Humans vary by sex, and not just in the preferred hip-to-waist ratio (Singh, 1993, 293). Firing the President of Harvard for wondering if this is true does not make facts go away (Pinker, 2006). Men are less empathetic than women (Baron-Cohen 2006; Singer et al., 266, 2006). Emotional differences between the sexes are widely recognized, even by critics of evolutionary psychology (see, for example, Buller, 2005, 317).
It is strange that genetic factors are controversial while environmental factors are widely recognized (see, for example, Elkind, 1997, 31), especially when such incontrovertible evidence like prisoners having elevated levels of testosterone (McDermott, 2006, 5)is considered. Is environmental determinism somehow less deterministic than determinism on the interaction of the environment and genetics? This has implicationss throughtout education. The existence of a disproportionately male engineering gender gap (as opposed to a disproportionately female university gender gap (Marklein, 2005) is problematic in one way if women are being unfairly excluded from opportunities (e.g., Raskin, 2005) but problematic in another way if many existing women engineers were forced into their career-paths by misguided environmental-determinists (Pinker, 2002, 359). This is not to say anything of the question if men and women learn best in different ways.
In the days where all undergrads were between 18 and 22 the interaction between DNA and age could be ignored. At most we were troubled with the issue of development (see, for example, Allen et al., 2005; Morrisey & Werner-Wilson 2005; Steinberg 2001; Steinberg & Morris, 2001). Yet once we see that certain ideas may become “hard” relatively early in life because of genetic factors (Alford, Funk, & Hibbing, 2005) the concept of teaching itself becomes troublesome. Likewise, old theories of learned development are being undermined by evidence of genetically-derived knowledge (Tooby & Cosmides, 1992), an idea once consigned to fiction (London, 1903). How will we deal with this knowledge?
Just as our experiences make students unique, so do their genes. Evolutionary simulations have shown that genetic populations instead of evolving toward agents with homogeneous behavioral strategies [that is, alleles], often evolve such that multiple strategies coexist at equilibrium” (Kurzban & Houser, 2005, 1803). This genetic polymorphism in students comes in two broad categories: genetic variation between individuals and genetic variation between groups (Rockman et al., 2005, 2214). In the future, educators will do well to be cognizant of these categories.
Some variation is merely between individuals. This is because variation between individuals is evolutionary useful for evolutionary groups (Smith et al, 2004, 5). As Sautter writes, “Evolution has cultivated a multitude of personality traits that vary amongst humans. This phenotypic variation allows for selective advantages on the group level” (2006, 4), even within just the past few thousand years (Wade, 2006). Fortunately, new technologies are helping us educate those who are smart in different ways (Yandell, 2002, 303) with different parts of their brains (Morgan, 2001) and with different “intelligences” (Gardner, 1983). But obviously we can now see only the shadows of the final consequences of the recognition genetic individuality.
But in other ways, populations vary (statistically) because of genetics, too. For instance, one pair of alleles, Dopamine Receptor D4 3 Repeat (DRD4 4R) and Dopamine Receptor D4 7 Repeat (DRD4 7R), was after some controversy found to be correlated with a type of ADHD (Castellanos et al, 1998; Grady et al, 2003) and perhaps other personality factors (Lynn, et al., 2005; Sullivan, et al., 1998).† The prevalence of “drd4 7r” varies by population, with some peoples (!Kung, Han Chinese and Sardinians) having very little of the “adhd” allele and other populations (American Indians, white Americans, Yanamamo) having elevated levels. Apparently this resulted from different evolutionary pressures (Ding, et al., 2002). Commenting on this, Harpending & Cochran (2002, 12) noted “It is probably no accident that two of the best known ethnographies of the twentieth century are titled ‘The Harmless People’ about the !Kung who have few or no 7R alleles, and ‘The Fierce People,’ about the Yanomamo with a high frequency of 7R.” As the population diversifies, population genetics will become more and more important to educators.