Behavioral Genetics in the Postgenomic Era

Though highly theoretical, this massive new book looks at where behavioral genetics is today and what needs to be done in the future to find the genes that make us tick.  Pinker, in his book The Blank Slate (see my review of his book), claims that behavioral genetics is of no interest to science - a statement so absurd one has to wonder how he could make such a claim amongst like-minded scientists.  Evolutionary psychology deals with the genetic similarities that all humans have that determine behavior, while behavioral genetics looks for the differences between people and between races.  Now that the human genome is being deciphered, behavioral geneticists are anxious to find the specific genes responsible for what we can observe are differences between people: differences in diseases and how individuals respond to treatment, differences in the causes for mental disorders, differences in personality traits, and differences in intelligence - and any other differences that we wish to look for.

My intention is not to review everything contained in the book by the numerous contributing authors, but to highlight those passages that support the current understanding that genes count, and they account for a lot.  The old eugenics was terribly flawed by assuming a few genes were responsible for a person's character or intelligence.  It now appears that any individual gene can impact a particular disease or behavioral trait at levels as little as 1%, with numerous genes contributing to and interacting with multiple human traits and diseases.  Nevertheless, the search for the responsible genes can still be determined using the new methods described in this book.

Several years ago, when the Human Genome Project was in its infancy, there was a lot of concern that employers and insurers would use a person's genetic information to discriminate against them.  One thing that stands out in the book is just how important it is to know each person's genome in order to cure diseases.  The model used now is one size fits all.  New medicines and procedures are assumed to affect everyone equally, but we know of course that this is a crude but necessary assumption based on our knowledge.  However, once we know how genes influence how a person responds to different medical conditions and medical interventions, we will have made a quantum leap in health care, not to mention other benefits such as educational programs that are targeted towards an individual's genetic differences from the norm.

Plomin et al. states that, Indeed, quantitative genetic research suggests that such common disorders are usually the quantitative extreme of the same genes responsible for variation throughout the distribution. Genes in such multiple-gene (polygenic) systems are called quantitative trait loci (QTLs) because they are likely to result in dimensions (quantitative continua) rather than disorders (qualitative dichotomies). In other words, in terms of the genetic etiology of common disorders, there may be no disorders, just dimensions. Other than simple and rare single-gene or chromosomal disorders, mental illness may represent the extreme of normal variation.  In summary, the individual differences perspective views variation as normal and distributed continuously; common disorders are viewed as the extremes of these continuous distributions

This observation has many policy implications.  For example, people who are mentally retarded are often not held responsible to the same degree as normal people.  And yet, mentally retarded people should have the same moral mental modules as everyone else!  But most importantly, there is nothing unique about most mental retards, they are merely people who fall far below the average just like there are people who fall far above the average.  It also begs the question, why do we segregate the mentally challenged in schools, have a few advanced classes for the intelligent, and then throw everyone else together into one large group?  To consider intelligence as a continuum suggests that all children should be allowed to move as fast as they are able - maintaining a certain minimal level of challenge - through the educational system.

It also brings up another interesting observation that if the average intelligence of sub-Saharan Blacks is about 70, the average intelligence of Whites is about 100, and the average intelligence of Ashkenazi Jews is about 115, then how do we determine who is mentally retarded?  If mentally retarded were defined as anyone falling below two standard deviations in intelligence below the mean, then a mentally retarded Ashkenazi Jew would be below 85, a mentally retarded White would be below 70, and a mentally retarded American Black would be below 55.  A definition of mental retardation and its classification makes no sense when it comes to judicial/criminal policies of punishment or educational policies.  Bush's new educational program - No Child Left Behind - ignores these racial differences.  The program will be a colossal failure.

Plomin et al. states that, Quantitative genetics focused on naturally occurring individual differences in complex phenotypes that are commercially important in agriculture and animal husbandry or socially important in the human species. Genetic tools were developed to assess the extent to which such traits were inherited. In nonhuman animals, these tools included experimental crosses, inbred strains, and artificial selection. In the human species, twin and adoption methods were developed in the 1920s. The essence of the theoretical foundation for quantitative genetics is the extension of Mendel's laws of single-gene inheritance to complex multifactorial traits influenced by multiple genes as well as multiple environmental factors. If multiple genes affect a trait, the trait is likely to be distributed quantitatively as each gene adds its effects to the mix. The goal of quantitative genetics is to decompose observed variation in a trait and covariation between traits into genetic and environmental sources of variation. The conclusion gradually emerged from quantitative genetic research that genetic factors contribute to nearly all complex-traits including behavior.

In short, all of the heated debate over nature versus nurture that has so divided the social sciences from the natural sciences, has been taking place without any knowledge about which genes were involved in say intelligence, or even about how many genes there were.  The tools used looked at expressions of intelligence and behaviors, but even so the understanding that genes impact intelligence and behavior far more than one's shared environment, whether home or educational, is irrefutable.  While educators and social scientists kept coming up with pseudoscientific excuses, behavior geneticists were producing research that was testable and falsifiable, the only type of research that is truly scientific.  Social science research has been stuck with Marxist hopes of humans as an infinitely malleable.

Plomin et al. states that, During the past three decades, the behavioral sciences have emerged from an era of strict environmental explanations for differences in behavior to a more balanced view that recognizes the importance of nature (genetics) as well as nurture (environment). This shift occurred first for behavioral disorders, including rare disorders such as autism (.001 incidence), more common disorders such as schizophrenia (.01), and very common disorders such as reading disability (.05). More recently, it has become increasingly accepted that genetic variation contributes importantly to differences among individuals in the normal range of variability as well as for abnormal behavior. The most well-studied domains of behavior are cognitive abilities and disabilities, psychopharmacology, personality, and psychopathology.

"When the working draft of the human genome sequence was published, much publicity was given to the finding that there appear to be fewer than half as many genes in the human genome as expected - about 30,000 to 40,000 genes, similar to the estimates for mice and worms. A bizarre spin in the media was that having fewer genes somehow implies that nurture must be more important than we thought because there are not enough genes to go around. There is, however, an important implication that follows from the finding that the human species does not have more genes than many other species: The number of genes is not responsible for the greater complexity of the human species. In part, the greater complexity of the human species occurs because during the process of decoding genes into proteins, human genes more than the genes of other species are spliced in alternative ways to create a greater variety of proteins. Such subtle variations in genes rather than the number of genes may be responsible for differences between mice and men. If subtle DNA differences are responsible for the differences between mice and men, even more subtle differences are likely to be responsible for individual differences within the species.

