Tag Archives: race

Variation, Within and Between

Occasionally, you will encounter someone who says this:

Variation between human races is greater than variation within human races

If you do, you know you’ve encountered someone who has been indirectly exposed to the work of Richard Lewontin.

There are two forms of “Lewontin’s fallacy.” One is the original claim that Lewontin made. It is demonstrably untrue, which is obvious once examined with graduate-level statistical knowledge. A later, weaker version is simply nonsensical. I’ll address these in order.

Lewontin’s Original Fallacy

In 1972, Lewontin published an article called The apportionment of human diversity, using blood group proteins. The work is pretty typical for its time, except it extremely political correct connotations, and so eventually took on a life of its own. Rather than discuss the original article, which has been thoroughly debunked, bizarrely focuses on blood proteins anyway, here’s an analogy. (I’m too tired to do matrix algebra now.)

Say someone comes to you, and says this:

“The racial groups that map to what we consider ‘East Asian’ or ‘Caucasian’ do not exist. There is no attribute of either race you can find, in which the majority of variation is between races, rather than within races. Hair, skin tone, skeletal shape, and so on all vary within both populations, so that means there is only one population.

In other words, the groups “East Asian” and “Caucasian” are entirely social groups. It is impossible to write a machine learning system to tell an East Asian apart from a European, if you don’t include purely social constructs like name, clothing style, and so on.

The obvious refutation (which mathematically requires matrix algebra) is to ask why in the world you would use only one dimension of variation (like height, or skin tone) to classify individuals as part of multiple populations.

You can just use multiple indicators, together. That way if there has been a murder, say, and the corpse has been stripped of clothing and identification and has been dumped, you can use multiple indicators together to determine the race of the victim.

If there is DNA evidence, you can do the same.

Indeed, you can do the same with “races” such as “German” and “French”!

european_races

If for some reason you’re transported back to the 1970s, and all you have is blood proteins, you can do the same.

The solution to Lewontin’s fallacy is to use multiple indicators together, and not just one.

These days, it seems crazy to suggest it would be impossible to tell the race of an individual from DNA. There’s even a popular PBS show about the concept! But in the 1970s, some people really were that ignorant.

finding_your_roots

The Remnant that Remains

There’s no reason to take Lewontin’s original fallacy seriously, but sometimes you’ll hear a variation of it

Variation in intelligence between human races is greater than the mean difference of intelligence of the races

This is like saying moisture is taller than speed. It makes no sense.

In some areas of life, differences in variation between groups is the fact that matters most. For instance, on many measures (say IQ, or time orientation) males have greater variation than females, while both tend to have the same average. From this you would expect you would see many more male violent criminals than female violent criminals, and also more male CEOs of large companies than female CEOs of large companies. There is little if any difference in the average of these traits between the sexes. There is substantial difference in the variation of these traits between the sexes, though.

In other areas, averages matter. For instance, the average IQ of American whites from the south-eastern United States is lower than the average IQ of American whites from the northern states. From this you might wonder if large companies have a disproportionately small number of CEOs from the American South, while white southerners have responded to this “dixie ceiling” by organizing politically to obtain political goods that they cannot gain in the marketplace.

I have never seen anyone talk, in a popular setting, about a comparison between a variation on the one hand and an average on the other. Typically one or the other is relevant to the conversation, and bizarre second-order comparisons (what is the variability in height of Australians compared t the average height of South Americans) are simply uninterpretable. But if you’ve never worked with variation as a real thing (through calculating a standard deviation to solve a problem, say), the remnant of the fallacy is a good-guess by an ignorant laymen of what Lewontin may have been talking about.

Conclusion

The phrase “Variation between human races is greater than variation within human races” is meaningless. It either refers to an empirical incorrect claim from the 1970s, on the impossibility of using “blood proteins” to predict race, or an incoherent claim that compares averages against variation.

Some Notes on Class in America

One can classify Americans as belonging to one of several economic classes, including the

  • Grand Bourgeoisie, who are able to live off their investments
  • The Petite Bourgeoisie, who have invested wealth but must work to maintain their life style
  • The Proletariat, who have no invested wealth, and must work to live
  • The Lumpenproletariat, criminals and rascals who are of no economic value.

