Some Fuss Over Sperm Competition: A Follow-Up

Posted on August 22, 2014 by Jesse Marczyk

Back in March, I had discussed an argument put forth by Greg Cochran concerning his conclusion that sperm competition had no real impact on humans. For the sake of repetition, sperm competition is a context in which sperm from more than one male are present in a female’s reproductive tract during a period in which she might conceive; for humans, this often involves infidelity, but could also represent cases of non-committed double mating. In some sense, the sperm from different males can be thought of as different teams competing for the goal of fertilization of an egg. The metaphor isn’t perfect, but it should suit us well enough for the purposes of this discussion. In any case, in March’s post, I suggested the following:

Adaptations for sperm competition might be more subtle than larger testicles, for instance. Perhaps the frequency of sex – or at least the frequency and intensity of sexual interest – correlates with infidelity cues; perhaps the number of sperm per ejaculate could be varied facultatively as a function of sperm competition risk.

Clearly, I’m not the only one with such ideas, as a recent study I came across by Pham et al (2014) put the first suggestion – that the frequency of sex might correlate with sperm competition risk – to the test.

That test wasn’t the only thing she would cheat on that day…

The paper begins by noting that the frequency of sex should contribute to a given male’s odds of winning this competition. The idea is pretty simple: more sex equals more viable sperm present in a female’s reproductive tract, and more viable sperm equals a higher probability of conception. It follows, then, that if a male perceives he is at a relatively high risk for sperm competition, we might expect his interest in engaging in sex with this partner to go up as a preemptive strike against non-paternity. The authors consider two factors which might correlate with the risk of sperm competition: a woman’s attractiveness and the number of opposite-sex friends or coworkers she has in her social circles. The former variable might play a role in that attractive women could be expected to draw proportionately more sexual attention or pursuit from males; the latter variable might matter because the larger the pool of males, the more overall interest a woman might receive. So, since more sexual interest equals more sperm competition risk, and since that risk can be mitigated by men by increasing the frequency of sex, we might expect that men should up-regulate their sexual interest in response to a perceived sperm competition risk.

To test this idea, Pham et al (2014) recruited approximately 400 men in committed relationships from a campus and community sample. These men were asked about their relationship length, their perceptions of their partner’s attractiveness, how many male friends and co-workers their partner had, and how often they had sex with their partner in the past week. Their analysis controlled for relationships length since, as almost anyone who has been in a relationship can attest to, the frequency of sex tends to decline over time. Predictable, this pattern also appeared in the results of the current study: men reported less sexual contact in the last week the longer they had been with their partner. There was also an effect of perceived partner attractiveness: the more attractive the men in the study thought their partner was, the more they report having sex in the last week as well. When it came to the risk of sperm competition – as indexed by the number of opposite sex individuals men perceived in their partner’s social circles – there was no effect on the frequency of sex. That is, whether the man reported their partners worked/were friends with few or many other men, there was no relationship to the frequency of sexual contact.

There was, however, a significant interaction between partner attractiveness and risk of sperm competition: when sperm competition risk was low, men with both high and low attractiveness partners reported the same frequency of sex in the last week: about 3 times. However, when the risk of sperm competition was high, men with attractive partners reported having sex about 4.5 times a week, whereas men with less attractive partners reported having sex about 1.5 times a week (though the absolute differences were about the same, only the former effect was significant). This would appear to be some evidence that is at least consistent with the idea that when men perceive there to be a higher risk of their partner having an affair with one or more other men (when other men are both present and interested), their interest in having sex with their partner increases.

I suppose that’s one way of cutting down on several types of cheating…

There are some limitations to the research, which the authors note. First, these reports came only from the men in the sample and it is possible that their perceived risk of sperm competition isn’t entirely accurate. Perhaps women worked/were friends with fewer (or more) men than their partner was aware of. The same could be said of the ratings of attractiveness. This is less of a problem than one might think, though, as we should expect men’s perceptions of their partner’s faithfulness – accurate or not – to predict how the men will subsequently react.

A second limitation is that no data was gathered on which member of the couple initiated the sex or was more interested in having it (though this is a tricky matter to get at). The authors note that it’s possible that women’s mating systems might be primed by receiving sexual attention, and this priming might in turn motivate them to have sex with their committed partner. In other words, the effect is driven less by male interest and more by female interest. While possible, I don’t think such a concern is necessarily warranted for two reasons: first, one could just as easily posit the opposite reaction. That is to say one might suggest that women receiving too much sexual attention might actually be disinclined from having sex, as most of the attention would likely be unwanted, priming the system towards inhibition.

The second reason is that even if sexual attention from other males did prime a woman to want to have sex, one might wonder about how such a system works. As noted above, most of this attention is likely going to be unwelcome, coming from less-than-desirable males. Accordingly, women with a cognitive system that functioned with some general-purpose goal like “increase desire for sex in the presence of attention” would likely be at an adaptive disadvantage, as it might cause women to make less-adaptive mating choices on the whole: attention from unwanted males should not necessarily influence how a woman responds to desired males. However, if such priming (provided it exists) instead directed the woman to have more sex with their in-pair partner specifically, one might again wonder as to why. There’s probably some optimal level of sexual frequency that balances trading off time spent having sex with a committed partner and time not spent doing other non-sexual things against conception probability, and using sexual attention received by other males as an input there wouldn’t seem to lead to better outcomes. However, such a mechanism could, at least in theory, function to assure her partner of his paternity, increasing his likelihood of investing in subsequent offspring. In that case, this mechanism would still owe its existence to sperm competition, albeit in a roundabout way.

“Why does it always have to be about sex with you people? Why not just self-esteem?”

It’s findings like these that suggest to me that ruling out sperm competition as having a measurable impact on people’s behaviors and physiology would be premature. Yes, the non-paternity rate in humans is relatively low (it needs to be if investment in offspring by males is a thing), and yes, mechanisms for maintaining fidelity (like jealousy) might do a better job at keeping that rate low, relative to mechanisms for sperm competition. Better to deal with the cause of the problem than treat the symptoms. However, whether the mechanism for reducing the risk of sperm competition resulting in non-paternity are physiological (larger testicles) or psychological (increased desire for sex when risk of affairs is high) in nature, they could both be categorized as serving the same function and owing their existence to the same cause. Further work is certainly needed to better interpret findings like these, but, well, that’s kind of the point; writing off sperm competition as important precludes certain, possibly-useful avenues of research.

References: Pham, M., Shackelford, T., Holden, C., Zeigler-Hill, V., Hummel, A., & Memering, S. (2014). Partner attractiveness moderates the relationship between number of sexual rivals and in-pair copulation frequency in humans. Journal of Comparative Psychology, 128, 328-331.

Is There Any Good Evidence That Porn Is Harmful To Relationships?

Posted on July 21, 2014 by Jesse Marczyk

In my last post, I noted briefly how technology has made it easier than ever to access a variety of pornographic images, whether produced personally or professionally. Much like concerns about how violent video games might make people who play them more violent, there have also been concerns raised about how pornography becoming more prevalent might also lead to certain, undesirable outcomes, such as rape as weakened relationships. As for the video game concern, there is some evidence that the aggression (or rather anger) caused by video games might have a lot less to do with violent content per se than it has to do with losing (full disclosure: I have been unable to locate the paper, so I can’t assess the claims made in it personally, but this explanation should be easily and intuitively understandable to anyone who has seriously engaged in competitive play. Gamers don’t rage quit over violent content; they rage quit because they lost). Similarly, there have been many concerns raised about pornography over the years, many of which hinge on the idea that pornography might lead to people (specifically men) to develop negative attitudes towards women and, accordingly, be more likely to rape them or to accept rape more generally.

Tissue companies vigorously denied that such a link existed

As pornography has become more widely available – thanks in no small part to the internet – rates of rape appear to have declining rather markedly over the same time period; in much the same way, violence has been declining despite violent video games being more common and accessible than ever. The world is a complex place and there are plenty of variables at play, so those correlations are just that. Nevertheless, the evidence that pornography causes any kind of sexual offending is “inconsistent at best” (Ferguson & Hartley, 2009) and, given the nature of the topic, one might reasonably suspect that at least some of that inconsistency has to do with researchers setting out to find certain conclusions. To be blunt about it, some researchers probably “have their answer”, so to speak, before they even begin the research, and might either game their projects to find that result, or interpret otherwise ambiguous results in a manner consistent with their favored hypothesis.

