Human Biological and Psychological diversity

An important new academic paper was recently published.

Many evolutionary psychologists have asserted that there is a panhuman nature, a species typical psychological structure that is invariant across human populations. Although many social scientists dispute the basic assumptions of evolutionary psychology, they seem widely to agree with this hypothesis. Psychological differences among human populations (demes, ethnic groups, races) are almost always attributed to cultural and sociological forces in the relevant literatures. However, there are strong reasons to suspect that the hypothesis of a panhuman nature is incorrect. Humans migrated out of Africa at least 50,000 years ago and occupied many different ecological and climatological niches. Because of this, they evolved slightly different anatomical and physiological traits. For example, Tibetans evolved various traits that help them cope with the rigors of altitude; similarly, the Inuit evolved various traits that help them cope with the challenges of a very cold environment. It is likely that humans also evolved slightly different psychological traits as a response to different selection pressures in different environments and niches. One possible example is the high intelligence of the Ashkenazi Jewish people. Frank discussions of such differences among human groups have provoked strong ethical concerns in the past. We understand those ethical concerns and believe that it is important to address them. However, we also believe that the benefits of discussing possible human population differences outweigh the costs.

Notable quotes include:

Mainstream textbooks, for example, document many instances of human biological diversity. Despite this, the basics of human biological diversity are not integrated into the social sciences.

Evidence from a variety of disciplines, including genetics, anthropology, archaeology, and paleontology, indicates that human populations evolved distinctive features after spreading from Africa and settling in different ecological and climatic niches (Bellwood 2013; Cavalli-Sforza et al. 1994; Molnar 2006; Wade 2014). Although such human biological variation is often ignored by social scientists, it is not really a matter of dispute among researchers in the relevant disciplines.

In a meta-analysis of racial and ethnic differences in self-esteem, Twenge and Crocker (2002) found a pattern of self-esteem differences (Blacks scored higher than Whites after the 1980s and Asians scored lower than both), but ruled out, a priori, the possibility that such differences were related to biology because, according to them, “racial and ethnic categorizations are socially constructed” and are not based on “shared biological characteristics” (p. 371). This means that an entirely legitimate and plausible hypothesis about the etiology of self-esteem differences was ignored, leaving only social or cultural hypotheses. It is, of course, possible that the differences are entirely environmental in origin, but it is not certain, and ruling legitimate hypotheses out a priori on flimsy arguments (see “Race and Human Populations” section) about the nonreality of human biological diversity potentially prevents researchers from fully understanding the causes of differences in self-esteem.

In a paper on racial and ethnic differences in violent crime rates, Sampson et al. (2005) asserted that biological differences among human populations do not hold “distinct scientific credibility as causes of violence,” and proceeded to adjudicate between three environment-only hypotheses about the causes of disparities in violence (p. 224). So, again, these researchers ruled out a priori a perfectly legitimate and plausible hypothesis and proceeded to approach the data with a self-imposed theoretical limitation.

I wonder why this academic blindness is so common? I also wonder why there are so few researchers willing to challenge the egalitarian orthodoxy despite plenty of empirical evidence to the contrary:

Rushton (1995), for example, forwarded an expansive account of population differences based on life-history theory. However, he was viciously attacked by many scholars (e.g., Barash 1995), and his work was quickly marginalized.

There are plenty of examples in the animal kingdom of both behavioral and physical evolution of species in what most biologists would consider a relatively short time. 20 generations or so seems to be enough time for noticeable adaptations to occur, which is approximately 400 years in humans.

Thus far, we have introduced what we called the SEPP, and noted that we were going to recalibrate two of its basic premises. The first premise was gradualism, which contends that evolution by natural selection is a very slow phenomenon and that human populations have not had enough time to evolve meaningful differences. We argued that this position requires adjustment because (1) natural selection can differentially sculpt traits quite rapidly, as documented by many researchers (see “Background” section), and (2) there is copious evidence that human populations differ from each other somewhat physiologically and that natural selection continues to affect human populations (Hawks et al. 2007; Zuk 2013). Adjusting gradualism in this manner requires that we reconsider the idea of a panhuman nature. It would be remarkable, as we will discuss below, if human populations were completely similar psychologically despite having endured different selective regimes in different environments.

