Strangers with Benefits: Ovulation and Attraction to Outgroup Men

The tendency for humans to behaviorally and attitudinally favor ingroups over outgroups is robust and pancultural. An evolutionary framework, however, provides reason to expect a systematic tendency toward outgroup-favoritism in a particular context. Ancestral females may have mated furtively with outgroup-males and returned to their cuckolded ingroup-male partner for child rearing, as a means of both maximizing genetic variability and promoting the long-term welfare of an offspring. The footprint of such a process may evidence in human females via increased physical attraction to outgroup (but not ingroup) males as ovulation approaches (conception-risk increases). Two studies of normally ovulating women tested this hypothesis. I procured via pilot testing photographs of ambiguously-Hispanic men, which enabled me to randomly assign the presumed race (Caucasian/Hispanic) of those men. In Study 1, Caucasian females rated the attractiveness of the photographed men, with each photograph randomly assigned the label "Caucasian" or "Hispanic." A Conception-Risk x Group-Membership interaction indicated women deemed outgroup (but not ingroup) males to be increasingly attractive as conception-risk increased. Study 2 replicated the interaction using different social groupings (In-state, Out-of-state student). These data provide rare (but theoretically derived) evidence of outgroup attraction and imply an evolved psychology resulting from plausibly furtive ancestral outgroup-mating.