Beyond Body Count: How Many Past Partners Are Too Many?
Our new paper in Nature's Scientific Reports
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By now, you’ve probably come across the term body count - not in the traditional military sense but in the modern dating sense. It refers to the number of past sexual partners a person has had. The phrase suddenly seems to be everywhere - or at least everywhere online - often in the context of criticizing people for supposedly having too high or too low a body count. A common claim is that a high body count is fine or even desirable for men but undesirable for women, suggesting the persistence of a traditional sexual double standard.
But do people really care about a prospective partner’s body count? If they do, is this just a Western thing, or is it found across countries and cultures? And is there really still a sexual double standard when it comes to people’s romantic history?
These are the questions that my colleagues and I set out to answer in recent cross-cultural research published in Scientific Reports. The work was led by my colleague, friend, and former PhD student Andrew Thomas of Swansea University in Wales, and built on earlier research we did together when I was a lecturer there. Our aim was to determine whether concern about a prospective mate’s body count is found across cultures, what exactly it is that people are concerned about, and whether men judge women’s sexual history more harshly than women judge men’s.
TL;DR: It’s not just how many partners someone’s had that matters, but when they had them and whether the pace is slowing down. And if there’s still a sexual double standard, we didn’t detect it in our data!
The Evolutionary Puzzle of Sexual History
Humans have an enduring fascination with other people’s sex lives. Tell someone about exciting new research on traffic patterns, and they’ll politely nod along. But merely hint at a romantic scandal, and you immediately have their full attention.
And we don’t process this information like dispassionate robots. Even the most open-minded among us often find ourselves judging other people’s romantic adventures and misadventures - sometimes positively; often not-so positively.
Why are we like this? Why are we so obsessed with other people’s love lives, and why do we make the particular judgments we make?
Many would argue that these things are purely sociological: Our interests and moral convictions are cultivated by the local culture and are ultimately arbitrary conventions, like whether we read from left to right or right to left. Change the culture, the argument goes, and we’d be just as interested in aardvarks or water polo, and we’d make the opposite moral judgments to those we make today.
I don’t buy it. For one thing, our fascination with other people’s sexual behavior - and our knee-jerk tendency to moralize about it - are found everywhere in the world. For another, many of the judgments we make seem to cut across cultural lines. Is there a society anywhere, for instance, where people think it’s wonderful when a partner cheats on them or when someone lies to get a friend into bed?
On top of that, our preoccupation with people’s sexual history makes good sense from an evolutionary perspective, especially in the context of mate choice. This is because past behavior is the best predictor of future behavior, and thus a person’s sexual history carries crucial information about possible risks and rewards of getting romantically involved with them. It would be surprising if people weren’t highly attuned to it.
One variable that might be particularly salient is a person’s past partner number, or what’s now known colloquially as their body count. There are good reasons to expect people to care about body count, and to prefer someone whose partner tally is relatively low rather than relatively high.
Why? Because although someone with an extensive résumé of past lovers could be a good long-term mate, they’re statistically a somewhat riskier bet. They may be more likely to stray, and less likely to commit for the long haul. For men throughout our evolutionary history, this meant an increased chance of ending up investing in another man’s child; for women, it meant an increased chance of being left holding the baby. And for both sexes, more past partners meant an increased risk of sexually transmitted infections.
Given these risks, it makes sense that people would generally prefer partners with fewer past lovers. They might not necessarily want partners with none; in societies where premarital sex is permissible and common, zero experience could also be seen as a red flag. In general, though, less may be more.
A Bit of a Past, But Not Too Much
In a 2017 study, Andrew Thomas, Caroline Butler, and I put these ideas to the test with a sample of young adults in the UK. The results were exactly what evolutionary reasoning would predict: People preferred prospective partners with a relatively low body count.
As shown in the graph below, the sweet spot was two to four past partners; fewer or more reduced attractiveness. In effect, people wanted someone with a bit of a past, but not too much (which was the title of our paper describing the research).
Intriguingly, we found no evidence for a sexual double standard: none, zilch, nada. Contrary to what’s often claimed, women weren’t judged any more harshly than men for having a high body count. That’s not to say they weren’t judged for it, but only that men were judged too.
This can be seen in the next graph. The left panel shows willingness ratings for long-term relationships, the right panel for short-term ones. As you can see, the sexes barely differed in their willingness to engage in long-term relationships. For short-term relationships, in contrast, men expressed greater willingness at every past-partner level.
These results fit nicely with a key claim of evolutionary psychology: namely that for short-term relationships, men are less choosy than women, whereas for long-term ones, the sexes are about as choosy as each other. The results don’t fit, however, with the idea that there’s a sexual double standard such that women are judged more harshly than men for their prior sexual behavior.