Chapter 8: test 3

adaptive problem

anything that impeded survival or reproduction, or anythin whose solution increases the odds of survival or reproductions -all adaptions must contribute to fitness during the period of time in which they evolve, by heloing an organism survive, reporduce or facilitate the reproductuve success of genetic relatives.

evolutionary-predicted sex differences

hold that the sexes will differ in precisely those domains where women and men have faced different sort of adaptive problems. key questions: 1. In what domains have women and men faced different adaptive problems? 2. what are the sex-differentiated psychological mechanisms of women and men that have evolved in response to these sex-differentiated adaptive problems? 3. which social, cultural and contextual inputs affect the magnitude of expressed sex differenceS?

evolutionary byproducts

incidental effects that are not properly considered to be adaptions ex. human nose designed for smelling, but fact that we use our noses to hold up our eyeglasses in an incidental byproduct

life history strategy (Individual difference and frequency-dependent selection)

individuals have evolved differences in the effort they allocate to reproductively relevant problems, such as survival, mating and parting-->there are trade-offs among these problems. -Effort allocated for mating, is effort taken away from parenting.

social anxiety

need to belong -defined as distress or worry about being negatively evaluated in social situations. -a species-typical adaptions that prevents social exclusion -people that were indifferent to being excluded by others may have suffered in the currency of survival by lacking the protection of the group. They may also have suffered by failing to find a mate -these individuals may have experienced lower reproductive success than those who psychological mechanisms caused them to maintain inclusion in the group by avoiding doing things that elicit criticism. -groups can be expected to shun those who inflict cost on others within the group. Showing cowardice in face of danger, aggression toward in-group members.

numerousness

(evolutionary psych) -our ancestors faced many sorts of adaptive problems in the course of human evolution, so we have numerous adaptive mechanisms. -body: large number of physiological and antomical mechanisms: heart to pump blood, larynx to prevent choking, and liver to detoxify poisons -mind: contains a large number of mechanisms--psycological adaptions--> most commons fears and phobias -just in the domain of fears, we have a large number of psychological mechanisms bc the number of hazardous hostile forces of natures has been so large. -psychological mechanisms for the selection of mates, the detection of cheaters in social exchanges, favoring of habitates, formation of strategic alliances. -large number of domain-specific psycholgical adaptions to correspond to the large number of distinct adaptive problems humans have recurrently confronted

functionality

(evolutionary psych) the notion that our psychological mechanism are designed to accomplish adaptive goals. -we cant understand out preferences for certain maters, without inquiring about the function of such preferences (e.g. healthy or fertile mate) -the search for function involves identifying the specific adaptive problem for which the mechanism is an evolved solution

unrestricted mating strategy

(evolved and maintained by frequency dependent selection) -female mating strategy a woman seeking a man for the quality of his genes, on the other hand, has less reason to relay sexual intercourse. A man's level of commitment to her is irrelevant, so prolonged assessment of his prior commitments are not necessary. -as number of unrestricted females in the population increases, the number of "sexy sons" in the next generation also increases--> as number of sexy sons increases, however, the competition among them also increases, then because there are so many sexy sons competing for a limited pool of women, their average success decline

difference detecting mechanism

(the big 5 and evolutionary problems) humans have evolved"difference-detecting mechanisms" designed to notice and remember those individual differences that have the most relevance for solving social adaptive problems. -who is likely to rise in the social hierarchy and hence gain access to status and position in the social hierarchy? (Dominance, Extraversion -Who is likely to be a good cooperator and reciprocator, and who will be a loyal friend or romantic partner? (Agreeableness) -Who will be reliable and dependable in times of need and work industriously to provide resources?(Conscientiousness) -Who will drain my resources, hinder me with their problems, monopolize my time, and fail to cope well with adversity? (Emotional stability) -Who can I go to for wise advice? (openness, intellect)

restricted sexual strategy

( evolved and maintained by frequency dependent selection) -female mating strategy a women seeking a high-investing mate would adopt a restricted sexual strategy marked by delayed intercourse and prolonged courtship. --> enable her to access the man's level of commitment, detect the existence of prior commitments to other women or children, and simultaneously signal to the man her sexual fidelity and hence assure him of his paternity of future offspring. -if number of restricted females seeking investing men increase in the population, bc there are so many women seeking investment, they end up competing with each other for men willing to invest. --> as number of women seeking investment increases, the average success of their strategy declines.