"Another relevant finding from the Human Genome Project is that less than 2% of the 3 billion letters in our DNA code involves genes in the traditional sense, that is, genes that code for amino acid sequences. This 2% figure is similar in other mammals that have been studied. On an evolutionary time scale, mutations are quickly weeded out from these bits of DNA by natural selection because their code is so crucial for development. When mutations are not weeded out, they can cause one of the thousands of severe but rare single-gene disorders. However, it seems increasingly unlikely that the other 98% of DNA is just along for the ride.


"For example, some variations in this other 98% of the DNA are known to regulate the activity of the 2% of the DNA that codes for amino acid sequences. For this reason, the other 98% of DNA might be a good place to look for genes associated with quantitative rather than qualitative effects on behavioral traits.

What is not stated above is WHY the media takes every new discovery about human genetics and spins it in such a way that it PROVES there are no differences between people, or more importantly between races.  Academia, the media, and the government are all three driven by an egalitarian agenda (MacDonald 1998b).  It is not possible to determine the complexity of the brain by counting the number of genes or alleles.  The differences between people can be observed and measured - and the differences between people and between races is real.  Much to their dislike, the egalitarian Left is being swamped with information about how genes affect our lives in ever increasing ways.  For example, one interesting story in the Chicago Tribune a few weeks ago had a story on how humans have altered the brains of dogs in such a way that they have the ability to interact with humans that not even chimpanzees have - are closest relatives. People are hearing about genes and their importance now on a daily basis, so no matter how much the Left tries to convince the masses that there is no such thing as races or that all people are essentially the same, most people will begin to connect the dots.

One way that behavioral geneticists are using to try to find the genes responsible for intelligence and behavior is to look for homogenous populations.  It has been recognized by these researchers that there are in fact large genetic differences between the different races of people, as well as a great deal of genetic similarities say between humans and mice.  So the approaches taken to find genes seems almost contradictory until the different methods are seen as a form of triangulation from different sides of the puzzle.

Cardon writes, In a simple case-control study of allelic association, the primary objective is to identify specific alleles [genes that differ] that have different frequencies among individuals with different traits (i.e., disease vs. healthy). Similarly, for quantitative measures, the objective is to identify alleles that delineate mean differences in trait scores among a sample of individuals. It is obvious, however, that differences in allele frequencies between groups [races] do not occur exclusively because of differences in disease or trait susceptibility. Different groups of individuals have different allele frequencies because of differences in ancestral histories; mating patterns; migration trends; and a host of other factors, including simple sampling variability. Whatever their origin, when allele frequency differences are coupled with differences in traits, evidence for association may be obtained. When this occurs and the allele is thought to be relevant to the trait, the finding is taken as evidence for genuine trait association. When this occurs and the allele is thought to reflect some other ethnic, geographic, or sampling issue, the finding (with respect to the trait) is referred to as 'spurious' due to population stratification.

"Fear of spurious results arising from population stratification has had a demonstrable and ongoing influence on human genetics studies of complex traits over the past decade, driving research away from population-based cohorts to family-based models. The move toward family-based controls was spurred by the development of a suite of association designs and statistical methods that use the genetic composition of the family (within which there is no stratification) as the background for comparing allele frequencies, instead of comparing frequencies across unrelated individuals. The most popular of these approaches, the transmission disequilibrium test (TDT), minimally involves parents and one offspring. Only heterozygous parents [they have different gene types] are informative in this design, so whenever parents are homozygous [same gene types], the genotype data are effectively useless for association testing. A number of quantitative-trait extensions of the TDT have been developed, broadening the discrete models by explicitly partitioning linkage and association effects in random samples and in phenotypically selected [selected because of observed differences say in intelligence] sib pairs."

What he is politely explaining above is that there is so much genetic variation for intelligence and behavior between families and between races, that those differences confound some types of behavioral genetic studies.  This should put and end to any notion that there are no races.  In fact, the reason that mice are so useful for genetic studies is because they are selectively inbred to make them as much alike genetically as possible.  So even in mice, there is too much behavioral variation in genes that determine mouse smarts - so they are bred to be exceptionally dull or exceptionally smart.  This form of selective breeding is very useful in genetic studies.

In fact, there is one race that has done to themselves what scientists have done with mice.  The Ashkenazi Jews have practiced selective breeding for 3000 years, and an interesting thing has resulted.  Not only do they have an exceptionally high average IQ (117), but it is an altered form of mental ability.  What the selective breeding program has produced is a skewed intelligence:  they have a verbal intelligence (Information, Arithmetic, and Vocabulary) of 127 and a performance intelligence (Spatial and Object Assembly) of 103.  No other known racial group has this separation.  In general, verbal and performance intelligences travel together - if you are smart on one you are smart on the other.  This uniquely homogenous group then could be very useful in behavior genetic studies to find the smart genes.

Rowe elaborates on using rodents for gene studies, A genotype to environment (GE) active correlation refers to the tendency of organisms with particular genotypes to seek out, create, and thrive in particular environments. Nonhuman animals show GE correlations. maze bright rats made fewer learning errors when reared in both normal and enriched environments; maze dull rats learned well under only enriched rearing. This effect constitutes an interaction because the effect of rearing environment depends on the particular line of inbred rats, that is, on their genotypic differences.

"We interpreted these results as indicating that among the offspring of poorly educated parents, some but not all family environments must be harmful to intellectual growth. Harmful family environments may include abusive and unconcerned parents, as well as other psychosocial and physical (i.e., lead exposure) influences. Such influences may produce a shared environmental effect of a greater magnitude. In families with unconcerned but better-educated parents, bright children may find other opportunities with which to accelerate their own intellectual growth. If their parents do not push them toward achievement, they may find equal intellectual challenges in schools or peer groups."

