The Evolutionary Psychology FAQ

Edward H. Hagen, Institute for Theoretical Biology, Berlin

Why couldn't humans have evolved during the last 10,000 years?

They could, but not much. Evolutionary psychologists downplay the possibility of significant cognitive evolution in the 10,000 or so years since the advent of agriculture (a period of time known as the Holocene) for reasons of both science and political correctness. Scientifically, 10,000 years (500 generations) is not much time for natural selection to act, and it certainly is not enough time to evolve new, complex adaptations—sophisticated mechanisms coded for by numerous genes.

It is possible, however, that humans could have evolved minor cognitive adaptations during the Holocene. Just as some populations whose subsistence relied on herds of domesticated animals evolved to digest lactose as adults, populations could have evolved simple cognitive adaptations that their hunter-gatherer ancestors did not possess. For this to occur, there would have had to have been environmental conditions that were (1) new, (2) constant over most of the Holocene, (3) relevant to reproduction, and (4) required novel cognitive abilities. Many of the changes experienced by humans over the Holocene, however, have been so rapid that natural selection just couldn’t keep up. Further, we know that very little has changed physiologically in the last 10,000 years—Australian aborigines were more or less isolated from other populations for perhaps 40,000 years, yet are essentially identical physiologically to other human populations—so probably very little has changed psychologically.

Politically, EPs are understandably desperate to avoid any association with past racist attempts to essentialize population differences that are best explained by culture. If it were possible that human cognition had undergone significant evolution during the Holocene, then it would be theoretically possible to ascribe significant differences in behavior between different populations to genes, and that would be EP’s worst nightmare.

If we had as thorough an understanding of our psychological adaptations as we do our physiological adaptations, then perhaps we might be able to identify some simple psychological adaptations based on one or two genes that evolved during the Holocene; these adaptations might be population specific, or they might be pan-human. But we understand almost nothing about our evolved cognitive abilities. Imagine studying skin color without knowing what skin is. That would be a complete waste of time! EP rightly emphasizes a current focus on pan-human, complex cognitive adaptations that, like the rest of the body’s adaptations, were selected for during the two million years of the Pleistocene.

Copyright 1999-2002 Edward H. Hagen