Competition exists both between and within these classes.

Between-class and within-class competition exists to establish the terms of trade of these classes within society.

While everyday politics can do little to change the terms of trade between classes, it can greatly effect the terms-of-trade within classes.

For instance, the Petite Bourgeoisie in the United States is heavily white, but south asians and east asians are disproportionately represented within it. Nonetheless, all asians combined are still a small minority of the Petite, so the Petite Bourgeoisie  spends most of its efforts on economically pointless cultural conflict (gar marriage, and so on).

The Proletariat, is much more diverse. Both blacks and hispanics are disproportionately represented in the proletariat. Further, unlike the petite bourgeoisie (where whites are a long-running and stable majority), immigration patterns created by the federal government (“the executive committee of the bourgeoisie” have lead to blacks being displaced as the largest minority in general, and even the largest non-white constituent group of the proletariat, by hispanics.

Whites in America really have no idea how hard life can be for blacks. Whites, whose leadership springs firmly from the petite bourgeoisie, are basically secure in their positions. In order to understand the plight of their fellow citizens, it is perhaps wise to imagine a United States in which Asians were already the dominant ethnic group.

The art of deciding who gets what is called politics. While political cartels can form among nearly all players in well established political communities, the immense tide of hispanic immigration in recent years means that it is impossible for factions within the proletariat to form a cartel without hispanic hegemony within that class. In the absence of a well established political community, the tools that will be used are democracy and organized violence. Democracy is a useful tool of the popular and numerous. Organized violence is the useful tool of the weak and small.

The lynching of George Zimmerman — the hispanic involved in a fatal confrontation with Treyvon Martin — only makes sense in the context of intraclass struggle. Organized violence — such as the eldery man beaten by 6 youths, the police car attacked, the death threats against the Zimmerman household etc — are clearly part of a LIHOP run by Al Sharpton on others to use the only means left at their disposal to save what remains of their hegemony within the proletariat.

People are murdered every day in the United States. Nothing’s special about that. No one cares.

What is unusual is for anyone to care.

And people do care in the case of Mr. Zimmerman.

Because lynching a hispanic is way cheaper for the petite bourgeoisie than facing a campaign of organized violence.

White petite bourgeoisie were getting hurt. Lynch a hispanic proletarian, and it all goes away.

A good deal, no?

A New People

We create a new people. Instead being refugees we we to be fighters. This very important. We were refugees. Harmless. We become now fighters. Freedom fighters. The next stage, you will see….

Yasser Arafat

We live in a world, radically artificial twice over, and we haven’t begun to see what it will hold.

tdaxp, 5 years ago

Razib Khan notes some new research on the possible identification of a gene that seems to encourage for brain size, and general intelligence. Interestingly, this gene ‘for’ larger brains and higher intelligence appears to be most present in African populations:

This is actually a good point to describe how races may will survive long after any racial difference in intelligence can be imputed through skin color.

Consider if the C version of the gene really is associated with lower and higher intelligence. If so, it should be a “simple” matter of engineering a retrovirus that would infect an embryo, fetus, or child in the womb in order to direct the DNA to code for one version, instead of the other.

Of course, this procedure will have risks, and doubtless be fatal in some cases.

Now consider that we’re able to make a retrovirus, fine-tuned to the individual, that could create a 15 point increase in general intelligence (say, the average difference between a 3rd year college drop out and an M.D; or between an average Gentile and an average Jew on a standardized verbal intelligence test), with the slight side-effect that a fourth of all unborn children treated with such a retrovirus will die before birth.

No developed society that values its children will engage in such a practice on a wide scale.

But a few poor and backwards societies might. Supposedly, Saddam Hussein (in his pre-war days) abolished illiteracy by announcing, a few years in advance, that illiteracy would be a capital crime. Most people got the message. Others got shot.

Highly centralized states are able to take large risks. The Chinese experience under Mao and Deng show how very similar leadership styles and personal backgrounds can lead to the greatest elimination of poverty in history (under Deng‘s economic reforms), or the greatest elimination of the poor in history (under Mao‘s autogenocidal policies).

Some country we don’t care about too much — perhaps Somaliland or Azawad — is in for a wild 21st century.