On that note, there was a recent post by Peg Streep concerning the negative effects that pornography might have on intimate relationships. In no uncertain terms, Peg suggests that (1) relationships with porn are less stable, (2) watching porn makes people less committed to their relationships, and (3) that it leads to people cheating on their partners. The certainty with which these points were made appears to stand in marked contrast to the methodological strength of studies she mentions, even from her own summaries of them (As an aside, in the comments section Peg also appears to insinuate that video games make people more violent as well; just a fun coincidence). Given that the studies are covered in less-than-adequate detail, I decided it track down the research she presented for myself and see if there was any good evidence that pornography use has a negative and causal relationship with commitment and intimate relationships.

The first study comes from Maddox et al (2011). This paper surveyed the pornography viewing habits of around 1,300 individuals (whether alone, with a partner, or not at all) and examined whether there was any relationship between viewing pornography and various relationship measures. Those who reported not viewing pornography tended to be more religious, tended to escalate fights less (d = 0.26), thought their relationship was going better (d = 0.22), and were more dedicated to their relationships (d = 0.25, approximately). Further, those who watched porn were less likely to report being satisfied sexually in their relationship (d = 0.21) and also appeared to be two- to three-times as likely to report infidelity. However, the authors explicitly acknowledge on more than one occasion that their data is correlational in nature and provided no evidence of causality. Such research might simply suggest those who like pornography are different than those who do not like it, or that “…individuals who are unhappy with their relationships seek out [pornography] on their own as an outlet for sexual energy”. The pornography itself might have very little to do with relationship strength.

It might have plenty to do with arm strength, though

The second paper Peg mentions at least contains an experiment, which should, in principle, be better for determining if there is any causal relationship here. Unfortunately, there exists a gap between principle and practice here. The paper, by Lambert et al (2012) is rather long, so I’m only going to focus on the actual experiment within it and ignore the other correlational work (as those issues would be largely a retread of the last paper). The experiment involved having current porn users to either (a) refrain from using porn or (b) eating their favorite food for three weeks. The participants (N = 20) also maintained a daily dairy of their porn use. Initially, the two groups reported similar porn usage (M = 3.73 and 4.07 viewings per month – I think – respectively) and relationship commitment (estimated 72% and 62% chance of being with their partner in the future, respectively). After the three week period, those who attempted to abstain from porn reported less viewing (M = 1.42) than those in the food-abstaining group (M = 3.88); the former group also reported greater relationship commitment (63% chance of staying together over time) relative to the food-abstainers (30% chance) at the end of the three weeks.

So was porn the culprit here? Well, I think it’s very doubtful. First of all, the sample size of 10 per group is pitifully small and I would not want to draw any major conclusions from that. Second, both groups were initially high on their relationship commitment despite both groups also watching porn. Third, and perhaps most importantly, what this study found was not an increase in commitment when people watched less porn, directly contradicting what Peg says about the results (that group saw a decrease as well, albeit only a 10% drop); it just found a large decrease in the group that continued to do what it had been doing this whole time. In other words, the authors are positing that a constant (porn usage) was responsible for a dramatic and sudden decline, whereas their manipulation (less porn usage) was responsible for things staying (sort of) constant. I find that very unlikely; more likely, I would say, is that one or two couples within the food-abstaining group happened to have hit a rough patch unrelated to the porn issue and, because the sample size was so small, that’s all it took to find the result.

The final paper Peg mentions comes from Gwinn et al (2013), and examined the relationship between porn and cheating. The authors report two studies: in the first, 74 students either wrote about a sexually explicit scene or an action scene from a movie or show they had seen in the last month; they were then asked to think about what options they had for alternative sexual partners. Those who wrote about the sexual scene rated their options as an average 3.3 out of 7, compared with the 2.6 for the action group (Of note: only half the subjects in the sex group wrote about porn; the other half wrote about non-porn sex scenes). Further, those in the sexual group did not report any difference in their current relationship satisfaction than those in the action group. In the second study, 291 students had their porn habits measured at time one and their cheating behavior (though this was not exclusively sexual behavior) measured at time two. They found a rather weak but positive correlation between the two: pornography use at time one could uniquely account for approximately 1% of the variance in cheating 12 weeks later. So, much like the first study, this one tells us nothing about causation and, even if it did, the effect was small enough to be almost zero.

But go ahead; blame porn. I’m sure you will anyway.

So, to summarize: the first study suggests that people who like porn might be different than those who do not, the second study found that watching less porn did not increase commitment (in direct contradiction to what Peg said about it), and the final study found that porn usage explains almost no unique variance in infidelity on its own, nor does it effect relationship satisfaction. So, when Peg suggests that “The following three studies reveal that it has a greater effect on relationships than those we usually discuss” and, ”Pornography is not as benign as you think, especially when it comes to romantic relationships“, and, “The fantasy alternative leads to real world cheating“, she doesn’t seem to have an empirical leg to stand on. Similarly, in the comments, when she writes “Who blamed cheating on porn? Neither the research nor I. The research indicates the watching porn elevates the odds of cheating for the reasons noted” (emphasis mine), she seems to either not be very careful about her words, or rather disingenuous about what point she seems to be making. I’m not saying there are absolutely no effects to porn, but the research she presents do not make a good case for any of them.

References: Ferguson, C. & Hartley, R. (2009). The pleasure is momentary…the expense damnable? The influence of pornography on rape and sexual assault. Aggression & Violent Behavior, 14, 323-329.

Gwinn, A., Lambert N., Fincham, F., Maner, J. (2013). Pornography, relationship alternatives, and intimate extradyadic behavior. Social Psychology & Personality Science, 4, 699-704.

Lambert, N., Negash, S., Stillman, T., Olmstead, S., & Fincham, F. (2012). A love that doesn’t last: Pornography consumption and weakened commitment to one’s romantic partner. Journal of Social and Clinical Psychology, 31, 410-438.

Maddox, M., Rhoades, G., & Markman, H. (2011). Viewing sexually-explicit materials alone or together: Associations with relationship quality. Archives of Sexual Behavior, 40, 441-448.

Some Free Consulting Advice For Improving Online Dating

Posted on July 14, 2014 by Jesse Marczyk

I find many aspects of life today to be pretty neat, owing largely to the wide array of fun and functional gadgets we have at our disposal. While easy to lose sight of and take for granted, the radical improvements made to information technology over my lifetime have been astounding. For instance, I now carry around a powerful computer in my pocket that is user-friendly, capable of accessing more information than I could feasibly process in my entire lifetime, and it also allows me to communicate instantly with strangers and friends all over the globe; truly amazing stuff. Of course, being the particular species that we are, such technology was almost instantly recognized and adopted as an efficient way of sending and receiving naked pictures, as well as trying to initiate new sexual or dating relationships. While the former goal has been achieved with a rousing success, the latter appears to still pose a few more complications, as evidenced by plenty of people complaining about online dating, but not about the ease by which they can send or receive naked pictures. As I’ve been turning my eye towards the job market these days, I decided it would be fun to try and focus on a more “applied” problem: specifically, how might online dating sites – like Tinder and OkCupid – be improved for their users?

Since the insertable portion of the internet market has been covered, I’ll stick to the psychological one.

The first question to consider is the matter of what problems people face when it comes to online dating: knowing what problems people are facing is obviously important if you want to make forward progress. Given that we are species in which females tend to provide the brunt of the obligate parental investment, we can say that, in general, men and women will tend to face some different problems when it comes to online dating; problems which mirror those faced in non-internet dating. In general, men are the more sexually-eager sex: accordingly, men tend to face the problem of drawing and retaining female interest, while women face the problem of selecting mates from among their choices. In terms of the everyday realities of online dating, this translates into women receiving incredible amounts of undesirable male attention, while men waste similar amounts of time making passes that are unlikely to pan out.

To get a sense for the problems women face, all one has to do is make an online dating profile as a woman. There have been a number of such attempts that have been documented, and the results are often the same: before the profile has even been filled out, it attracts dozens of men within the first few minutes of its existence. Perhaps unsurprisingly, the quality of messages that the profiles receive can also liberally be considered less-than optimal. While I have no data on the matter, almost every women who has talked with me about their online dating experiences tends to remark, at some point, that they are rather afraid of meeting up with anyone from the site owing to a fear of being murdered by them. Now it is possible that such dangers are, for whatever reason, being overestimated by women, but it also seems likely that women’s experiences with the men on the site might be driving some of that fear. After all, many of those same women also tell me that they start off replying to all or most of the messages they receive when they set up a profile, only to quickly stop doing that owing to their sheer volume or unappealing content. There are also reports of men becoming verbally aggressive when turned down by women, so it seems likely some of these fears about meeting someone from the site are not entirely without merit (to be clear, I think women are probably no more likely to be murdered by anyone they meet online relative to in person; it’s just that strangers online might be more likely to initiate contact than in person).

