; in the words of the Southern historian Bertram Wyatt-Brown, "Common law and lynch law were ethically compatible - The first enabled the legal profession to present traditional order, and the second conferred upon ordinary men the prerogative of ensuring that community values held ultimate sovereignty - The core of retribution for honor violations was, of course, violence. Sticks and stones might break your bones, but names will cause you to break the offender's bones - Dueling was commonplace, the point being not that you were willing to kill but that you were willing to die for your honor - Many a Confederate boy went off to war advised by his mother that better he come back in a coffin than as a coward who fled - The result of this all is a long, still-extant history of high rates of violence in the South. But crucially, violence of a particular type - I once heard it summarized by a Southern studies scholar describing the weirdness of leaving the rural South to start grad school in a strange place, Cambridge, Massachusetts, where families would get together at Fourth of July picnics and no one would shoot each other Nisbett and Dov Cohen have shown that the high rates of violence, particularly of murder, by white Southern males are not features of large cities or about attempts to gain material goods—we're not talking liquor store stickups - Instead the violence is disproportionately rural, among people who know each other, and concerns slights to honor (that sleazebag cousin thought it was okay to flirt with your wife at the family reunion, so you shot him) - Moreover, Southern juries are atypically forgiving of such acts

Stratified v. Egalitarian Cultures

Another meaningful way to think about cross-cultural variation concerns how unequally resources (e.g., land, food, material goods, power, or prestige) are distributed - Hunter-gatherer societies have typically been egalitarian, as we'll soon see, throughout hominin history. Inequality emerged when "stuff"—things to possess and accumulate—was invented following animal domestication and the development of agriculture - The more stuff, reflecting surplus, job specialization, and technological sophistication, the greater the potential inequality - Moreover, inequality expands enormously when cultures invent inheritance within families - Once invented, inequality became pervasive - Among traditional pastoralist or small-scale agricultural societies, levels of wealth inequality match or exceed those in the most unequal industrialized societies - Why have stratified cultures dominated the planet, generally replacing more egalitarian ones? - For population biologist Peter Turchin, the answer is that stratified cultures are ideally suited to being conquerors—they come with chains of command - Both empirical and theoretical work suggests that in addition, in unstable environments stratified societies are "better able to survive resource shortages [than egalitarian cultures] by sequestering mortality in the lower classes." - In other words, when times are tough, the unequal access to wealth becomes the unequal distribution of misery and death - Notably, though, stratification is not the only solution to such instability—this is where hunter- gatherers benefit from being able to pick up and move - A score of millennia after the invention of inequality, Westernized societies at the extremes of the inequality continuum differ strikingly - One difference concerns "social capital." - Economic capital is the collective quantity of goods, services, and financial resources - Social capital is the collective quantity of resources such as trust, reciprocity, and cooperation - You learn a ton about a community's social capital with two simple questions - 1. "Can people usually be trusted?" - A community in which most people answer yes is one with fewer locks, with people watching out for one another's kids and intervening in situations where one could easily look away 2. is how many organizations someone participates in—from the purely recreational (e.g., a bowling league) to the vital (e.g., unions, tenant groups, co- op banks) - A community with high levels of such participation is one where people feel efficacious, where institutions work transparently enough that people believe they can effect change - People who feel helpless don't join organizations - Put simply, cultures with more income inequality have less social capital - Trust requires reciprocity, and reciprocity requires equality, whereas hierarchy is about domination and asymmetry - Moreover, a culture highly unequal in material resources is almost always also unequal in the ability to pull the strings of power, to have efficacy, to be visible - (For example, as income inequality grows, the percentage of people who bother voting generally declines.) - Almost by definition, you can't have a society with both dramatic income inequality and plentiful social capital. Or translated from social science-ese, marked inequality makes people crummier to one another - this can be shown in various ways, studied on the levels of Westernized countries, states, provinces, cities, and towns - The more income inequality, the less likely people are to help someone (in an experimental setting) and the less generous and cooperative they are in economic games - Early in the chapter, I discussed cross-cultural rates of bullying and of "antisocial punishment," where people in economic games punish overly generous players more than they punish cheaters - Studies of these phenomena show that high levels of inequality and/or low levels of social capital in a country predict high rates of bullying and of antisocial punishment - Chapter 11 examines the psychology with which we think about people of different socioeconomic status; no surprise, in unequal societies, people on top generate justifications for their status - And the more inequality, the more the powerful adhere to myths about the hidden blessings of subordination—"They may be poor, but at least they're happy/honest/loved - In the words of the authors of one paper, "Unequal societies may need ambivalence for system stability: Income inequality compensates groups with partially positive social images - Thus unequal cultures make people less kind. Inequality also makes people less healthy - This helps explain a hugely important phenomenon in public health, namely the "socioeconomic status (SES)/health gradient"—as noted, in culture after culture, the poorer you are, the worse your health, the higher the incidence and impact of numerous diseases, and the shorter your life expectancy - Extensive research has examined the SES/health gradient. Four quick rule- outs: (a) The gradient isn't due to poor health driving down people's SES - Instead low SES, beginning in childhood, predicts subsequent poor health in adulthood (b) It's not that the poor have lousy health and everyone else is equally healthy. - Instead, for every step down the SES ladder, starting from the top, average health worsens (c) The gradient isn't due to less health-care access for the poor; it occurs in countries with universal health care, is unrelated to utilization of health-care systems, and occurs for diseases unrelated to health- care access (e.g., juvenile diabetes, where having five checkups a day wouldn't change its incidence) (d) Only about a third of the gradient is explained by lower SES equaling more health risk factors (e.g., lead in your water, nearby toxic waste dump, more smoking and drinking) and fewer protective factors (e.g., everything from better mattresses for overworked backs to health club memberships). - What then is the principal cause of the gradient? Key work by Nancy Adler at UCSF showed that it's not so much being poor that predicts poor health - It's feeling poor—someone's subjective SES (e.g., the answer to "How do you feel you're doing financially when you compare yourself with other people?") is at least as good a predictor of health as is objective SES - Crucial work by the social epidemiologist Richard Wilkinson of the University of Nottingham added to this picture: it's not so much that poverty predicts poor health; it's poverty amid plenty—income inequality - The surest way to make someone feel poor is to rub their nose in what they don't have. - Why should high degrees of income inequality (independent of absolute levels of poverty) make the poor unhealthy? Two overlapping pathways: A psychosocial explanation has been championed by Ichiro Kawachi of Harvard - When social capital decreases (thanks to inequality), up goes psychological stress - A mammoth amount of literature explores how such stress—lack of control, predictability, outlets for frustration, and social support—chronically activates the stress response, which, as we saw in chapter 4, corrodes health in numerous ways - A neomaterialist explanation has been offered by Robert Evans of the University of British Columbia and George Kaplan of the University of Michigan - If you want to improve health and quality of life for the average person in a society, you spend money on public goods—better public transit, safer streets, cleaner water, better public schools, universal health care - But the more income inequality, the greater the financial distance between the wealthy and the average and thus the less direct benefit the wealthy feel from improving public goods. Instead they benefit more from dodging taxes and spending on their private good—a chauffeur, a gated community, bottled water, private schools, private health insurance - As Evans writes, "The more unequal are incomes in a society, the more pronounced will be the disadvantages to its better-off members from public expenditure, and the more resources will those members have [available to them] to mount effective political opposition" (e.g., lobbying). Evans notes how this "secession of the wealthy" promotes "private affluence and public squalor." Meaning worse health for the have-nots - The inequality/health link paves the way for understanding how inequality also makes for more crime and violence. I could copy and paste the previous stretch of writing, replacing "poor health" with "high crime," and I'd be set - Poverty is not a predictor of crime as much as poverty amid plenty is - For example, extent of income inequality is a major predictor of rates of violent crime across American states and across industrialized nations - Why does income inequality lead to more crime? Again, there's the psychosocial angle—inequality means less social capital, less trust, cooperation, and people watching out for one another - And there's the neomaterialist angle— inequality means more secession of the wealthy from contributing to the public good - Kaplan has shown, for example, that states with more income inequality spend proportionately less money on that key crime-fighting tool, education - As with inequality and health, the psychosocial and neomaterial routes synergize - A final depressing point about inequality and violence - As we've seen, a rat being shocked activates a stress response - But a rat being shocked who can then bite the hell out of another rat has less of a stress response - Likewise with baboons—if you are low ranking, a reliable way to reduce glucocorticoid secretion is to displace aggression onto those even lower in the pecking order. It's something similar here—despite the conservative nightmare of class warfare, of the poor rising up to slaughter the wealthy, when inequality fuels violence, it is mostly the poor preying on the poor - This point is made with a great metaphor for the consequences of societal inequality - The frequency of "air rage"—a passenger majorly, disruptively, dangerously losing it over something on a flight—has been increasing - Turns out there's a substantial predictor of it: if the plane has a first-class section, there's almost a fourfold increase in the odds of a coach passenger having air rage - Force coach passengers to walk through first class when boarding, and you more than double the chances further. Nothing like starting a flight by being reminded of where you fit into the class hierarchy - And completing the parallel with violent crime, when air rage is boosted in coach by reminders of inequality, the result is not a crazed coach passenger sprinting into first class to shout Marxist slogans - It's the guy being awful to the old woman sitting next to him, or to the flight attendant

