A meta-analysis of women’s preferences for mates suggests that ovulating women have evolved to prefer men who display sexy traits, such as a masculine body type and facial features, dominant behavior and certain scents — traits that are not typically desired in a long-term partner.
For the study, researchers at the University of California-Los Angeles (ULCA) analyzed dozens of published and unpublished studies on how women’s preferences for mates change throughout the menstrual cycle.
They found that the desire for these masculine characteristics — thought to be signs of high genetic quality — don’t last all month, just the few days in a woman’s cycle when she is most likely to pass on genes that give her offspring a better chance of surviving.
“Women sometimes get a bad rap for being fickle, but the changes they experience are not arbitrary,” said Dr. Martie Haselton, a professor of psychology and communication studies at UCLA and the paper’s senior author. “Women experience intricately patterned preference shifts even though they might not serve any function in the present.”
Since the late 1990s, there has been a debate in the scientific world as to whether women’s preferences for a mate shift at times of high fertility, according to Haselton. She and Kelly Gildersleeve, a UCLA doctoral candidate in psychology and the study’s lead author, spent three years investigating this, soliciting raw data from dozens of scholars who have conducted research on the topic.
The researchers then translated data from 50 studies into the same mathematical format so that the findings could be statistically analyzed together.
The strength of women’s preference shift proved to be statistically significant, according to researchers. The scientists note that the shift was statistically comparable to the difference researchers have found between men’s and women’s self-reported number of heterosexual sex partners.
According to Haselton, the findings are less clear about which male characteristics are most alluring to ovulating women.
“The strongest effect seems to be women’s responses to male body scents,” the researcher said.
In the few scent studies, researchers asked women to smell T-shirts that had been worn by men with varying degrees of body and facial symmetry. That’s because body and facial symmetry is associated with larger body size, more pronounced sexual “ornaments” such as the plumage on male birds, and better health, suggesting that symmetry could be an indicator of genetic quality, the researchers explained.
Those studies found women preferred the odors of more symmetrical men when in the fertile portions of their cycles.
The UCLA meta-analysis also showed a large shift in women’s preferences for the body odor of symmetrical men. However, the researchers noted that more studies are needed in this area.
The presence of shifts in sexual preferences among women may generate debate, but these shifts are well documented in mammals from rats to orangutans, according to the researchers. They note that female chimpanzees are known to prefer to have sex with different males within the fertile phrase — a strategy thought to improve their offspring’s chances of survival, the scientists explained.
“Until the past decade, we all accepted this notion that human female sexuality was radically different from sexuality in all of these other animal species — that, unlike other species, human female sexuality was somehow walled off from reproductive hormones,” Haselton said. “Then a set of studies emerged that challenged conventional wisdom.”
Several hypotheses have been put forward to explain the shift, including one that says it may be an evolutionary adaptation to ensure the survival of the species.
“Under this hypothesis, women who preferred these characteristics were more likely to pass on beneficial genetic qualities to their children, thereby enhancing their children’s chances of survival and reproductive success,” Gildersleeve said.
In the past, Haselton also has proposed the “dual mating hypothesis,” in which ancestral women were driven to pursue kindness, reliability, and resources — so-called “good dad” traits — as well as sex appeal and a masculine personality — ‘”sexy cad” traits — even if both sets of qualities didn’t come in the same package.
“Ancestral women would have benefitted reproductively from selecting partners with characteristics indicating that they’d be good co-parents, such as being kind, as well as characteristics indicating that they possessed high genetic quality such as having masculine faces and bodies,” Haselton said.
“Women could have had the best of both worlds — securing paternal investment from a long-term mate and high-genetic quality from affair partners — but only if those affairs were timed at a point of high fertility within the cycle, and probably only if their affairs remained undiscovered.”
If women understand the logic behind their shifts in preferences for mates, it will help them make better sexual decisions, according to Haselton.
“If they notice suddenly that they’re attracted to the guy in the next cubicle at work, it doesn’t necessarily mean that they don’t have a great long-term partner,” she said. “They’re just experiencing a fleeting echo from the past.”
The findings are found in Psychological Bulletin, published by the American Psychological Association.