There would still be Somalis or Azawadis.

But they’d be a new people.

The recent origins of black female hostility to miscegenation

My friend Michael sent me a copy of “The aftermath of Loving v. Virginia: Sex asymmetry in African-American intermarriage,” by R. Richard Banks (PDF). The piece is an attack on stereotypes of black marriage nand miscegenation: educated black females are more likely to marry than uneducated black females, the difference socio-economic status between black husbands and white wives is comparable to the different among white husbands and white wives, and, most strikingly, that the skew in African-American interrmarriage (where black men are much more likely to outmarry than black woman) is recent.

While nowadays black-white marriage is stereotypically between a black man and white woman, going back just a few decades presented a more gender-balanced picture. The case that declared anti-miscegenation laws unconstitutional, Virginia v. Loving, was fought on behalf of a white husband and black wife. Likewise, the famous movie Guess Who’s Coming to Dinner, features two interracial romances: one between a black man and white woman, the other between a white man and black woman.

Banks’ piece is very well written. My only complaint is that it is not long enough! It reads like a literature review to a great analytical piece, and hopefully that second section is coming at a later time.

Read it (PDF).

The Races of the Ancients

Genetics is fascinating. The study of population structure — those nations and races that make of humanity — has been infinitely improved by careful analysis of our genes. DNA has replaced the imprecise tools of facial features, skin color, and linguistics as the best tool for understanding the group-level diversity we see today. It was once thought (at least 10 years ago, when I came upon the theory) than the Ashkenazi Jews were an inbred German population, given their Germanic language (Yiddish) and looks that were taken to be exaggerations of European features. It is now generally accepted that the Rhinelander Jews are a Southeast European/Levantine population that at one time were more numerous than “white” Europeans.

Genetics continues to look at these subpopulations — races, you might say — deeply. Now comes an article on two ancient races, that existed for half of humanity’s history — entirely on the African continent:

Mitochondrial Eve And Humanity’s 100,000 Year Genetic Divide | Scientific Blogging
The human race was divided into two separate groups within Africa for as much as half of its existence, says a Tel Aviv University mathematician. Climate change, reduction in populations and harsh conditions may have caused and maintained the separation.

Dr. Saharon Rosset, from the School of Mathematical Sciences at Tel Aviv University, worked with team leader Doron Behar from the Rambam Medical Center to analyze African DNA. Their goal was to study obscure population patterns from hundreds of thousands of years ago.

Rosset, who crunched numbers and did the essential statistical analysis for the National Geographic Society’s Genographic Project, said the team was trying to understand the timing and dynamics of the split into at least two separate groups.

Recent data suggests that Eastern Africa went through a series of massive droughts between 90,000 and 135,000 years ago. It is possible that this climate shift contributed to the population splits. What is surprising is the length of time the populations were separate — for as much as half of our entire history as a species.

Dr. Spencer Wells, director of the Genographic Project and Explorer-in-Residence at the National Geographic Society, said, “This new study illustrates the extraordinary power of genetics to reveal insights into some of the key events in our species’ history. Tiny bands of early humans, forced apart by harsh environmental conditions, coming back from the brink to reunite and populate the world. Truly an epic drama, written in our DNA.”

While much of this research is conducted because of scientific curiosity, the engine that keeps it going is pharmaceuticals. There’s big money in genes, in changing how they express themselves and even changing which ones are in a body. As we resurrect long-dead plants and animals, it will be fascinating to see how many “extinct genes” rise again through gene therapy and modern medicine.

AJ as a larger ancestral population than CEU


Once one of the largest races of man? Or just almost no whites?

From Dienekes and gnxp, part of the conclusion of “Analysis of genetic variation in Ashkenazi Jews by high density SNP genotyping” (pdf):

There were small but significant differences in measures of genetic diversity between
AJ [Ashkenazi Jewish] and CEU [Utah whites from the HapMap sample]. Analysis of genome-wide LD structure revealed a greater number of haplotype blocks which tended to be smaller in AJ. There was essentially no difference in global LD decay between AJ and CEU, although there was a tendency for faster decay of nearby SNPs and slower decay of intermediate distance SNPs in the AJ. These data are more consistent with the AJ as an older, larger population than CEU, and would suggest that, depending on regional differences in LD structure, AJ populations may not always provide an advantage for whole-genome association mapping.

