In this episode, Dr. David Buss joins Dr. Kelly to talk about why men cheat, why women cheat, and why they do it. Dr. Buss is widely regarded as one of the founders of the field of evolutionary psychology, and is a professor of psychology at the University of Toronto.
00:20:27.040We were just fooling around and, you know, it wasn't serious.
00:20:31.420And so you get sort of a reporting bias on both sides.
00:20:36.400But there's a third factor that's involved, and that is that almost all the studies that
00:20:44.640have been done on these body count numbers don't include prostitutes.0.65
00:20:51.200So if you include prostitutes, so let's say a prostitute can have sex with hundreds and
00:20:55.780hundreds and hundreds of guys, then there's one study that included prostitutes and did
00:21:05.580the statistical calculations and found that the numbers of men and women reporting sex
00:21:11.480partners were almost identical. And that is because prostitution is 99% plus a male consumer
00:21:21.940activity. Yes, thank you. I was looking for a word. Thank you. Activity. And so if men0.67
00:21:34.320including, yeah, I had sex with this prostitute and that prostitute and that prostitute, that's1.00
00:21:40.280three or four right there, then their body count is going to be higher. But I think all three1.00
00:21:47.380variables are at work. Males exaggerating, women under-reporting, and then inclusion of prostitutes
00:21:53.940is another issue. David, I was wondering as you were speaking about paternal uncertainty,
00:21:59.160Is that the reason that almost every society, or I don't know, maybe I'm wrong, correct me on this if I am,
00:22:05.300but societies have evolved mechanisms for restricting and controlling female sexuality0.97
00:22:11.540to sort of prevent women from sleeping around a lot. Is that why?0.93
00:22:17.600Yes. But the way I'd phrase it is it's typically the families of the women0.96
00:22:26.120that are, that have developed means of trying to restrict and cloister the females. They do0.99
00:22:34.700mention, this is actually a study that Diana Fleischman and I did with another graduate
00:22:41.340student. We call it the daughter guarding hypothesis, where, and we showed it even in
00:22:48.560America parents devote more effort to monitoring and restricting their0.90
00:22:54.980daughters sexual activity than their sons so and that's the more modest dress
00:23:01.460setting curfews or when the child has to be back home and in bed etc and so but
00:23:09.380it's typically the families of the daughters that do this sort of thing and
00:23:15.060And it ranges all the way to genital mutilation, to clitoridectomy and fibrillation where it's0.99
00:23:24.960the women within the family that inflict these genital wounds on their daughters, on the0.99
00:23:34.880young females, because it increases their mate value on the mating market.0.95
00:23:41.340And so families are very concerned about their daughter's sexual reputation because mating
00:23:49.640and marriage historically have not been just one man, one woman.
00:23:54.700It's been that the family's gotten involved and influences it.
00:23:58.280And it's often a political alliance or economic alliance between two families.
00:24:04.940And so they want to ensure, or they strive to ensure, the highest mate value, which is sexual reputation of the girls in their family, the daughters and women in their family.
00:24:20.280And you mentioned mate value and you talked about, you know, one person's pay going up or whatever.
00:24:26.920I imagine what makes up male mate value is very different than what makes female mate value on a number of things.
00:24:37.820Yeah. So, well, we have to distinguish between male and female mate value.
00:24:44.060We also have to distinguish between long-term mate mate value and short-term sexual value, if you will.
00:24:52.460And where this, so I assume we're talking about long-term mate value.
00:24:58.700And yes, there's, if you look at the components that make up for mate value,
00:25:06.580many of them are actually shared by the sexes.
00:25:09.760So intelligence, dependability, kindness, good health, et cetera.
00:25:17.460There are many shared components, but there are basically two clusters of sex differentiated contributors to mate value.
00:25:26.560So on the male side, it is his economic or financial provisioning, as well as his willingness to channel those resources to a specific woman and her offspring.
00:25:43.860And that's an important distinction because it's not just the number of digits in his bank account or stock portfolio.
00:25:52.400I mean, he can be Elon Musk, but if he's unwilling to channel those resources to a particular woman, then his mate value is correspondingly lower.
00:26:03.360And so those are more important components to a man's mate value than to a woman's, as well as a slightly older age.
00:26:12.880so women universally prefer partners who are a few years older than they are not not ancient
00:26:19.540um but uh typically a few years older you do you do get um in some cases very large age
00:26:27.060discrepancies but uh but those are rare so like a modern example would be bill belichick the
00:26:32.980football uh coach who is his girlfriend is apparently i guess in her mid-20s or so and
00:26:39.620He's in his, I think, 70s, but typically it's more women prefer guys who are a few years older but not ancient.0.94
00:26:50.100On the female side, you get youth and beauty.