adaptions

(evolutionary process) The primary product of the selective process, a reliably developing structure in the organism, which because it meshes with the recurrent structure of the world, causes the solution to an adaptive problem. -an adaption tends to emerge with regularity during the course of a person's life. -environments are always needed for the development of an adaption, and environmental events can always interfer with or enhance such development. -adaptions emerge from, and are structure by, the selective environment. features of the environment must be recurrent over time for an adaption to evolve. (the venemous snakes must be recurrently dangerous, ripe fruit recurrently nutrious, and enclosed caves recurrenly protective before adaption to them can emerge. -must facilitate the solution to an adaptive problem:

domain specificity

(evolutionary psych) -adaptions are presumed to be domain specific in the sense that they are designed by the evolutionary process to solve a particular adaptive problem -in the area of food selection, domain specificity is seen in our preferences for calorically rich fat and in our evolved sweet tooth, which leads us to objects rich in sugar, such as ripe fruit and berries. -different adaptive problems require different sorts of solutions: our taste preferences, which guide us to successful food choice, do not help us solve the adaptive problem of choosing a successful mate, if we were to use our food preferences as a genereal guide to the choice of mates, we would select strange mates indeed -successful mate choices require different mechanism--> domain specifity implies that selection tends to fashion at least somewhat specialized mechanism for each adaptive problem.

balancing selection

(the big 5 and evolutionary problems) these personality differences are maintained by balancing selection, which occurs when genetic variation is maintained by selection because different levels on a trait dimension are adaptive in different environments.

psychopathy

(frequency dependent selection) a cluster of personality traits marked my irresponsible and unreliable behavior, egocentrism, impulsivity, an inability to form lasting relationships, superficial social charm and a deficit in social emotions such as love, shame guilt and empathy -as number of cheaters increases, and hence the average cost to the cooperative hosts increases, adaptions will evolve in cooperators to detect and punish cheating, thus lowering its overall effectiveness --> as psychopaths get detected and punished, the average success of the strategy declines. -pursue a deceptive cheating strategy in their social interactions. -more common among men than women -pursue a strategy of exploiting the cooperative inclinations of other people -after pretending cooperation, psychopaths typically defect, cheat or violate the presumed relationship. --> cheating strategy might be pursued by those who are unlikely to outcompete others in more mainstream or traditional social hierarchies.

low K strategy

(frequency-dependent selection, individual difference, life history strategy) -formed weaker attachment to their biological parents, have a risk-taking personality, pursue short-term mating and invest little in their children.

high K strategy

(frequency-dependent selection, individual difference, life history strategy) greater effort is allocated to survival and heavy parenting over effort assigned to obtaining many mate. -these high-K individuals have formed strong attachment to the biological parents, avoid risk taking and would endanger survival, pursue long-term mating rather than short term mating, and invest heavily in children

need to belong

(human nature) -Hogan argues the most basic human motivators are status and acceptance by the group -the most important social problems early humans had to solve in order to survive and repoduce involved establishing cooperative relations with other members of the group and negotiating hierarchies -achieving status and popularity likely conferred a host or reproductively relevant resources on an individual: protection, food, desirable mate -being ostrasized from a group would have been extremely damaging--> humans have evolved psychological mechanism to prevent being excluded. (social anxiety) -social interactions on self-esteem -social rejection--> literally painful -humans have always been intensely group living, and lack of a group almost surely would have meant death in ancestral environments, so it is not suprising that we have a strong need to belong--a part of human nature.

helping and altruism

(human nature) -helping others is a direct function of the recipients' ability to enhance the inclusive fitness of the helpers. -helping should decreses, as the degree of genetic relatedness decreases between the helper and the recipient--> more likely to help your sibling (50% gnes) than you nieces or nephews(25%) -the tendency to help is a direct function of the degree of relatedness. -helping younger over older kind because older kin would have less impact on average in terms of reproductive success. -indivudals of higher reproductive value should be helped more than individuals of lower reproductive value. -central component of human nature is helping other people, but in highly domain-specific ways. -the ways in which humans help others--the distribution of helping acts across individuals--is highly predictable from an evolutionary perspective

universal emotions

(human nature) -three distinct perspectives on the study of emotions, such as fear, rage and jealousy -one view: examine whether facial expressions of emotion are interpreted in the same ways across cultures, on the assumptins that universality is one criterion for adaption. If all humans share an adaption, such as smiling to express happiness, that adpation is likely to be a core part of human nature. 2nd: emotions are adaptive psychological mechanisms that signal various "fitness affordances" in the social environment--> emotions guide the person toward goals that would have conferred fitness in ancestral environments or to avoid conditions that would have interfered with fitness (getting beat up) 3rd: manipulation hypothesis, which suggests that emotions are designed to exploit the psycholgical mechanisms of other people. ex. expression of rage might be designed to make a verbal threat more credible that the same threat made without displaying rage. -emotions are a central component of personality, are universally recognezed, thus fulfilling and important criterion for adaption.

