The high-fertility period of the ovulatory cycle is the only time when sex can result in conception. In nonhuman mammals, this period is often marked by dramatic changes in females' social interactions, especially with males. For example, two widespread patterns are that females exhibit increased sexual interest in certain males at high fertility relative to low fertility, and males exhibit increased sexual interest in females currently exhibiting cues of high fertility. Scientific interest in whether the ovulatory cycle has similar impacts on human social behavior has surged in the past two decades, producing a large body of published evidence that is largely supportive of this possibility. Two prominent findings in this literature are that women's sexual attraction to men possessing characteristics historically associated with high genetic quality increases at high relative to low fertility and that women's attractiveness to men also increases at this time. However, studies have varied widely in the methods they have used to examine these effects, findings have been somewhat mixed, and additional nonreplications could remain unpublished. In addition, several important questions have yet to be answered. For example, can women detect cues of high fertility in other women, and do they perceive these cues as attractive?

To address these questions, I conducted two meta-analyses and a laboratory study. The meta-analyses quantitatively evaluated and synthesized evidence across published and unpublished findings for a) changes in women's mate preferences and b) changes in women's attractiveness and other possible fertility cues across the ovulatory cycle. Both analyses revealed robust support in the extant empirical literature for the hypothesized cycle shifts. The laboratory study examined women's perceptions of other women's high- and low-fertility body scents and found that, like men, women perceive other women's high-fertility body scents as more attractive than their low-fertility scents. Taken together, these studies have potentially important implications for understanding the role of the ovulatory cycle--and psychological adaptations that evolved or have been maintained in the context of cyclic variation in human female fertility--in human social cognition, motivation, and behavior.