A new paper published in the Journal of Personality and Social Psychology examines women’s efforts to guard their mates from sexual competition — especially other ovulating females.

For women, close cooperative relationships with other women offer important opportunities but at the same time raises possible threats — mate competition being one of them. So women have developed mate guarding behaviors to maximize the benefits of these same-sex connections while reducing their risk to the minimum.

It’s all fun and games until the guys get involved.
Image via Quartz

Psychologists from Arizona State University studied how women go about guarding their mates. They found that members of the fairer sex are sensitive to both interpersonal and contextual cues indicating whether other women might be likely (and effective) mate poachers.

And they all have their sights firmly placed on other ovulating women.

The team carried out four studies involving a total of 478 heterosexual engaged or married women. The participants were recruited from Amazon Mechanical Turk, an online crowdsourcing marketplace. In each of the studies, participants were shown photographs of a series of women and then asked how willing they would be, on a seven-point scale, for the women in the picture to befriend their partner.

An interesting thing happened: the participants were more likely to want to put as much distance between their partner and the woman in the photograph as possible if the latter was ovulating. They weren’t told if the person in the picture was ovulating and, in all likelihood, they didn’t even consciously consider the idea, authors note. But studies have shown that humans do subconsciously pick up on the subtle cues that indicate when women are more fertile.

“Research across species demonstrates that social perceptions, cognitions, and behaviors do temporarily shift in response to ovulation, and that these shifts may enhance individuals’ reproductive fitness,” write the authors.

“Similarly, psychological research on humans has demonstrated that (a) women’s perceptions and behaviors shift across their own cycles and (b) men respond to these cyclic shifts.”

It also (unsurprisingly) became apparent to the team that women were especially protective when their mate was desirable to the other subjects, or when their mate found the woman in the photograph to be physically attractive. It’s not all about keeping distance, though. The authors also note that women employ other tactics to keep their partners close:

“Specifically, women with desirable partners reported that they would show increased sexual interest in their partners after viewing a high-fertility target, regardless of how attractive that target was,” the paper reads.

But, sadly, the study didn’t produce any evidence that women’s efforts are rewarded or that “mate guarding” is particularly effective.

The authors also note that the study relies on composite photos of strangers; In real life, when socializing with friends, colleagues, and acquaintances, women may well choose to trust their friends and worry less about ovulating threats.

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