Human Gadgets

Are human empathies, emotions, prejudices, etc. 'gadgets?' - programs that evolved to be adaptive for hunter-gatherer ancestors - why were they important for this lifestyle? - If evolution is an arms race, then humans overtake other organisms' fixed defenses via - cause-effect reasoning: tools, traps, poisons, plant preparations (medical devices) - MUCH more evolved than other species at doing this - cooperative action: working together, cultural transmission of know-how - increases survival of the group and is unique to human evolution - may have evolved from ancient brain gadgets

Is Everything Adaptive

As we've seen, variants of genes that make organisms more adapted to their environment increase in frequency over time - But what about the reverse —if a trait is prevalent in a population, must it mean that it evolved in the past because it was adaptive? "Adaptationism" assumes this is typically the case; an adaptationist approach is to determine whether a trait is indeed adaptive and, if so, what the selective forces were that brought it about - Much of sociobiological thinking is adaptationist in flavor - This was subject to scathing criticism by the likes of Stephen Jay Gould and Harvard geneticist Richard Lewontin, who mocked the approach as "just so" stories, after Kipling's absurdist fantasies about how certain traits came to be: how the elephant got its trunk (because of a tug-of-war with a crocodile), how the zebra got its stripes, how the giraffe got a long neck - So why not, supposedly ask the sociobiologists in this critique, how the baboon male got big cojones while the gorilla male got little ones? - Observe a behavior, generate a just-so story that assumes adaptation, and the person with the best just-so story wins. How the evolutionary biologist got his tenure - In their view, sociobiological standards lack rigor. As one critic, Andrew Brown, stated, "The problem was that sociobiology explained too much and predicted too little." - According to Gould, traits often evolve for one reason and are later co-opted for another use (fancy term: "exaptation"); for example, feathers predate the evolution of bird flight and originally evolved for insulation - Only later did their aerodynamic uses become relevant - Similarly, the duplication of a gene for a steroid hormone receptor (as mentioned many chapters ago) allowed one copy to randomly drift in its DNA sequence, producing an "orphan" receptor with no use—until a novel steroid hormone was synthesized that happened to bind to it - This haphazard, jury-rigged quality evokes the aphorism "Evolution is a tinkerer, not an inventor." - It works with whatever's available as selective pressures change, producing a result that may not be the most adaptive but is good enough, given the starting materials. Squid are not great swimmers compared with sailfish (maximum speed: sixty-eight miles per hour) - But they're damn good for something whose great-great-grandparents were mollusks - Meanwhile, ran the criticism, some traits exist not because they're adaptive, or were adapted for something else but got co-opted, but because they're baggage carried along with other traits that were selected for - It was here that Gould and Lewontin famously introduced "spandrels" in their 1979 paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme." - A spandrel is an architectural term for the space between two arches, and Gould and Lewontin considered the artwork on the spandrels of the Basilica San Marco in Venice - Gould and Lewontin's stereotypical adaptationist would look at these spandrels and conclude that they were built to provide spaces for the artwork - In other words, that these spandrels evolved for their adaptive value in providing space for art - In reality they didn't evolve for a purpose—if you're going to have a series of arches (which most definitely exist for the adaptive purpose of holding up a dome), a space between each pair is an inevitable by- product - No adaptation - And as long as these spaces were carried along as evolutionary baggage as a result of selection for the adaptive arches, might as well paint on them - In that view, male nipples are spandrels—they serve an adaptive role in females and came along for the ride as baggage in males because there's been no particular selection against males having them - Gould and Lewontin argued that numerous traits that prompted just-so stories from adaptationists are merely spandrels - Sociobiologists responded to spandrelism by noting that the rigor in pronouncing something a spandrel was not intrinsically greater than that in pronouncing it adaptive - In other words, the former provide just-not-so stories. Psychologist David Barash and psychiatrist Judith Lipton compared spandrelites to the character Topsy in Uncle Tom's Cabin, who states that she "just growed"—when faced with evidence of adaptation in traits, they'd conclude that those traits are mere baggage, without adaptive purpose, providing explanations that explained nothing—"just growed stories - Furthermore, sociobiologists argued, adaptationist approaches were more rigorous than Gouldian caricature; rather than explaining everything and predicting nothing, sociobiological approaches predict plenty - Is, say, competitive infanticide a just-so story? - Not when you can predict with some accuracy whether it will occur in a species based on its social structure - Nor is the pair-bond/tournament comparison, when you can predict a vast amount of information about the behavior, physiology, and genetics of species ranging across the animal kingdom simply by knowing their degree of sexual dimorphism - Furthermore, evolution leaves an echo of selection for adaptive traits when there is evidence of "special design"—complex, beneficial functions where a number of traits converge on the same function All this would be your basic, fun academic squabble, except that underlying the criticisms of adaptationism, gradualism, and sociobiology is a political issue - This is embedded in the title of the spandrel paper: the "Panglossian paradigm - This refers to Voltaire's Dr. Pangloss and his absurd belief, despite life's miseries, that this is the "best of all possible worlds." - In this criticism, adaptationism stinks of the naturalistic fallacy, the view that if nature has produced something, it must be a good thing - That furthermore, "good" in the sense of, say, solving the selective problem of water retention in deserts, is in some indefinable way also morally "good." - That if ant species make slaves, if male orangutans frequently rape females, and if for hundreds of thousands of years hominin males drink milk directly out of the container, it is because it is somehow "meant" to be that way - When aired as a criticism in this context, the naturalistic fallacy had an edge to it - In its early years human sociobiology was wildly controversial, with conferences picketed and talks disrupted, with zoologists guarded by police at lectures, all sorts of outlandish things - On one storied occasion, E. O. Wilson was physically attacked while giving a talk - Anthropology departments split in two, collegial relationships were destroyed. This was particularly so at Harvard, where many of the principals could be found—Wilson, Gould, Lewontin, Trivers, Hrdy, the primatologist Irven DeVore, the geneticist Jonathan Beckwith - Things were so febrile because sociobiology was accused of using biology to justify the status quo—conservative social Darwinism that implied that if societies are filled with violence, unequal distribution of resources, capitalistic stratification, male dominance, xenophobia, and so on, these things are in our nature and probably evolved for good reasons - The critics used the "is versus ought" contrast, saying, "Sociobiologists imply that when an unfair feature of life is the case, it is because it ought to be." - And the sociobiologists responded by flipping is/ought around: "We agree that life ought to be fair, but nonetheless, this is reality. Saying that we advocate something just because we report it is like saying oncologists advocate cancer." - The conflict had a personal tinge - This was because by chance (or not, depending on your viewpoint), that first generation of American sociobiologists were all white Southerners—Wilson, Trivers,* DeVore, Hrdy; in contrast, the first generation of its loudest critics were all Northeastern, urban, Jewish leftists —Harvard's Gould, Lewontin, Beckwith, Ruth Hubbard, Princeton's Leon Kamin, and MIT's Noam Chomsky - You can see how the "there's a hidden agenda here" charge arose from both sides - It's easy to see how punctuated equilibrium generated similar ideological battles, given its premise that evolution is mostly about long periods of stasis pierced by revolutionary upheaval - In their original publication, Gould and Eldredge asserted that the law of nature "holds that a new quality emerges in a leap as the slow accumulation of quantitative changes, long resisted by a stable system, finally forces it rapidly from one state into another." - This was a bold assertion that the heuristic of dialectical materialism not only extends beyond the economic world into the naturalistic one, but is ontologically rooted in the essential sameness of both worlds' dynamic of resolution of irresolvable contradictions - It is Marx and Engels as trilobite and snail Eventually the paroxysms about adaptationism versus spandrels, gradualism versus punctuated change, and the very notion of a science of human sociobiology subsided - The political posturing lost steam, the demographic contrasts between the two camps softened, the general quality of research improved considerably, and everybody got some gray hair and a bit more calm - This has paved the way for a sensible, middle-of-the-road middle age for the field - There's clear empirical evidence for both gradualism and punctuated change, and for molecular mechanisms underlying both - There's less adaptation than extreme adaptationists claim, but fewer spandrels than touted by spandrelites - While sociobiology may explain too much and predict too little, it does predict many broad features of behavior and social systems across species - Moreover, even though the notion of selection happening at the level of groups has been resurrected from the graves of self-sacrificial elderly wildebeest, it is probably a rare occurrence; nonetheless, it is most likely to occur in the species that is the focus of this book - Finally, all of this is anchored in evolution being a fact, albeit a wildly complex one The context and meaning of a behavior are usually more interesting and complex than the mechanics of the behavior - To understand things, you must incorporate neurons and hormones and early development and genes - These aren't separate categories—there are few clear-cut causal agents, so don't count on there being the brain region, the neurotransmitter, the gene, the cultural influence, or the single anything that explains a behavior - Instead of causes, biology is repeatedly about propensities, potentials, vulnerabilities, predispositions, proclivities, interactions, modulations, contingencies, if/then clauses, context dependencies, exacerbation or diminution of preexisting tendencies - Circles and loops and spirals and Möbius strips - No one said this was easy. But the subject matters - Synthesizing this material in order to look at realms of behavior where this matters the most

Agricultural Revolution

Before the agricultural revolutions, humans lived a hunter-gatherer (forager) lifestyle - did not plant food - lived in small nomadic bands for most of human history - high travel and nomadic lifestyle - majority of homo sapian history was nomadic - no stored food, government, law, strangers, permanent dwellings, social stratification, inequality of wealth, armies, written language, or science - all emerged AFTER agriculture - And then, 10,000-12,000 years ago...Agriculture - removed humans from the hunter-gatherer lifestyle - social stratification due to food emerged - Sapolsky thinks that agriculture had a negative effect on human evolution - Evolutionary psychologists tend to focus on what was adaptive prior to 10,000 years ago to understand human evolution - Other minor changes also happened in past 10,000 years but have not had that massive of an impact - The 10,000 Year Explosion Book - argues for things that have shifted in the past 10,000 years that have shifted evolution but there are no major changes only minor ones

Creationism

Belief that all life was created by God - founded in theology - idea that a creator deigned the complexity of life Issues - Pushes back the question - nothing about WHY - Why is there so much continuity of brain and behavior with animals? - There's continuity of: - vision - motor control - memory - emotion - social behavior - very similar across many animals (human, cat, rat) and is persevered through evolution - poses the question of why were parts reused? - Vestigial characters, both anatomical and behavioral - goose bumps & anger expression - we have no function for these behaviors and they don't get explained well - Why do anger expressions matter?

