Facial femininity of potential rivals predicts jealousy in both heterosexual and lesbian women.

Individuals displaying cues of higher mate value (e.g., attractive characteristics) are thought to represent a greater threat to pair bonds and, consequently, elicit greater jealousy. Previous studies reporting that more feminine potential rivals elicit greater jealousy in women used stimuli in which feminine characteristics were experimentally manipulated and assessed jealousy using forced-choice methods. However, this method for assessing perceptions has recently been criticised for lacking ecological validity. Consequently, in the current study, women rated how jealous they would feel if rivals depicted in natural (i.e., unmanipulated) face photographs were flirting with their romantic partner. Facial femininity was assessed using objective analyses of shape and via third-party ratings of facial femininity. For heterosexual participants, women reported significantly greater jealousy when imagining more feminine women flirting with their romantic partner. This pattern of results was also seen for lesbian participants, although the correlation between rival femininity and jealousy was significantly weaker for lesbian participants than it was for heterosexual participants. Collectively, these results present further evidence that facial femininity of potential rivals influences women's reported jealousy, particularly in heterosexual women, and is further evidence for the proposal that putative markers of the mate value of rivals play a role in women's jealousy.