Tag Archives: Cognition

Evolutionary Cognitivism, Part VI: More Than Genes

The central realization of Bjorklund & Pellegrini’s text is on page 335: “Evolutionary developmental psychology assumes that not only are the behaviors and cognitions that characterize adults the product of natural selection, but so are characteristics of children’s behaviors and minds.” For too long educators have assumed that children are incompetent adults when in fact they are competent, and adapted, as children. When we ignore this, or fight this, we place outside normative concerns about the vital task of educating children.

To their credit, the authors tackle this subject. They write that “formal school may represent the best example of the ‘evolved-mechanisms-are-not-always-currently adaptive principle” (340). Bjorklund & Pellegrini are surely write on the same page that “just because some tendencies… are ‘naturally” based on evolutionary examination does not mean that they are morally ‘good’ or inevitable,” surely it is morally wrong to ignore these differences out of a concern for political correctness. If our job as educators is to get the best from every student, then we must leverage the nature of those students.


For instance, the authors also report that “Beginning during the preschool years, boys in all cultures (and males in many nonhuman mammalian species) display higher rates of rough-and-tumble play (R&T) than girls” (338). The implication of this is that boys and girls run different sets of genetic programs, or at least genetic programs tuned in different ways, and are optimized for different environments. It may well be, for instance, that boys would do better with schooling where R&T play was used as a reward for academic achievement while girls would do best in an environment where R&T is absent. Unfortunately, our school system does not recognize this, and we pretend that both boys and girls can be optimally educated in a classroom designed for a generic, sex-neutral “child.”

Other changes may be more controversial, but should be addressed. If we expect the best out of each student, is it wise to expect all students to exceed in all areas? For instance, if there is a biological component to mathematical reasoning ability in which boys score higher (Benbow, 1988; Benbow, Lubinski, Shea, & Eftekhari-Sanjani, 2000), or a biological component to language ability in which girls score higher (Stanley, 1993) . Similarly, if males show more variation in many attributes, from chess ability to physical height (Howard, 2004). For that matter, if height predicts IQ when correcting for environmental variation (Magnusson, Rasmussen, & Gyllensten, 2006; Silvertoeinen, Posthuma, van Beijsterveldt, Bartels, & Boosma, 2006) would it make sense to divide a similarly age cohorot into classes by height than the current, semi-random system? Alternatively, if we prefer a policy of “dumbing-down” anti-elitism (Benbow & Stanley, 1996) then should this not be decided rationally and openly, instead of being the default result of the status quo?

On another note, I found the Bjorklund & Pellegrini’s concept of culture fascinating. For culture I what I think they mean when they write “[Infants are born with] epigenetic programs that have evolved over eons and are responsive to the general types of environments that our ancient ancestors experienced.” Bjorklund & Pellegrini share with Tooby & Cosmides (1992) an idea that genes and environment interact to produce behavior, this text’s author stress that “biological and environmental factors at multiple levesl of organization transact to produce a particular pattern of ontogeny” (335). This “developmental systems approach” teaches us to view culture not merely as a set of arbitrary dictates, but as a darwinian algorithm that has evolved just as our genes have evolved. We are rightfully fearful of large-scale genetic engineering because we do not understand how such complex machinery works. We should equally be fearful of large-scale social engineering because society, no less so than genetics, as both are equally part of our epigenetic inheritance. Both are programs designed to keep us alive in a species-typical environment.

Bibliography
Benbow, C.P. (1988). Sex differences in mathematical reasoning ability in intellectually talented preadolescents: Their nature, effects, and possible causes. Behavioral and Brain Sciences 11: 169-232.
Benbow, C.P. & Stanley, J.C. (1996). Inequity in equity: How “equity” can lead to inequity for high-potential students. Psychology, Public Policy, and Law 2(2): 249-292.
Benbow, C.P., Lubinski, D., Shea, D.L., Eftekhari-Sanjani, H. (2000). Sex differences in mathematical reasoning ability at age 13: Their status 20 years later. Psychological Sciences 11(6): 474-80.
Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Howard, R.W. (2005). Are gender differences in high achievement disappearing? A test in one intellectual domain. Journal of Biological Sciences 37: 371-380.
Magnusson, P.K.E., Rasmussen, F., & Gyllensten, U.B. (2006). Height at age 18 years is a strong predictor of attained education later in life: cohort study of over 950 000 Swedish men. International Journal of Epidemiology 35(3): 658-663.
Silvertoinen, K., Posthuma, D., van Beijsterveldt, T., Bartels, M., & Boosma, D.I. (2006). Genetic contributions to the association between height and intelligence: evidence from Dutch twin data from childhood to middle age. Genes, Brain, and Behavior 5(8): 585-595.
Stanley, J.C. Boys and girls who reason well mathematically. Ciba Foundation Symposium178: 119-134.
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.