hostile forces of nature

(natural selection) -the events that impeded survival. -hostile forces included food shortages, diseases, parasites, predators, and extremes of weather--> variants that helped organisms survive these hostile forces of nature led to an increased likelihood of successful reporduction -adaptions: inherited solutions to the survival and reproduction problems posed by the hostile forces of nature.

effective polygyny

(sex difference in aggresion) because female mammals bear the physical burden of gestation and lactation, there is a considerable sex difference in minimum oblgatory parental investment-->this difference leads to differences in the variance in reproduction between sexes -most females will have some offspring, whereas a few males will sire many offspring, and some will have not at all -the greater the variance in reproduction the more ferocious the competition within the sex that shows higher variance. -within primate species, the greater the effective polygyny ,the more the sexual dimorphism and the greater reproductive variance between sexes -some males gain more than their fair share of copulations, whereas other males are shut out entirely, banished from contributing--> ferocious competition within high-variance sex. -polygyny selects for risky strategies, including those that lead to violent combat with rivals and those that lead to increased risk taking to acquire the resources needed to attract member of the high-investing sex.

intersexual selection

(sexual selection) -members of one sex choose a mate based on their preferences for particular qualities. These characteristics evolve because those that possess them are chosen more often as maters, and their genes thrive. -animals that lack the desired characteristic are excluded from mating, and their genes perish.

intrasexual competition

(sexual selection) -members of the same sex compete with each other, and the outcome of their contest give the winner greater sexual access to members of the opposite sex. -the characteristics that lead to success in contest of this kind, such as greater strength, intelligence or attractiveness to allies, evolve because the victors are able to mate more often and hence pass their genes on.

sex differences in information-processing problems in some adaptive domains

-because fertilization occurs internally within the woman, men have faced the adaptive problem of uncertainty of paternity in their offspring--> men who failed to solve this problem risked investing resources in children who were no their own. -we are all descendants of a long line of ancestral men whose characteristics led to behave in ways that increased their likelihood of paternity and decreased the odds of investing in children who were presumed to be their but who genetic fathers were other men -women faced the problem of securing a reliable or replenishable supply of resouces to carry them through pregnancy and lactation, especially when food resources were scarce. --> we are all descendants of a long and unbroken line of women who successfully solved this adaptive challenge, by preferring mates who showed the ability to accrue resources and the willingness to channel them toward particualr women.--> women who failed to solve this problem failed to survive, imperiled the survival chances of their children, and failed to become our ancestors

heritable individual differences dependent on other traits

-evaluating ones personal strengths and weaknesses -ex. those that have a more musclare body build can more successfully carry out an aggressive strategy than those who are skinny or chubb.y -if human have evolved ways to evaluate themselves on their physical formidability, they can determine which social strategy is the more successful to pursue--an aggresive strategy or cooperative one -the combination of physical strength and physical attractiveness predicted the trait of extraversion--ex of how a personality trait can be contingent on other traits.

sex differences in agression

-humans apparently have a long evolutionary history of violence. -in all cultures men are overwhelmingly more often the killers, and most of their victims are other men. -in species in which females can bear only a small number of offspring (humans) females will express great care in their choice of amtes, and males will be forced to compete for access -men can have many more offspring than females -women who fear crime are especially more likely to prefer long-term mates who are aggressive and physically formidable. -males are more often the perpetrators of violence because they are the pdoducts of a long history of effective polygyny--> male strategies have been characterized by risky intrasexual competition for females or for the social status and resources that attract females -men die on average 5-7 years earlier than women --> aggressive and risk-taking intrasexual strategy

sex differences

-in other domains, men and women have faced substantially different adaptive problems: women have faced the problem of child birth, and therefore have evolved particular adaptions that are lacking in men

