Nature/Nurture Quiz 1

Why Eugenics Almost Makes Sense

Breeding obviously works in both plants and animals We no longer believe that humans are fundamentally different than other animals We face terrible intractable problems of poverty, crime, inequality. These things are not independent of genes. Why not take control of our own evolution?

Breeding

Breeding works by selecting organisms at the extreme of a trait for reproduction Botanists have been breeding plants for millennia Breeding can be done without knowledge of scientific genetics And even with such knowledge, it can be done without "genes for" anything in particular.

Genetic Differences in Maze Learning Ability in Rats

Tryon (1942), Tolman (1924) Maze bright and maze dull rats Learning to navigate a T-maze Selective breeding As the generation continued the the smarter got smarter and the more dumb got dumber

Abnormalities of Twinning

Twins are generally born smaller and lighter Higher rates of abnormalities related to crowding 10-15% MZ twins are mirror images Most twins are never discovered because they die in utero Conjoined twins always MZ 1:100000 births, 1:400 twin births

Variance

standard deviation squared start by calculating the mean, or average, of your sample. Then, subtract the mean from each data point, and square the differences. Next, add up all of the squared differences. Finally, divide the sum by n minus 1, where n equals the total number of data points in your sample; you can also just divide by n

Animal Behavior Genetics

studying the nature/nurture question in animals and transferring this data to humans, or trying to point out similarities

Personal Genomics

the branch of genomics focused on sequencing individual genomes Now possible to obtain complete individual genetic sequence What can you learn?

negative correlation

the relationship between two variables in which one variable increases as the other variable decreases negative correlation coefficient

Topics in Behavior Genetics

Personality Mental illness Criminality and aggression Human intelligence Race Sex and Gender

Weinberg method

Probability says that DZ twins should be ½ same sex and ½ opposite sex. Twice the number of opposite sex twins should be total of DZ ???? Rest are MZ Not perfectly correct Occasional op-sex MZ Mistakes about who is MZ and DZ

Using Twins To Compute A C E A = Heritability

Proportion of difference that "comes from" genetic differences Always about DIFFERENCES

Twinning Around the World

Rate of MZ twinning fairly constant around world Rate of DZ twinning differs 6:1000 in Asia 15-1000 in Europe 40:1000 in Africa 26:1000 African-Americans In Nigeria, 1:11 people is a twin

Some Problems with Adoption Studies: Restriction of Range

Restriction of range is a statistical phenomenon that makes it hard to detect relations with variables that don't vary much What is the correlation between SAT and GPA at UVa? What is it at ODU? Biological parents of adopted children come from a very wide range of backgrounds, including very bad and very good But it isn't possible to adopt a child if you are poor, disabled or dysfunctional Therefore most middle class homes are middle-class or better the biological parents come from a wide range of backgrounds where as the adoptive parents are usually of a "better" range because you must be more fit to adopt a child

Historiometry Galton

Searched through biographical studies to count whether "eminent" men had more eminent relatives Showed that proportion of eminence dropped off as you went from first to second to third degree relatives Limitations of Historiometry Families provide environments as well as genetics Victorian England was highly stratified Obviously people from wealthier families would be more eminent and have the relatives of the same socio-economic status

Reading #1 Turkheimer, E. The Nature-Nurture Question.

Some aspects of behavior feels as though they originate in our genetic makeup Others feel our behavior is the result of our upbringing OR our own hard work The scientific field of behavioral genetics attempts to study these differences empirically The scientific methods invented to quantify this question are often inconclusive "Genes and environments always combine to produce behavior, and the real science is in the discovery of how they combine for a given behavior." Three related problems at the intersection of philosophy and science The mind body problem The free will problem Nature /nurture problem One of the major problems with answering this question is how do you set up an ethical experiment?

Studies of Sweet Peas Galton

Studied the weights of pea seeds Distributed a bunch of parent seeds, grew plants, and collected the daughter seeds Not all seeds are the same size. They were: Normally distributed Had constant variance Regressed to the mean, this caused an issue to his theory Concept of correlation

Davenport's Eugenic Creed

"I believe in striving to raise the human race to the highest plane of social organization, of cooperative work and of effective endeavor." "I believe that I am the trustee of the germ plasm that I carry; that this has been passed on to me through thousands of generations before me; and that I betray the trust if (that germ plasm being good) I so act as to jeopardize it, with its excellent possibilities, or, from motives of personal convenience, to unduly limit offspring." "I believe that, having made our choice in marriage carefully, we, the married pair, should seek to have 4 to 6 children in order that our carefully selected germ plasm shall be reproduced in adequate degree and that this preferred stock shall not be swamped by that less carefully selected." "I believe in such a selection of immigrants as shall not tend to adulterate our national germ plasm with socially unfit traits." "I believe in repressing my instincts when to follow them would injure the next generation."

