Tag Archives: ovulation

How women subconsciously fight sexual competition

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.

painting woman red

Woman’s face look more attractive when they ovulate, but it’s not the blushing

Women’s faces are more attractive to men when they hit peak ovulation, past research showed. It’s not clear what the amplifying signals are. One suggestion was that women’s cheeks turn slightly red during ovulation, providing a subtle cue that enhance attractiveness. Using cameras specially designed to distinguish between subtle colour variations, researchers at University of Cambridge found that women’s faces show an increased redness. Peculiarly, this difference is so small that it’s not visually perceptible. Is the cue that subtle or can the enhanced attractiveness be attributed to some other factor or signal?

painting woman red

Photo: iStock

Dr Hannah Rowland and Dr Robert Burriss, one a zoologist, the other a psychologist, recruited undergrad female students and photographed them at the same time, each morning, for at least a month. The women’s faces, which didn’t had any makeup on, were photographed with a scientific camera typically used in the wild to discern camouflage. Then a computer program selected an identical cheek patch for each photograph.

Then researchers knew when each woman would ovulate since they screen for when the luteinising hormone surged in blood. This way, the researchers knew which photograph showed the woman at peak fertility. The team converted the imagery into red/green/blue (RGB) values to measure colour levels and changes. Indeed, the Cambridge researchers found redness varied across the ovulatory cycle, peaking at ovulation and remaining high during the later stages of the cycle after oestrogen levels have fallen. Once menstruation hit, the redness dipped.

However, when the photos showing the fertile women were ran through models of human visual perception, the average difference in redness was 0.6 units. A change of 2.2 units is needed to be detectable to the naked human eye.

“Women don’t advertise ovulation, but they do seem to leak information about it, as studies have shown they are seen as more attractive by men when ovulating,” said Dr Hannah Rowland, from the University of Cambridge’s Zoology Department, who led the study with Dr Robert Burriss, a psychologist from Northumbria University.    “We had thought facial skin colour might be an outward signal for ovulation, as it is in other primates, but this study shows facial redness is not what men are picking up on – although it could be a small piece of a much larger puzzle,” she said.

It’s interesting that this happens in the first place, even though it doesn’t explain the previously reported enhanced attractiveness. Some primate species advertise ovulation, while the males only express sexual interest in females when they appear to be fertile.  In humans, ovulation is less conspicuous and sexual behaviour is not restricted to the period of peak fertility. Seeing how women have this ‘ability’ can only mean that at some point cheek redness was visible, but this got tune down evolutionary over time. It may very well some antique adaptation from a common primate ancestor.

Primates, us humans included, really like red. Some women might augment face redness during ovulation by wearing red clothing or a blusher.

“As far back as the 1970s, scientists were speculating that involuntary signals of fertility such as skin colour changes might be replaced with voluntary signals, such as clothing and behaviour,” said Burriss. “Some species of primate advertise their fertility through changes in the colour of their faces. Even if humans once advertised ovulation in this way, it appears that we don’t anymore.”

Alright then, if facial redness doesn’t answer the question, what does? Well, there are other signals that might explain the enhanced attractiveness at ovulation. In may be that women have a greater propensity for blushing when around men they find attractive.

“Other research has shown that when women are in the fertile phase of their cycle they are more flirtatious and their pupils dilate more readily, but only when they are thinking about or interacting with attractive men,” said Burriss. “We will need to do more research to find out if skin redness changes in the same way”.

The research was published in the open-access journal PLOS ONE.

Women are more likely to wear pink and red during ovulation

It has been previously shown that during ovulation, women tend to increase their attractiveness to men (though not necessarily conscious). Not only do they change their voice pitch [1], but they also tend to dress more fashionable [2]. A new study published in Psychological Science adds to this growing body of research by suggesting that ovulating women may also choose inviting colors when ovulating.


The idea which sparked this research was a previous study, which concluded that men find women dressed in red most attractive. Why? That’s not entirely clear, but there are a few theories – the most notable is that women naturally become pink or red during sexual intercourse, in a type of ‘sexual blushing’. This idea is also strengthened by the fact that we like women who dye their face with red (lipstick).

In order to test this idea, researchers had 100 American and 24 Canadian women fill in a survey, in which they told the color of the shirt they were wearing, and the number of days since their last period. Specifically, in the American sample, 40% of the women in the likely ovulation group were wearing red/pink compared to 7% in the unlikely ovulation group (the numbers were 26% vs. 8%, respectively in the Canadian sample). Another way to look at the same data is that 80% of all women who are wearing red and pink are likely to be ovulating.

While this does seem like a very interesting ideqa and does make evolutionary and physical sense, I’d like to see the same study conducted on a much larger sample size, and preferably, from more countries – it’s quite possible that this may be a cultural variation.

[1] Haselton, M.G., Mortezaie, M., Pillsworth, E.G., Bleske-Rechek, A., & Frederick, D.A. (2007) Ovulatory shifts in human female ornamentation: Near ovulation, women dress to impress. Hormones and Behavior, 51, 40-45.

[2] Bryant, G.A., & Haselton, M.G. (2009). Vocal cues of ovulation in human females. Biology Letters, 5(1), 12-15.