Tag Archives: evolution

Multiple Inventions, Multiple Evolutions

My friend Jayson has emailed me a New Yorker article, “In the Air” by Malcom Gladwell. I previously saw it referenced by Peter Robinson over at The Corner, so it has now caught my eye twice.

The article talks about multiple discovery, where independent researchers or teams invent the same thing at about the same time — but have little to do with each other. The famous example is calculus for which (after being unknown for all of human history) Isaac Newton and Gottfiend Leibniz created systems so similar that their main difference was the philosophical question of whether the super-small things changing were “infinitesimals” or “fluxions.”

In truth, most discoveries are probably multiple discoveries.

Consider two papers, one an article and the other a blog post, which help explain the issues John Sweller’s peer-reviewed article, Instructional Design Consequences of an Analogy between Evolution by Natural Selection and Human Cognitive Architecture,” published in the January 2004 edition of Instructional Science,” describes how thinking relies on stored information in long-term memory, and how the random errors that happen during remembering provide opportunities for feedback, “good mistakes” are rewarded while bad mistakes are discarded. Similarly, Razib’s primer, “8th grade math for the rest of us,” published November 2005 at gnxp, describes the probability of an gene that is helpful actually becoming common in a population.

Essentially, chance operates two ways in evolution: introducing new versions of things by chance, and rewarding or discarding new versions by chance. In order to become common, a new thing both most be lucky enough to be crated, and lucky enough to spread. (Even if a mutation is helpful, for example, if the animal carrying it is struck by lightning, it’s gone.)

The same is true of inventions. Chance operates two ways: for the invention to be created, or the invention to be accepted. Just because an inventor is inspired to build a new product that works, and works better than anything else at its job, doesn’t mean that the creator will be able to convince other people that it’s worth while, etc.

Of course, sometimes multiple versions of an invention become known. This has happened with skin color: East Asian and European “whiteness” derive from different mutations. This has also happened with calculus: Newton’s and Liebenz’s systems derive from different assumptions. But in both cases, the need for the invention was there, the tools needed to create the invention was there: all it needed to do was happen.

Of course, there may have been a third version of calculus, created in about the same circumstances, that is now lost and forgotten. Likewise, there may have been another evolutionary fork for creating light skin that is lost.

All of this has important implications for intellectual property law. But that is a post for another time…

What if evolution works 15,000 times faster than we imagined?

It was only eighteen months ago that I wrote a post titled “The implication of evolution after the dawn of agriculture.” At the time, I was startled by the idea that there may have been evolutionary change within the human population in the last four centuries. Also at the time I was highly impressed by Evolutionary Psychology evolutionary functional analysis, and the concept of the Era of Evolutionary Adaption.

Not this quick. But quicker

Since that time I have learned more about how biology informs the social sciences. It appears that evolution is faster than I thought, and Evolutionary Psychology is weaker than I assumed.

Go fast

Up until recently, the theoretical maximum speed for one gene to replace all other variations was one every 300 generations. It now appears the rate among humans is 2 every year. If this result holds up, this has important implications.

Two dynamics appear to be driving the acceleration of natural selection among humans: larger population size (more mutations are given a chance to rise up) and the even quicker evolution of culture (preventing the establishment of an equilibrium optimal genetic state).

Evolutionary Psychology is wrong because there is no species-wide “Era of Evolutionary Adaption.” Indeed, one wonders if the term “Era of Evolutionary Adaption” even makes sense. If it does, are EEAs of populations that had possessed agriculture for a very long time (say, the peoples of the fertile crescent, and Chinese and Indians of the great river valleys) far more agrarian than the EEAs of traditionally hunter-gatherer societies?

Further, as both cultural complexity and breeding population (both in numbers in and genetic diversity) vary historically, might one say that the Era of Evolutionary Adaption of Australian Aborigines is tens of thousands of years deeper in time than that of Indus River Valley dwellers?

Both the population of man and the culture of man have been growing at faster and faster rates. The implication of this is clear.

The 19th century saw more natural selection in our species than any other century, ever.
The 20th century saw more natural selection in our species than any other century, ever.
The 21st century will see more natural selection in oru species than any other century, ever.

And that’s not counting genetic engineering.

(Thanks to Sean, DMH, Fulwider, Doug, and others for not letting me get past this discovery without thinking it through.)

In search of a darwinian ratchet: the ANC, the PLO, and the RAF

Evolution is the change in frequency of variations over time. The evolution of species by means of natural selection was first described by Charles Darwin.

With this in mind, Fabius Maximus’s tak of a “Darwinian ratchet” makes no sense:

the success of Israel’s counter-insurgency strikes against Hamas and Hezbollah have resulted in a “Darwinian ratchet”.

Israel’s security services cull the ranks of the insurgency. This eliminates the slow and stupid, clearing space for the “best” to rise in authority. “Best” in the sense of those most able to survive, recruit, and train new ranks of insurgents. The more severe Israel’s efforts at exterminating the insurrection, the more ruthless the survivors.

Back to evolution. In terms of nature, evolution has no purpose, goal, or direction. Pace to the Nazis and the Stalinists, to the Social Darwinists and the Creationists, evolution is not directed toward rewarding the strong, the social, the smart, or the sinful. Evolution is merely the change in the frequency of variations of some aspect of things.

Evolution happens in the context of an environment. If the environment rewards those with high general intelligence with more offspring than those less gifted, one might see general intelligence vary upward in the next generation (perhaps at the cost of something else, such as short term memory). If the environment rewards those who are cautious and nervous, then presumably frequencies of neuroticisms might change.