00:26:55.140So physical attractiveness looms much larger in a woman's mate value than a man's.
00:27:02.540and and it's people don't like this finding you know it goes against you know because again when
00:27:25.420I what I was taught when I was undergraduate and I'm sure you've all heard these phrases like
00:27:31.340beauty is only skin deep beauty is in the eyes of the beholder you can't judge a book by its cover
00:27:39.740but in fact physical appearance provides a wealth of information about a woman's health
00:27:49.500status and her fertility most important her fertility and so and so we know for example that
00:27:57.900um uh while it used to be believed that um beauty standards were infinitely cross-culturally
00:28:07.280variable we know now that they're not there are some at least some components that contribute to
00:28:14.840physical attractiveness that are universal so clear skin clear eyes smooth smooth skin lustrous
00:28:22.800hair, full lips, a waist-tip ratio of roughly 0.7, low waist-tip ratio, basically cues to youth
00:28:33.860and cues to health. Cues to youth because youth is very highly correlated with fertility.
00:28:42.320So we know what the fertility curves are for women and for men. And for women, they tend to
00:28:51.560peak in their, say, early to mid-20s, where women are most fertile. And then it declines
00:29:02.200with time. So much more steeply for women than for men. Now, fertility also declines
00:29:10.860for men, but much more gradually. So you do have men who are in their 60s, 70s, and occasionally
00:29:19.080older that actually do reproduce so i think of two recent examples would be um uh mick jagger
00:29:26.760uh well mick jagger would be would be one but i was thinking of al pacino and uh i think it's uh
00:29:34.220robert de niro uh also in their in their they're pretty old at this point uh but they've had
00:29:42.580children of course obviously with much younger women who are still fertile so
00:29:50.460so this this is a fundamental sex difference and one that people don't
00:29:55.580like and it's but you know I don't make these things up you know you have to go
00:30:01.000with the data and so these are fundamental differences in our
00:30:06.700reproductive biology it wasn't it wasn't sexist male scientists who invented the
00:30:12.480fact that fertility declines more rapidly in women than in men. It's just a biological fact.
00:30:20.000So getting back to your question, so you have, those are the two big clusters
00:30:25.460of sex-differentiated components of mate value. Resources and the ability to contribute those
00:30:35.260resources, and then youth and physical attractiveness. And people don't like either
00:30:41.300either of those actually so because people say well so you're saying women are gold diggers
00:30:46.660well no i'm not saying women are gold diggers you have this fundamental asymmetry in parental
00:30:52.840investment where uh you think of our ancestral mothers and their mothers and their mothers and1.00
00:31:01.100their mothers what would have aided a woman and her children's survival and their reproductive0.83
00:31:08.840of success? Well, an investing male who offered protection and provision and resources and who
00:31:17.140could ensure or increase probability the survival of the woman and the children. And so it's
00:31:25.920perfectly reasonable why women universally have evolved this standard of their mate preferences
00:31:33.840and what contributes to male mate value and from a man's point of view every one of us
00:31:40.960we are all the descendants of fathers and grandfathers and great-grandfathers all of whom
00:31:47.440have preferred to mate with fertile women so if if they preferred to mate with infertile women0.97
00:31:54.800we wouldn't be here it would have broken this inviolate chain of um of reproduction0.87
00:32:01.440So we are all, I mean, we could pat ourselves on the back. We're all evolutionary success stories
00:32:06.960in that sense. We've all come from this long, unbroken chain of successful males and females,
00:32:15.760all of whom have made wise mate choices and gotten through these tremendous slings and
00:32:24.720arrows of outrageous fortune to give rise to who we are here today.