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 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 IV: The Implicit and the Explicit

I am a big fan of Bjorklund & Pellegrini’s fifth chapter, “Classifying Cognition.”

The text divides thinking into “implicit” and “explicit” (2002, 114) thinking. This “implicit” thinking appears to be the same thing as “automatic,” “peripheral,” “heuristic,” and “unconscious” while “explicit” appears to be the same thing as “controlled,” “central,” “systematic,” and “conscious” (Morris, Squires, Taber, & Lodge, 2003, 4). Additionally, implicit memory is refered to as “Memory System I” and explicit memory is called “Memory System II” (Bjorklund & Pellegrini, 123).

One of the text’s most interesting sections is the application of implicit attitude tests on very young children. For instance, even if they could not answer a question about remembering old students, children act as if they recall old kindergarten classmates (119-120). The authors also mention other research (Clements & Perner, 1994) showing how implicit belief becomes more reliable than explicit belief before the child is three years old. This implicit superiority continues throughout life. It is interesting that explicit thinking has such little access to one’s implicit state, as self-reports can be unreliable predictors of behavior (Kurzban & DeScioli, 2005).


Not that all implicit attitudes are necessarily good, however: research implying a possible human predisposition towards xenophobia (Hammond & Axeldor, 2006) and research that shows that whites and blacks both hold negative implicit attitudes of blacks (Bower, 2006) show the potentially negative effects of implicit cognition, as well.

Bjorklund & Pellegrini also describe Donald’s (1991) division of the levels of culture into “episodic culture,” “mimetic culture,” “mythic culture,” and “theoretic culture” (123-124). However, if they are describing Donald’s work correctly I must disagree with Bjorklund & Pellegrini. In particular, I do not believe our ancestors were as primitive as this theory purports, nor as we so developed. The theory assumes that chimpanzees and early men live “entirely in the present” without “imitation, in which one individual represents the actions and goals of another and attempts to reproduce the the outcome archived by another…” However, complicated cultures with varying styles of dominance, grooming, and food gathering exist even within baboons (Sapolsky & Share, 2004). As it appears that primatese use technology together social strategies to achieve what they want (Tomasello & Call), I do not see how there is evidence deying chimpanzees access to mimetic culture.

Likewise, while it is clear that humans have access to “external symbolic storage systems” (Bjorklund & Pellegrini, 124) and other gizmos, I do not think that much of human behavior progresses much beyond mimetics. That is, while the development of moral reasoning and personal identity (see, for example, Moshman, 2005) would seem to follow theoretic or at least mythic cultural paths, I don’t think these things influences behavior that much. This ties into what I wrote above. One theory for why self-reports are so bad is that most behavior is driven by automatic processes the conscious brain simply does not have access to (Lieberman, Schreiber, & Ochsner, 2003). For instance, while moral reasoning is associated with some (but not other) forms of pro-social behavior (Eisenberg-Berg & Hand, 1979). I am not aware of any research demonstrating students who have more advanced moral reasoning behave more “morally” because of this reasoning (as opposed to students who learn moral reasoning acting more morally anyway, etc). This sentence is written out of ignorance – I simply don’t know the field that much – but I am skeptical that most human social behavior is more complicated than memetic culture.