These studies have again, important policy considerations.  First, there is no reason why an intelligent child needs an enriched environment.  I have a sister-in-law that surrounds her son with toys, gets him involved in all sorts of activities from playing the piano, to swimming, etc.  However, what does that really do in the end?  Eventually, children grow up and pursue their own interests and they may be far different from what mommy wanted.  For example, let's say that a young child is aggressively pushed into learning to play the violin.  It may even alter his developing brain such that his musical connections are enhanced to the detriment of other developing brain areas.  Now, if the child just happens to love music, fine, but what if he really has no real interest in music?  Has this enrichment program hindered or helped?  No one knows for sure, but it seems that smart kids are going to do just fine as long as they are brought up in a normal environment.  But more importantly, it makes the case absurd that certain children grow up to be smart because of the way they were raised (more on this later).  In the end, all of the studies that try to link social economic status (SES) with educational attainment just don't compute - parental genes are more important.  Only very dysfunctional families will have an adverse impact on their children's growth and accomplishments.

Behavioral geneticists distinguish several types of gene-environment interactions as follows: passive, where children are treated differently because of the type of environment; evocative, where children are treated differently because the child is different from other children (junior is so sweet and cute); and active, where children seek out their own favorable environmental niches according to their own interests and talents.  Children will seek out friends, hobbies, sports, and other activities because they seek out environments that fit their intellectual and behavioral types.

This gene-environment interaction can accentuate children's behavioral types.  Rowe states, "[Kandel] also observed a second phenomenon: friends becoming more similar during the duration of their friendships. Using a complex statistical analysis, Kandel determined that about half of friends' similarity was due to selection and half was due to influence.

"Another study examined an even earlier precursor to adolescents' behavior: infants' temper tantrums. In children all born in the same year (i.e., a birth cohort), 3-year-old children were distinguished according to whether they had temper tantrums. Anger and temper in the 3-year-old children predicted their criminal behavior, antisocial personality disorder, suicide attempts, and alcohol dependence at 21 years. Surely, selecting delinquent peer companions cannot have caused the explosive temperament of the 3-year-olds.

Posthuma, Geus & Boomsma note that, "The large genetic contribution to individual differences in cognitive abilities is well established. From childhood to early adulthood, the relative impact of genetic factors on cognitive abilities increases and becomes even higher from middle adulthood to late adulthood. Data from four large twin studies from the Dutch Twin Registry, which are partly longitudinal and partly cross-sectional, reflect this increasing heritability of cognitive abilities with age. Shared environmental influences play a role only before adolescence and are of relatively low importance between ages 7 and 16. This pattern of the relative impact of genetic and environmental influences on cognitive abilities corresponds to that found in many other countries.

Figure 9.1

Additive genetic/Shared environment/non-shared environment by age.

50 year old     85/0/15

26 year old     88/0/12

18 year old     82/0/18

12 year old     60/25/15

10 year old     54/26/31

 7 year old     40/29/31

 5 year old     26/50/24


In spite of the overwhelming evidence for the existence of 'genes for cognition,' actual identification of such genes is limited to neurological mutations with rather severe cognitive effects (e.g., Pick's disease, X-linked mental retardation, and Huntington's disease), as reviewed by Flint. Like the many rare diseases and disorders listed in online Mendelian Inheritance in Man, these genetic defects of cognition are largely Mendelian in nature. True polygenes that influence the normal range of cognitive ability have yet to be identified. One route to finding these genes is a better appreciation of individual differences in the anatomy and function of the main organ of information processing, the brain.


This relationship between genetic, shared environment and non-shared environment has been emerging now for over a decade and sheds new light on the social sciences, educational policy, and social intervention policies.  But numerous social programs are slow to respond.  The Chicago Tribune ran an article reporting the surprise results of the first test scores around the state of Illinois as part of President Bush's new program: No Child Left Behind.  What they found was that even in wealthy suburban schools, minority students, primarily Black and Hispanic, were still struggling to attain the minimal level of education.  But this is not surprising if innate intelligence determines a students success, and not the amount of money spent or the quality of the teachers - these factors count but they are not determinant.  The entire article was just a series of new excuses why minorities have so much trouble learning - but never is the genetic component even alluded to.

The changes between genetic/shared and non-shared environments also explains why social scientists have placed so much hope on early intervention programs like Head Start.  At the age of five-years-old, as shown in the above figure, genes only account for 26% of intelligence while the shared environment accounts for 50%.  These young minority students then, with intensive and on-going enrichment programs, are able to learn and excel far beyond the average of their peers.  Then, as they get older, disappointment sets in:  the early intervention starts to fade as the genetic component goes to 82% while the shared environment component goes to zero.

No wonder that social scientists and educators have been looking for excuses for this failure for early intervention to persist into adulthood.  They assumed that anyone can be equally educated with the right programs.  To explain the failures a whole litany of explanations emerged: racism, lack of money for education, crime, slavery, apprehension over test taking, bias in tests, pollution, poor nutrition, belonging to a lower caste, etc.  The excuses are endless and at times humorously creative - but they are never formulated into any falsifiable theory and therefore they cannot be tested (typical of most social science research).

There may be some hope outside of genes alone being responsible for one's intelligence as we near adulthood - some part of smarts is due to non-shared environment.  But so far, no one has been able to find a good explanation for this component of cognitive ability other than to state that smart kids seek out smart things to do and learn more, while stupid kids flitter away their time in activities that do not challenge the intellect.  That is, individuals just reinforce their own genetic leanings in intelligence, behavior, athletic abilities, etc.

Posthuma, Geus & Boomsma state, An obvious source of individual differences in cognitive abilities is the size of the brain. Since the second half of the 19th century, positive relations between head size and intelligence have been observed. Correlations generally range around 0.20 but can be as high as 0.44. Head size is usually measured with a measuring tape as circumference of the head. A more accurate measure of the size of the brain can be obtained through magnetic resonance imaging (MRI).


"Willerman, Schultz, Rutledge, and Bigler correlated brain size as measured through MRI within a sample of 40 unrelated participants. They found a correlation of 0.51, which was higher in men (0.65) than in women (0.35). In a follow-up study, Willerman, Schultz, Rutledge and Bigler suggested that, in men, a relatively larger left hemisphere better predicted verbal IQ than it predicted performance IQ, whereas in women the opposite was true. Since then, several studies have provided confirmative evidence that brain volume and IQ correlate around 0.40.