the big Five and evolutionary problems

-one approach views stable individual difference on the five-factor model as individual differences in "motivational reactions," or solutions to particular classes of adaptive problems. -Ex. Agreeableness reflect differences in the tendency to cooperate versus to act selfishly in conflicts over resources. -Emotional stability reflects differences in sensitivity to the adpative problem of social exclusion, high neuroticism can be beneficial in causing increased attentiveness to social danger but at a cost of increased stress and depression. -Extraversion reflects pursuit of a risk-taking social strategy marked by success in short-term mating versus adopting a more stable family life marked by long-term mating. -Conscientiousness reflects a long-term strategy of delayed gratification and tenacity of goal pursuit versus a more impulsive solution that involves grabbing immediate adaptive benefits. -heritable individual difference on these dimensions can be maintained in the population because different levels are adaptive under different conditions, the optimum level varies over time and space. -the Big Five was indeed closely linked with solutions to these critical adaptive problems. --> ex: in the context of romantic relationships, those who were high on Agreeableness, were also judged to be highly cooperative, devoted to their partners, and in love with their partners. -Ex: those high on extraversion were judged to be socially ascendent, taking leadership roles in the group and showing tendency to elevate themselves in social hierarchies. -Ex. People highly responsible and efficient (signs of Conscientiousness) were dependable in times of need, were well organized, and showed good potential for future earning. -It is reasonable to hypothesize that humans have evolved psychological sensitivities that are most relevant to solving critical social and adaptive problems --> problems that are ultimately linked to survival and reproduction

human nature

-psychological mechanisms that are successful in helping humans survive and reproduce tend to out-replicate those that are less successful. -over evolutionary time, these successful mechanism spread throughout the population and come to characterize a species -need to belong

sexual strategy being flexible

-responsive and flexible to aspects of the social situation -thus people shift int he restricted direction of sociosexual desire when they enter a new relationship and become more unrestricted again when they break up with an existing partner.

frequency-dependent (women mating strategies)

-some propose that human individual differences in women's mating strategies have been caused by frequency-dependent selection. -start with the observation that competition tends to be more intense among individuals who are pursuing the same mating strategy--> lays groundwork for the evolution of alternative strategies. -women's mating strategies should center on two key qualities of potential mates: the parental investment a man provides and quality of his genes. -a man who is able and willing to invest in a woman and her children can be an extraordinary valuable reproductive asset. -high-quality genes, which can be passed down to her children--> men may carry genes for good health, physical attractiveness or sexiness, which are then passed on to the woman's sons or daughters. -may be a trade off, between selecting a man for his parenting abilities and selecting a man for his genes--> men who are highly attractive to many women may be reluctant to commit to any one woman, thus a woman who is seeking a man for his genes may have to settle for a short-term sexual relationship without parental investment -The key idea clear idea behind frequency-dependent selection is that the success of each of the two strategies depends on how common each strategy is in the population--> as a given strategy becomes more common, it becomes less success; when it becomes less common, it becomes more successful.

sex differences in jealousy

-stems from the fact that fertilization occur internally and unseen within women-->means men have risked investing in children who were no their own. -from this perspective, a reproductively damaging act, from an ancestral man's point of view, would have been if his mate had had a pregnancy through sexual intercourse with another man.--> act that would have jeopardized his certainty of passing on his genes. -from an ancestral woman's point of view, the fact that her mate was having sex with another woman, would not jeoprodize her certainty in that she is the mother of her own children--> however risky to the woman's reproductive success: could risk losing her mate's resources, time, commitment, and investment all which could be diverted to another women. -men and women should differ in the weighting they give to cues the trigger jealousy: men have been predicted to become more jealous than women in responcse to cues to a sexual infidelity -women have been predicted to become more jealous than men in response to cue to the long-term diversion of a mate's commitment ex. men tented to interrogate partners more about the sexual aspects "did you have sex with him? whereas women interrogated their partners about the emotional aspects "Do you love her?"

frequency-dependent strategic individual differences

-the process of evolution tends to use up heritable variations, heritable variants that are more successful tend to replace those that less successful, resulting in species-typical adaptions that show little or no heritable variation. ex: the universal human design is two eyes. -in some context, two or more heritable variants can evolve within a population. ex biological sex itself. Within sexually reproducing species, the two sexes exist in roughly equal numbers because of frequency-dependent selection

psychopaths and evidence consitent with this theory of the evolution of this individual difference cluster