Scatterplot

a graphed cluster of dots, each of which represents the values of two variables line of best fit "runs through" the scatter plot

The Iowa Studies of Skodak and Skeels

139 Children placed for adoption before the age of 6 months In Iowa in the 1930s and 1940s Poor Mothers, low education and low IQ Average IQ 85.7 Average education 10th grade Average occupation of fathers was laborer Adopted kids IQs between 100 and 116 Apparently an environmental effect On the other hand, adopted children's IQs correlated .31 with bio mothers, 0 with education of adopted parents

Sterilization Laws

1907 Indiana first state to pass compulsory sterilization law During next two decades 30 states pass sterilization laws Those in need of sterilization included "criminals, rapists, idiots, feeble-minded, imbeciles, lunatics, drunkards, drug fiends, epileptics, syphilitics, moral and sexual perverts, and diseased and degenerate persons" By 1924 3,000 people had been involuntarily sterilized Feebleminded, insane, criminalistic, epileptic, inebriate, diseased, blind, deaf; deformed; and dependent, including Orphans, ne'er do wells, tramps, the homeless and paupers Carrie Buck Sterilization in Virginia 7000 people eventually sterilized involuntarily

Separated Siblings. Schiff and Lewontin

20 pairs of Half Siblings One adopted, one raised by biological mother Selected for large differences in environment Adopted children had mean IQ of 108.9 (higher) Home children had a mean IQ of 94.6 (lower) BUT Correlation with occup of biological father is .34 (higher) Correlation with occup of adoptive father . 21 (lower)

Reading #3 Final Solutions Lerner, R. M

A Path to Mass Murder: Foundation of the Nazi Program of Genocide "National Socialism is nothing but applied biology." --Rudolph Hess Very rare for the entire society to have as the primary aim of its government, political, legal, educational and medical institutions, the application of a given approach to a specific area of science This broad subservience of an entire society to a particular view of biological science is precisely what occurred in Germany under the Nazi Regime Rudolf Hess, a leader in the Nazi party, believed Naziism to be nothing but applied science Biology represented the cornerstone of the state The core mission of the Nazis was to apply a view of the genetic determination of the superiority of the Nordic or Aryan race to the people of Europe, if not the entire world Required a unification and subordination, Gleichschaltung Needed coordination to accomplish this goal Primacy of national biology over national economy Biology and politics became completely merged Hitler believed the laws of nature demanded inequality, hierarchy, and subordination in inferior forms to superior ones But human history can be viewed as a series of revolts against this kind of authority This lead to egalitarianism and threatened the biological integrity of the superior people of a nation A stronger race will drive out the weak because this happens in nature, the weak die off and the strong prevail The Nazi's biological world view was based on one idea: The german volk (people) were, across evolution, naturally selected to possess genes of leadership in and mastery of the world The union of a group of people with transcendental essence (volk) Nazi's adopted a tradition in german biological and medical science which placed the genes of the german volk at the basis of salvation of humanity made necessary by the threat of genetic pollution--miscegenation with genes from subhuman or nonhuman populations The German Racial Hygiene Movement Race was the criterion of value within a society, serve the race not protect individual rights Existing social policies were interfering with the advancement of the race Society had programs that amounted to the "negative social selections" caused by the social termination of the forces of natural selection--misguided humanitarian action was endangering the quality of the race by allowing the survival of weaker members Domesticated induced degeneracy--induced by society's termination of natural selection Racial degeneration due to wars and revolutions kills off the strong, fit, white men Medical solution to poor people producing too many children Do not give medical care to the inferior, the physician should serve the entire race Delaying support for the poor until they are past child bearing age and withholding medical care from the weak New forms of human breeding, only let the superior reproduce A positive social selection, new social program must put humans back on track toward natural selection Danger that the poorly fit would reproduce at a higher rate than the fit Allow the people who would die off without social institutions to do so

Positive correlation

A correlation where as one variable increases, the other also increases, or as one decreases so does the other. Both variables move in the same direction. positive correlation coefficient the closer the r value is to one, the better the regression line fits the set of data and the more high correlated the two variables are; whether a negative or positive trend

Regression line OR the line of best fit

A straight line that describes how a response variable y changes as an explanatory variable x changes y=mx+b shows the trend of the data half the data points on one side, half on the other

Analyzing Twin Studies Sources of Variance

A--variability coming from additive effect of genes C--variability coming from being raised in the same family E--individual variability, random variability Why are MZ Twins Similar? They share all their genes and their family environment A + C Why are DZ Twins Similar? They share half their genes and their family environment ½ A + C Using Twins To Compute A C E rMZ = A + C rDZ = ½ A + C A = 2 (rMZ -rDZ) C = 2(rDZ) - rMZ E = 1 - (A + C) A + C + E = 1 r=correlation coefficient Example rMZ=.7, rDZ=.5 A = 2*(.7-.5) = .4 C = 2*.5 - .7 = .3 E = 1 - .7 = .3

Twin studies

Another option in observing nature vs. nurture in humans There are two types of twins: monozygotic (MZ) and dizygotic (DZ). Monozygotic twins, also called "identical" twins, result from a single zygote (fertilized egg) and have the same DNA. They are essentially clones. Dizygotic twins, also known as "fraternal" twins, develop from two zygotes and share 50% of their DNA. To analyze the nature-nurture question using twins, we compare the similarity of MZ and to DZ pairs

Analyzing Twin Studies Variance

Basic concept in psychology Mean Arithmetic average Variance Differences around a mean Measure of a spread of a distribution of scores from a study compared to the normal distribution of the population at large So variables that differ among people have a mean and a variance Where Does Variance Come From? Think about height in males and females Why do individual people differ in height? Reason 1: Men are taller than women Reason 2: Individual men and women differ from each other Proportion of Variance Suppose male and female height were the same Then "Gender" would contribute 0% of variance Suppose all men and all women were the same height, but men and women differed Then "Gender" would be the only reason individuals differed and would contribute 100% of the variance In the actual world, it is in between This proportion, 0-1, is called a correlation How much more alike would everyone be if we were all the same gender? You can do the same thing with twin pairs Suppose you have a bunch of identical twin pairs If MZ twins are the same height as their co-twin But some pairs are taller than other pairs Then all height variance comes from the pairing Suppose you have a bunch of identical twin pairs If all pairs have the same average height But one twin is taller than the other Then 0 height variance comes from the pairing In reality, the MZ twin correlation for height is about .9 90% of the height variance is BETWEEN pairs 10% of the height variance is WITHIN pairs