00:32:30.000and it's a when you were saying we're all evolutionary success stories i was thinking
00:32:33.680back to my teaching career i've taught a few kids who want evolutionary success stories david but
00:32:37.600let's let's not focus on that now that is very interesting what you were talking about because
00:32:44.240as you were well aware over the last few years there has been a revolution
00:32:48.240in mating which has been the internet and apps and everything else so how has that kind of changed
00:32:55.200our predilections what we look for and how has that changed the relationships between the sexes
00:33:02.860more broadly yeah well that's a it's a great question and a complex question and there isn't
00:33:08.760one simple answer so what i can offer is some thoughts on the question and without um attaching
00:33:18.320uh an undue amount of certainty to those thoughts um so uh so one thing is so ancestrally
00:33:26.320we would have encountered perhaps a few dozen potential mates in our entire lifespan
00:33:32.640because we didn't have cars airplanes internet or anything else so you're geographically limited
00:33:40.400and now we live in large urban settings and then the internet with with dating sites they0.97
00:33:47.040provide us access to thousands or potentially millions of potential mates who live thousands
00:33:55.920of miles away. They can be in another country and sometimes are. So this is one huge, what
00:34:04.880we call an evolutionary mismatch. And sometimes this produces, and I think this is a speculation,
00:34:14.400but a reasonable one a decision paralysis so they've shown this in studies of you go to a
00:34:22.080high-end supermarket and they have these um six jams you can taste and then you taste several
00:34:29.440and then say oh i like the peach or whatever and you buy one but they've shown if you give people
00:34:34.72024 they taste some and they just can't decide there's too many too many to decide decision
00:34:41.840paralysis and i think some of that goes on in the mating world so you get you know wow there's so
00:34:48.320many potential mates to choose from and i got matched with this person now that person and
00:34:54.160maybe there's someone just a little bit better you know on the next match and so i think there's this
00:35:02.320reluctance to commit uh to one choice you know whereas in ancestral environments you have just
00:35:09.280a few to choose from and you choose one and make the commitment so that's one another thing that
00:35:18.000i think that really skews things is that what you get on the internet dating profiles is you get
00:35:24.080photographs and then written descriptions so uh i like fishing or um i'm into
00:35:32.800rugby or whatever you know i like uh you know heavy metal rock whatever the case
00:35:38.080an interesting woman you're describing she likes fishing rugby and heavy metal1.00
00:35:45.440she doesn't sound straight is like what we're saying hey there there's uh assortative matings1.00
00:35:54.560mates for all sorts of interests so but but i think that what you have is um what happens is
00:36:01.200the photograph is a visual image that tends to overwhelm all other sources of information
00:36:08.080And so people make their decisions heavily based on the photographs.
00:36:14.360And so physical appearance takes on a much larger share of people's attention than it would be as contrasted with meeting people in real life.
00:36:27.160There's the thing called in real life.
00:47:38.220So ancestrally and in almost all hunter-gatherer societies, traditional societies, women get married, all fertile women get married and they reproduce.
00:47:50.720And so there's not this pool of singles like you have now.
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00:49:14.100And we've obviously returned, I was going to say straight, but we returned to the topic of
00:49:19.600infidelity would i be right in saying that cheating is an evolutionary adaptation um
00:49:26.720well uh did we evolve to be monogamous i guess is what i'm uh i would say um i would rephrase
00:49:34.320the question so the way i would phrase it is have we evolved a long-term mating strategy
00:49:41.200and i would say yes we have as one strategy within our repertoire of mating strategies so
00:49:48.080So do we have adaptations for long-term pair-bonded attachment, committed mating?
00:56:47.920But if the guy's in love with another woman, that's going to signal that he's going to defect over the long term and devote his resources and commitment to another woman.
00:57:00.900But that must make women quite paranoid, really, because in a way, if someone really cheats on you because of love, you go, right, well, maybe I didn't care enough.
01:08:47.060what do we know about that yeah well what we know is that um there is female violence to men to their
01:08:55.180mates it's typically less extreme um and so i think there right now is there didn't used to be
01:09:04.140any there's one in the country one shelter for battered men in the country that's up in dallas
01:09:11.380whereas there are thousands for battered women and and so that that tells you something about it so
01:09:19.660um women do uh sometimes um abuse their partners physically um but um
01:09:27.980uh but uh it typically does less damage and i imagine the number of victims will be
01:09:35.380incomparably small yeah right is that fair yeah the number of victims is smaller now some argue
01:09:40.240It depends on if you get, sometimes there's a mutual abuse where you get, they'll get into a physical confrontation where one will slap the other, the other will slap back or hit and hit back.
01:09:54.600And so you get some of that. And so if you simply count up the number of acts of violence, the sexes are actually not that wildly discrepant.
01:10:06.600But in terms of the damage done, the damage done is much greater to men, and it's also predictable.
01:10:16.600The other predictor of it is if the guy suspects an infidelity or discovers an infidelity.
01:18:34.100And, you know, that's another interesting suite of topics of religion and morality and group norms and the degree to which they play, they have an influence on activating or deactivating some subset of our psychological adaptations.
01:18:52.480Yeah, because sorry that I'm delving into it as far as I am, but I think it's interesting
01:18:56.400because what it really makes, I think that's the way you've explained it, which is we have
01:19:02.300these adaptations in our brains and they're sitting there waiting to be triggered, we
01:19:19.860That sounds like that's really important.
01:19:21.980And if we don't do a good job of that, we're going to end up with people, otherwise decent people, running around doing terrible things because they haven't been prepared to avoid those pitfalls once those things are in place.
01:19:37.060Yeah. Yeah, I think that's right. Although I would say that there are, I think, elements of our morality that are part of our evolved psychology themselves. So fairness, for example. So like if you, you know, they have these economic games where I give you $100 and you can give, you know, it's up to you how to distribute the $100.
01:20:05.100You can keep $99 for yourself and give one to your partner.