The problems that men face are a bit harder to appreciate for a number of reasons, one of which is likely owing to the fact that they take longer to appreciate. As I mentioned, women’s profiles attract attention within minutes of their creation; a rather dramatic effect. By contrast, were one to make a profile as a man, not much of anything would happen: you would be unlikely to receive messages or visitors for days, weeks, or months if you didn’t actively try to initiate such contact yourself. If you did try to initiate contact, you’d also find that most of it is not reciprocated and, of the replies you did receive, many would burn out before progressing into any real conversation. If men seen a bit overeager for contact and angry when it ceases, this might owe itself in part to the rarity with which such contact occurs. While being ignored might seem like a better problem to have than receiving a lot of unwanted attention (as the latter might involve aggression, whereas the former does not), one needs to bear in mind that without any attention there is no dating life. Women might be able to pull some desirable men from the pool of interested ones, even if most are undesirable; a man without an interested pool has no potential to draw from at all. Neither is necessarily better or worse than the other; they’re just different.

Relationships: Can’t live with them; can’t live without them

That said, bickering about whose problems are worse doesn’t actually solve any of them, so I don’t want to get mired in that debate. Instead, we want to ask, how do we devise a possible resolution to both sets of problems at the same time? At first glance, these problems might see opposed to one another: men want more attention and women want less of it. How could we make both sides relatively better off than they were before? My suggestion for a potential remedy is to make messages substantially harder to send. There are two ways I envision this might enacted: on the one hand, the number of messages a user could send (that were not replies to existing messages) could be limited to a certain number in a given time period (say, for instance, people could send 5 or 10 initiate messages per week). Alternatively, people could set up a series of multiple choice screening questions on their profile, and only those people who answered enough questions “correctly” (i.e. the answer the user specifies) would be allowed to send a message to the user. Since these aren’t mutually exclusive, both could be implemented; perhaps the former as a mandatory restriction and the latter as an optional one.

Now, at first glance, these solutions might seem geared towards improving women’s experiences with online dating at the expense of men, since men are the ones sending most of the messages. If men aren’t allowed to send enough messages, how could they possibly garner attention, given that so many messages ultimately fail to capture any? The answer to that question comes in two parts, but it largely involves considering why so many messages don’t get responses. First, as it stands now, messaging is largely a costless endeavor. It can take someone all of 5 to 60 seconds to craft an opening message and send it, depending on how specific the sender wants to get with it. With such a low cost and a potentially high payoff (dates and/or sex), men are incentivized to send a great many of these messages. The problem is that every man is similarly incentivized. While it might be good for any man to send more messages out, when too many of them do it, women get buried beneath an avalanche of them. Since these messages are costless to send, they don’t necessarily carry any honest information about the man’s interest, so women might just start ignoring them altogether. There are, after all, non-negligible search costs for women to dig through and respond to all these messages – as evidenced by the many reports from women of their of starting out replying to all of them but quickly abandoning that idea – so the high volume of messages might actually make women less likely to respond in general, rather than more.

Indeed, judging by their profiles, many women pick up on this, explicitly stating that they won’t reply to messages that are little more than a “hey” or “what’s up?”. If messaging was restricted in some rather costly way, it would require men to be more judicious about both who they send the message to and the content of those messages; if you only have a certain number of opportunities, it’s best to not blow them, and that involves messaging people you’re more likely to be successful with in and in a less superficial way. So women, broadly speaking, would benefit by receiving a smaller number of higher-quality messages from men who are proportionately more interested in them. Since the messages are not longer costless to send, that a man chose to send his to that particular woman has some signal value; if the message was more personalized, the signal value increases. By contrast, men would, again, broadly speaking, benefit by lowering the odds of their messages being buried beneath a tidal wave of other messages from other men, and would need to send proportionately fewer of them to receive responses. In other words, the relative level of competition for mates might remain constant, but the absolute level of competition might fall.

Or, phrased as a metaphor: no one is responding to all that mess, so it’s better to not make it in the first place

Now, it should go without saying that this change, however implemented, would be a far cry from fixing all the interactions on dating sites: some people are less attractive than others, have dismal personalities, demand too much, and so on. Some women would continue to receive too many unwanted messages and some men would continue to be all but nonexistent as far as women were concerned. There would also undoubtedly be some potential missed connections. However, it’s important to bear in mind that all that happens already, and this solution might actually reduce the incidence of it. By everyone being willing to suffer a small cost (or the site administrators implementing them), they could avoid proportionately larger ones. Further, if dating sites became more user-friendly, they could also begin to attract new users and retain existing ones, improving the overall dating pool available. If women are less afraid of being murdered on dates, they might be more likely to go on them; if women receive fewer messages, they might be more inclined to respond to them. As I see it, this is a relatively cheap idea to implement and seems to have a great deal of theoretical plausibility to it. The specifics of the plan would need to be fleshed out more extensively and it’s plausibility tested empirically, but I think it’s a good starting point.

In The World Of The Blind, The Woman With A Low WHR Is Queen

Posted on May 4, 2014 by Jesse Marczyk

If you happen to have memories of watching TV in the 90s, chances are you might remember the old advertisements they used to run for the Cinnamon Toast Crunch cereal. The general premise of the ads followed the same formula: “Person X is really good at seeing Y, but can they see why kids love the taste of Cinnamon Toast Crunch?”. Inevitably, the answer was always “no”, as adults are apparently so square that they couldn’t wrap their minds around the idea that children happen to like sugar. Difficult concept, I know. Now, obviously, adults aren’t nearly so clueless in reality. In fact, as you’re about to see, even adults who are really rather poor at seeing things can still “see”, so to speak, why men tend to find certain features in women attractive.

Sauron majored in sociology, so he guessed “cultural conditioning”

The first paper up for consideration is a 2010 piece by Karremans et al. The researchers begin by noting that men appear to demonstrate a preference for women with relatively-low waist-to-hip ratios (WHRs). Women with low WHRs tend to have figures that resemble the classic hourglass shape. Low WHRs are thought to be found attractive by men because they are cues to a woman’s fertility status: specifically, women with lower WHRs – around a 0.7 – tend to be more fertile than their more tubular-shaped peers. That said, this preference – just like any of our preferences – does not magically appear in our minds; every preference needs to develop over our lives, and development requires particular input conditions. If these developmental input conditions aren’t met, then the preference should not be expected to form. Simple enough. The question of interest, then, is what precisely these conditions are; what factors are responsible for men finding low WHRs attractive?

One ostensibly obvious condition for the development of a preference for low WHRs might be visual input. After all, if men couldn’t see women’s WHRs – and all those unrealistic expectations of female body type set by the nefarious media – it might seem awfully difficult to develop a taste for them. This poses something of an empirical hurdle to test, as most men have the ability to see, Thankfully for psychological research – though not so thankfully for the subjects of that research – some men, for whatever reasons, happen to have been born blind. If visual input was a key condition for the development of preferences for low WHRs in women, then these blind men should not be expected to show it. While large samples of congenitally blind men are not the easiest to come by, Karremans et al (2010) managed to recruit around 20 of them.

These blind men were presented with two female mannequins wearing tight-fitting dresses. One of these mannequins had a WHR of 0.7 – around what most people rate as the most attractive – and the other had a slightly-higher 0.84. The blind men were asked to feel and rate each mannequins on attractiveness from 1 to 10. Additionally, the researchers recruited about 40 sighted men to complete the task as well: 20 completing it while blindfolded and 20 without the blindfold. Of note is that all data collection was carried out in a van (read: “mobile laboratory room”) because sometimes psychological research is just fun like that.

“How about coming into my van to feel my mannequins?”

The first set of results to consider come from the sighted men, who completed the task with the full use of their eyes: they gave the mannequin with the low WHR a rating of around an 8, whereas the mannequin with the higher WHR received only around a 6.5, as one might expect. In the blindfold condition, this difference was reduced somewhat (with ratings of 7.5 and around 7, respectively), suggesting that visual input might play some role in determining this preference. However, visual input was clearly not necessary: the blind men rated the low WHR mannequin at around a 7, but the high WHR mannequin at about a 6. In the words of the fine people over at Cinnamon Toast Crunch: “even blind men who can’t see much of anything can still see why men love the figures of women with low WHRs”.