There are notable adaptations in humans which likely evolved during geologically short periods of time, such as cold adaptations in high latitudes or low oxygen adaptations at high altitudes. Other examples include darker skin in mid latitudes to protect from ultraviolet radiation or conversely light skin in high latitudes to enhance vitamin D production, or lactose digestion in adults in communities which domesticate milk producing animals.

The article also goes over some of the common, and false, arguments against race being a biological construct including lewontin’s fallacy, which I have previously covered myself.

A final argument often forwarded against the use of racial classifications is that the genetic variation between human populations is small and dwarfed by the genetic variation within populations (Lewontin 1972; Templeton 2013). Therefore, so this argument goes, racial classifications contain almost no meaningful biological information. There are two counterarguments to this. First, if one focuses on the correlational structure among multiple genetic loci instead of serially examining single loci or averaging over multiple loci, then there are clear and biologically informative differences among human populations (Cochran and Harpending 2009; Edwards 2003; Tang et al. 2005). In other words, different human population groups are recognizable by their genetic profiles but only if one examines a pattern of genetic loci. Tang et al. (2005), for example, reported evidence that self-reported ethnicity corresponded very closely with genetic clusters derived from 326 microsatellite markers. Other studies have found similar power to detect accurately people’s ancestry (Guo et al. 2014; Moreno-Estrada et al. 2014). Of course, this would be impossible without sufficient genetic information to distinguish among human populations.

Importantly, it highlights the reality that personality and psychology also has a biological component, and this varies across races:

The human brain is the same as the human body in this regard and is not somehow immune to natural selection. Or, as Nicholas Wade (2014) succinctly noted, “brain genes do not lie in some special category exempt from natural selection. They are as much under evolutionary pressure as any other category of gene” (p. 106). It is almost certain that human populations vary psychologically in interesting, important, and scientifically meaningful ways because they were subject to different selective regimes (Rushton 1985; Wade 2007). To preview one example briefly, natural selection may have slightly dialed up the general intelligence knob on Ashkenazi Jews (i.e., an adjustment on an existing adaptation), who score roughly 110 on standardized intelligence tests (Cochran et al. 2006; Lynn 2011). Whether humans share a universal psychological profile depends upon the question one is trying to answer. If, for example, one wants to know how humans learn to recognize siblings, the concept of a panhuman psychical nature is probably fruitful (Lieberman et al. 2007). If, however, one wants to know why the Ashkenazim prosper in many societies, often despite virulent anti-semitism, then the concept of a universal psychical profile is not only wrong, but it also positively prevents researchers from accurately answering the question (because it leads to a fruitless exploration for sociocultural causes which cannot be the entire story).

Citing specific studies with specific genes, the authors discuss some personality traits which seem to vary over different populations, quite likely due to the genetic differences mentioned, including collectivism (east Asians) vs. individualism (NW Europeans) and Ashkanazi Jewish intelligence.

For additional information on the likely evolutionary pressures which led to an increase in pro-civilizational traits in Europeans, I recommend A Farewell to Alms: A Brief Economic History of the World by Gregory Clark. One of these days I am going to get around to doing a full review of this book.

By political necessity, the article is very conservative with its discussion of racial differences. However, it is a useful step in the right direction in gaining a mainstreamed understanding of the reality of race. The article calls out the social “scientists” who categorically rule out biological causes of racial differences as being unscientific. These “scientists” do so for no particular reason other than personal ideological preference. The article further proposes future research more openly and directly pursue possible biological explanations. Despite the obvious qualification that the article doesn’t go far enough in honestly admitting the primacy of biology in racial differences, it is still an important contribution in advancing the our understanding of human nature by addressing the largest problem currently extant in the academic community: Left-wing bias in favor of (false) universal egalitarianism.

We are not naive about the obstacles a Darwinian approach to human biological diversity faces. We hope only to start a candid discussion and to forward some suggestions about how to proceed with this paradigm. Doubtless, some will continue to resist the notion that human populations differ in biologically meaningful ways. But it seems clear to us that biological diversity is the rule across the vast tapestry of life. It is true among plants, among animals, among humans, and among human populations.

Read full article here.

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