"In a large MRI study including 111 twin pairs and 34 additional siblings, the heritability of volumes of several brain structures was investigated. Heritability estimates for intracranial volume, total brain volume, gray-matter volume, white-matter volume, and cerebellar volume were all between 80% and 90%. Genetic intercorrelations between these measures were all very high, indicating that a largely overlapping set of genes is responsible for individual differences in each of these measures. This indicates that about half of the genetic influences on either cerebral brain volume or IQ is due to genetic factors influencing both. Put differently, 80% of the phenotypic [observed human differences] correlation is explained by genetic mediation.

Boas claimed that head size and shape changed with the environment.  Recent analysis of his original work however has shown that the data was either falsified or interpreted incorrectly - we'll never know for sure.  Nevertheless, we do know that Boas was more interested in Marxist propaganda than in an empirical pursuit of the truth. The above data does make any claim that there are environmental causes that may be found for differences in average intelligences between races highly doubtful.  Rushton has shown that intelligence differences correlate with brain sizes, and brain sizes correlate with different races - Blacks have the smallest, then Whites, with East Asians having the largest when stature is factored in.  Now, if brain size is 80~90% heritable, and brain size correlates with intelligence which is also 80% heritable, how does one explain the large average differences in brain size between races without attributing it primarily to genetics?  No environmental explanation could account for this when this data has been collected in many different countries for over 150 years now.  The brain size-intelligence correlation occurs in every racial group that differs in average intelligence.

Posthuma, Geus & Boomsma explain why brain size correlates with intelligence: This suggests that genes important for brain size, reaction times, inspection time, and theta coherence may also be important for intelligence, which fits very well in the myelination hypothesis as formulated by Miller. According to this hypothesis, generally, the relation between speed and intelligence can be explained if part of the interindividual variance in intelligence can be ascribed to interindividual variance in the degree of myelination of cortico-cortical connections. If true, this could explain why more intelligent brains show faster nerve conduction, faster reaction times, and faster inspection times. And, all other things equal, thicker myelin sheaths will result in larger brain volume, thus explaining the positive relation between brain size and IQ.

Plomin, on mental ability states, "g is a quantitative trait that varies from a low end of mild mental retardation to a high end of gifted individuals. This chapter is about the normal range of variation in g - there is surprisingly little known about genetic and environmental etiologies of mental retardation or high ability. Although intelligence means different things to different people, g has a more precise definition: g is what diverse cognitive abilities have in common. One of the most consistent findings from individual differences research on human cognitive abilities and disabilities during the 20th century is that diverse cognitive processes intercorrelate, including tests as different as reasoning, spatial ability, verbal ability, and memory. Despite the diversity of such tests, individuals who perform well on one test tend to do well on other tests. In a meta-analysis of 322 studies that included hundreds of cognitive tests, the average correlation among the tests was about 0.30. Factor analysis, a technique in which a composite score is created that represents what is shared in common among the measures, indicates that g accounts for about 40% of the total variance of cognitive tests. However, g is not just a statistical abstraction - one can simply look at a matrix of correlations among such measures and see that there is a positive manifold among all tests and that some measures (e.g., spatial and verbal ability) intercorrelate more highly on average than do other measures (e.g., nonverbal memory tests). Because all of these measures intercorrelate to some extent, g also is indexed reasonably well by a simple total score on a diverse set of cognitive measures, as is done in IQ tests. This overlap emerges not only for traditional measures of cognitive abilities of the sort seen on IQ tests but also for information-processing tasks that rely on reaction time and other cognitive tasks used to assess, for example, working memory and theory of mind.

General cognitive ability was recognized nearly a century ago by Charles Spearman, who used g as a neutral signifier that avoided the many connotations of the word intelligence: g is one of the most reliable and valid traits in the behavioral domain, its long-term stability after childhood is greater than for any other behavioral trait, it predicts important social outcomes such as educational and occupational levels far better than any other trait, and it is a key factor in cognitive aging. As discussed later, although g has not yet entered the lexicon of neuroscience, g needs to be incorporated in research on learning and memory.

"Although the concept of g is widely accepted, acceptance is not universal. The arguments against g include ideological issues such as political concerns and the notion that g merely reflects knowledge and skills that happen to be valued by the dominant culture. Objections of a more scientific nature include theories that focus on specific abilities. However, when these theories are examined empirically, g shines through. For example, Sternberg and Gardner, advocates of a 'componential' view of cognitive processing, conceded, 'We interpret the preponderance of evidence as overwhelmingly supporting the existence of some kind of general factor in human intelligence. Indeed, we are unable to find any convincing evidence at all that militates against this view.' There are of course many other important noncognitive abilities such as athletic ability, but nothing seems to be gained by lumping all such abilities together as is done with the popular notion of 'multiple intelligences.' Also, g by no means guarantees success either in school or in the workplace; achievement also requires personality, motivation, and social skills as emphasized in the fashionable concept of 'emotional intelligence.' Thus, g is not the whole story, but trying to tell the story of cognitive abilities without g loses the plot entirely.

"Quantitative Genetic Research on g: Going Beyond Heritability

A year before the publication of Gregor Mendel's seminal paper on the laws of heredity, Francis Galton, the father of behavioral genetics, published the first family study of g-like ability and other abilities. The first twin and adoption studies in the 1920s also investigated g. Subsequently, more research has addressed the genetics of g than any other human characteristic other than personality assessed by self-report questionnaires. Dozens of studies including more than 8,000 parent-offspring pairs, 25,000 pairs of siblings, 10,000 twin pairs, and hundreds of adoptive families all converge on the conclusion that genetic factors contribute substantially to g."

The above is a succinct summation of what is known about mental ability - g - and puts to rest many of the criticisms the Left continues to make against studies in intelligence.  (For additional material on what Plomin summarizes above, the most thorough analysis is presented by Arthur Jensen in his 1998 book The g Factor.  This book is now available as on online book from for a small monthly fee that lets you read hundreds of books and journal articles, as well as helping students prepare term papers on line.)

