Functional variation in sensitivity to cues that a partner is cheating with a rival.

The costs imposed by a romantic partner's mixed reproductive strategy (MRS) generate selection pressures for anticipatory responses to mitigate or avoid those costs. People will differ in their vulnerability to those costs, based in part on the qualities of their romantic rivals. Thus, we predicted that individuals at high risk of a partner's MRS--women with many sexually accessible rivals and men with many rivals more physically attractive than themselves--would be more attentive to cues that an MRS was being employed than those at lower risk. Based on similarity judgments derived from a successive-pile-sort method, this prediction was supported in a study involving over 1,300 students and community members. These results complement a growing body of research on selection pressures generated by romantic rivals.