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.
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