On the whole, my take on this chapter is this: humans have very well developed and well evolved implicit memory and cognitive structures, which they use nearly all the time. Animals as well have very well developed and well evolved (for their typical lives) implicit memory and cognitive structures, which they use nearly all the time. Humanity is distinguished, not by a reliance on explicit memory and explicit cognitive structures, but by more explicit structures than other animals. Thus we are more reasonable and rational than other creatures in the jungle. But i do not believe that we are more reasonable and more rational than the reverse.

Bibliography
Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Bower, B. (2006). The Bias Finders: A Test of Unconscious Attitudes Polarizes Psychologists. Science News, 169(16), 250.
Clements, W.A., & Perner, J. (1004). Implicit understanding of belief. Cognitive Development 9: 377-395.
Donald, M. (1991). Origins of the modern mind: Three stages in the evolution of culture and cognition. Cambridge, MA: Harvard University Press.
Eisenberg-Berg, N. & Hand, M. (1979). The relationship of preschoolers’ reasoning about prosocial moral conflicts to prosocial behavior. Child Development 50(2): 356-363.
Hammond, R., & Axelrod, R. (2006) The Evolution of Ethnocentricism. Journal of Conflict Resolution, 50(6).
Kurzban, R., & DeScioli, P. (2005) “Characterizing reciprocity in groups: Information-seeking in a public goods game,” (Submitted), alternate draft at http://www.psych.upenn.edu/~descioli/kurzban%20descioli%20p
Lieberman, M., Schreiber, D., & Ochsner, K. (2003). Is Political Cognition Like Riding a Bicycle: How Cognitive Neuroscience Can Inform Research on Political Thinking. Political Psychology, 2003, 24(4), 681-704.
Morris, J., Squires, N., Taber, C., & Lodge, M. (2003). “The Automatic Activation of Political Attitudes: A Psychophysiological Examination of the Hot Cognition Hypothesis,” Political Psychology, 24, 727.
Moshman, D. (2005). Adolescent Psychological Development (2nd ed.). Mahwah, NJ: Lawrence Erlbaum Associates.
Sapolsky, R.M. & Share, L.J. (2004). A pacific culture among wild baboons: Its emergence and transmission. PloS Biology 2(4): e106.
Tomasello, M & Call, J. (1997). Primate Cognition. New York: Oxford University Press.


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

Evolutionary Cognitivism, Part II: Epigenetics and Diversity

The question of group-level human variation has been a hot one. Some research argues for continental, race-like groupings in which there is more variation between groups than within them (Jorde, et al., 2000) and that self-identified race is a reliable predictor for one’s genetic heritage Tang, et al,, 2005). Other research suggests while there is group-level genetic variation, it exists within a gradation of populations and not a small number of historically isolate draces (Serre & Paabo, 2004). While it is increasingly recognized that early scientific research, such as Lewtonin 1970, which denied any meaningful group-level variation was overly simplistic (Edwards, 2003). Though studies which look at only a few phenotypes continue to find little intergroup variation (Relethford, 2002), broad studies find definite intergroup variation (Rosenberg, 2005) and intragroup similarity (Rosenberg, et al., 2006) Several portions of Bjorklund & Pellegrini’s (2002) third chapter, History and Controversy, also hint at ways that human groups could be more different from each other than once thought.

One way that biological group level variation can increase is if experience can somehow be paseed from parent to child. For instance, even if two populations are genetically very similar, if they face different environments, and the effects of the environment can be passed down, you could have biologically-based differences in only one generation. This was once considered anathema to modern biology: Bjorklund & Pellegrini write that “Inheritance, and thus genetic variation, is found only within the germ line and is not influenced by experience” (47). However, i tis now recognized that “physical” and “behavioral” changes can be passed on (53). An early example of this was Jean Piaget’s experiment with epigenetic snails (54). In contemporary jargon, we should say that “females pass on cytoplasm (i.e., the cell body) to their offspring [and so environmental] changes that induce chemical changes in the cytoplasm can thus be inherited through the motehr but not through the father” (56). On the same page, the authors note that while this cytoplasm is not itself genetic, “Cytoplasmic inheritance should not be thought of as nongenetic [because] it necessarily expressed its effect on the genes.”