Plomin goes on to explain research in multivariate genetic analysis.  What this tract of research has found out is that if there is a gene that increases mental ability in one trait, the gene increases intelligence in all other traits.  This means g - or mental ability - is not made up of modules of different traits of intelligence, but that there is an underlying system of intelligence such as larger brains (myelination), cerebral glucose metabolism, and etc. that exists throughout the brain, and not isolated in any particular module.  That is, we do not have any genetic intelligence that contributes to multiple intelligences.  The engine of intelligence is the product of many genes, but they all contribute to the size of the engine, not individual components of the human vehicle.  And this means that what is IN COMMON with intelligence is almost completely genetic in origin."

"Conversely, differences between g scores and tests of school achievement are exclusively environmental in origin. This finding suggests two important implications. First, school achievement scores independent of intelligence test scores appear to be largely devoid of genetic influence and would thus provide a better measure of the effectiveness of the child's environment in fostering achievement. Second, the finding suggests that underachievement, defined as a discrepancy between ability and achievement, is largely due to environmental factors.

The above has important applications for educators, because it means that while teaching to the test may improve students grades on achievement tests, it also means that students should not be held to the same standards.  A child should only be considered to "fail if they are underachieving in relation to their innate intelligence or abilities.  It also indicates that teaching to the test, while making administrators happy by improving basic reading and math scores, we may be cheating children out of important educational components that may be of great benefit to those who are not going to college.  Such basic skills as carpentry, art, typing, or automotive mechanics may be far more important to many students than mathematics.  That is, holding all students to the same standards is not only unfair and absurd based on what we know about the heritability of intelligence, it is also harmful.  Children should be taught according to their personal needs, based on expectations of what they can achieve and what they naturally prefer - whether a computer geek or a mechanical gear-head. 

Plomin reiterates the new brain-size = intelligence discoveries, "What is known so far is surprising: The strongest correlate of g is brain volume. This association appears to be due to brain volume throughout the brain rather than to particular regions of the brain. Individual differences in brain volume are highly heritable, and genetic factors appear to mediate substantially the phenotypic correlation with g. The only other brain mechanisms known to correlate with g are electroencephalography measures, event-related potentials (especially P-300 latency), and cerebral glucose metabolism rate as assessed by positron emissions tomography.

One has to ask, did anyone bring up this point when the congress was discussing educational policies?  Too taboo I am afraid, but it makes the policies unworkable.  We know that different races have on average different brain sizes, and brain size indicates intelligence.  Both brain size and intelligence are 80% to 90% genetic after the age of eighteen, so there is no question, based on this recent research, that the differences between races in intelligence is mostly genetic in origin.

Plomin goes on to explain how human language and our species highly developed prefrontal cortex is independent of intelligence.  That is, similar intelligence is found in mice and mental ability can be tested using non-verbal tests.  In fact, what should be done by educators is to completely separate highly loaded g intelligence tests from achievement tests, to determine how well schools are performing, using the intelligence test as a guide to how much each child is capable of learning or should be expected to learn.  The radical environmentalist position is forty-years out of date, and the lies and excuses can't just keep piling up when behavioral genetics is moving along at such a fast pace that we may actually start to find the "intelligence genes" in a few years.

Plomin discusses the flawed research in education, "Other studies of older adoptive siblings also have found similarly low correlations for g. The most impressive evidence comes from a 10-year longitudinal follow-up study of more than 200 pairs of adoptive siblings. At the average age of 8 years, the g correlation was 0.26. Ten years later, their correlation was near zero. Thus, although shared environment is an important influence on g during childhood when children are living at home, its importance fades after adolescence as influences outside the family become more salient. Next to nothing is known about these mysterious nonshared environmental factors that make siblings growing up in the same family so different after adolescence.

"One possible explanation of this result is that parents respond to genetically influenced g in their children. A general rule in research of this sort is that genetic factors are responsible for about half of the phenotypic correlation between measures of the environment and measures of behavior. No longer can environmental measures be assumed to be entirely environmental just because they are called environmental. Taking this argument to the extreme, two recent books have argued that socialization research has been fundamentally flawed because it has not considered the role of genetics. A far-reaching implication of this research is that it supports a shift from passive models of how the environment affects individuals toward models that recognize the active role individuals play in selecting, modifying, constructing, and reconstructing in memory their experiences."

Recently, with news of the Human Genome Project, egalitarians have been making a lot of statements to try and deflect any consideration that race is more than skin deep.  However, as Plomin notes, behavioral geneticists are very aware of the uniqueness of the genome for different races, or ethnic groups as they like to call them: With the recent mining of [single nucleotide polymorphisms] SNPs, it will soon be possible to conduct a genome scan using 100,000 evenly spaced common SNPs. However, the pattern of linkage disequilibrium depends on several factors such as marker type, allele frequency, mutation, and recombination, and recent data suggest that it is highly variable between different regions of the genome and in different ethnic groups.

The idea that races do not differ genetically throughout their genome, including skin color, intelligence, behavioral traits, levels of ethnocentrism and etc., is now understood to be Marxist nonsense.  We keep getting these message from the media, but a look at the people actually doing the research tells a different story.

Heath et al. expands on the salience of racial differences: Compared with most Western societies, which comprise individuals of very diverse ancestral origins, Japan is considered a relatively genetically homogeneous society. This is an important consideration in the interpretation of case control data, such as the Higuchi series of alcoholics and community controls, because if there are sociocultural differences between individuals of different ancestral origins (e.g., Scandinavian Lutherans vs. Irish Roman Catholics), as well as gene frequency differences, then these sociocultural differences may be important confounding factors that can create false-positive associations, or alternatively mask associations, with individual genetic loci. In an extreme case, we may even find a genetic association for a nongenetic trait (e.g., a 'Lutheran' religious affiliation gene).

"Furthermore, interpretation of this traditional case control comparison in men is complicated by evidence for significant population stratification effects [differences between races], with the low-risk ADH2*2 allele associated particularly with English ancestry (e.g., significantly associated with a religious affiliation of Church of England, and with endorsement of Socialist social attitudes; Heath et al., 2001). Within-sibship comparisons identified five male like-sex sibpairs discordant for ADH2 genotype: In all five cases, quantitative measures of alcohol use and problems were elevated in the dizygotic (DZ) twin with the (high-risk) ADH2*1/*1 genotype compared with the heterozygous cotwin."

