Sperm competition is a theory of evolutionary psychology which argues that men are primed to engage in more sex, when they believe that they (and their sperm) might have to compete with the sperm of other men, in order to achieve conception. The theory has a lot of fascinating elements and offshoots, concerning biology, psychology and mating behaviors.
A recent study in this area looked at a new aspect of the theory, studying a phenomenon seen in nonhuman animals, where the amount of attention a female mate receives from other males, predicts the number of times the male mate has sex with the female. In other words, it’s been observed that male primates get jealous, when their female mate is getting lots of attention, grooming, etc., from other males. When this happens, the male mate is more likely to have lots more sex with the female, in a behavior believed to be an expression of sperm competition. By having more sex, the male mate is increasing the chances that his sperm will fertilize the female, as opposed to the possible sperm of these other male suitors.
In humans, it’s of course more complex. Most human relationships and environments don’t involve easily observed sex for one thing. Further, in today’s world, we commonly interact on a daily basis with far, far more people, of both sexes, than humans interacted with in the days of our ancient, evolutionary history.
The authors of this study used self-report strategies to get data from almost 400 men, who were in committed, heterosexual and monogamous relationships. The men reported not only how much sex they had with their female partner, but also how many male friends and coworkers their partner had, and how much attention they thought their partner got from those guys. Finally, in a clever twist, the guys also ranked how attractive they thought their female partner was, or at least, how attractive they thought those other guys would think she was.
The point of this last measure of attractiveness was to determine whether the degree to which men think their girlfriend/wife is seen as a “catch” by other men, affects how much the guys feel threatened when their partner is getting lots of attention from those other guys. So, if the guy doesn’t think other men are likely to find her that attractive, will he be worried by the idea that they are paying lots of attention to her?
The researchers found strong evidence that in fact, the more male friends and coworkers a woman had, did predict how much sex the woman had with their male mate, but only when the man believed that she was likely to be seen as “hot” and desirable to those other men. Whether those other males were friends or coworkers didn’t seem to make a difference, as apparently these guys judged those other men as threats, whether they were social or professional relationships. Given the wealth of evidence about how many sexual relationships start in the workplace, we can’t say the guys are wrong about this. (I do wish they’d also looked at social media friendships, as that reflects a new, often challenging, unique aspect of modern relationships.)
I have one, rather substantial, quibble with this study. It looks exclusively at the males’ self-report. Granted, the man’s self-report is a strong reflection of his perceptions, and it is his way of seeing things that is most likely to affect his behavior, if sperm competition is at root of this issue.
But, what about the women? The authors ignore a very, very strong variable here, which is likely to confound these results: Female libido. The higher a woman’s sexual libido, the more likely she is to have more male friends. Not because she is having sex with them, but because women with higher sexual desire get along better with other men, and often, are seen to act more like guys. Other women are more likely to “slut-shame” women with high libido, whereas guys simply view it as fun, exciting, and like themselves.
Men whose female partner has higher libido are likely to have more sex, on average, reflecting her interest in sex. AND, those guys are more likely to view their partners as being more attractive to other men, because they know that other guys desire highly sexual women. AND, the male mates of high libido females are likely to have significantly more concerns about their mates engaging in infidelity, or being tempted by it, compared to women with lower libido.
These two variables don’t have to be independent, but indeed, are likely interacting in a synergistic manner, where female libido may enhance sperm competition behaviors. But, ignoring the issues of female desire is a common failing in much evolutionary psychology, which sadly, contributes to the perception that evolutionary psychology can be somewhat misogynistic, or at least sexist.
Are women with more male friends more likely to cheat? Probably not, at least, not simply based on that single variable. Sexuality is a complex, over-determined behavior affected by many variables and environmental issues, which all interact. But, concerns that other men may be trying to “poach” one’s attractive, sexy female partner is definitely a worry for many men, and I know that I hear from many guys who worry over their female partners’ “guy friends” who might get too close.
But, guys can take this jealousy and concern, and turn it on its head, viewing this as a compliment to themselves. If they are lucky enough to have a female partner that other guys want to be around, that says something about the man’s value. Like the old song says:
You can dance, go and carry on
Till the night is gone and it's time to go
If he asks, if you're all alone
Can he take you home, you must tell him, no
'Cause don't forget who's taking you home
And in whose arm's you're gonna be
So darlin', save the last dance for me...