I asked:

Re: the population sizes, would a more reasonable non-mathematical rendering be that the smallest AJ bottleneck was larger than the smallest CEU bottleneck, or the average AJ population size was larger than the average CEU population size?

And the Henry Harpending (you may remember him) replied:

Re Dan’s question: either answer could be right. Instead of thinking about effective size think of the inverse of effective size, (1/Ne), which is the rate of diversity loss. This inverse can be averaged over time, like any speed. A bottleneck has a much larger effect on the average of (1/Ne) than it does on average Ne.

Will this put an end to the talk about a bottleneck in Ashkenazi history and about Ashkenazi disorders being the result of drift?

This is what is so exciting about widespread genetic testing: not only can we actually get answers for some old questions (are there different genepools within the human race? yes) we can ask questions that never would have occured to us before (what was the last year when Jews outnumbered whites?).

Race Wars

Robert Paterson reports on the horror-show violence in Kenya. Among other problems, Kenya is undergoing a ethnic/race-war between the Kikuyu, the Luo, and their affiliates.


The Master Race?

Racial violence is relatively rare in the Core, but occurs in microgaps, such as parts of Los Angeles and federal prisons.

Racial/ethnic violence is a form of insurgency, attempting to replace the State with “primary loyalties.” Race warriors should therefore be classified as insurgents, and (except for those who wear racial/gang insignia) unlawful combatants, as well.

Hate crime laws are probably a good idea, but msinamed, as they fight not crime, but war.

Review of "Before the Dawn" by Nicholas Wade

The front cover of New York Times-reporter Nicholas Wade’s new book, Before the Dawn, contains a quote by E.O. Wilson: “By far the best book I have ever read on humanity’s deep history.” I couldn’t agree more. Before the Dawn is more informative than Nature via Nurture, more readable than The Blank Slate, and proves (contra The Emperor’s New Clothes) that popularizations of population genetics don’t have to be deceitful and revolting.


The Lost History of Our Ancestors

Before the Dawn dwells on several major events in the human story: separation from chimpanzee-ancestors, the end of seperate sex hierarchies with the introduction of pair bonding, physically modern human, behaviorally modern human, and socially modern humans. From a founder population fo 150, the first behaviorally modern human beings who left Africa at the Gate of Grief would conquer three other human species (Neanderthals, Erecti, and Hobbits) and within fifty thousand years spread an African species all over the face of the world.

Every chapter in Before the Dawn is worth reading, but several stand out as some of the best in the history of scientific nonfiction: “Genetics & Genesis” outlines the author’s plan of attack, “Genesis” describes mitochondrial Eve and Y-chromosome Adam, “Exodus” tells of the seafaring conquest of the Coasts in the face of Erecti resistance to Australia, the second truly human continent, “Race” addresses the major family groupings of man, “Language” applies genetic technology to recovering the time and place for the first human tongue, and “Evolution” recaps the book and looks forward to the next human species.

Nick Wade is a science columnist for the New York Times, and his journalist touch is fully worked. I learned more about the Thomas Jefferson- Sally Hemmings twist than I did before, including that Sally his the half-sister of Tom’s first wife. The unique haplotypes of Icelanders and Jews are discussed. and the interesting that the current races appear not to have existed 15,000 years ago give one much to chew on.

Before the Dawn is very up to date, and includes fair criticism of Evolutionary Psychology that comes from our increased understanding of genetics. When John Tooby and Leda Cosmides founded EP, it was reasonable to presuppose that substantive human evolution had ended by the late stone age. That assumption is no longer tenable. We are not modern humans with stone-aged minds. We are modern humans with modern minds.

This great book has already made a buzz. John Derbyshire of The National Review loves it, while Nature hates it.

Before the Dawn is available for $15.72 from Amazon.com, and for $19.96 from Barnes & Noble.

Evolutionary Cognitivism, Part V: Man Among Men

I believe, as Bjoyklund & Pellegrini (2002, 193) do, “that the evolution of the human species’ unique intelligence was motivated by the need to deal with other members of our social group.” I think a large humanity’s genetic inheritance – that which is universal to all people as well as that which is particular to one breeding population (that is, race) or another – is the result of the coevolution of genes and society.