Throughout this book, the contributors are very conscious of differences between races to the point where much of the research is based on very homogenous racial groups such as the Japanese or Icelanders.  The more inbreeding, the less confounding the genetic data becomes. If humans were all the same genetically, this would not be a problem, and it is especially a problem in intelligence and in behavioral studies because there is such a huge difference in the average genomes of different races.  Of course, to be politically correct, they always label these differences as "stratification" or ethnic group differences rather than racial differences. The PC police are still abundant and getting stronger.  Just take note of how there is an increase in arrests and convictions of people who dare mention racial differences, especially in Europe.

When it comes to eugenics, aside from easily detected and terminated fetuses with single gene genetic diseases, behavioral traits are of great interest.  Most eugenicists are very cautious however with regards to altering behavioral trait frequencies, or personalities.  We favor a simple increase in intelligence as the only trait that we can state categorically: it is better to be more intelligent than less intelligent."  The desire to raise the average intelligence of the population group is fundamental to all eugenicists.

Nevertheless, personalities should be equally of interest to eugenicists, even if there is no definitive desire to alter the frequency of different personality types in the group.  First off, understanding personality types may give us a resolution of the ongoing and destructive battle between the Left and the Right.  This political obsession is evident in the media and throughout history - what makes one a caring egalitarian or a hard headed pragmatist, and all of the behavioral types in-between.

Then there is the question of finding friends and significant others, as well as explaining why some ethnic groups lean this way or that.  For example, why East Asia with a high average intelligence lags behind the West in innovation, while the West seems to be consumed by guilt over racial inequality, and the Middle East is embroiled in a campaign of terror against Jews and Christians.  Behavioral traits and differences are completely ignored by the media, policy analysts, the State Department, etc. They continue to think in terms of a universal genotype where culture alone determines personality. 

Ebstein, Benjamin & Belmaker report that, Diverse definitions of personality exist, but most genetic studies are based on the following definition: Personality may be considered the typical manner or style of an individual's behavior as opposed to the goals toward which it is directed or the machinery of its execution (cognitive and motor skills). Many other definitions of personality exist, but most genetic studies are based on this definition. For example, Bonnie and Clyde were (in the movie) flamboyant bank robbers, and many college professors show a similar extraverted style in their lectures. However, the goals of the behavior (robbing a bank vs. teaching students) are very different with very different social consequences. Personality may be described as the vigor, temper, or persistence of behavior or the emotional expression that accompanies it, such as fearfulness, exuberance, aggressiveness, or self-restraint. The vast majority of genetic research on personality involves self-report questionnaires administered to adolescents and adults. People's responses to such questions are remarkably stable, even over several decades. Additionally, personality trait structure appears to be universal and shows similarity across highly diverse cultures.

"A number of self-report questionnaires are in use, and they appear to measure similar personality traits. Descriptive taxonomists have agreed that a set of five dimensions can be identified consistently across methods. These 'Big Five' dimensions of self-report and peer description have been labeled Neuroticism, Extraversion, Agreeableness, Openness, and Conscientiousness and are commonly assessed using the NEO Personality Inventory-Revised. Other self-report personality inventories include Eysenck's Personality Inventory, Zuckerman's Sensation Seeking Scale, Cattell's 16 Personality Factor Questionnaire, Cloninger's Tridimensional Personality Questionnaire (TPQ), and Temperament Character Index (TCI). Underlining the similarity between questionnaires are formulas that can be used to convert NEO-PI-R scores into TPQ Harm Avoidance and Novelty Seeking. To summarize, all the major self-report questionnaires appear to reliably assess similar personality factors, especially the higher categories of novelty seeking (extraversion, conscientiousness, sensation seeking, and psychoticism) and harm avoidance (neuroticism and anxiety-related traits)."

Wow, that is pretty exciting!  Everyone could take a 100 question query in about thirty minutes, get their personality profiles by description or even a graph, and when we meet someone instead of trying to see if we have anything in common, we could just whip out our profiles and determine whether they will be a friend, an antagonist, a friendly competitor, or whatever.  From my perspective, personality types are an exciting and an underutilized knowledge base.  I remember working in a petrochemical plant some thirty years ago, and they would give personality tests to see if the prospective employee was prone to join a union or not.  Yes, like genetic testing, knowledge of behavioral traits can be abused (depending on your perspective - I thought it was pretty clever).

Personality types seem to be mediated by neurotransmitters - and that is where the research has been targeted.  There have been decades of research on brain chemistry and related affective disorders like depression, drug addition, attention deficit disorder, schizophrenia, etc.  The list is long and socially demanding - schizophrenia alone "accounts for more hospital bed occupancy than any other disease."  All of these conditions, like personality types, seem to involve many genes and are part of the normal bell curve.  Most people tend towards moderate expressions, but just like intelligence, some people fall towards the extremes.  They are the ones that may succumb, under the right environmental conditions, to the disorder.

With regards to heritable behavioral types, the three factor TPQ seems particularly interesting in terms of evolution: novelty seeking, harm avoidance, and reward dependence.  The first two are self-explanatory.  Reward dependence is the TPQ term for attachment to others, sentimentality, and warmth; its opposites are pragmatism and tough-mindedness.

"According to the biological theory behind the TPQ, harm avoidance is the inhibition of approach behaviors and the enhancement of escape behaviors, and these are principally served by the serotonin (5-HT) system in most animals. The trait has face-valid resemblance to human neuroticism and perhaps depression. Novelty seeking, the increased tendency to respond with approach to new and promising situations, is principally served by the meso-limbic dopamine system. Rewarding activities, including the use of illicit drugs, increase dopamine release or inhibit its reuptake in this system. Reward dependence reflects the persistence of behavior that is likely to be intermittently, rather than immediately, rewarded, so that a key subscale of reward dependence in the TPQ is persistence (Ebstein, Benjamin & Belmaker)."

This to me is fascinating because we can observe these traits in our canine friends.  I had two large German shepherds for over twelve years, and would take them to a large dog park twice a day.  If we look at breeds of dogs like races, we can see the variability within the breed (race) and the differences between breeds (races).  One of my dogs was dependent and cowardly - he would have to be on my lap, at my side at the computer, and he would actually purr when petted.  The female was arrogant (tough minded) and inquisitive (novelty seeking).  She would untie my shoelaces, watch me from a distance, slam doors and lock herself in rooms so I would have to go let her out, etc.  She was constantly trying to be dominant and pushing me to react to her whims.  I learned so much from them and the other dogs at the park, and one can see how evolution would have favored all three extremes of behavior under different ecological conditions.  No one behavioral type would go to fixation genetically, but some types of behavioral leanings would be accentuated in some groups more than in others over time.

