maybe maybe we could we could start our discussion of sexual differences and mating strategy with that so first of all what's the evidence that suggests that women are in fact choosier when it comes to sexual partners than men and how much choosier are they okay okay great question well so maybe first we could just define for listeners what sexual selection theory is uh because most people when they think about evolution they think of survival of the fittest and that sort of uh nature-written tooth and clock yes and a kind of a randomness too which you
know that that's kind of implicit in the natural selection theory where sexual selection is anything but random yeah absolutely so so sexual selection so if if natural selection this is oversimplified but is um the evolution of adaptations due to their survival advantage or the survival advantage that accrued to the possessors uh so things like fear of snakes fear of heights spiders darkness strangers and so forth food preferences things that led to better survival sexual selection deals with the evolution of qualities that lead to mating success and darwin identified two causal processes by which mating success
could occur one is same-sex competition or intra-sexual competition and the logic there is that whatever uh he he thought about it in terms of contest competition where there was a physical battle like two stags locking horns in combat with the victor gaining sexual access to the female loser ambling off with a broken antler dejected with low self-esteem and probably needing some psychotherapy but the logic was whatever qualities led to success in these same-sex battles whether it be athleticism uh strength agility cunning or whatever those qualities get passed on in greater numbers due to the sexual
access that the victors accrued uh qualities associated with losing basically bit the evolutionary dust the second component so that's intrasexual competition which actually the logic is more general than darwin and vision so like in our species as we were alluding to we often compete for position and status hierarchies uh and so we we can engage in intrasexual competition without engaging in this physical battle or contest competition although i think that the contest competition was also part of human evolutionary history with with males the other component process is basically what darwin called female choice and the
logic there is that whatever qualities if there's some consensus about the qualities that are desired that men possessing the desired qualities have a mating advantage they get preferentially chosen those lacking the desired qualities basically become in cells or involuntarily celibate they get shunned banished or ignored uh now the the twist on that and and so i think sexual selection is is by far a more interesting process and definitely has occurred with respect to humans but the twist there is that we have mutual mate choice at least when it comes to long-term mating especially i should
say especially when it comes to long-term mating uh and and that gets to the issue of uh trevor's theory of parental investment where he said he asked the question well which sex does the choosing which sex does the competing uh and he his answer was the sex that invests more uh in offspring tends to be cheesier sex that invest less tends to be more competitive for access to those desirable uh members of the opposite sex but in long-term mating now we know from our reproductive biology that women have that nine month pregnancy which is obligatory
so women can't say look i'm i'm really busy with my career i really only want to put in three months it's just part of our reproductive biology and to produce one child and men can produce that same child through one act of sex and so uh so women are at least in when it comes to sex the cheesier sex the higher investing sex in part because the costs of making a bad mating decision are much more severe for women than for men men and women hook up have sex for one night in the morning they
both realize oh this is a mistake i shouldn't have done that well if the woman gets pregnant then she might be pregnant with a guy who is not going to invest in her offspring a guy perhaps is someone that has poor genetic material it does not have a robust immune system etc so so anyway so that's uh that's a long-winded answer to your question about uh sexual selection good so but okay go ahead please go ahead oh i was just gonna say that the you asked about the evidence uh for females being cheesier and they
are cheesier primarily in the context of casual sex or short-term sex so that's where you find the big sex differences and so one of the classic uh and there is there's a ton of evidence for this this is a a sex difference that that i capture in the book under the category of desire for sexual variety uh so men have a much greater desire for meaning a variety of sex partners than than women do and so the choosing this comes in on i'll just give you one experiment this is a classic study done by elaine
hatfield and russell clark where they had male and female confederates which uh for listeners are members of the experimental team it doesn't mean people from the south united states uh there but they had male and female confederates simply walk up to members of the opposite sex on a college campus and say hi i've been noticing you around campus lately i find you very attractive would you and they asked them one of three questions would you go on a date with me tonight would you come back to my apartment with me would you have sex with
me and it was a between groups designs they simply recorded the percentage of individuals who agreed to these three different requests and of the women about half about little over 50 percent agreed to go out on a date with the guy six percent agreed to go back to his apartment zero percent agreed to have sex with him most women need a little more information uh about the guy before they're willing to have sex uh of the men approach also about 50 by the female confederate about 50 agreed to go out on the date 69 agreed
to go back to her apartment and 75 agreed to have sex with her and so if you talk about choosing us um uh are you willing to have sex with a total stranger who you've met for 30 seconds uh women unwilling to and in general uh men very willing to and this is a study that's been replicated now in several european studies very difficult to do this as you might imagine to get this by the irbs or ethics committees in in the united states anyway um i assume it's similar in canada or worse or we're
so but yeah the kinds of studies we really want to do are more difficult to do nowadays but it's been replicated in in several western europe european countries and you can get women off of the zero percent you can get a few percent of the women saying yes if the guys really really charming you know if he's a brad pitt or or i don't know what the modern equivalent is ryan gosling or one of the uh you know or or perhaps a famous rock star so um so but that's one illustration of uh the answer
to your question about well what is the evidence for female choosing us now the interesting thing here's i'll give you one more so there are studies that ask what is the minimum percentile of intelligence that you would accept in a potential partner so and then you and you know we explain percentiles to people so they understand 99 percentile first percentile 50th and so forth and um and basically for things like a marriage partner uh men and women are roughly equal they both are very exact and they say what they want like say 65th 70th percentile
intelligence uh where the sex difference comes up is just a sex partner a pure sex partner with no investment women still maintain they still want let's say 60th or 60 plus percentile in intelligence whereas men drop you know to embarrassing levels that doesn't really it becomes irrelevant the 35th 40th percentile men go you know if she can mumble a little bit that's fine or or even not so um that's another indication of female choosiness that is they maintain greater choosiness when it comes to short-term sex and um and are simply less comfortable with having sex
with total strangers or casual sex and uh here's i'll give you one more now that i'm rambling on and then i'll get to some other uh interesting issues is uh this is an item on the sociosexuality inventory that colleagues uh steve gangstad and jeff simpson developed a long time ago but one of the items is that's an attitude item and it says sex without love is okay do you agree with that or disagree with that and there you get a large sex difference so in the seven point scale where four is the midpoint uh men
average about 5.5 so they say yes sex without love yeah yeah that's okay uh women are about 3.5 okay they're below the uh that midpoint it's another indication um of this sex difference in choosing this do you know if that's modulated by big five trait agreeableness oh that's a great question i i haven't seen any studies that link that okay uh big five two to that item or the sociosexuality inventory in general yeah well you'd wonder why if compassion and empathy might be one of the things driving that and the value that's placed on that
as a consequence of being high or low in agreeableness and that would fit into some degree with the dark triad work that because the primary difference there is we'll talk about the dark trend in a minute is that the dark triad types are low and agreeable to centrally it's not the only thing but that's central yeah and that's where there's a big there's a big sex difference
