Date of Award


Degree Type


Degree Name

Master of Arts



Major Professor

Lowell Gaertner

Committee Members

Gordon Burghardt, Jim McNulty, Michael Olson


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.

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