The Competitive Rhythms of Ovulation

Interestingly, the degree to which women sexualize their appearance depends on their ovulation cycle—at least among women not taking oral contraceptives. Evolutionary psychologist Kristina Durante and her colleagues had non-pill-taking women come to her lab twice—once during the fertile window of their cycle and once during the infertile phase. She took full-body photographs of the women at each time and had them draw illustrations of clothing that they might wear to a social event that evening.

Ovulating women wore more sexy and revealing clothing to the lab, and drew dramatically more revealing clothing that they would wear to the imagined event, compared with the same women when they were not ovulating. Sexually unrestricted women—those who said they tend toward sexually freer conduct and seek sex with a wider variety of partners—showed this ovulation effect more strongly than the other women. Durante and her colleagues argue that this shift toward sexy clothing reflects increased female-female competition at ovulation for the most desirable sex partners.

Studies conducted in Germany discovered a similar effect by using digital photography to capture what women wore to singles bars and interviewing them afterward. Using a computer program that calculated the percentage of skin revealed by women’s clothing choices, they discovered that women in the most fertile phase of their ovulation cycles wore more revealing most fertile phase of their ovulation cycles wore more revealing clothing and showed more skin than women in the nonfertile phase.

Ovulating women dress for sexual success. Another group of researchers, led by UCLA evolutionary psychologist Martie G. Haselton, found that women in the fertile phase of their cycles wore nicer and more fashionable clothes and showed more upper and lower body skin than the same women in the low-fertility phase of their cycles.

Women’s ovulation cycles also influence their patterns of consumer behavior. One study created a simulated online shopping program designed to track women’s spending patterns on items such as clothes, shoes, underwear, jewelry, and other fashion accessories. As we have seen, these are all products that women use to enhance their appearance for competition with same-sex rivals. Near ovulation, women tended to shift their spending patterns toward revealing and sexy items. And the shift was most dramatic when women were led to believe that attractive same-sex rivals were present!

Several other scientific studies support the theory that ovulating women sexualize their appearance for success in mate competition. Women report more desire to go to parties and clubs where they can meet men on their high-fertility days. They are more likely to flirt with men other than their primary partners when they are in or near the ovulatory phase of their cycles. They even judge other women to be less attractive when they rate them near the middle of their own ovulation cycles—a finding that evolutionary psychologist Maryanne Fisher interprets finding that evolutionary psychologist Maryanne Fisher interprets as evidence that women are more sexually competitive with other women near ovulation and feel the urge to “put down” their potential rivals. Finally, when evolutionary psychologist Karl Grammer interviewed women at a discotheque, those who rated their attire as “sexy” and “bold” also indicated a specific sexual motivation: a desire to flirt with men or find a sex partner.

From an evolutionary perspective, women are most competitive for the best mating opportunities near ovulation because this is precisely the time when mating decisions are most consequential. It is the phase in which mating mistakes are most costly, the phase in which women are highest in reproductive mate value, and the phase in which beating out rivals for the most desirable mate yields the greatest adaptive benefits.