History of Darwin

Born in Shrewsbury England—the 5th of 6 children in a wealthy family • Unremarkable student - Attended University Edinburgh Medical School, where he neglected his studies but became interested in natural history & geology - Father has him change his studies to Cambridge University with the hope of making Charles become a Anglican country parson - Reads William Paley's works, studied geology, and then offered a job as a naturalist on the HMS Beagle (a 5-year voyage around the world). Takes Lyell's books with him - There is a geology museum that talks abut Darwin and the HMS Beagle - Voyage of the Beagle from 1831 to 1836 around Australia, Africa and South America - Darwin did a geological survey about formations in many places Key Publications - On the Origin of Species (1859) - evolution theory - The Descent of Man (1871) - human evolution theory - Expression of the Emotions in Man and Animals (1872) - smaller book of a case example of human evolution

Darwin's Impact on Psychology

Comparative Psychology - profound impact on the field - Developmental Psychology - "A biographical sketch of an infant" published in Mind in 1877 - day to day diary of his children's development - Emphasis on Adaptation (see in work of William James, John Dewey, and G. Stanley Hall) - helped influence psych. adaptations

War and Hunter-Gatherers Criticism

Criticisms: Mislabeling—some HGs cited by Pinker, Keeley, and Bowles are, in fact, hunter-horticulturalistsMany instances of supposed HG warfare, on closer inspection, were actually singular homicides - Some violent Great Plains HG cultures were untraditional in the sense of using something crucial that didn't exist in the Pleistocene—domesticated horses ridden into battle - Like non-Western agriculturalists or pastoralists, contemporary HG are not equivalent to our ancestors - Weapons invented in the last ten thousand years have been introduced through trade; most HG cultures have spent millennia being displaced by agriculturalists and pastoralists, pushed into ever tougher, resource-sparse ecosystems - Once again, the cherry-picking issue, i.e., failure to cite cases of peaceful HGs - Most crucially, there's more than one type of HG - Nomadic HGs are the original brand, stretching back hundreds of thousands of years - But in addition to HG 2.0 equestrians, there are - "complex HGs," who are different—violent, not particularly egalitarian, and sedentary, typically because they're sitting on a rich food source that they defend from outsiders - In other words, a transitional form from pure HGs. And many of the cultures cited by Ember, Keeley, and Pinker are complex HGs - This difference is relevant to Nataruk, that northern Kenyan site of a ten-thousand-year-old massacre—skeletons of twenty-seven unburied people, killed by clubbing, stabbing, or stone projectiles - The victims were sedentary HGs, living alongside a shallow bay on Lake Turkana, prime beachfront property with easy fishing and plentiful game animals coming to the water to drink. Just the sort of real estate that someone else would try to muscle in on - The most thoughtful and insightful analyses of HG violence come from Fry and from Christopher Boehm of the University of Southern California. They paint a complex picture - Fry has provided what I consider the cleanest assessment of warfare in such cultures - In a notable 2013 Science paper, he and Finnish anthropologist Patrik Söderberg reviewed all cases of lethal violence in the ethnographic literature in "pure" nomadic HGs (i.e., well studied before extensive contact with outsiders and living in a stable ecosystem) - The sample consisted of twenty-one such groups from around the world. Fry and Söderberg observed what might be called warfare (defined by the fairly unstringent criterion of conflict producing multiple casualties) in only a minority of the cultures - Not exactly widespread - This is probably the best approximation we'll ever get about warfare in our HG ancestors - Nonetheless, these pure HGs are no tie-dyed pacifists; percent of the cultures experienced lethal violence. What are their causes? - In his 2012 book Moral Origins: The Evolution of Virtue, Altruism, and Shame, Boehm also surveys the literature, using slightly less stringent criteria than Fry uses, producing a list of about fifty relatively "pure" nomadic HG cultures (heavily skewed toward Inuit groups from the Arctic) - As expected, violence is mostly committed by men - Most common is killing related to women —two men fighting over a particular woman, or attempts to kidnap a woman from a neighboring group - Naturally, there are men killing their wives, usually over accusations of adultery - There's female infanticide and killing arising from accusations of witchcraft - There are occasional killings over garden-variety stealing of food or refusals to share food. And lots of revenge killings by relatives of someone killed - Both Fry and Boehm report killings akin to capital punishment for severe norm violations - What norms do nomadic HGs value most? - Fairness, indirect reciprocity, and avoidance of despotism. Fairness - HGs pioneered human cooperative hunting and sharing among nonrelatives Meat - This is most striking with meat - It's typically shared by successful hunters with unsuccessful ones (and their families) -individuals playing dominant roles in hunts don't necessarily get much more meat than everyone else; crucially, the most successful hunter rarely decides how the meat is divided—instead this is typically done by a third party - There are fascinating hints about the antiquity of this. Big-game hunting by hominins 400,000 years ago has been documented; bones from animals butchered then show cut marks that are chaotic, overlapping at different angles, suggesting a free-for-all - But by 200,000 years ago the contemporary HG pattern is there—cut marks are evenly spaced and parallel, suggesting that single individuals butchered and dispensed the meat - This does not mean, though, that sharing is effortless for pure HGs - Boehm notes how, for example, the !Kung perpetually kvetch about being shortchanged on meat. It's the background hum of social regulation - Indirect reciprocity - Boehm emphasizes how nomadic HGs specialize, instead, in indirect reciprocity - Person A is altruistic to B; B's social obligation now isn't necessarily as much being altruistic to A as paying the altruism forward to C. C pays it forward to D - This stabilizing cooperation is ideal for big-game hunters, where two rules hold: -(a) your hunts are usually unsuccessful -(b) when they are successful, you typically have more meat than your family can consume, so you might as well share it around - As has been said, an HG's best investment against future hunger is to put meat in other people's stomachs now - Avoidance of despotism -Considerable evolutionary pressure for detecting cheating (when someone reneges on their half of a reciprocal relationship) - For nomadic HGs, policing covert cheating is less of a concern than overt evidence of intimidation and power-mongering - HGs are constantly on guard against bullies throwing their weight around. - HG societies expend lots of collective effort on enforcing fairness, indirect reciprocity, and avoidance of despotism - Accomplished with that terrific norm-enforcement mechanism, gossip - HGs gossip endlessly, and as studied by Polly Wiessner of the University of Utah, it's mostly about the usual: norm violation by high-status individuals - People magazine around the campfire Gossiping serves numerous purposes - It helps for reality testing ("Is it just me, or was he being a total jerk?"), passing news ("Two guesses who just happened to get a foot cramp during the hairiest part of the hunt today"), and building consensus ("Something needs to be done about this guy"). - Gossip is the weapon of norm enforcement HG cultures take similar actions—collectively subjecting miscreants to criticism, shaming and mockery, ostracizing and shunning, refusing to share meat, nonlethal physical punishment, expulsion from the group, or, as a last resort, killing the person (done either by the whole group or by a designated executioner). - Boehm documents such judicial killings in nearly half the pure HG cultures - What transgressions merit them? - Murder, attempts at grabbing power, use of malicious sorcery, stealing, refusal to share, betrayal of the group to outsiders, and of course breaking of sexual taboos - All typically punished this way after other interventions have failed repeatedly So, Hobbes or Rousseau? - a mixture of the two - This lengthy section makes clear that you have to make some careful distinctions: -(a) HGs versus other traditional ways of making a living - (b) nomadic HGs versus sedentary ones -(c) data sets that canvass an entire literature versus those that concentrate on extreme examples - (d) members of traditional societies killing one another versus members being killed by gun-toting, land-grabbing outsiders - (e) chimps as our cousins versus chimps erroneously viewed as our ancestors - (f) chimps as our closest ancestors versus chimps and bonobos as our closest ancestors - (g) warfare versus homicide, where lots of the former can decrease the latter in the name of in-group cooperation - (h) contemporary HGs living in stable, resource-filled habitats with minimal interactions with the outside world versus contemporary HGs pushed into marginal habitats and interacting with non-HGs Once you've done that, I think a pretty clear answer emerges - The HGs who peopled earth for hundreds of thousands of years were probably no angels, being perfectly capable of murder - However, "war"—both in the sense that haunts our modern world and in the stripped-down sense that haunted our ancestors—seems to have been rare until most humans abandoned the nomadic HG lifestyle - Our history as a species has not been soaked in escalated conflict - And ironically Keeley tacitly concludes the same—he estimates that 90 to 95 percent of societies engage in war And whom does he note as the exceptions? - Nomadic HGs Agriculture - its invention was one of the all-time human blunders - Agriculture makes people dependent on a few domesticated crops and animals instead of hundreds of wild food sources, creating vulnerability to droughts and blights and zoonotic diseases - Agriculture makes for sedentary living, leading humans to do something that no primate with a concern for hygiene and public health would ever do, namely living in close proximity to their feces - Agriculture makes for surplus and thus almost inevitably the unequal distribution of surplus, generating socioeconomic status differences that dwarf anything that other primates cook up with their hierarchies It wasn't until humans began the massive transformation of life that came from domesticating teosinte and wild tubers, aurochs and einkorn, and of course wolves, that it became possible to let loose the dogs of war