Behavior Genetics, Psychology and Biology

Bottom up vs Top down explanations of complex human behavior Why do people get depressed? "chemical imbalance" (biology) problems in living and ways of thinking (psychology)

Karl Pearson

Chi-square test of goodness of fit; Correlation coefficient; Applied statistics Student and successor to Galton Mathematical statistician Proponent of eugenics "Improvement in social conditions will not compensate for a bad hereditary influence. The only way to keep a nation strong mentally and physically is to see to it that each new generation is derived chiefly from the fitter members of the generation before." Increasingly concerned with "dysgenics" Idea that lower classes or less intelligent had more children Therefore the "genetic quality" of the population would decrease "No training or education can create intelligence, you must breed it." He privately asserted to Galton that charities for the children of the "incapables" were "a national curse and not a blessing." In his opinion, such measures as the minimum wage, the eight-hour day, free medical advice, and reductions in infant mortality encouraged an increase in unemployables, degenerates, and physical and mental weaklings. Natural selection, he believed, had been suspended, and replaced by "reproductive selection," which gave the battle "to the most fertile, not the most fit.

Summary of Adoption Studies of Intelligence

Children "rescued" from poorer environments have higher IQs than their biological mothers or non-adopted siblings This seems like nurture IQs of children are better predicted by their biological parents than their adoptive parents This seems like nature Often both these results occur in the same study, contradicting What Could be going on? Environment Either Changes IQ or It Doesn't One reason the threshold in-between biological and adoptive homes Another Reason Mean difference captures ALL the environmental advantages that an adopted kid experiences Parental education or SES as a predictor only captures part of the advantage.

Very Simple Behavior, Animals

Common disease in bees called American foulbrood Bacillus attacks and kills larvae in cells Resistant bees uncap the cells with the dead larvae and push them out of nest (hygienic) Susceptible bees don't do it. Turns out to be under control of two genes: One for uncapping the cells One for pushing from nest

Individual Differences Psychology

Concept of variation Height Fingerprints Facial appearance Psychological characteristics Statistical approaches to variation Correlation and regression

Parenting

Does it matter how we raise our children?

naturalist fallacy

Drawing a conclusion about what ought to be, based (in substance) only on what is this fallacy occurs when one argues that by observing what is the case (what someone sees on a day to day basis) one can know what should be the case Just because social relationships, laws and customs exists does not mean they ought to exist

The Implications of Genetics for Human Society

Easy to forget how modern and how revolutionary evolution and genetics are. eg Thomas Jefferson, a botanist, had no conception of either one In the 1800s it was still common for people to think that humans were special, created in the image of God (literally). My grandfather was born before Darwin died DNA was discovered the year I was born

Harry Laughlin

Established Eugenics Record Office in Cold Spring Harbor, NY Developed Model Sterilization Law Testified against immigration in US Congress Guided development of Virginia Racial Integrity Act Later became prominent Nazi sympathizer Americans held a Nazi Rally in Madison Square Garden, 1939 American gene pool is being polluted by a rising tide of intellectually and morally defective immigrants Immigration Restriction Act of 1924--a United States federal law that prevented immigration from Asia, set quotas on the number of immigrants from the Eastern Hemisphere, and provided funding and an enforcement mechanism to carry out the longstanding ban on other immigrants. Restricted "dysgenic" southern Europeans and Jews Calvin Coolidge: "America must remain American"

Using Twins To Compute A C E E = Nonshared Environment individual variability, random variability

Everything else How much people vary AFTER considering genes and families Variation among MZ twins reared together

What have we learned about Nature vs. Nurture?

Everything has turned out to have some footing in genetics. The more genetically-related people are, the more similar they are—for everything: height, weight, intelligence, personality, mental illness, etc. While certain psychological traits, such as personality or mental illness (e.g., schizophrenia), seem reasonably influenced by genetics, it turns out that the same is true for political attitudes, how much television people watch and whether or not they get divorced

Regression to the Mean Created a Problem Galton

Fathers over 6' 5" have sons who are shorter than them Fathers under 5' 5" have sons who are taller than them If extreme groups tended to regress to the mean, what could keep eminent populations eminent? We must have to intervene to ensure that evolution is not "dysgenic"--exerting a detrimental effect on later generations through the inheritance of undesirable characteristics eugenics is the self direction of human evolution "like a tree eugenics draws its materials from many sources and organizes them into a harmonious entity"

Curtis Merriman (1924) Psychological Monographs The Intellectual Resemblance of Twins

First quasi-modern twin study of intelligence Used the Stanford-Binet IQ test Found correlations around .9 for IQ scores and teacher ratings the first descriptions of the twin method appeared in this article by Curtis Merriman 50 years after Galton's paper

Sir Francis Galton (1822-1911) "Hereditary Genius, An Inquiry into its Laws and Consequences" 1892

First to use stats in psych (created correlation coefficient), used Darwinian principles to promote eugenics Born Feb 16, 1822 Wealthy family, didn't need to work Half-cousin of Charles Darwin Child prodigy Explorer In 1840s, traveled down Nile to Sudan Produced some of the first European maps of Africa Produced anthropological studies Created first weather map Founder of psychometrics Strongly influenced by The Origin of Species in 1959 First person to undertake systematic study of fingerprints Proposed twin and adoption studies Development of Statistics The idea that you could study human beings or even biology empirically was novel The concept of variation The normal curve Correlation and regression Galton wasn't wrong There are no "genes for" complex human traits But neither is it the case that human behavior is completely independent of genetics

The genetic impact on behavior is broken up over many genes, each with very small effects.