Fabius appears to have a different notion of evolution. A “ratchet,” of course, is a tool that turns only one way. A “Darwinian ratchet” implies that evolution is determined to maximize some quality or trait, so that each new generation possesses more of it than the one preceding. One assumes that Fabius is looking to evolution to maximize, again and again, effective violence against Western societies..

But of course, evolution does not work this way, because the environment is not static. Even if the outside world remains the same, the population subjected to evolutionary forces will change, and as the population is part of the evolutionary landscape, the environment thus changes.

Fabius is concerned that Western violence against enemies of the West will ratchet up the fitness of our enemies, giving us more and more effective enemies. But of course, all that happens is that our activities alter their fitness landscape, leading to different proportions of different types of them. Take three examples of anti-Western forces subjected to continuous Western assault

  • The African National Congress

    The ANC began as a cookie-cutter Communist terrorist organization located in South Africa, aiming to bring down an economically productive yet antidemocratic ruling class. The South African government fought back, imprisoning the ANCs leaders, turning natural ANC allies against it, and generally engaging in Systems Administration duties. Fabius’s “Darwinian ratchet” would lead us to expect that the ANC became more and more virulent, but what actually happened was that the removal of ANC members capable of conducting guerrilla campaigns morphed the ANC into a peaceful democratic movement. The fall of Apartheid and the ANC victory brought something completely unlike what the ANC founders envisioned, and ushered in a new South African regime roughly as compatible with Western goals as the Afrikaner state that preceded it.

  • The Palestine Liberation Organization
  • “At first, we were refugees. Harmless. Now, we become fighters. Freedom fighters.” So Yasser Arafat rallied his troops, aiming to liberate the Palestinian people from Jewish and Hashemite occupation in Israel and Jordan. Once again, the West responded, offering hostility and partnership to the PLO in a bewildering series of deadly assaults. Again, the concept of a “darwinian ratchet” would lead us to believe that the PLO is now on the verge of achieving its objectives. But by the late 1990s the PLO had evolved into a corrupt rentier syndicate, completely unable to wage war on either of its historic enemies. When it tried in the Second Intifada it lost what freedom of maneuvered it had. The PLO is now protected by its old enemies from a reform movement (Hamas), in a divide-and-conquer strategy that makes true Palestinian statehood farther away than ever.

  • The Red Army Faction (Japan)

    But what if an enemy population adjusts to an increasingly hostile fitness landscape not by becoming soft and effective (the ANC), or soft and impotent (the PLO), but harsh and deadly? What if those reformists and crooks can be kept out, and the true believers are able to maintain power? Surely a “darwinian ratchet” will kick in then.

The radical wing of the RAF tried such a strategy, killing off the less radical half in a blood bath designed to weed out the disloyal. How it ends is predictable.

This is not to say that our enemies can’t win. Of course they can. But pseudo-scientific talk of darwinian ratchets and other mechanisms that guarantee us ten-foot-tall enemies do not help matters. They do not clarify the strategic environment or accurately capture reality. They are tools for myopic, conceited schools of analysis which imagines that we are so important that our enemies very thought and desire is for our harm (rather than their benefit).

Also in the blogsophere: A.E. defends his take, while Sean ponders a law of evolution.

What if group ancestry matters?

Elam Bend emails in a fascinating review of A Farewell to Alms. The review is by Nicholas Wade, he who wrote Before the Dawn, so you know it’s worth your time. Farewell is derived from a study of England’s population, which concludes that the contemporary English are descendants from the upper class of the Middle Ages. Further, Farewell argues that agricultural societies generally are biased to the well off, that that they feature downward-mobility, such that descendants of the incompetent can fill the ranks of the (genetically extinguished) ranks of the (starved and infertile) lower classes. Perhaps, Farewell proposes, the reason that the Industrial Revolution started in Europe was that natural selection had produced a generation or two of Europeans fit for revolutionizing industry.

The converse of this is that areas without this harsh selective environment — say, those inhabited by comparatively well-fed hunter-gatherers — would not so select their populations. Thus, the reason that some places (unspoken, but think Africa) have less culture, less wealth, less security, less safety, less happiness, and less peace than other places (unspoken, but think Europe) might be evolution.

I cannot comment on this, Farewell‘s most controversial claim. The issue is complex and there’s good-but-circumstantial evidence both for and against. But it’s clear that one day Farewell‘s claim will be testable.

Only the foolish should have views on human equality that rely on facts alone.

Evolving Humans, but to what end?

Humanity, like all species, evolves through changes in the frequency of genetic variants over time. Where there is less diversity — less possible genetic variants to have their frequency varied — there is less evolution. The aboriginies of Austarlia, for example, are dark skinned in spite of living at a mid-lattitute for thousands of years. This does not mean that there is some health advantage to being dark skinned at a mid latitute — quite the opposite! Rather, there simple was not enough diversity in the the population of aborginies to enable evolution over that time frame.

Populations with greater diversity are able to evolve faster for their conditions. Thus, it is slightly horrifying than the region with the worst living conditions (where selection pressures are least like those of the developed world)

The Long War for Africa and Islam

and the region with the highest birthrates:

is also the region with the most genetic diversity: Africa.

Extrapolating from other species, behavioral change from natural selection might occur in human beings in as little as 200 years. We are approximately fifty years into the Declonization of Africa, and the genocidal nightmare that unleasehd.

Forgetting about the actual human cost of this gappish hell, there is still time to be patient. There is time to let a plan work to shrink the gap.

But it must begin soon.

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.

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.

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.

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.

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