Violence in Cultures of Honor

Culture-of-honor violence is not just about outside threat—the camel rustlers from the next tribe, the jerk at the roadhouse who came on to some guy's girlfriend - Instead it is equally defined by its role when honor is threatened from within - norm violations by members of your own group provoke cover-ups, excuses, or leniency, and when they provoke severe public punishment - The latter is when "you've dishonored us in front of everyone," a culture-of-honor specialty. Which raises the issue of honor killings What constitutes an honor killing? - Someone does something considered to tarnish the reputation of the family - A family member then kills the despoiler, often publicly, thereby regaining facE - Some characteristics of honor killings: - While they have been widespread historically, contemporary ones are mostly restricted to traditional Muslim, Hindu, and Sikh communities - Victims are usually young women. Their most common crimes? - Refusing an arranged marriage - Seeking to divorce an abusive spouse and/or a spouse to whom they were forcibly married as a child - Seeking education - Resisting constraining religious orthodoxy, such as covering their head - Marrying, living with, dating, interacting with, or speaking to an unapproved male, Infidelity, Religious conversion - In other words, a woman resisting being the property of her male relatives - And also, stunningly, staggeringly, a frequent cause of honor killings is being raped - In the rare instances of men being subject to honor killings, the typical cause is homosexuality There has been debate as to whether honor killings are "just" domestic violence, and whether morbid Western fascination with them reflects anti- Muslim bias - if some Baptist guy in Alabama murders his wife because she wants a divorce, no one frames it as a "Christian honor killing" reflecting deep religious barbarity - But honor killings typically differ from garden-variety domestic violence in several ways: (a) The latter is usually committed by a male partner; the former are usually committed by male blood relatives, often with the approval of and facilitation by female relatives (b) The former is rarely an act of spontaneous passion but instead is often planned with the approval of family members (c) Honor killings are often rationalized on religious grounds, presented without remorse, and approved by religious leaders (d) Honor killings are carried out openly—after all, how else can "honor" be regained for the family?—and the chosen perpetrator is often an underage relative (e.g., a younger brother), to minimize the extent of sentencing for the act - By some pretty meaningful criteria, this is not "just" domestic violence - According to estimates by the UN and advocacy groups, five to twenty thousand honor killings occur annually - And they are not restricted to far-off, alien lands. Instead they occur throughout the West, where patriarchs expect their daughters to be untouched by the world they moved them to, where a daughter's successful assimilation into this world proclaims the irrelevance of that patriarch

Culture

Definition by de Waal - Culture is a way of life shared by the members of one group but not necessarily with the members of other groups of the same species - covers knowledge, habits, and skills, including underlying tendencies and preferences, derived from exposure to and learning from others - The way individuals learn from each other is secondary, but that they learn from each other is a requirement - the "culture" label does not apply to knowledge, habits, or skills that individuals can and will readily acquire on their own - Humans may be uniquely able to produce "cumulative culture"—through language and customs they can build upon the work of others that results in a product that is too complex to be innovated by a single person (Tomasello) Sweet Potato Monkeys - More than half a century after the sweet-potato washing habit spread among Japanese macaques on Koshima Island, they are still doing it even though the current population has never known the innovator. Nowadays transmission is mostly from mother to offspring, although this was not so in the early years of the habit. (de Waal & Bonnie) - a population of monkeys would wash sweet potatoes and eat them then others learned and followed. 50 years later the monkeys on the island still do it which is evidence of cultural passing that does NOT require language

Jean-Baptiste Lamarck (1744-1829)

French naturalist who proposed two laws of evolution 1. the law of use and disuse - in your lifetime if there is something you do - behavioral os anatomical) that you don't use then it will not get passed to the next generation - disease selected out 2. law of inheritance of acquired characteristics - giraffe long neck - longer neck = more calories = better survival - pass on useful things however most of these ideas were proven wrong BUT it is a similar theory to epigenetics

Culture Conclusions

From our biological perspective, the most fascinating point is how brains shape cultures, which shape brains, which shape . . . That's why it's called coevolution - We've seen some evidence of coevolution in the technical sense—where there are significant differences between different cultures in the distribution of gene variants pertinent to behavior - But those influences are pretty small - What is most consequential is childhood, the time when cultures inculcate individuals into further propagating their culture - In that regard, probably the most important fact about genetics and culture is the delayed maturation of the frontal cortex—the genetic programming for the young frontal cortex to be freer from genes than other brain regions, to be sculpted instead by environment, to sop up cultural norms - To hark back to a theme from the first pages of this book, it doesn't take a particularly fancy brain to learn how to motorically, say, throw a punch - But it takes a fancy, environmentally malleable frontal cortex to learn culture-specific rules about when it's okay to throw punches - Cultural differences manifest themselves in monumentally important, expected ways—say, whom it is okay to kill (an enemy soldier, a cheating spouse, a newborn of the "wrong" sex, an elderly parent too old to hunt, a teenage daughter who is absorbing the culture around her rather than the culture her parents departed) - But the manifestations can occur in unlikely places—e.g., where your eyes look within milliseconds of seeing a picture, or whether thinking of a rabbit prompts you to think of other animals or of what rabbits eat - Paradoxical influence of ecology - Ecosystems majorly shape culture—but then that culture can be exported and persist in radically different places for millennia - Stated most straightforwardly, most of earth's humans have inherited their beliefs about the nature of birth and death and everything in between and thereafter from preliterate Middle Eastern pastoralists - Has it been hundreds of thousands of years of Hobbes or of Rousseau? - Answer to that question greatly shapes what you'll make of something we'll consider in the final chapter, namely that over the last half millennium people have arguably gotten a lot less awful to one another

Proposed Cultural Universals

If the similarities seem most interesting, there are plenty—after all, multiple groups of humans independently invented agriculture, writing, pottery, embalming, astronomy, and coinage - At the extreme of similarities are human universals, and numerous scholars have proposed lists of them - One of the lengthiest and most cited comes from the anthropologist Donald Brow - Here's a partial list of his proposed cultural universals: the existence of and concern with aesthetics, magic, males and females seen as having different natures, baby talk, gods, induction of altered states, marriage, body adornment, murder, prohibition of some type of murder, kinship terms, numbers, cooking, private sex, names, dance, play, distinctions between right and wrong, nepotism, prohibitions on certain types of sex, empathy, reciprocity, rituals, concepts of fairness, myths about afterlife, music, color terms, prohibitions, gossip, binary sex terms, in-group favoritism, language, humor, lying, symbolism, the linguistic concept of "and," tools, trade, and toilet training -Staggeringly large cultural differences in how life is experienced, in resources and privileges available, in opportunities and trajectories, are most interesting - Just to start with some breathtaking demographic statistics born of cultural differences: a girl born in Monaco has a ninety-three-year life expectancy; one in Angola, thirty-nine. - Latvia has 99.9 percent literacy, Niger, 19 percent - More than 10 percent of children in Afghanistan die in their first year, about 0.2 percent in Iceland - Per-capita GDP is $137,000 in Qatar, $609 in the Central African Republic - A woman in South Sudan is roughly a thousand times more likely to die in childbirth than a woman in Estonia - The experience of violence also varies enormously by culture - Someone in Honduras is 450 times more likely to be murdered than someone in Singapore - 65 percent of women experience intimate-partner violence in Central Africa, 16 percent in East Asia - A South African woman is more than one hundred times more likely to be raped than one in Japan. Be a school kid in Romania, Bulgaria, or Ukraine, and you're about ten times more likely to be chronically bullied than a kid in Sweden, Iceland, or Denmark (stay tuned for a closer look at this) - there are the well-known gender-related cultural differences -There are the Scandinavian countries approaching total gender equality and Rwanda, with 63 percent of its lower-house parliamentary seats filled by women, compared with Saudi Arabia, where women are not allowed outside the house unless accompanied by a male guardian, and Yemen, Qatar, and Tonga, with 0 percent female legislators (and with the United States running around 20 percent) - Then there's the Philippines, where 93 percent of people say they feel happy and loved, versus 29 percent of Armenians - In economic games, people in Greece and Oman are more likely to spend resources to punish overly generous players than to punish those who are cheaters, whereas among Australians such "antisocial punishment" is nonexistent. And there are wildly different criteria for prosocial behavior - In a study of employees throughout the world working for the same multinational bank, what was the most important reason cited to help someone? Among Americans it was that the person had previously helped them; for Chinese it was that the person was higher ranking; in Spain, that they were a friend or acquaintance - Your life will be unrecognizably different, depending on which culture the stork deposited you into. In wading through this variability, there are some pertinent patterns, contrasts, and dichotomies.