For most behavioral traits, the effects are so small and distributed across so many genes that we have not been able to catalog them in a meaningful way. The same is true of environmental effects. We know that extreme environmental hardship causes catastrophic effects for many behavioral outcomes, but fortunately extreme environmental hardship is very rare. Within the normal range of environmental events, those responsible for differences (e.g., why some children in a suburban third-grade classroom perform better than others) are much more difficult to grasp. One of the most important things modern genetics has taught us is that almost all human behavior is too complex to be nailed down, even from the most complete genetic information, unless we're looking at identical twins.

Galton and Twins 1875 article on twins

Galton mentioned twins in English Men of Science But since he didn't understand genetics per se, he didn't recognize two kinds Though obviously same and op-sex Used twins in a different way than they are usually used today Assumed that they are somehow similar genetically, studied how they become different environmentally Galton did not propose the comparison between identical and fraternal twin resemblance which is the essence of the twin method

Reading #2 In the Name of Eugenics: Genetics and the Uses of Human Heredity Francis Galton

Galton's conclusion--race improvement could only occur when nature provided a distinct and heritable organic change Here natural selection is acting on ability He insisted that human beings could at least hope to achieve eugenic improvement indirectly "We may not be able to originate but we can guide" "The processes of evolution are in constant and spontaneous activity, some towards bad and some towards good. Our part is to watch for opportunities to intervene by checking the former and giving free play to the latter" For hereditary data, he compared the seeds from a parental generation of a sweet pea plant with those from its progeny Established an Anthropometric Laboratory at the International Health Exhibition, opened in 1884 Within a few months, 9000 people (parents and grown children) were measured for height, weight, arm span, breathing and more He also published the Record of Family Faculties--a questionnaire on heredity and offered prizes of up to five hundred pounds for the most detailed set of data 1876, sweet pea data: each group of parental seeds of the same weight produced a family of daughter seeds in which the weights were distributed around a mean in Gaussian fashion No matter the weight of the parent seeds, the distributions had the same statistical variability The same proportion of seeds could be found on the bell curve within a given distance from the family mean He then concluded that the laws governing heredity whether of men or sweet peas could be treated mathematically in terms of units of statistical deviation First published his eugenics idea in 1865 Hereditary Genius, 1869 Investigate the origins of natural ability Those qualifications of intellect and disposition which led to reputation Drew on a sample population, spanning to centuries, of distinguished statesman, jurists, military commanders, scientists, poets, painters etc A disproportionately large amount of them were related, blood relatives Families of reputation were much more likely than ordinary families to produce offspring of "ability" Heredity governed not only physical features but also talent and character Quite predictable to produce a highly gifted race of men by arranged marriages and consecutive generations The state should support the spawning of numerous eugenically golden offspring The unworthy would be comfortably segregated into monasteries and convents where they would be unable to propagate their kind Reputation indicated ability The lack of this bespoke the absence of ability Neither outcome depended on social circumstance High reputation could not be won by social advantage alone Talent was rarely impaired by social disadvantage, meaning if you were "able" due to good genes you could rise aside from your social circumstances hindering advancement He brushed aside the idea that without social advantage professional men of moderate ability might not have gotten as far as they did Without social hindrance, those with high ability might have travelled a good deal farther

How "genetic" is a trait?

Heritability coefficients between 0 and 1, provides a numerical value that indicates how strongly a trait is related to genetics example of something that should make sense; for example height is more "genetic" than weight the harder you look the less sense this characteristic makes

Using Twins To Compute A C E C = Shared Environment

How much of our difference comes from being raised in separate families?

Discrete and Continuous Genetics

Mendel, who had not been re-discovered in Darwin's time, studied discrete characteristics of peas. Smooth vs, wrinkled. Modern genetics is based on the idea that genes are discrete. But then how does height work? Height is not discrete. Mixed tall and short parents have middling children.

Marriage Laws

In 1915 28 states had laws against interracial marriage Miscegenation Lots of pseudo-scientific beliefs about pure races, mongrels, etc Modern-ish racist ideas about "racial suicide" Virginia Racial Integrity Act (1924) a white person could not marry a non white person, native americans were an exception a white person was only white if he or she was a purebred and not mixed with any other race; the 1/16 rule of blood

Nazi Eugenics

In 1927, Rockefeller Foundation provided funds for the Kaiser Wilhelm Institute for Anthropology, Human Heredity and Race Hygiene Hitler read Fischer's Principles of Human Heredity and Race Hygiene First Nazi eugenics law was modeled on American Law Harry Laughlin given honorary degree in Heidelberg in 1935 By 1939 400,000 people had been involuntarily sterilized 70,000 mental patients were gassed

The Inequality Problem

In some ways, our thinking may need to change—for example, when we consider the meaning behind the fundamental American principle that all men are created equal. Human beings differ, and like all evolved organisms they differ genetically. We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness. Is this true? Why are some people poor? Is it their fault (they are stupid, lazy) or society's fault (they are oppressed)? Is this a question that can be asked scientifically?