1. moderately heritable 2. psychopaths often pursue and exploitive sexual strategy, which could be the primary route by which genes for psychopathy increase or are maintained. Ex. psychopathic men tend to be more sexually forward, have sex with higher numbers of women and have more illegitimate children, and are more likely to get divorced if they get married. -this short-term exploitative sexual strategy would increase in populations marked by high geographic mobility in which the costs to reputation are muted. --> leads to alarming ideas that we many be witnessing an increase in psychopaths in modern times, as society becomes increasingly geographically mobile. -normal personality variation

groups serve several key adaptive functions for individuals

1. share food, info, and other resources 2. offer protection from external threat, or defense against rival 3. contain concentrations of mates, which are needed for reproduction 4. usually contain kin, which provide opportunities to receive altruism and to invest in genetic relatives -more intense the external threat, the greater the social bonding -when resources are linked with group membership, people become increasingly bonded with their groups

limitations of evolutionary psychology

1st. adaptions are forged over the long expanse of thousands of millions of generations, and we cannot go back in time and determine with absolute certainty what the precise selective forces on humans have beens. Scientist have inferences about past environments and past selection pressures. for ex: our fear of snakes and heights suggest that these were hazards in our evolutionary past, intense male sexual jealousy suggest that uncertain paternity was an adaptive problem in evolutionary past, the intense pain we feel on being ostracized from a group suggest that group membership was critical to survival and reproduction in our evolutionary past. 2nd: is that evolutionary scientist have just scratched the surface of understanding the nature, details and design features of evolved psychological adaptions. Ex. in case of jealousy, there is lack of knowledge about the range of cues that trigger it, and precise nature of the thoughts and emotions that are activated when a person is jealous, and the range of behaviors such a vigilance and violence that are manifest outcomes. 3rd: is that modern conditions are undoubtedly different from ancestral conditions in many respects, so that what was adaptive in the past might not be adaptive in the present. Ex. ancestral humans lived in smalls groups in the context of close extended kin, today we live in large cities with strangers, this it is important that selection pressure have changes--> humans can be said to live in the modern world with an ancient brain 4th: is is sometimes easy to come up with different and competing evolutionary hypothesis for the same phenomena. In this sense, the existence of competing theories is not an embarrassment but rather an essential element of science. The critical obligation of scientist is to render their hypotheses in a sufficiently precise manner so that specific empirical predictions can be derived from them--> the competing theories can be pitted against each other, and the hard hand of empirical evidence can be used to evaluate the competing theories. 5th: evolutionary hypotheses have sometimes been accused of being untestable and hence unfalsifiable. No doubt some evolutionary hypotheses have indeed been framed in ways that are too vague to be of much scientific value. The solution to this problem is to hold the same high scientific standards for all competing theories. To be scientifically useful, theories and hypotheses should be frames as precisely as possible, along with attendant predictions, so that empirical studies can be conducted to test their merits.

frequency-dependent selection

Within sexually reproducing species, the two sexes exist in roughly equal numbers because of frequency-dependent selection -if one sex become rare relative to the other, evolution will produce an increase in the number of rarer sex. -causes the frequency of men and women to remain roughly equal.

key domains in which the sexes have been predicted to differ

aggression, jealousy, desire for sexual variety, and mate preference

products of evolutionary process.

all humans are products of the evolutionary process, the descendants of a long line of ancestors who succeeded in surviving, reproducing and helping their genetic relatives. -the evolutionary process acts as a series of filters: in each generation only a small subset of genes passes through the filter.--> the recurrent filtering process lets only three things pass through: adaptions, by products of adaptions and noise, or random variation

individual differences

challenging, less of a foundation for adaptive individual differences. -most common is explaining individual differences as a result of environmental differences acting on human nature psycholical mechanisms. -all humans have essentially the same (callus-producing mechanisms) so individual differences are the result of environmental differences that activate the mechanisms to differing degrees. -individual differences in jealousy may be explained by difference in the degree to which individuals are exposed to evoking conditions (cues of infidelity) 2nd: individual difference can emerge from contingencies among traits: rather than the trait;s expression being contingent on the environment, its expression is contingent on other traits the person has like size and strength of one's body 3rd: frequency-dependent selection: the process whereby the reproductive success (fitness) of a trait depends on its frequency relative to other traits in the population 4th: the optimum level of a personality trait can vary over time and space. Ex Food, in times of food scarcity, selection favors a risk-taking personality traits, in times of food abundances, selection favors a more cautious personality dispositon to reduce the risk of venturing widely in the environment--> variations over time and space int he optimum level of a trait can create heritable individual difference in personality that are maintained in the population.

