She’s Not One of Us

The ability to differentiate in-group from out-group members on the basis of symbolic cues may be unique to Homo sapiens. The current research examined whether meaningful cues of in-group status moderate ovulatory shifts—a psychological adaptation that likely evolved earlier in humans’ evolutionary timeline. Four studies demonstrated that men were more attracted to fertile than nonfertile women’s voices only when men were evaluating in-group members. In Study 1, the fertility of Caucasian, but not Hispanic, women’s voices positively predicted 92 Caucasian male students’ attraction ratings. Study 2a ( N = 56) replicated this effect among older participants, and Study 2b ( N = 233) included a public preregistration and replicated it again. Study 3 replicated the effect in a sample of 47 Caucasian male students, and an experimental manipulation of the targets’ school membership produced a conceptual replication. These results stress the utility of considering the phylogeny of human evolution when testing evolutionary hypotheses.