Menstruation & Attraction: Why Females Shouldn’t Flirt While Menstruating, and Why Bears Can Smell the Menstruation

To my female readers who read the title and said, “duh, you didn’t need science to figure that one out,” (minus the bears part) hear me out. Though the negative behavioral effects of menstruation may be obvious, several recent studies have empirically illustrated just how influential they can be. In other words, psychologists now have data that shows the relationship between menstruation and attraction. Let’s start with strippers.

In 2007, psychologists from the University of New Mexico wanted to know if their was a connection between the menstrual cycles of female strippers, and the tips they earned during a given night. So they ran a study, collected the data, and published the results. Their paper begins with the most objective description of a strip club you will ever read. Makes sense, PhD psychologists are not exactly the “strip club type,” and some background research was necessary for “academics [who] may be unfamiliar with the gentle-men’s club subculture.” They even went into the intricate details:

Dancers typically wear very little perfume, but they often have breast implants, dye their head hair, trim their pubic hair, shave their legs and underarms, and adopt a “stage name” different from their real first name. They typically do regular aerobic and resistance exercise to maintain a fit, lean body shape.

After that was made clear, the researchers recruited 18 strippers and tracked their tips and menstrual cycle for 60 days (to prevent the strippers from knowing what the study was about, psychologists asked them report a number of other variables including, mood, work location, and work hours. They also distinguished between those on the pill and those not on the pill). They found two things. First, the amount of tips earned varied greatly; and second, strippers made significantly more tips when they were most fertile – just before ovulation, or a little over a week after their period ended.  As the graph illustrates, “during peak fertility, dancers [who weren’t on the pill] raked in an average of $68 an hour, [and] when they were menstruating, they earned only about $35.” Moral of the story? If you’re a stripper, don’t take birth control, and double your efforts on shifts just before ovulation.

For some (again, female readers), it may seem like the researchers have pointed out the obvious – that strippers were least sexy when they were menstruating. And it is probably not a surprise  that they were all male. Nevertheless, give them credit for actually accumulating the data to prove it.

What about more ordinary examples? In a 2006 study, researchers from the Czech Republic found that men can recognize if females are on their period through smell, no joke. The researchers gathered odor samples from 12 women by having them place cotton pads under their armpits for 24 hours. Then, they had men smell the cotton pads and rate their intensity, and attractiveness. They found that “odor from women in the follicular (i.e. fertile) phase was rated as the least intense and the most attractive [and vice versa].” In a related study, men were asked to smell t-shirts worn by women in different stages of the menstrual cycle and rate how attractive they smelled. Similar to the previous study, “men exposed to the scent of an ovulating woman subsequently displayed higher levels of testosterone than did men exposed to the scent of a nonovulating woman or a control scent.” So it turns out that there is some truth to Brick’s worry about bears smelling “the menstruation;” if he only knew that he (human males) can smell it to.

It gets better. A study done in January showed that “men and women judge photographs of women’s faces that were taken in the fertile window of the menstrual cycle as more attractive than photographs taken during the luteal phase.” Put differently, women are most attractive just before ovulation, a finding consistent with the stripper study. In addition, Gangestad, Thornhill, and Garver  found that when females are most fertile, their male partners are extra protective: “Among 31 mated women not using the pill, their sexual partners were reported as using more mate-guarding behaviors, including higher proprietaries, attentiveness, and vigilance (e.g., calling the women’s cell phones at random times to see what they were doing).” Researchers also found that this effect was most prevalent within relationships that had just started, or were not formally established i.e., just hooking up or friends with benefits.

So what does all this say? In short, that “there is now good evidence of human ovulation cues— therefore, at some level, men may be able to detect ovulation.” This suggests that there is a deeper, more important point here, and it is that men and women are attractive to each other for reasons that are largely unconscious. When we go out to party, have drinks at a bar, and flirt with those we are attracted to, we are influenced by mental processes that we largely unaware off. As neuroscientist David Eagleman says in his great new book Incognito, “our ability to make subtle distinctions is exquisitely fine-grained; our brains are engineered to accomplish the clear-cut task of mate selection and pursuit. All of it rides under the surface of conscious awareness – we get to simply enjoy the lovely feelings that bubble up” (2011, p. 95). 

Evolutionarily speaking, this all makes sense; females are most attractive when they are most susceptible to becoming pregnant, (right before ovulation), and least attractive when they least susceptible to becoming pregnant (during menstruation). Likewise, males are most aggressive towards females when females are most fertile, suggesting that males recognize when their genes have the best chance of being passed on. The most interesting part of these studies, as I have said, is that they illuminate things that normally go under the radar. Yes, it is not a surprise that strippers make less money when they are menstruating, but it’s not like men in strip clubs can consciously distinguish the menstruating strippers from the fertile strippers. Similarly, I doubt that the men in the cotton pads and t-shirt studies were consciously able to tell menstruation pads or t-shirts from fertile pads or t-shirts. 

So the next time you (male or female) go out, keep in mind that your biological forces are hard at work, and that they are unconsciously influencing that killer pick-up line.

1. MILLER, G., TYBUR, J., & JORDAN, B. (2007). Ovulatory cycle effects on tip earnings by lap dancers: economic evidence for human estrus?☆☆ Evolution and Human Behavior, 28 (6), 375-381 DOI: 10.1016/j.evolhumbehav.2007.06.002
2. Havlicek, J., Dvorakova, R., Bartos, L., & Flegr, J. (2006). Non-Advertized does not Mean Concealed: Body Odour Changes across the Human Menstrual Cycle Ethology, 112 (1), 81-90 DOI: 10.1111/j.1439-0310.2006.01125.x
3. Miller, S., & Maner, J. (2009). Scent of a Woman: Men’s Testosterone Responses to Olfactory Ovulation Cues Psychological Science, 21 (2), 276-283 DOI: 10.1177/0956797609357733
4. Roberts, S., Havlicek, J., Flegr, J., Hruskova, M., Little, A., Jones, B., Perrett, D., & Petrie, M. (2004). Female facial attractiveness increases during the fertile phase of the menstrual cycle Proceedings of the Royal Society B: Biological Sciences, 271 (Suppl_5) DOI: 10.1098/rsbl.2004.0174
5. Gangestad SW, Thornhill R, & Garver CE (2002). Changes in women’s sexual interests and their partners’ mate-retention tactics across the menstrual cycle: evidence for shifting conflicts of interest. Proceedings. Biological sciences / The Royal Society, 269 (1494), 975-82 PMID: 12028782
6. Haselton, M., & Gildersleeve, K. (2011). Can Men Detect Ovulation? Current Directions in Psychological Science, 20 (2), 87-92 DOI: 10.1177/0963721411402668