It’s relatively easy to imagine how this could work. Imagine two otherwise similar populations which are divided from each other. This division forces both to become relatively self-contained breeding populations and leads to differences in diet, with one population eating nutritious food and the other near starvation. After just a few generations, cytoplasmic variants adept to surviving and reproducing in starvation-conditions could become very widespread in the one population, while an opposite set of cytoplasmic variants become widespread in the other population. Frighteningly, this may be happening in Korea. The height difference between North and South Koreans is already four inches (Ser & Team, 2006). If some of this difference is epigenetically, cytoplasmically inherited, this could create a de-facto “racial” divide among Koreans that might last centuries, even after a return to environmental equality.

Non-coding DNA is another thing that may have led to a discounting of human intergroup genetic diversity. Bjorklund & Pellegrini describe this DNA as “dormant” and “underused” (57). However, the 97% of our genome that is intergenetic “can have dramatic effects on the way that nearby genes are activated to make proteins” (Pinker, 2002, 78). One such piece of junk DNA, Dopamine Receptor D4 7 Repeat – has been tied to ADD and novely seeking (Laucht, Becker, & Schmidt, 2006). As earlier studies of human differences focused on coding DNA, such as protein loci and blood group loci (Latter, 1980), these studies have essentially just ignored 97% of human genetic difference. This is especially sad as junk DNA can be inserted into RNA, thus becoming functional (Lev-Maor, Sorek, Shomron, & Ast, 2003).

Yet the idea of intergroup genetic diversity among homo sapiens causes controversy. Indeed, the idea that genes matter in the human species causes controversy Richard Lewtonin, whose work denying the existence of races was cited earlier, famous accused E.O. Wilson of mirroring “the ideologies of the bourgeois revolutions of the eighteenth century” (Ridley, 2003, 243). How much more disturbing it might be if not only do children already know about “language… objects… and social relations” (Bjoklund & Pellegrini, 2002, 61), but that groups of children vary in their knowledge of these objects. For instance, if one group has a higher general intelligence ability while another group as a higher rythmatic intelligence (Lynn, 2006). Does this imply that one genetic grouping is more valuable than another?

The answer, of course, is no. As Steven Pinker (2002, 145) wrote “The case against bigotry is not a factual claim that humans are biologically indistinguishable. It is a moral stance…” We are all equally human. We are all equally valuable. No evidence, ever, could change that.

Bibliography
Bjorklund, D. F., & Pellegrini, A. D. (2002). The origins of human nature: Evolutionary developmental psychology. Washington, DC: American Psychological Association.
Ding, Y., et al. (2002). Evidence of positive selection acting at the human dopamine receptor D4 gene locus. PNAS, 99(1) 309-314.
Edwards, A.W.F. (2003). Human genetic diversity: Lewtonin’s fallacy. BioEssays 25(8): 798-801.
Jorde, L.B., Watkins, W.S., Bamshad, M.J. Dixon, M.E., Ricker, C.E., Seielstad, M.T., & Batzer, M.A. (2000). The Distribution of Human Genetic Diversity: A Comparison of Mitochondrial, Autosomal, and Y-Chromosome Data. American Journal of Human Genetics
Latter, B.D.H. (1980). Genetic differences within and between populations of the major human subgroups. The American Naturalist 116(2): 220-237.
Laucht, M., Becker, K., & Schmidt, M.H. (2006). Visual exploratory behaviour in infancy and novelty seeking in adolescence: two developmentally specific phenotypes of DRD4?. Journal of Child Psychology and Pschiatry 47(11): 1143-1151.
Lev-Maor, G., Sorek, R., Shomron, N., & Ast, G. (2003). The birth of an alternatively spliced exon: 3` splice-site selection in Alu exons. Science 300(5623): 1288-1291.
Lewontin RC. The Genetic Basis of Evolutionary Change. New York: Columbia University Press. 1974.
Lynn, R. (2006). Race differences in intelligence: An evolutionary analysis. Washington Summit Publishers: New York:
Pinker, S. (2002). The Blank Slate: The Modern Denial of Human Nature. Viking Adult: New York, NY.
Relethford, J.H. (2002). Apportionment of global human genetic diversity based on craniometrics and skin color. American Journal of Physical Anthropology 118(4): 393-398.
Ridley, M. (2003). Nature via Nurture. Harper Collins: New York, NY.
Rosenberg NA, Mahajan S, Ramachandran S, Zhao C, Pritchard JK, et al. (2005) Clines, Clusters, and the Effect of Study Design on the Inference of Human Population Structure. PLoS Genet 1(6): e70 doi:10.1371/journal.pgen.0010070
Rosenberg NA, Mahajan S, Gonzalez-Quevedo C, Blum MGB, Nino-Rosales L, et al. (2006) Low Levels of Genetic Divergence across Geographically and Linguistically Diverse Populations from India. PLoS Genet 2(12): e215 doi:10.1371/journal.pgen.0020215
Ser, Myo-ja & Team. At the DMZ, average height changes 4 inches. JonhAng Daily. November 21, 2006. Available online: http://joongangdaily.joins.com/200611/20/200611202311326539900090409041.html.
Serre, D. & Paabo, S. Evidence for gradients of human genetic diversity within and among continents. Genome Research 14:1679-1685.
Tang H, Quertermous T, Rodriguez B, Kardia SL, Zhu X, Brown A, Pankow JS, Province MA, Hunt SC, Boerwinkle E, Schork NJ, Risch NJ (2005) Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies. Am J Hum Genet 76:268–275