Intersexual Genetic Conflict

In some species the fetus has an ally during maternal/fetal conflict—the father - Consider a species where males are migratory, mating with females and then moving on, never to be seen again - What's a male's opinion about maternal/fetal conflict? Make sure the fetus, i.e., his child, grabs as much nutrition as possible, even if that lessens Mom's future reproductive potential— who cares, that won't be his kid down the line - He's more than just rooting for his fetus. - This helps explain a mysterious, quirky feature of genetics - Normally a gene works the same way, regardless of which parent it comes from. But certain rare genes are "imprinted," working differently, or only being activated, depending on the parent of origin - Their purpose was discovered in a creative synthesis by evolutionary biologist David Haig of Harvard. Paternal imprinted genes bias toward more fetal growth, while maternal imprinted genes counter this - For example, some paternal genes code for potent versions of growth factors, while the maternal genes code for growth factor receptors that are relatively unresponsive - A paternally derived gene expressed in the brain makes newborns more avid nursers; the maternally derived version counters this. It's an arms race, with Dad genetically egging on his offspring toward more growth at the cost of the female's future reproductive plans, and Mom genetically countering this with a more balanced reproductive strategy - Tournament species, where males have minimal investment in a female's future reproductive success, have numerous imprinted genes, while pair-bonders don't

Telzer et al. 2015 Study

In the current study, we made group membership salient by recruiting Chinese and American participants to engage in a prosocial decision-making task during fMRI with an American and Chinese confederate - Found across all participants that donations to the in-group relative to out-group was associated with increased activation in the ventral striatum - found increases reward for the in-group - got the same for both populations METHOD - 13 EuropeanAmerican and 13 Chinese participants given the option to donate money to a European or Chinese confederate whom they met - They did this 124 times! - They had been told before the experiment began that (randomly) 5 of their decisions would be honored (i.e., the money would be given) - choose between self and out-group, self and in-group or self and self - varied per trial blocks RESULTS - Both groups of participants showed increased activation in the ventral striatum when donating to their ingroup than their outgroup - Those who identified more with their ethnic group showed more activation in VLPFC and ACC (self-control) and mentalising (TPJ, DMPFC) when donating to outgroup members - showed increased VS activity for in-group v. out-group donation exhibiting activation of reward pathways - increased cultural identity = increased ACC, VLPFC, TPJ/DMPFC when donating to the outgroup CAVEATS - Conducted at the University of Illinois, USA - All American participants were born in the United States, and all Chinese participants were born in China and had moved to the United States less than one year prior to their scan - "Prior to the scan, all participants were trained on the prosocial task. Chinese participants were trained in Chinese by a native Chinese speaking experimenter and American participants were trained in English by an American experimenter - In order to bolster the validity of the task as well as the salience of cultural identity, following the training, each participant interacted with one American confederate and one Chinese confederate (both gender-and age-matched). " How cross -cultural is this? - all the Chinese participants can fully speak and learn in English - very hard to do exactly the same study in two different studies - this is not a true cross-cultural study - not the same as doing it in China - these Chinese participants could have adopted WEIRD customs in the year they have lived in the US - Conducting Social Neuroscience in different cultures is challenging

Collective vs. Individualistic Cultures

Individualist: USA, independent, uniqueness, personal liberties, change reality, defined by self, lots of relationships, casual or temporary, behavior reflects attitudes and behavior. Collectivist: China/Japan, interdependent, Maintain connections, perform role, us mentality, group goals, duty, accommodate to reality, defined by social network, few relationships, behavior reflects social norms and roles There may be a genetic propensity to be more collective vs. individualistic - Collectivistic nations show an increased prevalence of people carrying the S allele of the 5-HTTLPR, the serotonin transporter gene (Chiao & Blizinsky, 2010) - The S allele is related to lower anxiety and mood disorders ---depends on childhood trauma or stress - even so, collectivist people are able to better belong to a collectivist group due to decreases anxiety and mood disorders - decreased independence in this culture - We do not know the cause and effect of this relationship just that it occurs

Genes and Evolution

Ipointed out earlier a requirement for neo-group selection, namely that genes be involved in a trait that differs more between than within groups - This applies to everything in this chapter. The first requirement for a trait to evolve is that it be heritable. But this is often forgotten along the way, as evolutionary models tacitly assume genetic influences - Tenuous is the idea that there is "the gene," or even genes, "for" aggression, intelligence, empathy, and so on. Given that, even more tenuous would be the idea of a gene(s) for maximizing your reproductive success by, say, "mating indiscriminately with every available female," or by "abandoning your kids and finding a new mate, because the father will raise them. - So critics will often demand, "Show me the gene that you assume is there - And sociobiologists will respond, "Show me a more parsimonious explanation than this assumption."

Predictions for biological non-adaptiveness of modern behaviour

Junk Food - brain is equipped to hunt out sources of energy and it could also mean that you go longer periods of time without food - once you find food you then will eat a lot seeing that it is hard to find - in modern society we can just open the fridge and eat tons of food even though have east access to food and it is not hard to find - innate mechanism that tells us to get quick energy fast Gambling - sensitive to things that give reward and make us want to repeat it - when activities lead to reward people wanted to repeat it as it could increase survival - gambling corrupted this gadget Contraception - sex primarily done to get pregnant and reproduce - mating advantage - instead sex is pleasure and children are bad - satisfy pleasure of sex but removes unwanted side effect of child Drugs - modern drugs - brain not developed for complex drugs - Way NS and NTs operates it increases addiction with repeated use

lOFC and ACC

Lateral orbitofrontal cortex & ACC (Brodmann Areas 10 & 24) - especially large areas in humans and may be where most social phenotypic traits are created - mPFC areas - See lecture for image - the Human areas 10 - is much larger than that for other primates - see lecture for graph

The Importance of Cross-Cultural Research

Most people are not WEIRD - People from Western, educated, industrialised, rich, and democratic (WEIRD) societies—and particularly American undergraduates—are some of the most psychologically unusual people on Earth - not representative of people on Earth but most studies use people from only WEIRD cultures - However, the vast majority of psychology studies use WEIRD participants - In 2008, a survey of the top psychology journals found that 96% of subjects were WEIRD even though they make up just 12% of the world population - not representative of global culture and the effects culture has on biology

Evolution Shapes Behavior

Organisms are amazingly well adapted - A desert rodent has kidneys that excel at retaining water; a giraffe's huge heart can pump blood up to its brain; elephants' leg bones are strong enough to support an elephant - it has to work that way: desert rodents whose kidneys weren't great at retaining water didn't pass on copies of their genes - Thus there is a logic to evolution, where natural selection sculpts traits into adaptiveness. Importantly, natural selection works not only on anatomy and physiology but on behavior as well—in other words, behavior evolves, can be optimized by selection into being adaptive. - Various branches of biology focus on the evolution of behavior Sociobiology - premised on social behavior being sculpted by evolution to be optimized, just as biomechanical optimization sculpts the size of a giraffe's heart - Sociobiology emerged in the 1970s, eventually generating the offshoot evolutionary psychology—the study of the evolutionary optimization of psychological traits; as we'll see, both have been plenty controversial - people who study the evolution of social behavior as sociobiologists

Individual Selection

Passing on lots of copies of one's genes is accomplished most directly by maximizing reproduction - This is summarized by the aphorism "A chicken is an egg's way of making another egg"—behavior is just an epiphenomenon, a means of getting copies of genes into the next generation. - Individual selection fares better than group selection in explaining basic behaviors - A hyena bears down on some zebras - What would the nearest one do if she's a group selectionist? - Stand there, sacrificing herself for the group - In contrast, an individual selectionist zebra would run like hell - Zebras run like hell - Or consider hyenas that have just killed a zebra - Group selection mind-set— everyone calmly takes turns eating. Individual selection—frenzied free-for-all. Which is what occurs. - But wait, says the group selectionist, wouldn't the zebra species benefit if it is the fastest animals who survive and pass on those fast-running genes? - Ditto for the group benefits of the fiercest hyena getting the most food. - As more nuances of behavior are observed, clinging to group selection requires increasingly tortuous arguments - But one single observation devastates group selection. In 1977 the Harvard primatologist Sarah Blaffer Hrdy documented something remarkable—langur monkeys in the Mount Abu region of India kill one another - People already knew that some male primates kill one another, fighting for dominance—okay, makes sense, boys will be boys - male langurs were killing infants - since babies are cute and inhibit aggression, something pathological must be happening - Maybe the Abu langur population density was too high and everyone was starving, or male aggression was overflowing, or infanticidal males were zombies - Hrdy eliminated these explanations and showed a telling pattern to the infanticide - Female langurs live in groups with a single resident breeding male - Elsewhere are all-male groups that intermittently drive out the resident male; after infighting, one male then drives out the rest - Here's his new domain, consisting of females with the babies of the previous male - And crucially, the average tenure of a breeding male (about twenty-seven months) is shorter than the average interbirth interval - No females are ovulating, because they're nursing infants; thus this new stud will be booted out himself before any females wean their kids and resume ovulating - All for nothing, none of his genes passed on. - What, logically, should he do? Kill the infants - This decreases the reproductive success of the previous male and, thanks to the females ceasing to nurse, they start ovulating - What about the females? - They're also into maximizing copies of genes passed on. - They fight the new male, protecting their infants - Females have also evolved the strategy of going into "pseudoestrus"— falsely appearing to be in heat. They mate with the male - And since males know squat about female langur biology, they fall for it—"Hey, I mated with her this morning and now she's got an infant; I am one major stud." They'll often cease their infanticidal attacks. Despite initial skepticism, competitive infanticide has been documented in similar circumstances in 119 species, including lions, hippos, and chimps - A variant occurs in hamsters; because males are nomadic, any infant a male encounters is unlikely to be his, and thus he attempts to kill it - Another version occurs among wild horses and gelada baboons; a new male harasses pregnant females into miscarrying - Or suppose you're a pregnant mouse and a new, infanticidal male has arrived - Once you give birth, your infants will be killed, wasting all the energy of pregnancy - Logical response? Cut your losses with the "Bruce effect," where pregnant females miscarry if they smell a new male - Thus competitive infanticide occurs in numerous species (including among female chimps, who sometimes kill infants of unrelated females) - None of this makes sense outside of gene-based individual selection. - Individual selection is shown with heartbreaking clarity by mountain gorillas, my favorite primate - They're highly endangered, hanging on in pockets of high-altitude rain forest on the borders of Uganda, Rwanda, and the Democratic Republic of the Congo - There are only about a thousand gorillas left, because of habitat degradation, disease caught from nearby humans, poaching, and spasms of warfare rolling across those borders - And also because mountain gorillas practice competitive infanticide - Logical for an individual intent on maximizing the copies of his genes in the next generation, but simultaneously pushing these wondrous animals toward extinction - This isn't behaving for the good of the species.