Further evidence from earlier research points towards a similar conclusion (that these preferences are unlikely to be the result of portrayals of women in the media). A paper by Singh (1993) analyzed a trove of data on the female bodies that appeared in Playboy as centerfolds (from 1955-1965 and 1976-1990) and that won Miss America pageants (1923-1987). One might imagine that depictions of women in the media or found to be attractive might change somewhat over six decades if the type of women being portrayed were favored for some arbitrary set of reasons. Indeed, there was one noticeable trend: the centerfolds and pageant winners tended to be getting a little bit skinnier over that time period. Despite these changes in overall BMI, however, the WHR of the groups didn’t vary. Both grounds hovered around a consistent 0.7. Presumably, if blind men were consuming pornography, they would prefer the women depicted in Playboy just as much as non-blind men do.

“We’ll be needing more “databases” for the mobile laboratory room…”

Given the correlation between WHR and fertility, this consistency in men’s preferences should be expected. That’s not to say, of course, that these preferences for low WHR aren’t modifiable. As I mentioned before, every preference needs to develop, and to the extent that certain modifications of that preference would be adaptive in different contexts, we should expect it to fluctuate accordingly. Now that matter of precisely what input conditions are responsible for the development of this preference remain shrouded: while visual inputs don’t seem to be necessary, the matter of which cues are – as well as why they are – are questions that have yet to be answered. For what it’s worth, I would recommend turning research away from the idea that the media is responsible for just about everything, but that’s just me.

References: Karremans, J., Frankenhuis, W., & Arons S. (2010). Blind men prefer a low waist-to-hip ratio. Evolution and Human Behavior, 31, 182-186.

Singh, D. (1993). Adaptive significance of female physical attractiveness: Role of waist to hip ratio. Journal of Personality and Social Psychology, 65, 293-307.

The Best Mate Money Can Buy

Posted on April 24, 2014 by Jesse Marczyk

There’s a proud tradition in psychological research that involves asking people about how much they value this thing or that one, be it in a supermarket or, for our present purposes, in a sexual partner. Now there’s nothing intrinsically wrong with doing this kind of research, but while there are certain benefits to it, the method does have its shortcomings. One easy way to grasp a potential issue with this methodology is to consider the dating website Okcupid.com. When users create a profile on this site, they are given a standard list of questions to answer in order to tell other people about themselves. Some of these questions deal with matters like, “What are six things you couldn’t do without?” or “what are you looking for in partner?”. The typical sorts of answers you might find to questions like these are highlighted in a video I really like called “The Truth About Being Single“:

“All these people keep interrupting my loneliness!”

The problem with questions like these is that – when they are posed in isolation – their interpretation can get a bit difficult; they often seem to blur the lines between what people require and what they just want. More precisely, the ratings people give to various items or traits in terms of their importance might not accurately capture their degree of actual importance. A quick example concerns cell phones and oxygen. If you were to ask people on Okcupid about five things they couldn’t do without on a day-to-day basis, more people would probably list their phones than the air they breathe. They would also tell you that, in any given year, they likely spend much more money on cell phones than air. Despite this, air is clearly the more important item, as cell phones stop being useful when the owner has long since asphyxiated (even if the cell phone would allow you to go out playing whatever bird-themed game is currently trending).

Perhaps that all seems very mundane, though: “Yes, of course,” you might say, “air is more important than iPhones, but putting ‘I need air’ on your dating profile or asking people how important is the air they breathe on a survey doesn’t tell you much about the person, whereas iPhone ownership makes you a more attractive, cool, and intelligent individual”. While it’s true that “people rate breathing as very important” will probably not land you any good publications or hot dates, when we start thinking about the relative importance of the various traits people look for in a partner, we can end up finding out some pretty interesting things. Specifically, we can begin to uncover what each sex views as necessities and what they view as luxuries in potential partners. The key to this method involves constraining the mate choices people can make: when people can’t have it all, what they opt to have first (i.e. people want air before iPhones if they don’t have either) tells us – to some extent – where their priorities lie.

Enter a paper by Li et al (2002). The authors note that previous studies on mating and partner selection have found sex differences in the importance placed on certain characteristics: men tend to value physical attractiveness in a partner more than women, and women tend to value financial prospects more than men. However, the ratings of these characteristics are not often found to be of paramount importance, relative to ratings of other characteristics like kindness, creativity, or a sense of humor (on which the sexes tend to agree). But perhaps the method used to derive those ratings is missing part of the larger picture, as it was in our air/iPhone example. Without asking people to make tradeoffs between these characteristics, researchers might be, as Li et al put it, “[putting the participants in] the position of someone answering a question about how to spend imaginary lottery winnings”. When people have the ability to buy anything, they will spend proportionately more money on luxuries, relative to necessities. Similarly, when people are asked about what they want in a mate, they might play up the importance of luxuries, rather than necessities if they are just thinking about the traits in general terms.

“I’m spending it all on cans of beans!”

What Li et al (2002) did in the first experiment, then, was to provide 78 participants with a list of 10 characteristics that are often rated as important in a long-term partner. The subjects were told to, essentially, Frankenstein themselves a marriage partner from that list. Their potential partners would start out in the bottom percentile for each of those traits. What this means is that, if we consider the trait of kindness, their partner would be less kind than everyone else in the population. However, people could raise the percentile score of their partner in any domain by 10% by spending a point from their “mating budget” (so if one point was invested in kindness, their partner would now be less kind than 90% of people; if two points were spent, the partner is now less kind than 80% of people, and so on). The twist is that people were only given a limited budget. With 10 traits and 10 percentiles per trait, people would need 100 points to make a partner high in everything. The first budget people started with was 20 points, which requires some tough calls to be made.

So what do people look for in a partner first? That depends, in part, on whether you’re a man or a woman. Women tended to spend the most – about 20% of their initial budget (or 4 points) – on intelligence; men spent comparably in that domain as well, with about 16% of their budget going towards brains. The next thing women tended to buy was good financial prospects, spending another 17% beefing up their partner’s yearly income. Men, on the other hand, seemed relatively unconcerned with their partner’s salary, spending only 3% of their initial budget on a woman’s income. What men seemed much more interested in was getting physical attractiveness, spending about 21% of their initial budget there; about twice what the women spent. The most vital characteristics in a long-term partner, then, seemed to be intelligence and money for women, and attractiveness and intelligence for men, in that order.

However, as people’s mating budget was increased, from 20 points to 60 points, these sex differences disappeared. Both men and women began to spend comparably as their budgets were increased and tradeoffs became less pressing. In other words, once people had the necessities for a relationship, they bought the same kinds of luxuries. These results were replicated in a slightly-modified second study using 178 undergraduates and five traits instead of ten. In the final study, participants were given a number of potential dates to screen for acceptability. These mates were said to be have been rated along the previous 5 characteristics in a high/medium/low fashion. Participants could reveal the hidden ratings of the potential dates for free, but were asked to reveal as few as possible in order to make a decision. As one might expect, men tended to reveal how physically attractive the potential mate was first more than any other trait (43% of the time, relative to women’s 16%), whereas women tended to first reveal how much social status the men had (35% of the time, relative to men’s 16%). Men seem to value good looks and women tend to value access to resources. Stereotype accuracy confirmed.

A now onto the next research project…

This is the reason I liked the initial video so much. The first portion of the video reflects the typical sentiments that people often express when it comes to what they want in a partner (“I just want someone [who gets me/to spend time with/ to sleep next to/ etc]“). These are, however, often expressions of luxuries, rather than necessities. Much like the air we breathe, the presence of the necessities in a potential mate are, more or less, taken for granted – at least until they’re absent, that is. So while traits like “creativity” might make an already-attractive partner more attractive, being incredibly creative will likely suddenly count for quite a bit less if you’re poor and/or unattractive, depending on who you’re trying to impress. I’ll leave the final word on the matter to one of my favorite comedians, John Mulaney, as I think he expresses the point well: “Sometimes I’ll be talking to someone and I’ll be like, “yeah, I’ve been really lonely lately”, and they’ll be like, “well we should hang out!” and I’m like, “no; that’s not what I meant”.

