Recent research suggests that men find portraits of ovulatory women more attractive than photographs of the same women taken during the luteal phase. Only few studies have investigated whether the same is true for women. The ovulatory phase matters to men because women around ovulation are most likely to conceive, and might matter to women because fertile women might pose a reproductive threat. In an online study 160 women were shown face pairs, one of which was assimilated to the shape of a late follicular prototype and the other to a luteal prototype, and were asked to indicate which face they found more attractive. A further 60 women were tested in the laboratory using a similar procedure. In addition to choosing the more attractive face, these participants were asked which woman would be more likely to steal their own date. Because gonadal hormones influence competitive behaviour, we also examined whether oestradiol, testosterone and progesterone levels predict women's choices. The women found neither the late follicular nor the luteal version more attractive. However, naturally cycling women with higher oestradiol levels were more likely to choose the ovulatory woman as the one who would entice their date than women with lower oestradiol levels. These results imply a role of oestradiol when evaluating other women who are competing for reproduction.
BackgroundOvulation cues in humans are subtle but perceivable (for a review, see [1] [6,7] and look [8][9][10][11] more attractive during the fertile days of their menstrual cycle. Most of these studies looked exclusively at preferences of men [2,[5][6][7][10][11][12] as men directly benefit from ovulation detection in women: the likelihood of reproducing is highest with a woman who is in her fertile cycle phase (cf. [7]). For women, the benefit of detecting other women's fertility is less clear. Some researchers negate any adaptive function for women being sensitive to ovulation cues in other women (e.g. [13]) while others have claimed that it is also beneficial for women to detect ovulation in other women, especially in the context of intra-sexual competition (cf. [14]). For example, ovulatory women may be more likely to engage in poaching behaviours and they might be more attractive to men, posing a potential threat to other (non-ovulating) women. Indeed, previous studies have shown that men find ovulatory faces more attractive [10,11].Here we investigate whether women show a similar preference for ovulatory faces to men. Women were shown pairs of faces, one of which depicted an ovulatory face, the other a luteal face, and were asked to choose the more attractive woman. According to some authors ([8], see also [15]), facial signals of ovulation might be identical to what is typically seen as attractive in women's faces. If this were true we would expect that both women and men should find female faces showing ovulation cues more attractive. Alternatively, if detecting ovulation cues is beneficial