Gigantic Question #2: How Can Cooperation Ever Start?

So a handful of Tit for Tat-ers can outcompete a mix of other strategies, including highly exploitative, uncooperative ones, losing the battles but winning the war - But what if there's only one Tit for Tat-er in a population of ninety-nine Always Defect-ers? - Tit for Tat doesn't stand a chance. Always Defect-ers playing each other produces the second-worst outcome for each - But a Tit for Tat-er playing an Always Defect-er does worse, getting the sucker payoff that first round before becoming a de facto Always Defect-er - This raises the second great challenge for reciprocal altruism: forget which strategy is best at fostering cooperation—how do you ever start any type? Amid a sea of Always Defect-ers, the first black hamlet fish, mole rat, or Dictyostelium amoeba who, after reading Gandhi, Mandela, Axelrod, and Hamilton, takes the first altruistic step is screwed, lagging behind everyone else forever. One can practically hear the Always Defect amoebas chortling derisively. Let's make it slightly easier for Tit for Tat to gain a foothold. - Consider two Tit for Tat-ers amid ninety-eight Always Defect-ers. Both will crash andburn . . . unless they find each other and form a stable cooperative core, where the Always Defect-ers either must switch to Tit for Tat or go extinct - A nidus of cooperation crystallizes outward through the population - This is where green-beard effects help, conspicuous features of cooperators that help them recognize one another - Another mechanism is spatial, where the cooperative trait itself facilitates cooperators finding one another. Another route has been suggested for jump-starting reciprocal altruism - Occasionally a geographic event occurs (say, a land bridge disappears), isolating a subset of a population for generations -What happens in such a "founder population"? Inbreeding, fostering cooperation via kin selection - Eventually the land bridge reappears, the inbred cooperative founder population rejoins the main group, and cooperation propagates outward

Gender

Society is conflicted over how much "culture" vs. "biology" play a role - This controversy comes up again when considering the role of evolution in understanding mate selection and sexual behavior - We don't tend to think that the way kangaroos mate is influenced by culture, yet, trying to argue that human gender is strongly influenced by evolution and genetics may be hard to separate from cultural influences - Gender and culture are very hard to separate and just isolate the biological effects - Cordelia Fine, an Associate Professor at Uni Melbourne, has warned that some biological explanations of gender differences are built on faulty research and identified "neurosexism" as a problem in this area - some research has preconceived ideas about gander differences they will find in the brain - they design experiments to support these twisted views - Delusions of Gender - book by Fine in 2010 - Testosterone Rex - book by Fine in 2017 - talks about the misrepresentation of the past, present and future in gender with misdirected research and the wrong status quo

Timetable for Human Evolution

Some important dates: - 8 million years ago - chimps and gorilla split - chimp-human split: 6-8 million years ago - first fossil hominids: ~4-5 million years ago (e.g., Lucy, Australopithecus afarensis 4 mya) - Homo habilis ("Handyman"): 2 mya - Homo erectus ("Peking/Java Man"): 1 mya Diff Timeline - 4-7 mya - humans and chimps diverage - 4 mya - bipedal walking is well-developed - 2.6 mya - oldest stone tool making - 1.8 mya - Homo Erectus expands from Africa - 800,000-200,000 ya - rapid brain expansion - 250,000-30,000 ya - neanderthals emerge then become extinct, Homo Sapians emerge in Africa and expand to other continents - symbolic culture begins to flourish - 12,000 - 10,000 ya - origin of agriculture - fairly new invention on human timeline - 4,500 ya - origins of writing, state societies, established civilizations: Sumar and Egypt

Reciprocal Altruism

Sometimes a chicken is an egg's way of making another egg, genes can be selfish, and sometimes we gladly lay down our lives for two brothers or eight cousins - Does everything have to be about competition, about individuals or groups of relatives leaving more copies of their genes than the others, being more fit, having more reproductive success? - Is the driving force of behavioral evolution always that someone be vanquished? - Not at all - One exception is elegant, if specialized. Remember rock/paper/scissors? Paper envelops rock; rock breaks scissors; scissors cut paper. Would rocks want to bash every scissors into extinction? No way. Because then all those papers would enwrap the rocks into extinction. Each participant has an incentive for restraint, producing an equilibrium. - Remarkably, such equilibriums occur in living systems, as shown in a study of the bacteria Escherichia coli - The authors generated three colonies of E. coli, each with a strength and a weakness - Strain 1 secretes a toxin. Strength: it can kill competitor cells. Weakness: making the toxin is energetically costly - Strain 2 is vulnerable to the toxin, in that it has a membrane transporter that absorbs nutrients, and the toxin slips in via that transporter. Strength: it's good at getting food. Weakness: vulnerability to the toxin - Strain 3 doesn't have the transporter and thus isn't vulnerable to the toxin, and it doesn't make the toxin. Strength: it doesn't bear the cost of making the toxin and is insensitive to it. Weakness: it doesn't absorb as much nutrients - Destruction of strain 2 by strain 1 causes the demise of strain 1 thanks to strain 3 - The study showed that the strains could exist in equilibrium, each limiting its growth. Cool. But it doesn't quite fit our intuitions about cooperation. Rock/paper/scissors is to cooperation as peace due to nuclear weapons-based mutually assured destruction is to the Garden of Eden. - Which raises a third fundamental, alongside individual selection and kin selection: reciprocal altruism. "I'll scratch your back if you scratch mine. I'd rather not actually scratch yours if I can get away with it. And I'm watching you in case you try the same." - Despite what you might expect from kin selection, unrelated animals frequently cooperate. Fish swarm in a school, birds fly in formation. Meerkats take risks by giving alarm calls that aid everyone, vampire bats who maintain communal colonies feed one another's babies - Depending on the species, unrelated primates groom one another, mob predators, and share meat. - Why should nonrelatives cooperate? Because many hands lighten the load. School with other fish, and you're less likely to be eaten (competition for the safest spot—the center—produces what Hamilton termed the "geometry of the selfish herd") - Birds flying in a V formation save energy by catching the updraft of the bird in front (raising the question of who gets stuck there) - If chimps groom one another, there are fewer parasites. In a key 1971 paper biologist Robert Trivers laid out the evolutionary logic and parameters by which unrelated organisms engage in "reciprocal altruism"— incurring a fitness cost to enhance a nonrelative's fitness, with the expectation of reciprocation - It doesn't require consciousness to evolve reciprocal altruism; back to the metaphor of the airplane wing in the wind tunnel - But there are some requirements for its occurrence. - Obviously, the species must be social - Furthermore, social interactions have to be frequent enough that the altruist and the indebted are likely to encounter each other again - Individuals must be able to recognize each other. - Amid reciprocal altruism occurring in numerous species, individuals often attempt to cheat (i.e., to not reciprocate) and monitor attempts by others to do the same to them. This raises the realpolitik world of cheating and counterstrategies, the two coevolving in escalating arms races - This is called a "Red Queen" scenario, for the Red Queen in Through the Looking-Glass, who must run faster and faster to stay in place - This raises two key interrelated questions: - Amid the cold calculations of evolutionary fitness, when is it optimal to cooperate, when to cheat? - In a world of noncooperators it's disadvantageous to be the first altruist - How do systems of cooperation ever start?

