Trait-covariation, behavioral genetics and life history theory

In this chapter we critique evolutionary-developmental explanations of variation and covariation in psychological traits, with special emphasis on psychological ‘life history theory’. We argue that findings from behavioral genetics and developmental biology provides evidence that large proportions of individual differences in traits are caused by differences in genes, and differences in intrinsic randomness (and environmental damage) during embryo development. Further, behavioral genetic findings suggest that covariation between traits can often be attributed to genetic processes—such as pleiotropy and assortative mating—rather than the output of evolved mechanisms that use environmental cues. Overall, we argue that the relevant evidence leaves little room for evolved mechanisms that shape trait-levels and trait covariations in psychology.