References: Li, N., Bailey, J., Kenrick, D., & Linsenmeier, J. (2002). The necessities and luxuries of mate preferences: Testing the tradeoffs. Journal of Personality and Social Psychology, 82, 947-955.

Interesting Information On Cricket Sex

Posted on April 17, 2014 by Jesse Marczyk

Our experiences of the goings on in our mind tend to paint a less-than-accurate picture of precisely how the mind is structured. Specifically, we tend to consciously experience the functioning of our mind as, more or less, unified; that there’s some “self” running the show, so to speak. There are a great number of theoretical problems with the idea of a self – that I won’t get into here – which has led to a growing conceptual rejection of it. Rather than some unified self processing all sorts of cognitive information, there are thought to be a series of domain-specific cognitive modules performing a variety of independent tasks using unique sets of information. Though the idea of a “self” has been thrown out in favor of, essentially, very many “sub-selves”, there is still some sense in which the functioning of all these different parts can be considered a psychological “you”: the outputs of all these different modules need to be integrated in some way so as to produce behavior, even if they don’t go through a central self. This is just a round about way of saying that though one part of your brain might want to stick to a diet and another part might wish to break the diet, you – your body, anyway – can’t do both of these things at the same time.

Thankfully, you can do both with the proper temporal spacing.

So we might consider the sum of all these different pieces interacting to be, in some non-technical sense, a psychological “you”. As we’re about to see, however, how precisely we want to define this psychological “you” gets even trickier than that. This is because some aspects of our behavior (and, by extension, our psychological functioning) can be affected by other organisms that happen to be taking up residence in our bodies; organisms that would “prefer” we do things to achieve their evolutionary goals at the expense of our own. This brings us nicely to a recent paper by Adamo et al (2014) examining the sexual behavior of crickets.

The researchers had been collecting crickets for some reason not directly related to matter of pathogens, as far as their paper suggests. However, they eventually noticed that some of the females had stopped laying eggs. When these females were dissected, the researchers noticed that the fatty body inside these females had an iridescent blue sheen. As it turns out, this was indicative of a type of viral infection; it also turns out that this particular virus is spread via sexual contact. Let’s consider the pathogen’s fitness interests for a moment: first, and perhaps most obviously, this virus would prefer that the crickets have sex with some regularity. Since the virus is spread sexually, the more sex the cricket is having, the more opportunities the virus has to find new hosts and reproduce itself. Accordingly, we might imagine that this virus would prefer their hosts are more eager to mate than non-infected crickets.

However, the virus would also prefer that the crickets not behave as if they’re sick. As someone who has just recently recovered from an infection myself, I can attest to the fact that sick animals often behave much differently than healthy ones. Sick animals might try to conserve energy, for instance, opting to spend their energy budget on an immune response to fight off the infection rather than moving around their environment and doing other things. This poses a problem for the sexually transmitted virus, as animals which are conserving their energy budget might not be interested in pursuing mating effort at the same time. So if the virus could prevent this suite of sickness-related behaviors from taking place, it could potentially benefit itself as well.

“Stupid, lazy host; get out of bed and fuck something!”

Now this is all very interesting in the abstract, but is there any evidence that these viruses actually had the ability to manipulate the host’s behavior? Since I wouldn’t be writing about this issue if there wasn’t, yes; there seems to be. Compared to non-infected crickets, the male crickets sporting the infection were quicker to try and court females. In the case of crickets, this means the males started to produce courtship signaling, in the form of “singing”, quicker. Infected males starting singing around 200 seconds after being exposed to females, whereas their uninfected counterparts took a little over 400 seconds to begin the process. Unfortunately for the eager lovers, there also seemed to be pretty good evidence that the virus had a nasty habit of rendering them sterile, so the mating wasn’t doing the crickets a whole lot of good..

That wasn’t the only behavioral effect of the infection observed, though. The researchers also injected healthy crickets and infected crickets with a bacteria that had been killed by heat prior to the injection. While this renders the bacteria relatively harmless to the crickets, their immune system still responded to what it perceived to be a potential threat. Accordingly, the immune response tended to trigger certain sickness behaviors, like not eating and taking longer to try and court females. However, this was only the case the for non-infected crickets, which now took about 800 seconds to begin courting; the infected crickets showed no sickness behaviors when injected with the dead bacteria and continued on eating and mating as they had beforehand.

While it’s not entirely clear whether the sickness behavior was inhibited as byproduct of the virus partially shutting down its host’s immune response abilities more generally or whether the capacity to inhibit the behavior had been directly selected for, the main point doesn’t change: the viral infection seemed to be having an effect on the host’s behavior and, presumably, this effect was at least partially realized through a change in the host’s psychology. While it’s hard for me to say what, if anything, it’s “like” to be a cricket, to the extent that they feel things like hunger or lust, such feelings might well have been modified by the effects of the infection (making them not lose their appetite in the presence of invading pathogens as healthy crickets did, and making them more eager to court females). Indeed, the results of this study appear to be conceptually similar to the paper suggesting that mosquitoes infected with malaria might preferentially feed from human hosts, owing to the pathogen reproducing in humans and being spread by mosquitoes. The more people the infected mosquitoes bite, the greater the chance the pathogen has to spread, and the parasite seems to be able to push its host in the preferred direction.

Side effects of infections include an insatiable thirst for human blood and sex…

So while the idea of “the self” is already a theoretical non-starter, even the colloquial sense of the word poses some interesting definitional problems. After all, if we were to label the sum total of the interactions within our brains as “the self” then, in some sense, the effect of the presence of certain pathogens may well be included in the “you” side of this equation, though most of us wouldn’t think of them that way. Some of our preferences are, no doubt, influenced by particular pathogens when they are infecting us, and some of our preferences might also be shaped in a more long-term fashion by the presence of infectious agents present during our development as well. It’s unfortunate that more hasn’t been written about the subject (or at least I haven’t seen too much about it around the psychology departments I’ve been in), as there are likely a great many pathogens that have all sorts of interesting effects on our behavior, from the symbiotes we carry around in body to those trying to make meals of us.

References: Adamo, S., Kovalko, I., Easy, R., & Stoltz, D. (2014). A viral aphrodisac in the cricket Gryllus texensis. The Journal of Experimental Biology, doi:10.1242/jeb.103408

Some Fuss Over Sperm Competition

Posted on March 28, 2014 by Jesse Marczyk

Say what you will about Greg Cochran, but one thing is for certain: he’s certainly not one to present his opinions meekly. Recently, Greg posted his feelings about the relevance of sperm competition in humans, and he is of the mind that sperm competition is not terribly important for humans. For those of you not in the know, sperm competition refers to conditions under which a female has mated with more than one male at a time during which she might conceive. As the name might suggest, the sperm from different males can be thought of as “competing” to fertilize the egg in question (or eggs, depending on the species). The question of interest, for our present purposes, then, is whether or not such conditions (a) might have existed in ancestral human populations and (b) have been important enough to potentially drive male adaptations for solving the problem and winning the competition.

…And when they’re not, cheat to win.

Greg begins his post by making, what I feel, is an poor point, writing: “The non-paternity rate is an upper limit to the rate of sperm competition”. Unless I’m misunderstanding his meaning here, the rate of non-paternity (when a child is being unknowingly raised by a male that is not their father) would not be not the upper limit for sperm competition unless every single instance of sperm competition resulted in non-paternity. Presumably, there are many instances of sperm competition that the in-pair male would win, meaning that the non-paternity rate would be an underestimate of how much sperm competition there might be. The upper limit of sperm competition should, it seems, be the infidelity rate (how often men are being cheated on by their partners) or the number of times when report having sex with more than one male within the period of a few days. Depending on what numbers one wants to use there, the potential amount of sperm competition that might exist can go up dramatically.

On the other hand, however, not every instance of non-paternity results from sperm competition: sometimes a female might cheat on her partner while also not sleeping with him, allowing the rival’s sperm a competition-free environment. In such cases, non-paternity rates would overestimate the amount of sperm competition that exists. As to which set of issues are more common, I can’t say. There’s also the matter of how contraceptives and abortion might affect the issue, but I won’t consider them further. So while the non-paternity data is certainly informative in some sense, it’s far from what we might consider a complete picture when it comes to sperm competition. In any case, I’ll use Greg’s numbers of approximately 2% non-paternity on the whole across human populations and across time, just for the sake of argument.