Some Problems with Adoption Studies: Selective Placement

In the real world, adoption is not conducted at random Children are (or were) "placed" in adoptive homes Often children were "matched" by ethnicity or social class So children of well-off biological parents were placed with well-off adoptive parents This can be corrected for statistically, to some extent

Two Aspects of Adoption Studies

Individual differences What is a better predictor of adopted child's outcome, biological parents or adoptive parents? Depends on having differences among families, especially in adoptive families Group differences Differences in average outcome in adopted children compared to either Biological parents (usually mothers) Non-adopted siblings

Ethics and Freedom

Is Sexual Orientation Genetic Does the Genetics of Sexual Orientation say something about the ethics and legality?

Why Eugenics Was Popular

It was especially popular among liberals A scientific explanation of poverty seemed superior to a moral one Changes in sexual mores Hope for social improvement Seductiveness of the idea that science could be applied to the human condition--suffering Eugenics Becomes Popular "Family Hygiene" booths at state fair Fitter families contests Family planning Early days of contraception Kellogg- Race Betterment Foundation Galton society Race differences Control of human breeding 1928: 376 college courses on eugenics

Sterilization at UVa

Jordan Hall renamed Pinn Hall previously named over prominent eugenicist J. H. Bell, Superintendent of the Virginia Colony in Lynchburg (Virginia State Colony for Epileptics and Feebleminded)-- had been established in order to separate the disabled from criminal populations, for example, many of the first inhabitants of the Virginia State Colony had previously been housed in prisons and state hospitals "The fact that a great state like the German Republic, which for many centuries has helped furnish the best that science has bred, has in its wisdom seen fit to enact a national eugenic legislative act providing for the sterilization of hereditarily defective persons seems to point the way for an eventual worldwide adoption of this idea."

More Recent Examples

Kendler, Turkheimer et al. (2014) Swedish "population" study 436 Pairs of separated full siblings (brothers) 2,341 separated half-brothers Adopted brothers had IQs 4.4 points higher Adopted half-brothers 3.2 points higher Each additional year of bio and adoptive parent education in school is associated with about 1-2 IQ points in offspring Correlations in expected direction, but not enough to explain increase Difference between twins as a function of difference in environment because they are the same genetically

Social Origins of Eugenics

Late 19th Century was a time of great upheaval Industrial revolution, capitalism Increasing democratization Labor unions Immigration End of traditional aristocracies Aristocracy as a kind of environmental heredity wanted to give others in society who were "fit" for status and power the chance to achieve this; those of royalty or considered noble sometimes failed in ruling therefore the environment in which one is raised (the royal family) does not always produce the best fit individual(s) Failure of traditional social approaches to poverty Eugenics seemed democratic.

Zygosity

MZ Arise from a single fertilized egg All same sex Clones DZ Arise from two eggs fertilized by two sperm Siblings, same sex and opposite sex

Twins Reared Apart

MZ or DZ twins separated from each other shortly after birth; such twins share genetic material but not specific environmental influences Occasionally, in the normal course of events, twins are separated at birth Mostly adoption, which is increasingly rare In some ways, twins reared apart are the purest form of twin study They don't share an environment But the rarity of separated twins makes them less useful scientifically You hear lots of stories about using the same toothpaste, etc, but these are probably coincidental Minnesota Study of Twins Reared Apart (MISTRA)

Genetic influence on behavior is a relatively recent discovery

Middle of the 20th century, psychology was dominated by the doctrine of behaviorism, which held that behavior could only be explained in terms of environmental factors. Psychiatry concentrated on psychoanalysis, which probed for roots of behavior in individuals' early life-histories. The truth is, neither behaviorism nor psychoanalysis is incompatible with genetic influences on behavior, and neither Freud nor Skinner was naive about the importance of organic processes in behavior. The basic fact that the best predictors of an adopted child's personality or mental health are found in the biological parents he or she has never met, rather than in the adoptive parents who raised him or her, presents a significant challenge to purely environmental explanations of personality or psychopathology. You can't leave genes out of the equation. But keep in mind, no behavioral traits are completely inherited, so you can't leave the environment out altogether, either. When your subjects are biologically-related, no matter how clearly a situation may seem to point to environmental influence, it is never safe to interpret a behavior as wholly the result of nurture without further evidence. This is a case where "correlation does not imply causation". The most disappointing outcome has been the inability to organize traits from more- to less-genetic. As noted earlier, everything has turned out to be at least somewhat heritable (passed down), yet nothing has turned out to be absolutely heritable, and there hasn't been much consistency as to which traits are more heritable and which are less heritable

Loving vs. Virginia (1967) US Supreme Court Case

Mildred Jeter (Black) and Richard Loving (White) were married in DC Moved to VA Indicted under Racial Integrity Act Sentenced to year in jail, suspended, on condition they leave state for 25 years; could return to or live in VA OVERTURNED a landmark decision of the U.S. Supreme Court that struck down all state laws banning interracial marriage as violations of the Equal Protection and Due Process Clauses of the Fourteenth Amendment to the U.S. Constitution. The decision was followed by an increase in interracial marriages in the U.S. and is remembered annually on Loving Day.