Racial differences are now coming under investigation, because if we assume everyone is alike, the data will be confounded as I stated before. For example, the Japanese and Chinese populations have very low frequencies of the DRD4 7-repeat compared with many other groups, signifying that the role of this specific repeat number in novelty seeking and related traits cannot be of general significance in East Asian participants.

"It is interesting to note that more than 10 variants have been observed for the serotonin transporter in a Japanese study, and significant differences in allele frequency were observed between Japanese and White groups (Ebstein, Benjamin & Belmaker)."

It should be obvious by now that races differ as well as individuals in intelligence and  personality types.  Lesch writes, Finally, difficulties in interpretation of population-based association studies due to ethnic differences in 5HTTLPR allele frequencies, which are most prominent in the Japanese population with Ul genotype frequencies around 5%, have also been raised by more recent studies. From an evolutionary psychological perspective, anxiety is a pervasive and innately driven form of distress that arises in response to actual or threatened exclusion from social groups. Notably, Nakamura et al. discussed the higher prevalence of the anxiety and depression-related Us and s/s genotypes in the context of extraordinary emotional restraint and interpersonal sensitivity in Japanese people as a possible population-typical adaptation to prevent social exclusion.

"Accumulating evidence demonstrates the complex interplay between individual differences in the central 5HT system and social success. In monkeys, lowered 5HT functioning, as indicated by decreased CSF 5HIAA levels, is associated with lower rank within a social group, less competent social behavior, and greater impulsive aggression. It is well established that although subjects with low CSF 5HIAA concentrations are no more likely to engage in competitive aggression than other monkeys, when they do engage in aggression it frequently escalates to violent and hazardous levels. A presumed role of s allele-dependent low 5HTT function in nonhuman primate aggressive behavior would be in agreement with the association in humans between NEO subscales Neuroticism (increased angry hostility) and Agreeableness (decreased compliance = increased aggressiveness and hostility) and 5HTTLPR S genotypes."

The above may have some interesting insights into terrorism coming out of the Middle East.  Lynn and Vanhanen (2002) have compiled average intelligences in 81 nations, and the average IQ of the Islamic world is around 80 to 90 (see my free on-line book Shattering the Myth of Racism Volume II for a review of the book and a table of the nations' average IQs).  In the last decade, the Middle East, even under repressive governments, has been exposed to Western culture including the humiliation of seeing all too clearly that they are less innovative and intelligent than we are in the West.  If we couple that with the ability to bring certain personality types together through the Internet, we have an explosive combination.  Young Islamist males, angered by their lower rank, lash out in nihilism.  It is better to die than to be humiliated, especially when martyrdom is socially acceptable.  Most humans will readily accept death for the tribe - most of us will during war.  Young men stand in line, volunteering to lay down their lives for country and kin.  MacDonald (1994) has shown that Semites are far more ethnocentric than individualistic Europeans.  If war breaks out in the Middle East, we may well be flooded by many millions of displaced persons in the aftermath, and Europe and the United States will be no more - swamped by an alien race.

But who then is really a threat to whom?  The West is fully equipped militarily, technologically, and with regards to resources except for oil, to fully and unilaterally destroy the Middle East nations.  Bush screams that the United States must attack Iraq (followed no doubt by Iran, Syria, Lebanon and any other country that poses a threat to Israel) preemptively. And yet, can't the terrorists claim the same thing?  They are using terrorism because the West is a danger to the Middle East?  We desperately need to have an understanding of how races differ in ethnocentrism, intelligence, etc. if we are going to understand how to relate on a global scale.

"Specific DNA polymorphisms will provide much sharper scalpels to dissect these issues with greater precision. It is important that functional genomics be applied to behavior sooner rather than later because of the societal importance of behavioral dimensions and disorders such as mental health and illness and cognitive abilities and disabilities. The behavioral genomics level of analysis seems likely to yield quicker returns on investment in terms of diagnosis, treatment, and prevention than starting from the molecular biology of the cell. Behavioral genomics will lead to gene-assisted diagnoses and treatment programs as well as to early identification of potential problems that might lead to behavioral interventions that prevent the onset of problems before they create collateral damage. Moreover, the behavioral genomic level of analysis may be the most appropriate level of understanding for evolution because the functioning of the whole organism drives evolution. That is, behavior is often at the cutting edge of natural selection (Plomin, DeFries, Craig, and McGuffin)."

From the study of primates to dogs to mice - evolution depends on being able to change cognition and behavior far faster than the shape of the nose or the color of our skin.  Anyone who states that the human race is one big family of like-minded people, that there are differences between people in intelligence and personalities and yet there are no differences between races, is just not being truthful.  Last night I was reading a new book Intelligence, Race, and Genetics: Conversations with Arthur R. Jensen (Jensenism), and he discussed the special issue of INTELLIGENCE where the experts in the field of intelligence discuss his life's work.  Jensen is the researcher who was vilified in 1969 for saying that the IQ difference between Blacks and Whites was primarily genetic in the Harvard Educational Review.  He states now that virtually no researcher believes differently than he does with regards to the heritability of intelligence and the differences between races.  But what many of the researchers do object to is telling the public what they know - that we are what our genes make us, and we are all very unequal.  Some researchers think the masses are not ready for the truth - Jensen tells it like it is, as do the authors of Behavioral Genetics - though they alter the words slightly to not offend.