On top of “how common is sperm competition”, then, another question we want to consider to get a full picture of the issue is, “how important is non-paternity?” As Greg notes, humans aren’t built for sperm competition in the way that, say, a chimpanzee male is. However, the corollary question he fails to consider concerns whether or not the consequences of non-paternity are identical between humans chimps. For a chimp, male paternal investment tends to reach the heights of not killing infants; for human males, investment might involve decades of protecting and provisioning. On that front, while pair-bonded human males might be far more assured of their paternity than your average chimp, the consequences of being mistaken that respect are also far larger for humans than chimps. In humans, a little bit of sperm competition goes a long way, so to speak. In such cases, a simple comparison between how much sperm competition exists will miss the bigger picture.

“Why’s everyone so upset? It’s just one guy that got shot…”

So we should expect the non-paternity rate to be low, in some absolute sense, as the consequences to non-paternity are so high; if non-paternity was too high, pair-bonding strategies would be unlikely to evolve in the first place, or persist once they had. Now, as Greg also mentions, there are likely adaptations humans possess to deal with the non-paternity issue that do not deal with sperm competition. As Greg so eloquently put it:

If, for example, your old lady knows that you will knock her block off if she strays, that deters all kinds of paternal uncertainty, not just those involving sperm competition. Your jealousy might also deter other guys from trying – adaptations for sperm competition don’t do deterrence.

This is certainly true enough: if a female partner knows that her straying will lead to physical aggression or the withdrawal of investment, she might be pressured into not having that affair; the same goes for rival males. However, aggression is not always the smartest strategy, as aggression carries costs. That rival male you seek to deter might well be bigger and stronger than you, and on top of being cheated on, you might also end up with an ass-kicking if you tried anything. Women may also have friends and family that prefer you didn’t hurt her, thank you very much. So while sperm competition doesn’t serve a deterrent function, it also avoids costs associated with the aggressive deterrent function. Further, if deterrence fails, for whatever reason, sperm competition might also be able to serve as a secondary buffer against the non-paternity outcome.

This also raises the follow question: is non-paternity low, at least in part, because opportunities for sperm competition are rare or are they low because counter strategies by pair-bonded males are relatively effective? Perhaps the non-paternity rate might be substantially higher if in-pair males had no way of effectively mitigating the risks of sperm competition from rival males. After all, given that any particular sexual act is unlikely to result in conception, 2% non-paternity implies there were likely many more opportunities for non-paternity that were not realized. Now, to be clear, I’m not saying that we should expect human males to be absolutely chock-full of adaptations for sperm competition, nor am I suggesting that we show evidence of one particular strategy or another. I just want to point out some of the nuances of the argument for or against it that I think Greg gets wrong, or at least fails to discuss.

Adaptations for sperm competition might be more subtle than larger testicles, for instance. Perhaps the frequency of sex – or at least the frequency and intensity of sexual interest – correlates with infidelity cues; perhaps the number of sperm per ejaculate could be varied facultatively as a function of sperm competition risk. As Shackelford, Pound, & Goetz (2005) put it, humans might not show some hallmarks of adaptations designed for persistently-high levels of sperm competition (as such contexts were not persistent themselves, as they might be in chimps, for instance), but might show evidence of adaptations designed for contexts in which sperm competition risk is temporarily elevated. These adaptations might not be readily detected, but to write off their existence entirely on the basis of low-non-paternity rates itself would be premature.

“I wish my wife wasn’t such a premature climaxer…”

The question in my mind is not one of whether sperm competition matters or not for human populations, but rather to what degree it has. Dichotomizing such variables (“sperm competition was/was not important, depending on what precisely important means”) is unlikely to help us get a full picture of sperm competition in humans specifically or other species more generally. After all, chimps, humans, and gorillas were all descendent from a common ancestral species, and that species was unlikely to display the full range of mating behaviors evidence by all it’s future relatives. Some small initial degree of sperm competition must have been sufficient to get the ball rolling on later adaptations for such conditions. Now perhaps humans have been facing less sperm competition over time, and what we see are the degraded remnants of previous adaptations designed to deal with more of it. Then again, perhaps our species has gone the other way, or perhaps we have some adaptations designed for some modest levels of sperm competition. To be sure, some hypothetical adaptations for dealing with sperm competition will be wrong, and people’s estimates of how common it is or isn’t might be way off. I just wouldn’t close the door on the matter (or claim, as Greg does, that such adaptations “don’t exist”) because of that.

References: Shackelford, T., Pound, N., & Goetz, A. (2005). Psychological and physiological adaptations to sperm competition in humans. Review of General Psychology, 9, 228-248.

What Does Online Dating Tell Us About Racial Views?

Posted on January 19, 2014 by Jesse Marczyk

Preferences can be funny things, or at least our judgments of them. If I were to state that, “I have no interest in hiring a black person to do this job”, I would receive more than a little condemnation for that view. If I were to state instead that, “I have have no interesting in dating a black woman”, I would likely still receive some condemnation, but probably less than for the first statement. Finally, if I were to state that, “I have no interest in dating a man”, I would receive very little, if any, condemnation for it, even from those who advocate strongly for gay rights. As one of my colleagues recently posed the question, “Why is discrimination based on reproductive / sexual preferences OK, but other forms of discrimination are not?” The issue of discrimination is one I’ve discussed before, considering why discrimination on the basis of standardized test scores is deemed to be appropriate, whereas discrimination of the basis of obesity is often not. So let’s turn our attention towards discrimination in the sexual realm today.

“Free?! I’d have to be an idiot not to find the Asian of my dreams!”

A recent post by Jenny Davis over at the Pacific Standard suggests that “Online dating shows us the cold, hard facts about race in America“. In her article, Jenny discusses some data released from a Facebook-based dating app that figures out which people are interested in which other people on some sexual or romantic level. The data is labeled “unfortunate” in some respects, because there appear to be winners and losers, and those winners and losers seem to break down along racial lines. When it comes to mating, it seems that everyone doesn’t get to join hands and cross the finish line at the same time so that we all end up with equally-high self-esteem (I know; I was shocked too). To give you a sense for the data (and so you don’t have to click back and forth between links), here’s the breakdown of the response rates for people who are interested.

As anyone can clearly see, there are favorites. When it comes to the highest positive response rate, most women, regardless of their race, appear to favor white men, whereas most men, again, regardless of their race, tend to favor Asian women. In terms of the lowest response rate, women appeared to shun black men, whereas men tended to shun black women. Ouch. Jenny, using what I can only assume is that same “high-powered sociological lens” I’ve encountered before, concludes that this clearly demonstrates that race matters, and serves to counter accusations that we are living in a color-blind, post-racial world. As Jenny puts it we “fetishize Asian women while devaluing blacks”. Now tone doesn’t come across well through text-based communications at time, but neither “fetishize” nor “devalue” sound as if they have a particularly positive connotation to me. It sounds as if she’s condemning other people for their sexual preferences in that respect.

There are many comments to make about this, but let’s start with this one: apparently, there’s something of a no-win situation being erected from the get go. When one group is preferred, it’s a “fetish”, whereas when they’re not preferred, they’re “devalued”. Well, sort of, anyway; if she were being consistent (and who is?) Jenny would also say that women “fetishize” white males. Strangely, she does not. One can only guess as to why she does not, because Jenny makes no apparent attempt to understand the data in question. By that, I mean that Jenny offers no potential alternative explanations through which we might understand the data. In fact, she doesn’t seem to offer any explanation whatsoever for these patterns of responses. If I had to, I would guess that her explanation, if simplified somewhat, would reduce to “racism did it”, but it’s hard to tell.

“But are they the Black singles of my dreams, like the Asians?”

I would like to try and pick up some of that explanatory slack. Despite initial appearances, it is possible that this data has very little, if anything, to do with race per se. Now I happen to think that race likely does matter to some extent when it comes to dating preferences, but the degree of that extent is anyone’s guess. To see why I would say this only requires that one understands a very basic statistical concept: correlation does not equal causation. This is something that I imagine Jenny understands, but it likely slipped her mind in the midst of trying to make a point. There are few examples to consider, but the first is by far the simplest. Most men, if you polled them, would overwhelming respond to women on dating websites, and not other men; women would likely do the reserve. This does not mean, however, that men (or women) “devalue” other men (or women). Similarly, just because people on these dating sites might respond to black people at the lowest rates, it does not mean they “devalue” black people more generally.

