For a long time, the construction of gendered sexual behavior went like this: Men aren't hardwired for monogamy, but women, being more invested in emotional bonds and offspring resources, are. But it's becoming increasingly clear that women aren't exactly thrilled with the same old every night either. Research shows that the truth about monogamy may be simply that some people are inclined to it, and some are not—and your gender doesn't have too much to do with which side of the line you fall on.
This wouldn't be shocking to anyone who has spent time dating other humans, but here goes: A psychologist at the University of Oxford, Rafael Wlodarski, looked at sociosexual attitude data from 600 men and women, Brit and Yank, which included their responses about their propensity for cheating or promiscuity. Tia Ghose at LiveScience writes that scientists generally consider most human sexual behavior as concentrated in the middle of a bell curve with more extreme behavioron the ends. But these results, published in Biology Letters, were different:
"When we looked at the data, it has this very weird shape," Wlodarski told Live Science. "Rather than it being a whole gamut of mating strategies, there seems to be two potential phenotypes within males and within females."
Both men and women tended to split into two groups: one made up of people who valued faithfulness, and another with people seeking flings. Slightly more than half of the men could be classified as having the promiscuous orientation, compared with just under half of the women.
Surprise! The number of men and women who want more long-term commitments versus those who don't are just about equal, with monogamy only slightly favored in women. But this isn't common in the animal kingdom, where most species fit in one group or the other. Primates are one of the few types of animals who also exhibit both tendencies. "It's very, very rare to find two competing phenotypes that can both be sustained in a population," Wlodarski told PS Mag, which notes that this study is "the first to suggest that women also cluster into either promiscuous or monogamous groups."
But there's more: The research group also looked at data about the correlation between ring finger length and short-term dating attitudes. Longer ring fingers in men and women mean a higher exposure to prenatal testosterone, which, they found, aligned with greater interest in casual sex. However, Wlodarski is careful to note that this data was not any kind of reliable predictor of likelihood to cheat on a case-by-case basis:
Finger length can't predict individual behavior, though; the relationship between finger length and mating strategy only emerges with large datasets.
"At this stage, there's no way of predicting whether someone will preferentially pursue one strategy or another," Wlodarski says. "You can't just look at someone's digit ratio and say, 'You're definitely promiscuous.' "
If only. What's interesting about all this, though: Women don't have a clear monopoly on monogamy, and men don't have a clear monopoly on promiscuity.
Monogamy may even be harder for women than men, for a host of reasons that aren't entirely clear. But isn't it strange and telling that we have long associated women losing interest in sex as a sign they are better suited to monogamy, when signs point clearly to the situation being much the opposite? Writes Daniel Bergner for the NYT:
But for many women, the cause of their sexual malaise appears to be monogamy itself. It is women much more than men who have H.S.D.D. [hypoactive sexual-desire disorder], who don't feel heat for their steady partners. Evolutionary psychologists argue that this comes down to innate biology, that men are just made with stronger sex drives — so men will settle for the woman who's always near. But the evidence for an inborn disparity in sexual motivation is debatable. A meta-analysis done by the psychologists Janet Hyde and Jennifer L. Petersen at the University of Wisconsin, Madison, incorporates more than 800 studies conducted between 1993 and 2007. It suggests that the very statistics evolutionary psychologists use to prove innate difference — like number of sexual partners or rates of masturbation — are heavily influenced by culture. All scientists really know is that the disparity in desire exists, at least after a relationship has lasted a while.
And still, cultural conditioning keeps both groups routed on rigidly different paths, beset with all sorts of generic assumptions about what sorts of relationships we should want as men or women—even when none of these strict types seem to serve us very well.
Ultimately, our predilections towards monogamy or promiscuity may be far more dependent on forces much less obvious gender. There's a good bit of discussion out there about the chemicals that are released when we fall in love, which can generally be understood in three stages: lust, then attraction or infatuation, then attachment. Each of these phases is accompanied by a different set of chemicals—testosterone, dopamine, norepinephrine, oxytocin, vasopressin—that determine the nature of the phase. It's entirely possible that different people have different responses to these phases or chemical sets.
On the chemical level, love may be addiction between two people. Could it not also be addiction between the person and the particular chemical release during the phase they fancy most, just as some of us prefer the buzz of booze over weed? So perhaps people who like more short-term relationships are more addicted to the pleasure of the first high, the first part, the first blush of romance—whereas those more inclined toward the slow and steady comfort of monogamy are into, simply, a different kind of buzz.
This idea is worth taking seriously if we're interested in a future where people and advertisers and institutions stop treating men and women as at odds in the game of love and romance, but rather, as individuals who want different things that don't line up based on genitalia. We could stop suggesting that literally everything men do is about spewing seed, and that literally everything women do is about guarding the purity of their uterus. It's clear, in 2015, that the influence a person's gender has over their sexual orientation is anything but hardbound.
Just don't forget that scientific research generally approaches the term monogamy differently, or as a more multifaceted concept. Social monogamy is living with only one partner usually to raise children, even if one has an adulterous affair; sexual monogamy means an exclusive sexual relationship. This should probably be clarified for the purposes of these studies, because a person in a monogamous relationship who has affairs would still be considered monogamous. Eh, let's call the whole thing off.
Illustration by Tara Jacoby