The Resurrection of Group Selection

Sometimes it makes the most sense to pay attention to the recipe, sometimes to the baking process - the recipe is what is replicated, the taste what is chosen But there's another level - Sometimes cake sales can be changed most consequentially by altering something other than recipe or taste— advertisements, packaging, or the perception of whether the cake is a staple or a luxury - Sometimes sales are changed by tying the product to a particular audience—think of products that advertise fair-trade practices, the Nation of Islam's Your Black Muslim Bakery, or the Christian fundamentalist ideology of Chick-fil-A restaurants - And in those cases recipe and taste can both be trumped by ideology in purchasing decisions - This is where neo-group selection fits into multilevel selection—the idea that some heritable traits may be maladaptive for the individual but adaptive for a group - This has cooperation and prosociality written all over it, straight out of the analysis of Tit for Tat-ers finding one another in a sea of Always Defect-ers. Stated more formally, it's when A dominates B but a group of Bs dominates a group of As - Here's a great example of neo-group selectionism: - As a poultry farmer, you want your groups of chickens to lay as many eggs as possible - Take the most prolific egg layer in each group, forming them into a group of superstar chickens who, presumably, will be hugely productive - Instead, egg production is miniscule - Why was each superstar the egg queen in her original group? - Because she would aggressively peck subordinates enough to stress them into reduced fertility - Put all these mean ones together, and a group of subordinated chickens will outproduce them - This is a world away from "animals behave for the good of the species." - Instead, this is the circumstance of a genetically influenced trait that, while adaptive on an individual level, emerges as maladaptive when shared by a group and where there is competition between groups (e.g., for an ecological niche) - There's been considerable resistance to neo-group selectionism - Part of it is visceral, often pronounced among the old guard—"Great, we've finally confiscated all the Wild Kingdom videos, and now we're back to playing Whac- A-Mole with group selection sentimentality?" - But the more fundamental resistance is from people who distinguish bad old group selection from neo- group selection, accept that the latter can occur, but think it's very rare - Maybe so, across the animal kingdom - But neo-group selection plays out with great frequency and consequence in humans - Groups compete for hunting grounds, pastures, water sources Cultures magnify the intensity of between- group selection and lessen within-group selection with ethnocentrism, religious intolerance, race-based politics, and so on - The economist Samuel Bowles, of the Santa Fe Institute, emphasizes how intergroup conflict like war is the driving force for intragroup cooperation ("parochial altruism"); he refers to intergroup conflict as "altruism's midwife." - Most in the field now both accept multilevel selection and see room for instances of neo-group selection, especially in humans - Much of this reemergence is the work of two scientists. The first is David Sloan Wilson of the State University of New York at Binghamton, who spent decades pushing for neo-group selection (although he sees it not really as "neo" but rather as old- style group selection finally getting some scientific rigor), generally being dismissed, and arguing his case with research of his own, studies ranging from fish sociality to the evolution of religion - He slowly convinced some people, most importantly the second scientist, Edward O. Wilson of Harvard (no relation) - E. O. Wilson is arguably the most important naturalist of the last half of the twentieth century, an architect of the sociobiology synthesis along with a number of other fields, a biology god. E. O. Wilson had long dismissed David Sloan Wilson's ideas - And then a few years back, the octogenarian E. O. Wilson did something extraordinary—he decided he was wrong - And then he published a key paper with the other Wilson—"Rethinking the Theoretical Foundation of Sociobiology." - My respect for these two, both as people and as scientists, is enormous - Thus something resembling détente has occurred among the advocates for the importance of differing levels of selection - Our three-legged chair of individual selection, kin selection, and reciprocal altruism seems more stable with four legs

Nisbett Violence Study

Southern violence was explored in one of the all-time coolest psychology studies, involving the use of a word rare in science journals, conducted by Nisbett and Cohen - Undergraduate male subjects had a blood sample taken - They then filled out a questionnaire about something and were then supposed to drop it off down the hall - It was in the narrow hallway, filled with file cabinets, that the experiment happened - Half the subjects traversed the corridor uneventfully. But with half, a confederate (get it? ha-ha) of the psychologists, a big beefy guy, approached from the opposite direction - As the subject and the plant squeezed by each other, the latter would jostle the subject and, in an irritated voice, say the magic word—"a-hole"—and march on - Subject would continue down the hall to drop off the questionnaire - What was the response to this insult? It depended - Subjects from the South, but not from elsewhere, showed massive increases in levels of testosterone and glucocorticoids—anger, rage, stress - Subjects were then told a scenario where a guy observes a male acquaintance making a pass at his fiancée—what happens next in the story? - In control subjects, Southerners were a bit more likely than Northerners to imagine a violent outcome - And after being insulted? No change in Northerners and a massive boost in imagined violence among Southerners. Where do these Westernized cultures of honor come from - Violence between the Crips and the Bloods in LA is not readily traced to combatants' mind-sets from growing up herding yak - Nonetheless, pastoralist roots have been suggested to explain the Southern culture of honor - The theory as first propounded by historian David Hackett Fischer in 1989: Early American regionalism arose from colonists in different parts of America coming from different places - There were the Pilgrims from East Anglia in New England. Quakers from North Midlands going to Pennsylvania and Delaware. Southern English indentured servants to Virginia. And the rest of the South? - Disproportionately herders from Scotland, Ireland, and northern England - Naturally, the idea has some problems - Pastoralists from the British Isles mostly settled in the hill country of the South, whereas the honor culture is stronger in the Southern lowlands - Others have suggested that the Southern ethos of retributive violence was born from the white Southern nightmare scenario of slave uprisings - But most historians have found a lot of validity in Fischer's idea

Pair-Bonding Versus Tournament Species

Suppose you've discovered two new species of primates. - Despite watching both for years, here's all you know: In species A, male and females have similar body sizes, coloration, and musculature - in species B, males are far bigger and more muscular than females and have flashy, conspicuous facial coloration (jargon: species B is highly "sexually dimorphic") - We'll now see how these two facts allow you to accurately predict a ton of things about these species First off, which species has dramatic, aggressive conflict among males for high dominance rank? - Species B, where males have been selected evolutionarily for fighting skills and display - Species A males, in contrast, are minimally aggressive—that's why males haven't been selected for muscle. What about variability in male reproductive success? - In one species 5 percent of the males do nearly all the mating; in the other, all males reproduce a few times - The former describes species B—that's what all the rank competition is about—the latter, species A - Next, in one species, if a male mates with a female and she conceives, he'll do a ton of child care -In contrast, no such male "parental investment" is seen in the other species - No-brainer: the former describes species A; the few species B males who father most of the kids sure aren't doing child care - One species has a tendency to twin, the other not. Easy—the twinning is in species A, with two sets of parental hands available - How picky are males about whom they mate with? In species B, males mate with anyone, anywhere, anytime—it only costs the price of some sperm - In contrast, males of species A, with its rule of "You get her pregnant, you do child care," are more selective. Related to that, which species forms stable pair-bonds? Species A, of course - After correcting for body size, which species' males have bigger testes and higher sperm count? - It's species B, ever prepared for mating, should the opportunity arise - What do females look for in a potential mate? - Species B females get nothing from a male except genes, so they should be good ones - This helps explain the flamboyant secondary sexual characteristics of males—"If I can afford to waste all this energy on muscle plus these ridiculous neon antlers, I must be in great shape, with the sorts of genes you'd want in your kids." - In contrast, species A females look for stable, affiliative behavior and good parenting skills in males - This is seen in bird species with this pattern, where males display parenting expertise during courtship—symbolically feeding the female with worms, proof that he'd be a competent worm winner - Related to that, among bird versions of species A and B, in which is a female more likely to abandon her offspring, passing on more copies of her genes by breeding with another male? - Species A, where you see "cuckoldry"—because the male is going to stick there, caring for the kids. - Related to that, in species A, females compete aggressively to pair-bond with a particularly desirable (i.e., paternal) male - In contrast, species B females don't need to compete, since all they get from males is sperm, and there's enough to go around from desirable males - Remarkably, what we've described here is a broad and reliable dichotomy between two social systems, where A is a "pair-bonding" species, B a "tournament" species. Primates that pair-bond include South American monkeys like marmosets, tamarins, and owl monkeys, and among the apes, gibbons (with nonprimate examples including swans, jackals, beavers, and prairie voles) - Classic tournament species include baboons, mandrills, rhesus monkeys, vervets, and chimps (with nonprimate examples including gazelles, lions, sheep, peacocks, and elephant seals) - Not all species fit perfectly into either extreme (stay tuned) - Nonetheless, the point is the internal logic with which the traits of each of these types of species cluster, based on these evolutionary principles

Religion and Culture

Theories abound as to why humans keep inventing religions - It's more than a human pull toward the supernatural; as stated in one review, "Mickey Mouse has supernatural powers, but no one worships or would fight—or kill—for him - Our social brains may help explain why children the world over are attracted to talking teacups, but religion is much more than that - Why does religion arise? - Because it makes in-groups more cooperative and viable (stay tuned for more in the next chapter) - Because humans need personification and to see agency and causality when facing the unknown - Or maybe inventing deities is an emergent by-product of the architecture of our social brains Amid these speculations, far more boggling is the variety of the thousands of religions we've invented - they vary as to number and gender of deities; whether there's an afterlife, what it's like, and what it takes to enter; whether deities judge or interfere with humans; whether we are born sinful or pure and whether sexuality changes those states - whether the myth of a religion's founder is of sacredness from the start (so much so that, say, wise men visit the infant founder) or of a sybarite who reforms (e.g., Siddhārtha's transition from palace life to being the Buddha) - whether the religion's goal is attracting new followers (say, with exciting news—e.g., an angel visited me in Manchester, New York, and gave me golden plates) or retaining members (we've got a covenant with God, so stick with us) - There are some pertinent patterns amid this variation - As noted, desert cultures are prone toward monotheistic religions; rain forest dwellers, polytheistic ones - Nomadic pastoralists' deities tend to value war and valor in battle as an entrée to a good afterlife. Agriculturalists invent gods who alter the weather. As noted, once cultures get large enough that anonymous acts are possible, they start inventing moralizing gods - Gods and religious orthodoxy dominate more in cultures with frequent threats (war, natural disasters), inequality, and high infant mortality rates - Before turfing this subject to the final chapter, three obvious points: (a) a religion reflects the values of the culture that invented or adopted it, and very effectively transmits those values (b) religion fosters the best and worst of our behaviors (c) it's complicated. - We've now looked at various cultural factors—collectivism versus individualism, egalitarian versus hierarchical distribution of resources, and so on

Gender and Math

There is a very small difference - the ver small effect size does NOT suggest profound differences in ability - slight effect size could make a large difference in under representation in math, science and engineering fields for women and culture might cause this edge - over 254 studies and 3 million students they found very trivial differences in which males are a small bit higher but not by much at all - Culture has a large influence on this relationship - looked at gender equality measures in 10 countries (economic and political opportunity, education, and well-being) - show a LARGE cultural interaction - Countries that had MORE gender equality showed better female scores in math (SWE, NOR) and some countries females did better than males (ISL) - As countries have less gender equality typically males will have the largest advantage of doing better in math (TUR, KOR, ITA) - Countries like the USA and PRT are in the middle where males do better but not by as much as seen in other countries