But maybe we do devalue certain racial groups, at least when it comes to dating them. This brings us to the second issue: mating decisions are often complex. There are dozens of potential variables that people assess when choosing a mate – such as how much money they have, how much they weigh, how tall they are, their age, their relatedness to us, etc – and the importance of these qualities also varies somewhat depending on the nature of the relationship (whether it is more short- or long-term, for instance). The important point here is that even if people are picking mates on the basis of these other characteristics alone and not race, we might still see racial differences in outcomes. Let’s say, for instance, that men tend to prefer women shorter than themselves as dating partners (the reasons for this preference or it’s actual existence need not necessarily concern us). If that were the case, provided there are any average differences in height among the races, we would still see different response rates to and from each racial group, even though no one was selecting on the basis of race.

Rather than just considering the direction the preferences in the data above, then, let’s consider some of the actual numbers: when it came to response rates, regardless of whether we were considering men or women, and regardless of whether we’re considering the highest or lowest response rates, black individuals seem to respond more often than any other group; sometimes around twice as often. This could be indicative of a number of different factors, though I won’t speculate as to which ones on the basis of the numbers alone. The only point is that those factors might show up in user’s profiles in some way. If other people pick up on those factors primarily, then race itself might not be the primary, or even a, factor driving these decisions. In fact, in terms of response rates, there was a consistent overall pattern: from lowest to highest, it tended to be Latinos, Whites, Asians, and Blacks, regardless of sex (with only a single exception). Whatever the reasons for this, I would guess that it shows up in other ways in the profiles of these senders and responders.

Strangely, I can’t find a picture of a white dating site. Odd…

As I said, I don’t think that race per se is entirely unrelated to mating choices. However, to determine the extent to which it uniquely predicts anything, you need to control for other relevant factors. Does obesity play a role in these decisions? Probably. Is obesity equally common across racial groups? Nope. How about income; does income matter? In some cases it sure seems to. Is income the same across racial groups? Nope. We would likely find the same for many, many other factors.

In addition to determining the extent of how much race matters, one might also wish to explain why race might matter. Simply noting that there appear to be some racial differences doesn’t tell us a whole lot; the same goes for correlations of match percentages and response rates over at OkCupid, which find a similar pattern with respect to race. In the instance of OkCupid, a match percentage of 10% between two people corresponds to about a 25% reply rate; a 90% match percentage gets you all the way up to… a 37% reply rate. Even at around 100% match, the response rate still only lingers at around 50%. There appears to be a lot more that goes into mating decisions than people typically appreciate or even recognize. For what it’s worth, I would rather work to understand those complexities than pat myself on the back for how bad I think racism is.

Begging Questions About Sexualization

Posted on December 23, 2013 by Jesse Marczyk

There’s an old joke that goes something like this: If a man wants to make a woman happy, it’s really quite simple. All he has to do is be a chef, a carpenter, brave, a friend, a good listener, responsible, clean, warm, athletic, attractive, tender, strong, tolerant, understanding, stable, ambitious, and compassionate. Men should also not forget to compliment a women frequently, give her attention while expecting little in return, give her freedom to do what she wants without asking too many questions, and love to go shopping with her, or at least support the habit. So long as a man does/is all those things, if he manages to never forget birthdays, anniversaries, or other important dates, he should be easily able to make a woman happy. Women, on the other hand, can also make men happily with a few simple steps: show up naked and bring beer. (For the unabridged list, see here). While this joke, like many great jokes, contains an exaggeration, it also manages to capture a certain truth: the qualities that make a man attractive to a woman seem to be a bit more varied than the qualities that make a woman attractive to a man.

“Yeah; he’s alright, I guess. Could be a bit taller and richer…”

Even if men did value the same number of traits in women that women value in men, the two sexes do not necessarily value the same kinds of traits, or value them to the same degree (though there is, of course, frequently some amount of overlap). Given that men and women tend to value different qualities in one another, what should this tell us about the signals that each sex sends to appeal to the other? The likely answer is that men and women might end up behaving or altering their appearance in different ways when it comes to appealing to the opposite sex. As a highly-simplified example, men might tend to value looks and women might tend to value status. If a man is trying to appeal to women under such circumstance, it does him little good to signal his good looks, just as it does a woman no favors to try and signal her high status to men.

So when people start making claims about how one sex – typically women – are being “sexualized” to a much greater extent than the other, we should be very specific about what we mean by the term. A recent paper by Hatton & Trautner (2011) set forth to examine (a) how sexualized men and women tend to be in American culture and (b) whether that sexualization has seen a rise over time. The proxy measure they made use of for their analysis were about four decades worth of Rolling Stone covers, spanning from 1967 to 2009, as these covers contain pictures of various male and female cultural figures. The authors suggest that this research has value because of various other lines of research suggesting that these depictions might have negative effects on women’s body satisfaction, men’s negative attitudes about women, as well threatening to increase the amount of sexual harassment that women face. Somewhat surprisingly, in the laundry list of references attesting to these negative effects on women, there is no explicit mention of any possible negative effects on men. I find that interesting. Anyway…

As for the research itself, Hatton & Trautner (2011) examined approximately 1000 covers of Rolling Stone, of which 720 focused on men and 380 focused on women. The pictures were coded with respect to (a) the degree of nudity, from unrevealing to naked on a 6-point scale, (b) whether there was touching, from none to explicitly sexual on a 4-point scale, (c) pose, from standing upright to explicitly sexual on a 3-point scale, (d) mouth…pose (I guess), from not sexual to sexual on a 3-point scale, (e) whether breasts/chest, genitals, or buttocks were exposed and/or the focal point of the image, all on 3-point scales, (f) whether the text on the cover line related to sex, (g) whether the shot focused on the head or the body, (h) whether the model was engaged in a sex act or not, and finally (i) whether there were hints of sexual role play suggested at. So, on the one hand, it seems like these pictures were analyzed thoroughly. On the other, however, consider this list of variables they were assessing and compare them to the initial joke. By my count, all of them appear to fall more on the end of “what makes men happy” rather than “what makes women happy”.

Which might cause a problem in translation from one sex to the other

Images were considered to be “hypersexualized” if they scored 10 or more points (out of the possible 23), but only regular “sexualized” if they scored from 5 to 9 points. In terms of sexualization, the authors found that it appeared to be increasing over time: in the ’60s, 11% of men and 44% of women were sexualized; by the ’00s these rose to 17% and 89% respectively. So Hatton & Trautner (2011) concluded that men were being sexualized less than women overall, which is reasonable given their criteria. However, those percentages captured both the “sexualized” and “hypersexualized” pictures. Examining the two groups separately, the authors found that around 1-3% of men on the covers were hypersexualized in any given decade, whereas the comparable range for women was 6% to 61%. Not only did women tend to be sexualized more often, they also tended to sexualized to a great degree. The authors go so far as to suggest that the only appropriate label for such depictions of women were as sex objects.

The major interpretative problem that is left unaddressed by Hatton & Trautner (2011) and their “high-powered sociological lens”, of course, is that they fail to consider whether the same kinds of displays make men and women equally sexually appealing. As the initial joke might suggest, men are unlikely to win many brownie points with a prospective date if they showed up naked with beer; they might win a place on some sex-offender list though, which falls short of the happy ending they would have liked. Indeed, many of the characteristics highlighted in the list of ways to make a woman happy – such as warmth, emotional stability, and listening skills – are not quite as easily captured by a picture, relative to physical appearance. To make matters even more challenging for the interpretation of the authors, there is the looming fact that men tend to be far more open to offers of casual sex in the first place. In other words, there might about as much value to signaling that a man is “ready for sex” as there is to signaling that a starving child is “ready for food”. It’s something that is liable to be assumed already.

To put this study in context, imagine I was to run a similar analysis to the authors, but started my study with the following rationale: “It’s well known that women tend to value the financial prospects of their sexual partners. Accordingly, we should be able to measure the degree of sexualization on Rolling Stone covers by assessing the net wealth of the people being photographed”. All I would have to do is add in some moralizing about how depiction of rich men is bad for poorer men’s self-esteem and women’s preferences in relationships, and that paper would be a reasonable facsimile to the current one. If this analysis found that the depicted men tended to be wealthier than the depicted women, this would not necessarily indicate that the men, rather than the women, were being depicted as more attractive mates. This is due to the simple, aforementioned fact, that we should expect an interaction between signalers and receivers. It doesn’t pay for a signaler to send a signal that the intended receiver is all but oblivious to: rather, we should expect the signals to be tailored to the details of the receptive systems it is attempting to influence.

The sexualization of images like this might go otherwise unnoticed.