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 I: Selection and Cognition

I am very enthusiastic about Bjorklund & Pellegrini’s 2002 text, Evolutionary Developmental Psychology. I am going to discuss four places I believe that the book’s discussion can be extended, on ADD, domain generality, geological time, and group selection. While I feel the authors’ work to be incomplete in these areas, I choose these areas because otherwise the book seems flawless.

On page 5, the authors mention mention that “natural selection has similarly shaped domain-general information processing mechanisms,” and that “working memory” and “speed of processing” are examples of such domain-general mechanisms. I agree that these things exist, are important, and were shaped through evolution, though I do not know if they are “domain general.”


For instance, I think it is clear that working memory effects how we memorize names, how we do long division, and how we solve complicated puzzles. But does working memory capacity load only cheater detection, or in the hundred subconscious ques we receive to tell us how the person we talk to is feeling? I believe the authors could have been more accurate had they spoken of these “conscious, domain-multiple” skills instead of domain-general ones.

Additionally, I think the author’s words on the nature of selection cover much of evolution. They write that “natural selection does not necessarily yield what is ‘best for the group’ but rather works on the level of the individual” (14). Sometimes this is true. However, eusocioal adaptations (those that benefit the group but harm an individuals’ inclusive fitness) have been observed in the wild (Wilson & Holldobler, 2005) and computer simulations (Hammond & Axelrod, 2006) and network analysis (Bloom, 2000) imply that something similar may exist among men . Selection pressure is not limited to the individual level, or the genetic level, or the group level, but exists on every level of organization (Alford & Hibbing, 2004).

Relatedly, the authors claim that “individuals who truly have ADHD would be at a disadvantage in any environments” (28). This may or may not be true, but the Goldstein & Barkley (1998) paper they say they agree with goes further, arguing that ADHD could not be “adaptive” (1) or “adapted” (2) (it is not clear that Goldstein & Barkley understand the difference in these concepts) because because it is not shown to be beneficial in some economic activity (hunting, wading, etc). Goldstein & Barkley then bizarrely state: “[Advocates for ADHD] can not on the one hand argue that ADHD needs to be taken seriously as a legitimate developmental disability. Then on the other hand simultaneously sing its praises as a once successful adaptation that leads to higher intelligence, greater creativity, and heightened sensory awareness, but that now results in suffering due to an overcontrolled, linear-focused, and intolerant culture” (4-5). Why this should be true is beyond me. It may well be that ADHD is adapted on a genetic level to increase reproduction. For instance, if ADHD leads to rape (Giotakos, Markianos, & Vaidakis, 2005) then it easily could be an adaptation that is beneficial to a selfish gene while being harmful to individuals and society. Alternatively, ADHD may well be a stable polymorphism, in other words humanity may be “a mixed population [that] is evolutionary stable” (Buller, 2005, 42) with regard to ADHD. This could arrive if at certain times a group’s survival hinged on having hyperactive members, and at other times hinged on having members capable of concentration.