Reciprocal Altruism and Neo-Group Selectionism

There's not much to say here other than that this is the most interesting stuff in the chapter - When Axelrod got his round-robin tournament all fired up, he didn't canvass, say, fish for their Prisoner's Dilemma strategies - He asked humans. - We're the species with unprecedented cooperation among unrelated individuals, even total strangers - Dictyostelium colonies are green with envy at the human ability to do a wave in a football stadium - We work collectively as hunter-gatherers or as IT execs. Likewise when we go to war or help disaster victims a world away - We work as teams to hijack planes and fly them into buildings, or to award a Nobel Peace Prize - Rules, laws, treaties, penalties, social conscience, an inner voice, morals, ethics, divine retribution, kindergarten songs about sharing—all driven by the third leg of the evolution of behavior, namely that it is evolutionarily advantageous for nonrelatives to cooperate. Sometimes - One manifestation of this strong human tendency has been appreciated recently by anthropologists - The standard view of hunter-gatherers was that their cooperative, egalitarian nature reflected high degrees of relatedness within groups—i.e., kin selection - The man-the-hunter version of hunter-gatherers viewed this as arising from patrilocality (i.e., where a woman, when marrying, moves to live with the group of her new husband), while the groovy-hunter- gatherers version tied it to matrilocality (i.e., the opposite) - However, a study of more than five thousand people from thirty-two hunter-gatherer societies from around the world* showed that only around 40 percent of people within bands are blood relatives - In other words, hunter-gatherer cooperativeness, the social building block of 99 percent of hominin history, rests at least as much on reciprocal altruism among nonrelatives as on kin selection (with chapter 9's caveat that this assumes that contemporary hunter-gatherers are good stand-ins for ancestral ones) - So humans excel at cooperation among nonrelatives. We've already considered circumstances that favor reciprocal altruism; this will be returned to in the final chapter - Moreover, it's not just groups of nice chickens outcompeting groups of mean ones that has revivified group selectionism - It is at the core of cooperation and competition among human groups and cultures - Thus humans deviate from the strict predictions concerning the evolution of behavior - Pertinent when considering three major criticisms of sociobiology

Recognizing Relatives

These findings concerning kin selection require animals to recognize degrees of relatedness. How do they do this? - Some species have innate recognition - For example, place a mouse in an arena; at one end is an unrelated female, at the other, a full sister from a different litter, never encountered before - The mouse spends more time with the sister, suggesting genetically based kin recognition. - Rodents produce pheromonal odors with individual signatures, derived from genes called the major histocompatibility complex (MHC) - This is a super variable gene cluster that produces unique proteins that form a signature for an individual - This was first studied by immunologists - What does the immune system do? It differentiates between you and invaders —"self" and "nonself"—and attacks the latter - All your cells carry your unique MHC-derived protein, and surveillance immune cells attack any cell lacking this protein password - And MHC-derived proteins also wind up in pheromones, producing a distinctive olfactory signature. - This system can indicate that this mouse is John Smith - How does it also tell that he's your never-before-encountered brother? - The closer the relative, the more similar their cluster of MHC genes and the more similar their olfactory signature - Olfactory neurons in a mouse contain receptors that respond most strongly to the mouse's own MHC protein - Thus, if the receptor is maximally stimulated, it means the mouse is sniffing its armpit. If near maximally stimulated, it's a close relative - Moderately, a distant relative. Not at all (though the MHC protein is being detected by other olfactory receptors), it's a hippo's armpit - Olfactory recognition of kin accounts for a fascinating phenomenon - Recall from chapter 5 how the adult brain makes new neurons - In rats, pregnancy triggers neurogenesis in the olfactory system. Why there? So that olfactory recognition is in top form when it's time to recognize your newborn; if the neurogenesis doesn't occur, maternal behavior is impaired - Then there is kin recognition based on imprinted sensory cues - How do I know which newborn to nurse? - The one who smells like my vaginal fluid. Which kid do I hang out near? - The one who smells like Mom's milk. Many ungulates use such rules. So do birds. Which bird do I know is Mom? The bird whose distinctive song I learned before hatching. - And there are species that figure out relatedness by reasoning; my guess is that male baboons make statistical inferences when identifying their likely offspring: "How much of this mom's peak estrus swelling was spent with me? All. Okay, this is my kid; act accordingly." Which brings us to the most cognitively strategic species, namely us. How do we do kin recognition? In ways that are far from accurate, with interesting consequences. We start with a long theorized type of pseudo-kin recognition - What if you operate with the rule that you cooperate with (i.e., act related to) individuals who share conspicuous traits with you? This facilitates passing on copies of genes if you possess a gene (or genes) with three properties: - (a) it generates that conspicuous signal - (b) recognizes it in others - (c) makes you cooperate with others who have that signal. It's a kind of primitive, stripped-down kin selection. Green-beard effect Hamilton speculated about the existence of such a "green-beard effect" - if an organism has a gene that codes for both growing a green beard and cooperating with other green bearders, green bearders will flourish when mixed with non- green bearders - "the crucial requirement for altruism is genetic relatedness at the altruism locus [i.e., merely a multifaceted green-beard gene] and not genealogical relationship over the whole genome." - Green-beard genes exist - Among yeast, cells form cooperative aggregates that need not be identical or even closely related. Instead, it could be any yeast that expresses a gene coding for a cell-surface adhesion protein that sticks to copies of the same molecule on other cells - Humans show green-beard effects - Crucially, we differ as to what counts as a green-beard trait - Define it narrowly, and we call it parochialism - Include enmity toward those without that green-beard trait and it's xenophobia - Define the green-beard trait as being a member of your species, and you've described a deep sense of humanity.

Definition of culture

Tylor definition - culture is that complex whole which includes knowledge, belief, art, morals, law, custom, and any other capabilities and habits acquired by man as a member of society - Jane Goodall blew off everyone's socks in the 1960s by reporting the now-iconic fact that chimps make tools - Her study subjects modified twigs by stripping off the leaves and pushing them into termite mounds; termites would bite the twig, still holding on when it was pulled out, yielding a snack for the chimps - Chimps were subsequently found to use various tools —wood or rock anvils for cracking open nuts, wads of chewed leaves to sponge up hard-to-reach water, and, in a real shocker, sharpened sticks for spearing bush babies - Different populations make different tools - new techniques spread across social networks (among chimps who hang with one another); kids learn the ropes by watching their moms; techniques spread from one group to another when someone emigrates - chimp nut-cracking tools in excess of four thousand years old have been excavated. - also did accessorizing, a female in Zambia got it into her head to go around with a straw-like blade of grass in her ear. The action had no obvious function; apparently she just liked having a piece of grass sticking out of her ear. So sue her. She did it for years, and over that time the practice spread throughout her group. A fashionista. - In the decades since Goodall's discovery, tool use has been observed in apes and monkeys, elephants, sea otters, mongoose - Dolphins use sea sponges to dig up fish burrowed into the sea floor - Birds use tools for nest building or food acquisition—jays and crows, for example, use twigs to fish for insects, much as chimps do - tool use in cephalopods, reptiles, and fish - cultural transmission doesn't show progression—this year's chimp nut-cracking tool is pretty much the same as that of four thousand years ago - with few exceptions, nonhuman culture is solely about material culture (versus social organization) - classical definition of culture isn't specific to humans - most cultural anthropologists weren't thrilled with Goodall's revolution - de Waal: "culture" is how we do and think about things, transmitted by non-genetic means

Cultural Caveats

concerning collectivist/individualist comparisons: - The most obvious is the perpetual "on the average"—there are plenty of Westerners, for example, who are more collectivist than plenty of East Asians - In general, people who are most individualist by various personality measures are most individualist in neuroimaging studies - Cultures change over time - levels of conformity in East Asian cultures are declining (one study, for example, shows increased rates of babies in Japan receiving unique names) - one's degree of inculcation into one's culture can be altered rapidly - For example, priming someone beforehand with individualist or collectivist cultural cues shifts how holistically he processes a picture. This is especially true for bicultural individuals - genetic differences between collectivist and individualist populations - There is nothing resembling genetic destiny about this—the best evidence for this conclusion comes from one of the control groups in many of these studies, namely East Asian Americans - In general, it takes about a generation for the descendants of East Asian immigrants to America to be as individualist as European Americans - Obviously, "East Asians" and "Westerners" are not monolithic entities - Just ask someone from Beijing versus the Tibetan steppes - Or stick three people from Berkeley, Brooklyn, and Biloxi in a stalled elevator for a few hours and see what happens - there is striking variation within cultures

Playing Vinyl Records

• "My vinyl ritual is lights out, candles lit and glass of wine in hand - best way to spend an evening with your old favourites." - "Listening to a record is more than just pressing play to me. It is a ritual consisting of many steps: powering on the entire setup; opening the dust cover on my turntable; taking out the record and gently placing it down on the spindle. Pressing the play button making the platter spin. Gently brushing the spinning record for dust and dirt before finally placing the stylus in the grooves." (Frederik Lauridsen, Laced) - Large comforting ritual associated with playing vinyl - provides a sense of nostalgia and safety - uses little steps to listen to music which increases relaxation - drinking tea is another ritual like this