The Evolutionary Psychology FAQ

Edward H. Hagen, Institute for Theoretical Biology, Berlin

Is evolutionary psychology racist?

No! Evolutionary psychology is the study of the functional organization of the brain, and this organization must be pan-human. Because humans are a single species, everyone on the planet has essentially the same functional organization of both the body and the brain. Why? The functional properties of organisms, including the functional properties of the nervous system (like vision, smell, locomotion, etc.) arose by natural selection. Natural selection builds adaptations like vision one piece at a time. The first pieces must be ubiquitous in the species before later pieces can evolve. For example, a species must have evolved a light-sensitive patch of tissue before there will be a selection pressure to evolve a lens to focus light onto that patch. If the genes coding for a light sensitive patch experience a reproductive advantage, they will very quickly spread in the population. After a relatively small number of generations, *every* individual in the population will possess genes for a light-sensitive patch. At this point, there will be a selection pressure to evolve a lens. Should a gene arise in the population that produces a lens (e.g., by a fortuitous mutation), and if having a lens provides a reproductive advantage through improvements in vision, this gene will quickly spread through the population as well. Virtually every individual will therefore possess an identical genetic blueprint for vision--both the gene for the light-sensitive patch, and the gene for a lens (in real life, many genes will be needed to code for both retinas and lenses). In general, the genetic blueprints for complex adaptations must be essentially identical in every individual in a sexually reproducing species (the one exception--sex differences--will be discussed elsewhere).

Sexual reproduction provides additional evidence for this view. Our genetic blueprint is partitioned into 23 pairs of chromosomes. Each parent contributes only one chromosome of each pair to their offspring, the other coming from their mate. If the genetic blueprints of the parents differed in any significant way, that is, if one parental genome contained instructions for building a complex adaptation but the other parent lacked such genetic instructions, it is very unlikely that their offspring, whose genome derives equally from both parents, would be viable. Imagine taking half the blueprints for a four cylinder engine with a carburetor, combining them with half the blueprints for an eight cylinder engine with fuel injection, and attempting to build an engine from the plan that results. The odds that this engine would work at all are essentially nil. The fact that individuals from one population can mate with individuals from any other population and produce offspring that are completely normal means that humans everywhere share genetic blueprints that are essentially identical.

Notwithstanding the above, just as it is possible for different populations to possess *minor* innate physical differences, it is also *theoretically* possible for different populations to possess *minor* innate cognitive differences , although no such differences are known to exist, nor have any plausible possibilities been put forth. People living near the equator have darker skin than those living farther north. This is certainly an adaptation. It arose because protection from ultraviolet radiation is a constant selection pressure near the equator. Since skin color relies on only a few genes, the shuffling of these genes that results from sexual reproduction does not interfere with the normal development of offspring. To make the case for simple, innate cognitive differences between populations, a specific and constant selection pressure would have to be identified that applied to one population for a large number of generations but did not apply to other populations (and in fact was selected against). Further, this selection pressure would have to have plausibly resulted in cognitive differences rather than physiological differences. Finally, it would have to be shown that members of one population actually possessed a specific cognitive ability not possessed by other populations. None of these requirements have been met, so innate, minor cognitive differences between populations remains merely a theoretical possibility.

Copyright 1999-2002 Edward H. Hagen