Fertile Attraction

One of the things that sets humans apart from most other creatures is that we don't have a "mating season" or period of going "into heat" which is the only period during which we're interested in getting it on with the opposite sex -- we are notoriously interested in Topic A all the time. However, several recent studies have been digging into the question of whether, unconsciously, men can actually sense when a woman is fertile and respond to her differently as a result.

The New York Times wrote up one of these stories a couple weeks ago in which Florida State researchers had various men come into their laboratory, and spend a few minutes playing Legos with a demure 21-year-old research assistant:

The 21-year-old woman was carefully trained not to flirt with anyone who came into the laboratory over the course of several months. She kept eye contact and conversation to a minimum. She never used makeup or perfume, kept her hair in a simple ponytail, and always wore jeans and a plain T-shirt.

Each of the young men thought she was simply a fellow student at Florida State University participating in the experiment, which ostensibly consisted of her and the man assembling a puzzle of Lego blocks. But the real experiment came later, when each man rated her attractiveness. Previous research had shown that a woman at the fertile stage of her menstrual cycle seems more attractive, and that same effect was observed here — but only when this woman was rated by a man who wasn’t already involved with someone else.

The other guys, the ones in romantic relationships, rated her as significantly less attractive when she was at the peak stage of fertility, presumably because at some level they sensed she then posed the greatest threat to their long-term relationships. To avoid being enticed to stray, they apparently told themselves she wasn’t all that hot anyway.

This is, it seems, part of a growing body of data suggesting that while we as humans are not consciously aware of when a woman is fertile, there are in fact observable differences in how women behave and how men react to women that correlate to the woman's fertility cycle.

One major question, however, is how exactly it is that men get these queues to which they respond differently. Is it some sort of physical difference? Does a woman look or smell different when she is fertile, in some way that men are not consciously aware of but respond to? Or is it that women unconsciously act differently?

In one recent study, it was found that women tended to give more attention to their hair, make-up and clothing when near their peak fertility:

Using a sample of 30 partnered women photographed at high and low fertility cycle phases, we show that readily-observable behaviors – self-grooming and ornamentation through attractive choice of dress – increase during the fertile phase of the ovulatory cycle. At above-chance levels, 42 judges selected photographs of women in their fertile (59.5%) rather than luteal phase (40.5%) as “trying to look more attractive.” Moreover, the closer women were to ovulation when photographed in the fertile window, the more frequently their fertile photograph was chosen.

And perhaps most interestingly, though firmly in the "don't try this at home" category, a group of researches got exotic dancers to provide daily information about the tips they earned from lap dancing and also their ovulatory cycle. Dancers received dramatically more tips during their fertile days:

Eighteen dancers recorded their menstrual periods, work shifts, and tip earnings for 60 days on a study web site. A mixed-model analysis of 296 work shifts (representing about 5300 lap dances) showed an interaction between cycle phase and hormonal contraception use. Normally cycling participants earned about US$335 per 5-h shift during estrus, US$260 per shift during the luteal phase, and US$185 per shift during menstruation.

The kicker? Exotic dancers on The Pill did not show the fertility peak in earnings, and earned less overall than the non-pill using dancers. The authors of the study seem to think this probably suggests some sort of subtle scent or appearance difference during fertile times, though (going from our experience as a married couple charting fertility over the last decade in relation to NFP) I would strongly suspect that it's instead that the non-pill using dancers in some sense telegraph more sincerity or desire when fertile.

Whatever the reason, it's a mildly interesting area of developing research. And for those NFP-using husbands out there who find fertile periods frustrating, this now provides scientific evidence that it is not just their imagination: their wives really are hotter than most other women.