Scientists give dogs their day. Research unexpectedly suggests they may hold answers to some basic biological questions. By Peter Gorner and Jeremy Manier Tribune staff reporters. November 22, 2002; Chicago Tribune, page 1 world news.  Using high-tech genetic tools and clever behavioral tests, researchers have begun to uncover the surprising story of how dogs evolved--and how humans bred their constant companions to have minds uniquely able to communicate with people.  Three studies published Friday in the journal Science join a fast-growing body of evidence about the genetic origins and behavior of dogs, including where they were first domesticated.  The reports suggest that people first bred dogs in or near China around 15,000 years ago, creating a remarkable species that outperforms wolves and even chimpanzees on some tests of social savvy.  Based on everything from simple behavioral tests to ancient dog DNA dug up from the Alaskan permafrost, the new research reflects a mounting realization among scientists that the study of dogs, once relegated mainly to veterinary schools, may hold the key to some of the most basic questions in biology.  Experts now believe that tracing the origins of dogs could reveal an unparalleled laboratory of evolution in action, as humans have made dogs the most wildly diverse species of mammal on the planet in just a fraction of the time natural evolution would require. One of the new genetic studies by Swedish and Chinese researchers, based on hundreds of canine DNA samples from around the world, indicates that just a few original groups of wolves in East Asia gave rise to all of today's canines, ranging from toy poodles to huge mastiffs. 

Another new study, by anthropologist Brian Hare of Harvard University, suggests that dogs do better on some tests of cognitive ability than chimpanzees, long considered the animal with mental prowess most similar to our own.  In the past, everybody wanted to study primates because they're our closest genetic relative, Hare said. We think dogs offer a gold mine of information that has been neglected simply because dogs are so popular.  Raymond Coppinger, a biologist at Hampshire College in Massachusetts who has bred or trained thousands of dogs, said the Harvard paper offers some of the first evidence that dogs have minds capable of complex thoughts about other dogs or people.  I'm not ready to make that jump quite yet, said Coppinger, co-author of the book "Dogs: A Startling New Understanding of Canine Origin, Behavior and Evolution. But [Hare] is certainly moving me in that direction."  A third report by scientists at the University of California, Los Angeles, examined centuries-old DNA samples taken from dogs that lived in the Americas before European explorers arrived, including 11 specimens dug from the permafrost in Alaska and others taken from archaeological sites from Mexico to Peru.  After comparing the old DNA with that of modern wolves and dogs, the team concluded that Native Americans brought their dogs with them from Asia, rather than domesticating native wolves they found in the Americas.  Dogs may have been the technological innovation that allowed people to survive in the Arctic and move over longer distances," said Robert Wayne, an evolutionary biologist at UCLA and co-author of the study. They could have provided security or helped in the hunt."  Dogs fascinate genetic researchers because they have blossomed into hundreds of specialized breeds with apparently only a few genetic changes. Such subtle changes have yielded an astonishing variety of physical forms and talents, including abilities such as tracking, herding and sled racing that require the right mix of genetics and training by humans.  "The reason I study dogs is that I'm interested in the evolution of behavior," Coppinger said. "Each breed of dog is a specialist in some behavior that no other animal in the world can do as well."  For example, he said, Sled dogs are the fastest marathon runners in the world. In the Iditarod they run five marathons a day, day after day."  The Harvard study shows that when it comes to understanding certain social cues from humans, dogs will trounce captive-raised chimpanzees and home-raised wolves. In this case, the researchers gauged the animals' ability to read signals from people indicating the location of hidden food.  Puppies only a few weeks old--even those that had little human contact--caught on immediately, Hare said. They performed much better than either the chimps or wolves."  Each animal in the study tried to find food in one of two containers after a researcher had given a subtle cue: pointing to, looking at or placing an object on top of the container with food. (Both containers smelled of food.) Only two of 11 chimps got it right the first time, compared with nine of 11 dogs that used the cues to get the food.  Wolves, which also were tested, need to read the social cues of other wolves to coordinate the hunting of the pack. Moreover, they need to expand that ability to their prey, so they know that when a moose looks to the left, for instance, it will run to the left.  Our experiments showed that wolves aren't any good at taking that ability and generalizing it to humans, Hare said. But my dog does. He uses social cues from me. Without this ability, we could never train dogs to do specific tasks.  Many researchers have assumed chimps have more social cunning on such tests than virtually any other animal. But every dog owner is an expert on such matters, and the canine prowess is no shock to those who train dogs for a living.  Of course dogs would do that, said Jennifer Boznos, owner of the Call of the Wild School for Dogs in Chicago. These guys who work in labs are just unbelievable."  But Hare said his experiments have a deeper point: The ability to understand such cues from humans means that dogs may be able to think about the thoughts of others.  There's no question that animals can think, Hare said. They take in information and make decisions about what to do all the time. Tons of experiments show the same thing.  But do they think about the thinking of others? Do they realize that other individuals know different things and they can learn from them? Or if they know things that the others don't, can they use that information to manipulate or deceive them?"  Those abilities are thought to have helped shape the evolution of human intellect millions of years ago. Depending on Hare's further studies, it may turn out that people crafted the minds of dogs in their own image. 

The study of dogs could even yield medical benefits for people and answer larger questions about evolution.  The National Human Genome Research Institute, having already sequenced the human genome, recently indicated that the dog genome will be one of its next priorities.  Dogs are a great system for understanding diseases and disorders linked to the genes that cause skeletal changes, said UCLA's Wayne. The difference between a Chihuahua and a big mastiff is probably just a handful of genes--and when we find those genes it will be a profound advance in the study of cranial and skeletal development."

The New York Times; 10/8/2002; A New Look at Old Data May Discredit a Theory on Race By NICHOLAS WADE.  Two physical anthropologists have reanalyzed data gathered by Franz Boas, a founder of American anthropology, and report that he erred in saying environment influenced human head shape. Boas's data, the two scientists say, show almost no such effect.Boas measured the heads of 13,000 European-born immigrants and their American-born children in 1909 and 1910 and reported striking effects on cranial form, depending on the length of exposure to the American environment.  But in re-examining his published data, Dr. Corey S. Sparks of Pennsylvania State University and Dr. Richard L. Jantz of the University of Tennessee find that the effects of the new environment were insignificant and that the differences between parents and children and between European- and American-born children were negligible in comparison to the differentiation between ethnic groups, they are reporting today in The Proceedings of the National Academy of Sciences.The new report raises the issue of whether an earlier generation's efforts to play down the role of genetics in fields like behavior and racial variation may not have been carried to extremes. Dr. Steven Pinker, who assigns a larger role to genetics in shaping behavior in his new book, "The Blank Slate, said it was not Boas but his disciples, including the anthropologists Ruth Benedict, Margaret Mead and Ashley Montagu, who "helped establish the blank-slate, social-constructionist, antibiology mindset of the social sciences.

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