Human-general adaptations are well described by the text. This species general social cognition (which the text describes as “cognition about social relationships and social phenomena” on page 193) include things such as social learning, a theory of mind, and cheater detection. Social learning, which ranges from local enhancement and mimicry to emulation and imitation (194-196) involves learning because of the actions of others. Some creatures are born with everything they need to survive, but humans need to be able to learn a culture to survive. The theory of mind assists in social learning by informing individuals that “other people have knowledge and desire that may be different from one’s one” (203), and the mental processes this fact entails. Relatedly, cheater detection, or the ability to use “deontic reasoning, which is reasoning about what one may, should or out to do” (216) allows us to effortlessly discover those who have violated social rules.


The book leaves out adaptations that are related to different human populations. This is not surprising, as most Evolutionary Psychologists are skeptical of race-specific adaptations (Kurzban, Tooby, & Cosmides, 2001), preferring instead to believe that most adaptations occurred in the late stone age and thus are shared by all human beings are genetically very similar (Tooby & Cosmides, 1992, 2005). Nonetheless, some issues should be address. Phenotypic differences directly impacting athletic ability vary between Africans, Europeans, and Orientals (Rushton, 2000). One possibility is that this is an adaptation to different physical environments, these could equally be social adaptations. If different cultural styles existed in these physical locales for a sufficiently long duration (perhaps no more than four hundred years, see see Pinker, 2002, 111, or a few thousand, see Buller, 2005, 56) then evolution would lead to adaptations for that cultural style.

Perhaps a less speculative case of society-specific genetic adaption comes via research into HIV and AIDS. A genetic factor that increases the risk of aquiring AIDS is higher in Africans than non-Africans (Gonzalez, et al., 2001) and a mutation that slows-down AIDS was found in Europeans but not non-Europeans (Martinson, Chapman, Rees, Lui, & Clegg, 1997). While some may view such findings as evidence that HIV is a tool of genocidal warfare devised by a racist elite (Ross, Essien, & Torres, 2006), perhaps a more likely explanation is that a disease similar to AIDS has previously ravaged the European race before dieing out. Thus, cultural phenomenona related to the spread of an HIV-like sexually transmitted disease effected the evolution of one human breeding population but not others.

There are other examples of selection by society as well. European adult lactose tolerance, for example, appears to be a relatively recently adaptation that increased dairy farming, which in turn spread the lactose tolerant genes (Bersaglieri, et al., 2004). A more brutal example may be possible strong positive selection for intelligence in Jews as a result of centuries of hateful persecution and bigotry (Cochran, Hardy, & Harpending, 2005) Others have gone into this area in some detail (Wrangham, 2005). My purpose here is merely to applaud Bjorklund & Pellegrini for emphasizing the power of society in shaping our psyches, and outline other ways society achieved the same ends in diverse groups of people.

The authors close their chapters discussing ways development may influence species evolution. They write that not only social complexity, similar to the dairy example mentioned above, but also “extension of the juvenile period may have prompted modifications of reasing conditions, which in turn led to the ability to understand the intention of others and eventually the creation of culture” (218). I wonder if this impacts human group diversity as well, in a racial, clinal, or some other sense. Could some breeding populations of man have a more extended juvenile period than other. If juvenile period extension is indeed linked with eusociality, are some populations more eusocial than others. Or, in the juvenile period is linked with more rambunctousness, may children from some parts of the world do best in more chaotic conditions than others? I do not know, and nothing I have read answers this question for me. Hopefully in the future, great evolution cognitive psychologists like Bjorklund & Pellegrini will find this out. Science will progress.