Immigration

Naturalization law of 1790-- provided the first rules to be followed by the United States in the granting of national citizenship. This law limited naturalization to immigrants who were "free white persons ... of good character". It thus excluded Native Americans, indentured servants, slaves, free blacks and later Asians. 1882 Act to Regulate Immigration (1) a United States federal law. It imposed a head tax on noncitizens of the United States who came to American ports and restricted certain classes of people from immigrating to America, including criminals, the insane, or "any person unable to take care of him or herself. (2) Chinese Exclusion Act--a United States federal law signed by President Chester A. Arthur on May 6, 1882, prohibiting all immigration of Chinese laborers. Building on the 1875 Page Act, which banned Chinese women from immigrating to the United States, the Chinese Exclusion Act was the first law implemented to prevent all members of a specific ethnic or national group from immigrating Opposition to Immigration Believed immigrants would take American jobs Immigrants had lower IQs 1.25 million immigrants in 1907 Ellis Island stations to detect "hereditary defectives"

Sex and Gender One of the main topics of behavior genetics

Not exactly "genetic" in the same sense But many of the same issues Obviously there are biological differences between the sexes And it wouldn't be surprising for those differences to be related to behavioral differences But are those differences fixed? How? Should we try to change them?

Cross-Fostering offspring are removed from their biological parents at birth and raised by surrogates

Not really Capron and Duyme (1989) identified adopted children in four groups High bio parent education, high adoptive parent education (119.6) Low bio parent education, low adoptive parent education (92.4) Low bio, hi adoptive (103.6) Hi bio, low adoptive (107.5)

Intelligence One of the main topics of behavior genetics

One of the great questions of human psychology Why are some people smarter than others? Can we measure intelligence? Nature-nurture, etc The Bell Curve, in comparison to others

DZ Twinning

Opposite of MZ twins most animals are polyovulatory and produce multiples, puppies and kittens Only other animal that produces MZ twins is the armadillo Rates of DZ twinning were declining (better nutrition and increasing maternal age) But lately have been increasing In vitro fertilization Rate of DZ twinning varies with sunlight Rate of DZ twinning runs in families

19th Century Genetics 19th Century Classism / Racism

Origin of Species was published in 1859 But Origin of Species was about evolution, not genetics. Mendel was doing his work with peas in obscurity People had a folk conception of familial similarity, but no idea of mechanism DNA not discovered for 100 years It was accepted among upper class Europeans that they were superior To lower-class Europeans To other races And that races were real and biological And that men were superior to women

Chorion

Outermost layer of the two membranes surrounding the embryo; it forms the fetal part of the placenta Placental membranes begin to form early in development (day 4) MZ pairs are either monochorionic (75%) or dichorionic (25%) All DZ twins are dichorionic

Proceedings of the First National Conference on Race Betterment

The Race Betterment Foundation was founded in 1911 in Battle Creek, Michigan with money from the Kellogg cereal fortune. The Foundation sponsored three national conferences on race betterment (1914, 1915, and 1928) and started its own eugenics registry. The Galton Society, founded in New York City in 1918, was the most overtly racist of the American eugenics organizations. Its members used physical anthropology to confirm their bigoted notions about the supposed superiority of the Nordic race. "Under the present estimate it would be necessary to sterilize during this period approximately 15,000,000 persons-beginning with 92,400 per year in 1915 and increasing to 415,000 per year by 1980."

gene-environment interaction

The heritability of a trait is not simply a property of that trait, but a property of the trait in a particular context of relevant genes and environmental factors. Turns out to be the case that, for many traits, genetic differences affect behavior under some environmental circumstances but not others—a phenomenon called gene-environment interaction, or G x E In one well-known example, Caspi et al. (2002) showed that among maltreated children, those who carried a particular allele of the MAOA gene showed a predisposition to violence and antisocial behavior, while those with other alleles did not. However in children who had not been maltreated, the gene had no effect. Being maltreated in a sense activated the predisposition towards violence

Adoption Studies

The most direct way to separate genetic and environmental influences on an outcome In "full" adoption design. You have scores on biological parents, adoptive parents and adopted children. Might also have non-adopted siblings of adopted children, or biological children of adopted parents Adoption studies are less common now because American-based adoption has gotten rarer Biological parents generally not available for foreign adoptions

Mean or Average

The sum (+) of all data divided by the number of data points

Reading #4 Who discovered the twin method?

