The Reasons for Female vs. Male Infidelity Explained by Evolutionary Psychologist David Buss

And there have been, you know, maybe four or five leading hypotheses about why women do it. And this is one area where I've changed my mind on pretty dramatically. So early on, a former student of mine, Marty Hazel, two years down, I was a professor at UCLA, and other friends and colleagues like Steve Gangestad and Randy Thornton, put forward this idea that the reason that women do it is that they're pursuing a dual mating strategy. That is, they're trying to get investment from one guy, like the good dads, but good genes from another guy. And so it's... And... But is there any research done on what type of mate a woman is likely to cheat on? Well, that's a good question. So there's been some, and it's not conclusive, but basically the only way this could work, and I have to back up just a second on that, we know that affairs are very costly for women. So if discovered, they result in... Infidels result in violence. Sometimes they result in killing, you know, getting to the killing. I don't know if we want to get into that, maybe later in our conversation. Then you wrote a whole book on murder. I wrote a whole book on murder, yeah. The murderer next door. But also women suffer more than men. If an infidelity is discovered, they suffer reputational damage. They suffer sometimes social ostracism. It's cataclysmic for their relationship. So, you know, in fact, it's one of the leading causes of divorce worldwide across cultures is if there's a female infidelity. And so the issue is what benefit could be so great to a woman that she's willing to risk all these costs if it's discovered? And so the Good Genes dual mating strategy argument could work in principle, and it could work if there were no costs. And this is, you know, one of the reasons why men and women commit infidelities in secret. You know, it's been driven underground. People don't go on Twitter and say, hey, I just had an affair on my partner, you know. It's driven underground. People try to keep it under wraps so they don't experience the costs. And of course there are costs to men as well by being discovered. They're just not as cataclysmic as they are for women. So the only way it would work, though, is if the—getting back to your original question—is if there's a large discrepancy between the woman's regular partner and her affair partner in terms of the quality of his genes. And so with these Good Genes dual mating strategy theorists proposed is that there are certain markers of good genetic quality. They hypothesized masculine features, and there's a logic behind that. They hypothesized symmetrical features. So we are a bilaterally symmetrical species. So normal development, you know, we have, you know, our hands or arms or legs grow, you know, more or less symmetrically. But there are things that cause deviations from symmetry. So mutations, so genetic mutations can cause deviations. This can cause asymmetries and environmental insults in a variety of ways. And so what the Good Genes theorists argue is that if someone is—if a male is very symmetrical, then that's a marker that he's not experienced a history of disease or environmental insults or a high mutation load or has a—what they call a developmental system that's very kind of impervious to these insults. So even though they've suffered the slings and arrows of outrageous fortune, they still maintain that symmetry. Well, I think there are problems with that. But anyway, back to Backtrack a second, why it changed my mind. So I used to advocate this. Well, it seems—it's logically plausible, but I started to doubt it, and I started to doubt it for two reasons. One is some replication, some larger scale replications of the work started to fail to replicate the original findings. So what they did is—how did they test this? What they looked at is, do women change their preferences when they're ovulating? So because it's only in that narrow window of ovulation that she's going to be getting the Good Genes. So what they looked at is women's normal mate preferences, and they tracked them over the ovulation cycle, and do they change to prefer more masculine, more symmetrical features when they're ovulating and then go back to their normal preferences? And the initial study suggested, yes, they do. Initial study suggested that when women have affairs, it tends to coincide with when they're ovulating and some other things like that. How do they gather this data? Well, it's very difficult in time-consuming data, but it started out with crude methods such as estimating the woman's time of ovulation through a backward counting method. But I mean, how do they get people to even become a part of a study where they admit that they have cheated on their husbands? Oh, well, so that's a different question. These studies just looked at changes in mate preferences. So— Right, but you're talking about affairs. It's not just changes in mate preferences. It's a decision to have intercourse with someone other than your husband. How do you run a study with them? And they haven't run studies like that. So they haven't said— They haven't? No, no. So how do they know? They don't. It's just, do the mate preferences change at ovulation in the ways predicted by the theory? Okay, so how would they find that out? How would they find out if a woman's mate strategies changed and if her preference has changed based on ovulation? So they basically get women and then they track them throughout the cycle. And so they can do this. Now they can do it through hormonal assays. So there are ovulation kits that they can assess. So what do they have? Like a survey they fill out? Like who you attracted to today? Harry Styles. What about tomorrow? Something like that. Jason Momoa, I must be ovulating. Right, right. Basically, they show photographic images. And so women just rate, oh, how attractive is this guy? And so what they find—and then independently they can assess masculinity like Jason—how do you pronounce the name? Momoa. Momoa. Aquaman. Yeah, he's like