Bibliography
Bersaglieri, T., et al. (2004). Genetic signatures of strong recent positive selection at the lactase gene. American Journal of Human Genetics 74: 1111-1120.
Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Buller, D.J. (2005). Adapting Minds. MIT Press: Cambridge, MA.
Cochran, G., Hardy, J., & Harpending, H. (2006). Natural history of Azhkenazi intelligence. Journal of Biosocal Science 38: 659-693.
Kurzban, R., Tooby, J., & Cosmides, L. (2001). Can race be erased? Coalitional computation and social categorization. PNAS 98(26):15387-15392.
Gonzalez, E., et al. (2001). Global survey of genetic variation in CCR5, RANTES, and MIP-1alpha : Impact on the epidemiology of the HIV-1 pandemic. PNAS 98(9): 5199-5204.
Pinker, S. (2002). The Blank Slate: The Modern Denial of Human Nature. Viking Adult: New York, NY.
Ross, M.W., Essien, E.J., & Torres, I. (2006). Conspiracy beliefs about the origins of HIV/AIDS in four racial/ethnic groups. Journal of Aquired Immune Deficiency Synddrome 41(3): 342-344.
Rushton, J.P. (2000). Race, evolution, and behavior: A life history perspective (3rd edition). Port Huron, MI: Charles Darwin Research Institute.
Martinson, J.J., Chapman, N.H., Rees, D.C., Lui, Y.T., & Clegg, J.B. (1997). Global distribution of the CCR5 gene 32-basepair deletion. Nature Genetics 16(1): 100-103.
Tooby, J., & Cosmides, L. (1992) The Psychological Foundations of Culture. In The Adapted Mind, Jerome Barkow, Leda Cosmides and John Tooby, eds. New York: Oxford University Pres.
Tooby, J. & Cosmides, L. (2005). Evolutionary psychology: Conceptual foundations, in David M. Buss (Ed.), Handbook of Evolutionary Psychology. New York: Wiley.
Wrangham, W.H. (2005). Interaction of genetic and cultural evolution: Models and examples. Human Ecology 10(3): 399-334.


Evolutionary Cognitivism, a tdaxp series
1. Selection and Cognition
2. Epigentics and Diversity
3. Children and Civilization
4. The Implicit and the Explicit
5. Man Among Men
6. More Than Genes
7. Bibliography

Evolutionary Cognitivism, Part III: Children and Civilization

For most of hominid evolution, newer meant bigger. Newer species had bigger brains than older ones, and later members of a species had bigger brains than earlier members (Rightmire, 2001). And for generations researchers have puzzled over the Neanderthal’s quick demise (Hrdlicka, 1927), especially puzzling in light of apparently developed communicative abilities (Arsenburg, Tilier, Vandermeersch, Duday, Schepartz, & Rak, 1989) and the fact that some Neanderthals may be more closely related to humans than other members of their own species (Paablo, 2003). Yet fifteen thousand years ago the human brain began shrinking (Ridley, 2003). Though perhaps the decline is older than that – Neanderthals may have had larger brains than we do (Klein, 2003).

I do not know what this means. We know that “within primates the relative size of the neocortex is significantly correlated with group size” (Bjorklund & Pellegrini, 2002, 102). We like to think that our brains make us special, though apparently the seemingly-simpleminded purposes are large-brained as well (92). Additionally, considering that “brain size is correlated (negatively) with litter size” and that larger-brained “animals tend to have smaller litters and to give birth to infants at longer intervals” (97), this implies that modern humans are more expendable and less precious than our ancestors of fifteen thousand years ago, or even the ancient Neanderthals! Clearly humans are evolving, but how and why?


Bjorklund & Pellegrini give hints of an answer. They write that “brain growth continues into adolescence” (100) and (quoting Bjorklund & Green, 1992) “lessons learned as a young child will not interfere with the qualitatively different tasks required of an adult” (108). These facts must be synthesized with a view of evolution that leads to us, an agricultural species, to having smaller brains and the Neanderthals, another recent non-agricultural species, to have larger ones. The most likely explanation to me is that human agriculture allowed even young children to become productive workers, as there are a myriad of tasks on a farm requiring little muscluar or intellectual strength (such as feeding chickens, etc.), and that human society allowed the formation of an “anatomically distinct worker caste” (Wilson & Holldobler, 2005, 13368). In other words, children are something like worker bees, who learn lessons appropriate for worker bees, but upon adolescence are able to be reprogrammed to be functioning adults. Thus the claim that “childhood and adolescence, are not observed in any other species” (Bjorklund & Pellegrini, 2002, 99) misses the mark – asexual workers exist in many species, and adolescence is a form of functional cocooning. And this is why (quoting Mason, 1968) “Developmental stages are less sharply delineated in humans than in other primates. Sensitive periods in development are more difficult to establish…” (Bjorklund & Pellegrini, 2002, 106): humans develop twice, once into a worker, and then into an adult.