sexual selection

darwin's answer to the mystery of the peacock's tail and the stag's antlers was that they evolved because they contributed to an individual's mating success, providing an advandage in the competition for desirable mates. -the evolution of characteristics because of their mating benefits, rather than because of their survival benefits -takes two forms: intrasexual competion and intersexual selection

sex difference in mate preferences

differ in the qualities they desire in a long-term mate. -because women bear the burdens of the heavy obligatory parental investment, they are predicted to place more value on a potential mate's financial resouces and qualities that lead to such resources -men in contrast are predicted to place greater value on women's physical apperance, which provide cues to her fertility.

sex similarities

evolutionary psychology predicts that males and females will be the same or similar in domains in which the sexes have faced the same or similar adaptive problems. ex. both sexes have sweat glands, because both have faced the adaptive problem of thermal regulation, both have similar taste preferences for fat, sugar and salt because both sexes have faced similar food consumption problems.

environmental triggers of individual differences

ex. children who grow up with a father-absent home during the first five years of their life, develop expectations that parental resouces will not be reliably or predictably provided. --> adult pair bonds will not be enduring. -such individuals cultivate a sexual strategy marked by early sexual maturation, early sexual initiation, and frequent partner switching. --> larger number of offspring. (extraverted and impulsive personalities. -resources sought from brief sexual encouters are opportunistically attained and immediatly extracted. -in contrast, individuals who experience a reliable, investing fathering, develop a different set of expectiations about the nature and trustworthiness of others. People are seen as reliable and trustworth, and relationships are expected to be enduring. -->this environmental experience predispose individuals toward a long-term mating strategy, marked by a delated sexual maturation, later onset of sexual activity, a search for a long term, securely attached adult relationships, and heavy investment in kids. -men or women who are genetically pre-disposed to pursue a short-term mating strategy may be more likely to get divorced and pass on their children genes for that strategy.

noise or random evolutionary variable

random variations that are neutral with respect to selection. -neutral variations introduced into the gene pool through mutation, for example, are perpetuated over generations if they do not hinder the functioning of adaptions.

hallmark of adaption

special design -the features of an adaption are recognized as components of specialized problem-solving machinery. -Factors such as: efficiency, precision and reliability -adaptions are like keys that git only specific locks.

sexually dimorphic

species that show high variance in reproduction within one sex tend to be highly sexually dimorphic, highly different in size and structure. -the more intense the effective polygny, the more dimorphic the sexes are in size and form. -humans are mildly dimorphic, with males roughly 12 percent large than females, although some specific body are larger. -greater body size and strength in males is also likely due to a long history of females who select as mates males with these qualities.

sex differences in desire for sexual variety

stems from parental investment and sexual selection theory. -the members of the sex that invest less in offspring, are predicted to be less discriminating in their selection of mate and more inclined to seek multiple mates. -in ancestral time, men could increase their reproductive success by gaining sexual access to a variety of women. -the sex difference in the desire for sexual variety appears to be large and universal.

byproducts of adaptions

the evolutionary process also produces things that are not adaptions ex. lightbulb designed to produce light, but may also produce heat, not bc it is designed to produced heat, but as a consequence of design for light

inclusive fitness

the modern evolutionary theory based on differential gene reproduction -"inclusive": the fact that the characteristics that facilitate reproduction need not affect the personal production of offspring. They can affect the survival and reproduction of genetic relatives as well ex. if you take a personal risk to defend your sister or another close relative, then this might enable her to better survive and reproduce, because you share genes with your sister, then helping her survive and reproduce will also lead to successful gene reproduction -one's personal reproductive success plus the effects you have on the reproduction of your genetic relatives, weighted by the degree of genetic relatedness. -can lead to adaptions that incline you to take some risk for the welfare of your genetic relatives, but not too great a risk

natural selection

the process by which adaptions are created and change take place over time -Darwin noticed that species seemed to produce many more offspring than could possibly survive and reproduce --> reasoned that changes, or variants, that better enabled an organism to survive and reproduce would lead to more descendants--> the descendants would inherit the variants that led to their ancestors' survival and reproduction--> through this process the successful variants were selected and unsuccessful variants weeded out. -gradual change in a speciece over time, as successful variants increase in frequency and eventually spread throughout the gene pool, replacing less successful variants -overtime successful variants come to characterize the entire species; unsuccessful variants decrease in frequency and vanish from the species.

reactively heritable

the tendency toward aggression is not directly heritable, rather reactively heritable: it is a secondary consequence of heritable body build -physically stronger males are quicker to anger and are more likely to believe in the utility of warefare

premises of evolutionary psychology

three key premices: domain specificity, numerousness, and functionality