The twin method is usually credited to Francis Galton's 1875 article on twins however Galton did not propose the comparison between identical and fraternal twins which is the essence of the twin method Although the twin method was in the air in the mid 1920s, the first descriptions of the method appeared in an article by Curtis Merriman and in a book by Herman Siemens, both in 1924 50 years following Galton's paper Francis Galton and Twins The discovery of the twin method is usually accorded to Galton's 1875 article entitled the "The History of Twins, as a Criterion of the Relative Powers of Nature and Nurture" Test the power of the environment to change twins, to make initially similar twins different and to make initially different twins similar He did not propose that the resemblance of identical twins be compared to the resemblance of fraternal pairs to assess genetic influence Galton proposed to study nonshared environmental factors in adulthood by following the life history of identical twins after leaving their families He concluded that nature prevails enormously over nurture He was aware of the two types of twins, acknowledged one egg and two egg twins; close similarity and great dissimilarity In summary Galton's delight in discovering twins was to assess the ability of the environment to make initially similar twins different and to make initially different twins similar He thought that all of the twins, similar and dissimilar were one egg or identical twins Not correct to claim that Galton proposed the twin method E.L. Thorndike No other studies of twin resemblance were published until 1905, since Galton's publication in 1875 E.L. Thorndike, learning psychologist famous for his work on trial and error learning Reported twin resemblance for younger and older twins on a battery of cognitive tests He DID NOT compare identical and fraternal twins Together with R.A. Fisher he was a leading proponent of the view that there were NOT two kinds of twins He extended Galton's twin research by using objective tests of cognitive abilities and by formulating additional tests of environmental effects He attributed performance on these tasks to hereditary influence because he found that twins do not grow more similar during childhood and that twins do not resemble each other more for the tasks Curtis Meriman's Nearly 20 years after Thorndike's twin study and 50 years after Galton's published article, a twin study published in Psychological Monographs provides what appears to be the first explicit description of the twin method (1924): "Since the two distinct species theory is more widely accepted, let us assume that it is the correct theory and then list the principle claims that it makes and the results should follow..." (1) There are two distinct groups, fraternal and identical (2) The fraternal being of the two egg origin should know no greater resemblance than ordinary siblings, because they develop differently from two separate eggs in gestation (3) The duplicate, being of one egg origin, should show a very much higher degree of resemblance than the fraternal because each member of the pair develops from the same egg He was the first to apply the Stanford-Binet IQ test and the group administered Army Beta test to this type of research He was also concerned about sampling issues and took pains to test all twins in a given school that agreed closely with the observed frequency of the entire population His study also used physical similarity to identify same sex twins who are identical, because they could be fraternal All identical twins are the same sex but fraternal can be either both or different However, he did not identify a group of fraternal twins and thus he did not compare identical twin correlations to fraternal twin correlations Herman Siemens During the same year that Merriman's article appeared in America, a book published in Germany provided the first explicit description of the twin method A dermatologist, proposed that hereditary influence on features such as skin disorders could be assessed by comparing the occurrence of the feature in identical twins with the occurrence in fraternal twins Although the emphasis of his book were skin disorders, psychological features were also examined He argues that the comparison of identical and fraternal twins can be used to assess hereditary influence on features which are not totally determined by heredity

Individual Differences and Species Typical Traits

Two basic ways to think about the science of human behavior Species typical--why humans in general are the way they are why are we social beings? why and how are people intelligent? Individual differences--why humans differ from each other why can some people hear better than others? why are some people more social than others? why are some people more social than others?

Why is Eugenics Wrong?

Two broad reasons why eugenics is wrong: (1) Political reasons. Civil liberties, racism. (2) Scientific reasons This is the hard one Many sources say, well the eugenicists were wrong that genes had anything to do with complex behavior--But this isn't right Rest of course is about how understanding relationship between genes and behavior in HUMANS that helps us understand why eugenics is wrong scientifically

Biology of Twinning

Two kinds of twins MZ, (monozygotic) genetically identical DZ, (dizygotic) ordinary siblings, 50% identical About 1 in 80 live births are twins About 1 in 40 babies are twins

Charles Davenport (1866-1944)

US Cold Spring Harbor Eugenics Record Office Biological Laboratory Experimental Evolution Some basic studies of eye color and stature Mendelian Required pedigrees Moved on to personality and intelligence "Shiftlessness" Davenport and Race As always, race was a particularly American obsession Slavery and immigration Davenport equated national and "racial" identity, and assumed as well that race determined behavior. He held that the Poles, the Irish, the Italians, and other national groups were all biologically different races; so, in his lexicon, were the "Hebrews." Davenport found the Poles "independent and self-reliant though clannish"; the Italians tending to '"crimes of personal violence".........

Carrie Buck Trial Buck vs Bell (1927)

Upheld in Virginia courts Judge ruled she should be sterilized Taken to Supreme Court Oliver Wendell Holmes (was an American jurist who served as an Associate Justice of the Supreme Court of the United States from 1902 to 1932, and as Acting Chief Justice of the United States in January-February 1930) "It is better for all the world, if instead of waiting to execute degenerate offspring for crime or to let them starve for their imbecility, society can prevent those who are manifestly unfit from continuing their kind... Three generations of imbeciles are enough" Decision has never been overturned

Using Twins To Compute A C E Facts About Heritability

Varies from 0 to 1 Not a fixed characteristic of a trait Describes a trait in a population Depends on variance of A and E A = Heritability E=individual variability, random variability Heritability of having two arms is 0, this is not varied, every human has two arms no matter how different your genes are (unless a defect or environmental accident) Not really a good measure of "how genetic" something is Not an indication of malleability Phenylketonuria

Late Nineteenth Century Sexuality Changes in sexual mores

Was a time of loosening of sexual traditions Feminism Freud Contraception Idea that sex was: To be enjoyed, especially by women Not solely a means of reproduction A part of the system through which human characteristics were transmitted contributed to the growth in approval/popularity of the idea of eugenics

Evaluating Eugenics

What do you make of the proposition that "All Men Are Created Equal"? Is it literally true? Does genetics have something to say? What is the correct attitude toward racist people from the 19th Century? What are some problems with eugenics? Is it ever justified?

Race

What exactly does "race" mean biologically, genetically and socially is a very difficult problem Kind of like sex, races differ biologically Though in very different ways Obviously races/cultures differ in behavior Is any of that fixed by genetics and biology?

Ethics and Responsibility

When are we morally responsible for our behavior? Presumably people who carry a genetic defect are not responsible for the consequences But what if aggression is "genetic" in a more general way?

