The relationship between familial resemblance and sexual attraction: an update on Westermarck, Freud, and the incest taboo.

Foundational principles of evolutionary theory predict that inbreeding avoidance mechanisms should exist in all species--including humans--in which close genetic relatives interact during periods of sexual maturity. Voluminous empirical evidence, derived from diverse taxa, supports this prediction. Despite such results, Fraley and Marks claim to provide evidence that humans are sexually attracted to close genetic relatives and that such attraction is held in check by cultural taboos. Here, the authors show that Fraley and Marks, in their search for an alternate explanation of inbreeding avoidance, misapply theoretical constructs from evolutionary biology and social psychology, leading to an incorrect interpretation of their results. The authors propose that Fraley and Marks's central findings can be explained in ways consistent with existing evolutionary models of inbreeding avoidance. The authors conclude that appropriate application of relevant theory and stringent experimental design can generate fruitful investigations into sexual attraction, inbreeding avoidance, and incest taboos.