It seems that the assumptions made by the authors stacked the deck in favor of them finding what they thought they would. By defining sexualization in a particular way, they partially begged their way to their conclusion. If we instead defined sexualization in other ways that considered variables beyond how much or what kind of skin was showing, we’d likely come to different conclusions about the degree of sexualization. That’s not to say that we would find an equal degree of it between the sexes, mind you, but it would be a realization that there are many factors that can go into making someone sexually attractive which are not always able to be captured in a photo. We’ve seen complaints of sexualization like these leveled against the costumes that superheroes of various sexes tend to wear, and the same oversight is present in them as well. Unless the initial joke would work just as well if the sexes were reversed, these discussions will require more nuance concerning sexualization to be of much profitable use.

References: Hatton E. & Trautner, M. (2011). Equal opportunity objectification? The sexualization of men and women on the cover of Rolling Stone. Sexuality and Culture, 15, 256-278.

What Predicts Religiosity: Cooperation Or Sex?

Posted on November 21, 2013 by Jesse Marczyk

When trying to explain the evolutionary function of religious belief, there’s a popular story that goes something like this: individuals who believe in a deity that monitors our behavior and punishes or rewards us accordingly might be less likely transgress against others. In other words, religious beliefs function to makes people unusually cooperative. There are two big conceptual problems with such a suggestion: the first is that, to the extent that these rewards and punishments occur after death (heaven, hell, or some form of reincarnation as a “lower” animal, for instance), they would have no impact on reproductive fitness in the current world. With no impact on reproduction, no selection for such beliefs would be possible, even were they true. The second major problem is that in the event that such beliefs are false, they would not lead to better fitness outcomes. This is due to the simple fact that incorrect representations of our world do not generally tend to lead to better decisions and outcomes than accurate representations. For example, if you believe, incorrectly, that you can win a fight you actually cannot, you’re liable to suffer the costs of being beaten up; conversely, if you incorrectly believe you cannot win a fight you actually can, you might back down too soon and miss out on some resource. False beliefs don’t often help you make good decisions.

“I don’t care what you believe, R. Kelly; there’s no way this will end well”

So if one believes they being constantly observed by an agent that will punish them for behaving selfishly and that belief happens to be wrong, they will tend to make worse decisions, from a reproductive fitness standpoint, than an individual without such beliefs. On top of those conceptual problems, there is now an even larger problem for the religion-encouraging-cooperation idea: a massive data set doesn’t really support it. When I say massive, I do mean massive: the data set examined by Weeden & Kurzban (2013) comprised approximately 300,000 people from all across of the globe. Of interest from the data set were 14 questions relating to religious behavior (such as the belief in God and frequency of attendance at religious services), 13 questions relating to cooperative morals (like avoiding paying a fare on public transport and lying in one’s own interests), and 7 questions relating to sexual morals (such as the acceptability of causal sex or prostitution). The analysis concerned how well the latter two variable sets uniquely predicted the former one.

When considered in isolation in a regression analysis, the cooperative morals were slightly predictive of the variability in religious beliefs: the standardized beta values for the cooperative variables ranged from a low of 0.034 to a high of 0.104. So a one standard deviation increase in cooperative morals predicted, approximately, one-twentieth of a standard deviation increase in religious behave. On the other hand, the sexual morality questions did substantially better: the standardized betas there ranged from a low of 0.143 to a high of 0.38. Considering these variables in isolation only gives us so much of the picture, however, and the case got even bleaker for the cooperative variables once they were entered into the regression model at the same time as the sexual ones. While the betas on the sexual variables remained relatively unchanged (if anything, they got a little higher, ranging from 0.144 to 0.392) the betas on the cooperative variables dropped substantially, often into the negatives (ranging from -0.045 to 0.13). In non-statistical terms, this means that the more one endorsed more conservative sexual morals, the more religious one tended to be; the more one endorsed cooperative morals, the less religious one tended to be, though this latter tendency was very slight.

This evidence appears to directly contradict the cooperative account: religious beliefs don’t seem to result in more cooperative behaviors or moral stances (if anything, it results slightly fewer of them once you take sex into account). Rather than dealing with loving their neighbor, religious beliefs appeared to deal more with who and how their neighbor loved. This connection between religious beliefs and sexual morals, while consistently positive across all regions sampled, did vary in strength from place to place, being about four-times stronger in wealthy areas, compared to poorer ones. The reasons for this are not discussed at any length within the paper itself and I don’t feel I have anything to add on that point which wouldn’t be purely speculative.

“My stance on speculation stated, let’s speculate about something else…”

This leaves open the question of why religious beliefs would be associated with a more-monogamous mating style in particular. After all, it seem plausible that a community of people relatively interested in promoting a more long-term mating strategy and condemning short-term strategies need not come with the prerequisite of believing in a deity. People apparently don’t need a deity to condemn people for lying, stealing, or killing, so what would make sexual strategy any different? Perhaps the fact that sexual morals show substantially more variation that morals regarding, say, killing. Here’s what Weeden & Kurzban (2013) suggest:

We view expressed religious beliefs as potentially serving a number of functions, including not just the guidance of believers’ own behaviors, but as markers of group affiliation or as part of self-presentational efforts to claim higher authority or deflect the attribution of self-interested motives when it comes to imposing contested moral restrictions on those outside of the religious group. (p.2, emphasis mine)

As for whether or not belief in a deity might serve as a group marker, well, it certainly seems to be a potential candidate. Of course, so is pretty much anything else, from style of dress, to musical taste, to tattoos or other ornaments. In terms of displaying group membership, belief in God doesn’t seem particularly special compared to any other candidate. Perhaps belief in God simply ended up being the most common ornament of choice for groups of people who, among other things, wanted to restrict the sexuality of others. Such an argument would need to account for the fact that belief in God and sexual morals seem to correlate in groups all over the world, meaning they all stumbled upon that marker independently time and again (unlikely), that such a marker has a common origin in a time before humans began to migrate over the globe (possible, but hard to confirm), or posit some third option. In any case, while belief in God might serve such a group-marking function, it doesn’t seem to explain the connection with sexuality per se.

The other posited function – of involving a higher moral authority – raises some additional questions: First, if the long-term maters are adopting beliefs in God so as to try and speak from a position of higher (or impartial) authority, this raises the question of why other parties, presumably ones who don’t share such a belief, would be persuaded by that claim in anyway. Were I to advance the claim that I was speaking on behalf of God, I get the distinct sense that other people would dismiss my claims in most cases. Though I might be benefited if they believed me, I would also be benefited if people just started handing me money; that there doesn’t seem to be a benefit for other parties in doing these things, however, suggests to me that I shouldn’t expect such treatment. Unless people already believe in said higher power, claiming impartiality in its name doesn’t seem like it should tread much persuasive water.

Second, even were we to grant that such statements would be believed and have the desired effect, why wouldn’t the more promiscuous maters also adopt a belief in a deity that just so happens to smile on, or at least not care about, promiscuous mating? Even if we grant the more promiscuous individuals were not trying to condemn people for being monogamous (and so have no self-interested motives to deflect), having a deity on your side seems like a pretty reasonable way to strengthen your defense against people trying to condemn your mating style. At the very least, it would seem to weaken the moralizer’s offensive abilities. Now perhaps that’s along the lines of what atheism represents; rather than suggesting that there is a separate deity that likes what one prefers, people might simply suggest there is no deity in order to remove some of the moral force from the argument. Without a deity, one could not deflect the self-interest argument as readily. This, however, again returns us to the previous point: unless there’s some reason to assume that third parties would impressed by the claims of a God initially, it’s questionable as to whether such claims would carry any force that needed to be undermined.

Some gods are a bit more lax about the whole “infidelity” thing.

Of course, it is possible that such beliefs are just byproducts of something else that ties in with sexual strategy. Unfortunately, byproduct claims don’t tend to make much in the way of textured predictions as for what design features we ought to expect to find, so that suggestion, while plausible, doesn’t appear to lend itself to much empirical analysis. Though this leaves us without a great of satisfaction in explaining why religious belief and regulation of sexuality appear to be linked, it does provide us with the knowledge that religious belief does not primarily seem to concern itself with cooperation more generally. Whatever the function, or lack thereof, of religious belief, it is unlikely to be in promoting morality in general.

References: Weeden, J., & Kurzban, R. (2013). What predict religiosity? A multinational analysis of reproductive and cooperative morals. Evolution and Human Behavior (34), 440-445

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