super masculine. I remember him—I don't think I saw Aquaman, but I remember him from Game of Thrones. Yeah. And yeah, women— Toni and the Barbarian too. Yeah. So yeah, he would be a perfect example. Highly masculine features, you know, the square jaw, heavy brow ridges, you know, a good shoulder to hip ratio. So typically masculine features. And so they would look at do women rate the photos of these masculine and symmetrical guys more attractive when they're ovulating than when they're not ovulating? That's basically what they did. And the bottom line is so there's some conceptual problems with that of, you know, does symmetry and masculinity—why are these the sole features that mark good genes? Because there are also a lot of things that have moderate heritability. It's one of the things we know from the heritability studies. A zillion things show moderate heritability. But here's what really convinced me. So one is the failures to replicate those studies. So the larger scale studies failed to find those preference shifts at ovulation. But when I started to look at the literature about women who were having affairs and the reasons that they're having affairs and the nature of the affairs, there are things that cropped up like this. One study found 79% of women fell in love with or became emotionally involved with her affair partner. And to me, this is exactly the opposite of what you'd want if you're trying to pursue that dual mating strategy idea. You want to get the good genes and then forget about the guy. So it's not to jeopardize your investment from the regular partner. And so it's really a design feature that's counter to that notion. It gets up here, doesn't it? But it seems to me that you're pursuing this as if it's a logical endeavor that's based on trying to achieve an outcome. And I think it's far more likely you're dealing with mental illness, alcohol, you know, emotional imbalance, extreme desire for attention, narcissism, which leads people to seek out exorbitant amounts of attention from other people. You have to take that into account, don't you? Yeah, yeah. Okay. So that's a fair point. And those things aren't necessarily inconsistent if you ask like who has affairs and what are their personality characteristics. But affairs happen in all cultures or virtually all cultures unless the women are extremely cloistered as they are in some cultures where they're like they cannot leave the home without a male bodyguard. But affairs happen in all cultures. Would you like some coffee? Sure, I'd love some. All right. Thank you. So affairs happen in all cultures? Yeah, affairs happen in all cultures. And so a competing hypothesis about why, and this is the one I'm currently putting my money on if there's a horse race, is what I call the mate-switching hypothesis. And this is the notion that women who are in relationships, who are where the relationship is going south, perhaps the partner starts out looking promising but has failed to live up to his promise. Perhaps he becomes an alcoholic or a drug addict or loses his job or starts abusing her, starts beating her up, that women use affairs as a mate-switching device either to divest herself of her regular partner and or to trade up in the mating market to someone who's more desirable or to make it easier to transition back into the mating market on the notion, on the assumption that she'll be able to find someone more desirable out there. And so there's at least a fair amount of circumstantial evidence that supports the mate-switching hypothesis, like the one I just mentioned. Women with 79% of women becoming emotionally involved or falling in love with their partner, this suggests, you know, it's not just, oh, I'm seeking transient attention, as you mentioned, that some women might do it for that, of course, but it suggests that they're forming a long-term attachment to this other guy rather than their regular partner. So here's another one, and this may seem like super, super obvious, is that women who are unhappy with their regular relationship, either sexually unhappy or generally unhappy with their overall relationship, they're more likely to have affairs. Now, this seems like the most obvious thing in the world, right? Yeah, sure. Tell me something I don't, your grandmother couldn't tell you, you're unhappy in the relationship, you're more likely to have an affair. But it turns out the same is not true for men. That is, there are at least some studies that show that if you compare men who have affairs with men who don't, there's no difference in how happy they are with the relationship. And that's why you can have men, and just to bring up, I don't know, movie star examples, like this is an older one, but Hugh Grant was involved with Elizabeth Hurley. I don't know if you remember that one, and he's like having sex with a prostitute in LA. Why is he cheating with Elizabeth Hurley? Kind of crazy. Now, in his case, in that case, the male motivation for affairs differs on average substantially from the female motivation. And that is that men have this tremendous desire for sexual variety, meaning a variety of sex partners. Men tend to have a higher sex drive in general on average. And so they try to satisfy. So even men who are involved with or married to classically beautiful, beautiful women sometimes have affairs, and people are very puzzled by this. But that desire for sexual variety is what drives most men into affairs. And so there's a dramatic sex difference in why men have affairs with desire for sexual variety pushing most men into it. It's like, I think it was Chris Rock said, men are only as faithful as their opportunity. You get a low cost opportunity, a lot of men act on it. You're like an academic, you're away at a conference, you're in a different town, some fall into bed with someone else. One night stand, a brief affair, and that's that. But women, it's really different. Of course, some women do it just for sexual variety too. But that's a minority. If you ask the question, why do most women have an affair, I think that's the mate switching notion.