Psychiatric Genetics

Why are some people depressed? Is it a genetic disorder of the brain? Treated with drugs (biological) Or a problem in living? Freud and psychoanalysis Skinner and behaviorism Modern cognitive behavior therapy (psychology)

Herman Siemanns (1924)

a German dermatologist who first described multiple skin diseases and was one of the inventors of the twin study. Siemens' work in twin studies is influential in modern genetics and is used to address the environmental and genetic impacts upon traits. Siemens was involved in racial hygiene and affiliated with the Nazi Party the first descriptions of the twin method appeared in a book he wrote concerning his work studying skin diseases and birthmarks in twins, 50 years after Galton's paper

Genetic architecture

a description of all the genetic and environmental factors that influence a trait One often hears talk about a "gene for" depression or intelligence or whatever. In fact it has turned out that there isn't a "gene for" anything Yet most human traits are in some sense "genetic" Single gene disorders vs polygenic traits.

Minnesota Study of Twins Reared Apart (MISTRA)

a longitudinal research project headed by Thomas Bouchard, in which twins were studied over a period of years to learn about genetic and environmental influences on behavior.

Adoption study

analysis of how traits vary in individuals raised apart from their biological relatives When children are put up for adoption, the parents who give birth to them are no longer the parents who raise them easiest opportunity we have to observe the nature/nurture question

The Nature-Nurture Problem

are people different because they are born that way? no necessarily genetic OR because their environment makes them that way? not necessarily entirely how they were raised self determination, free will for example

How malleable is a trait? Genetics and Malleability

can we make ourselves taller, thinner smarter, more extraverted or change our sexual orientation? how much of this is set in stone at a certain baseline and how much do we have the autonomy to change? Seems reasonable to think that highly genetic traits are less malleable more complex than this assumption Consider phenylketonuria Completely genetic, single gene disorder treatment is completely environmental Phenylketonuria is an inborn error of metabolism caused by a single gene; it prevents the body from metabolizing phenylalanine. Untreated, it causes mental retardation and death. But it can be treated effectively by a straightforward environmental intervention: avoiding foods containing phenylalanine.

Bell Curve

distribution of scores in which the bulk of the scores fall toward the middle, with progressively fewer scores toward the "tails" or extremes 34.1%, 13.6%, 2.1% and 0.1% Z scores on the x axis, number that indicates how many SD a raw score is away from the mean SD go in both the positive and negative direction

Lower animals and humans

problems of behavior genetics are much easier in lower animals dogs are bred for behavioral characteristics methodological issues psychological issues Methodological Problems Most of the time, parents raise their own biological children They provide them with both genes and environment Therefore, correlations between parental behavior and child behavior are not necessarily causal and environmental because genes passed down can also play a role A lot of BG involves finding ways around this problem--twin studies, adoption studies, the study of lower animals

Eugenics Galton invented the term

science dealing with improving hereditary qualities One idea that occurs to people from time to time is that maybe we can use behavior genetics to improve ourselves Genetic counseling But what of preventing the mentally ill or low-IQ from reproducing Or what of rewarding high-IQ people for reproducing? Basic idea that goes along with human genetics If we accept that human characteristics are influenced by genes Then shouldn't we do something to enhance the characteristics that we want?

quantitative genetics

the study of continuous phenotypic traits and their underlying evolutionary mechanisms the scientific discipline in which similarities among individuals are analyzed based on how biologically related they are Twin and adoption studies are two instances of a much broader class of methods for observing nature vs nurture called quantitative genetics Contentions about nature-nurture have intensified because quantitative genetics produces a number called a heritability coefficient

Epigenetics

the study of environmental influences on gene expression that occur without a DNA change a process in which the DNA itself is modified by environmental events, and those genetic changes transmitted to children Height seems like a trait firmly rooted in our nature and unchangeable, but the average height of many populations in Asia and Europe has increased significantly in the past 100 years, due to changes in diet and the alleviation of poverty.

Behavior Genetics

the study of the relative power and limits of genetic and environmental influences on behavior the science of how genes and environments work together to influence behavior Basically the study of how human behavior is influenced by genes. One of the great intellectual problems of human existence Free will problem Mind body problem

heritability coefficient

varying from 0 to 1, that is meant to provide a single measure of genetics' influence of a trait In a general way, a heritability coefficient measures how strongly differences among individuals are related to differences among their genes. Simple to compute, are deceptively difficult to interpret. The heritability coefficient, and, in fact, the whole quantitative structure that underlies it, does not match up with our nature-nurture intuitions.

Behavior Genetics as a Choice

version of the free will problem can we self determine what kind of person we are or is this predetermined by our genetics for example, the question of sexual orientation do people have a choice or are they born this way?

Carrie Buck

was ordered to undergo compulsory sterilization for purportedly being "feeble-minded" as part of the state of Virginia's eugenics program unlawfully sterilized in 1927 because she was falsely diagnosed as feeble-minded and promiscuous 17 year old from Charlottesville First person to be picked for sterilization under Virginia law Housed at the Virginia Colony for the Epileptic and Feebleminded (Madison Heights) Carrie and mother shared hereditary traits of Feeblemindedness and sexual promiscuity Probable parent of socially undesirable offspring "These people belong to the shiftless, ignorant, and worthless class of anti-social whites of the south"

Personality Selected Along with Genetics

when selecting for one trait you can also breed unforeseen personality traits such as anxiety in rats the smart rats experienced no anxiety in the maze, but when handled by a human they freaked out oppositely, the dumb rats experienced anxiety when trying to navigate the maze but did not when being handled by humans Emotionality in rats Free field urination and defecation Broadhurst (1960, 1967)