Clearly, a view of children as “worker humans” should not be taken to extremes. Deprived environments will hamper children through the rest of their lives (Bjorklund & Pellegrini, 2002, 105) and children are safer when cared for by biological parents (Buller, 2005). Yet many children are surprisingly resilient to early traumas (Caspi, et al., 2003) and the traits that predict criminality may be largely heritable (Pinker, 2002, 315) so most children may be all but assured a good life. Other policy implications of resilient cihldren – everything from social services to educational styles – are too many to list.

Yet this gets me away somewhat from my primary question, about brain size. Clearly it would be possible for humanity to develop children as a worker caste without limiting the skull size of adults. Even if skull size and less reproductively valuable children correlate, unless these effects are caused by the same alleles there still has to be a reason for our smaller brains. My guess is that this is also from socialization, and that there is less need for us to think now that we have evolved to live in agricultural communities. If a caveman is largely on his own, with only his band to protect him, he must be a jack-of-all-trades. Everything from possible ritual cannibalism (White, et al., 1991) to warfare (Zollikofer, Ponce de Leone, Vandermeersch, & Leveque, 2002) would have to be done with the same band, meaning a successful live with a cognitively flexible life. However, humans in a modern economy rely on others for most of their needs, and they only need to learn a few things well. Thus the human brain may be evolved to be a specialist – an extraordinary mind (Gardner, 1998) — in only one domain, and a naïve generalist in others. Anyway – that’s my guess.

Bibliography
Arensburg, B., Tillier, A. M. , Vandermeersch, B. , Duday, H., Schepartz, L. A. & Rak, Y. (1989). A Middle Palaeolithic human hyoid bone. Nature (338): 758-760.
Bjorklund, D.F. & Green, D.L. (1992). The adaptive nature of cognitive immaturity. American Psychologist 47: 46-54.
Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Buller, D.J. (2005). Adapting Minds. MIT Press: Cambridge, MA.
Capsi, A., et al. (2003). Influence of Life Stress on Depression: Moderation by a Polymorphism in the 5-HTT Gene. Science. Vol. 301 No. 5631 pp. 386-289.
Gardner, H. (1998). Extraordinary Minds. Basic Books: New York, NY.
Hrdlicka, A. (1927). The Neanderthal phase of man. The Journal of the Royal Anthropological Institute of Great Britain and Ireland 57: 249-274.
Klein, R.G. (2003). Whither the Neanderthals? Science 299(5612): 1525-1527.
Mason, W.W. (1968). Early social deprivation in the nonhuman primates: Implications for human behavior. In D.C. Glass (Ed.), Environmental influence (pp. 90-101). New York: Rockefeller University Press.
Paabo, S. (2003). The mosaic that is our genome. Nature 421: 409-412.
Pinker, S. (2002). The Blank Slate: The Modern Denial of Human Nature. Viking Adult: New York, NY.
Ridley, M. (2003). Nature via Nurture. Harper Collins: New York, NY.
Rightmire, G.P. (2001). Brain size and encephalization in early to Mid-Pleistocene Homo. American Journal of Physical Anthropology 124(2): 109-123.
White, T.D., et al. The question of ritual cannibalism at grotta guattari [and comments and replies]. Currently Anthropology 32(2): 118-138.
Wilson, E. O., & Holldobler, B. (2005). Eusociality: Origin and Consequences. PNAS 102(38)-13367-13371.
Zollifoker, C.P., Ponce De Leone, M.S., Vandermeersch, B., & Leveque, F. (2002). Evidence for interpersonal violence in the St. Cesaire Neanderthal. PNAS 99(9): 6444-6448.


Evolutionary Cognitivism, a tdaxp series
1. Selection and Cognition
2. Epigentics and Diversity
3. Children and Civilization
4. The Implicit and the Explicit
5. Man Among Men
6. More Than Genes
7. Bibliography