Last, while I agree that the “human mind has been prepared by natural selection, operating over geological time, for life in a human group” (Bjorklund & Pellegrini, 4). However, human minsd have also been prepared by natural selection, operating over historical time, for life in human groups (Voight, et al., 2006). That is, human genomes of different populations have undergone selection within the past few thousand years. Evolution acted in the past, giving us stone-age brains for our modern lives. But it also acted more recently, adapting those stone-age brains for live in agricultural communities.

However, while these are nit-picks, Bjoklund & Pellegrini’s contribution to the field should not be underrated. Their text competently integrates evolutionary psychology and cognitive psychology, two fields who share many assumptions but whose practitioners are often unaware of each other’s advances. It is through books like this can scientists in both domains leverage each other’s unique contributions and advance the state of our unified, scientific view of the world.

Bibliography
Alford, J. & Hibbing, J. (2004) .The Origin of Politics: An Evolutionary Theory of Political Behavior. Perspectives on Politics, 2(4), 707-723
Bloom, Howard. (2000). Global Brain. Wiley & Sons: New York, NY.
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.
Goldstein, S., & Barkley, R. (1998). ADHD, hunting, and evolution: “just so” stories. The ADHD Report 6(5): 1-4.
Giotakos, O., Markianos, M., & Vaidakis, N. (2005). Aggression, impulsivity, and plasma sex hormone levels in a group of rapists, in relation to their history of childhood attention-deficit/hyperactivity disorder symptoms. Journal fo Forensic Psychiatry and Psychology 16(2): 423-433.
Hammond, R., & Axelrod, R. (2006) The Evolution of Ethnocentricism. Journal of Conflict Resolution, 50(6).
Spielman, R.S., Bastone, L.A., Burdick, J.T., Morley, M., Ewens, W.J., & Cheung, V.G. (2007). Common genetic variants account for differences in gene expression among ethnic groups. Nature doi:10.1038/ng1955.
Voight BF, Kudaravalli S, Wen X, Pritchard JK (2006) A Map of Recent Positive Selection in the Human Genome. PLoS Biol 4(3): e72 DOI: 10.1371/journal.pbio.0040072
Wilson, E. O., & Holldobler, B. (2005). Eusociality: Origin and Consequences. PNAS 102(38)-13367-13371.


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, Introduction: Race of Man, Races of Men

This series is a companion to Biopsychological Development. While that series focused on my reaction to The Scientist in the Crib and The Emperor’s New Clothes, this series centers on The Origins of Human Nature: Evolutionary Developmental Psychology. Of the three books assigned for the class, Origins is by far the most academic. It is a very competent synthesis of Cognitive Psychology’s concepts of working memory, cognitive load, and the like with Evolutionary Psychology’s era of evolutionary adaption, massive modularity, and such.

A theme that emerged while I wrote these reaction with group-level human genetic diversity. The idea is that humanity is composed of major breeding populations that differ in their frequencies of genetic variation. I had been skeptical of this polygenism for some time, but within the last year I upgraded the idea from “dubious” to “reasonable.” I do not know if humanity is composed of races or clines, but advocatges group-level genetic diversity present good evidence that needs to be intellectual engaged. Unfortunately, (advocates mostly on) the Left concluded that if group-level human diversity exists, it implies that some humans are “better” than others. Therefore the hypothesis had to be rejected on ideological grounds, whatever the facts are. To these Marxists, the thought that we are all equal, regardless of our nationality or genetic predisposition, is apparently anathema.

I have to give special props to Steven Pinker, an author previously featured on tdaxp. Pinker is skeptical of group genetic diversity, and he has given better arguments in favor of his position than anyone else I have read. He also admits the possibility that he may be wrong, however, and his skepticism towards his skepticism helped provoke my self-reflection. The tone of the posts in this series tend to be pro-diversity, if only because (outside of Pinker) I am more impressed by the honest tone of the diversitarians than the monists. However, the best part of blogging is the very high-level of reader comments. Please readers, correct me, or tell me where my writing is lazy!

(Any in the meantime — read up on Lewtonin’s fallacy.)


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