Some Fuss Over Sperm Competition

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.

Dante’s Inferno

I’d like to begin with a quick apology for the tardiness of this latest update. It’s not that there’s anyone holding me to my usual weekly schedule except myself, but I am disappointed I haven’t gotten around to updating sooner. I had planned to take a week to myself to enjoy a new game (and enjoy it thoroughly I did, so mission accomplished there), but that week ended with my getting sick for another one, and I haven’t been able to concentrate on much as a result. With those excuses out of the way, I’m going to start off today like most middle/high-school students: by summarizing part of a book (or epic poem, really) that I haven’t read personally. Instead, I’ll be summarizing it – or at least part of it – by using the Wikipedia cliff notes. That story, as the title suggests, is Dante’s Inferno. What I really like about this Wikipedia page describing the story is that Inferno is kind enough to order the circles of hell for the reader with respect to increasing wickedness; the deeper one goes, the worse the sins needed to get there. The reason I like this neat and tidy ordering is that it gives us some insight as to the author’s moral sense.

I might not have read the book, but I did play the video game. Close enough.

As a quick rundown of the circles of hell, from least bad to worst, there’s: Limbo, Lust, Gluttony, Greed, Wrath, Heresy, Violence, Fraud, and finally Treachery. Now what’s particularly interesting here is that, according to Dante, it would seem to be worse to be a flatterer or a corrupt politician than a murderer. Misrepresenting your stances about people or politics is bad bad bad in Dante’s book. More interesting still is the inner-most circle: Treachery. Treachery seems to represent a particular kind of fraud: one in which the victim is expected to have some special relationship to the perpetrator. For instance, family members betraying each other seems to be worse than strangers doing similar harms. In general, kin are expected to behave more altruistically towards each other, owing in no small part to the fact that they share genes in common with one another. Helping one’s kin, in the evolutionary-sense of things, is quite literally like helping (part of) yourself. So if kin are expected to trade off their own welfare for family members at a higher rate than they would for strangers, but instead display the opposite tendency, this makes kin-directed immoral acts appear particularly heinous.

Now, of course, Dante’s take on things isn’t the only game in town. A paper which I have repeatedly discussed (DeScioli & Kurzban, 2013) has a different take on the issue of morality. That take is that morality serves, more or less, a coordination function for punishers: the goal is to get most people in agreement about who should be punished in order to avoid the fighting costs that are associated with disagreement in that realm. In order for this coordination function to work, however, the pair suggest that morality needs to function on the basis of acts; not the identity of the actors. As DeScioli & Kurzban (2013) put it:

“The dynamic coordination theory of morality holds that evolution favored individuals equipped with moral intuitions who choose sides in conflicts based, in part, on “morality” rather than relationship or status”

Identity shouldn’t come into play when it comes to moral condemnation, then; it is “[crucial that the signal] must not be tied to individual identity”. As Monty Python put it, “let’s not bicker and argue about who killed who“, and let’s not do that because killing should be equally as wrong no matter who does it and who ends up on the receiving end.

Now in fairness to DeScioli & Kuzrban (2013), they also hedge their theoretical bets, suggesting that identity also ought to matter when it comes to picking sides in disputes. However, it seems that, according to the dynamic coordination model, anyway, when people do take sides on the basis loyalty to their friends or family, they should be motivated by systems that do not deal with morality. This suggestion seems to be at odds with Dante’s less-formalized interpretation of the importance of identity in the realm of morality, who instead would appear to hypothesize, at least implicitly, that the identity of the actors ought to matter a great deal. So let’s take a look at some research bearing on the matter.

And let’s do so quickly, before I get back to being addicted to this game.

The first piece of research comes to us from Lieberman & Linke (2007) who were examining whether the identity of an individual (either a foreigner, schoolmate, or family member) mattered when it came to the wrongness of an act and amount of punishment deemed to be appropriate for it (in this case, stealing $1500). When the individual in question was the perpetrator, participants (N = 268) suggested that the foreigner deserved more punishment than the schoolmate, and that the schoolmate deserved more punishment than the family member. Family members were also perceived to be more remorseful about their act, relative to schoolmates, relative to strangers. On the other hand, people’s rating of the immorality of the act did not vary as a function of the actor’s identity; no matter who one was, the act was rated as just as morally wrong (though ratings in all cases were close to ceiling levels here).

The next experiment (N = 288) examined essentially the same question, but this time the individual in question was the victim of the offense, rather than the perpetrator. When the offense was committed against a family member, people tended to be more punitive towards the perpetrator than when it was committed against a schoolmate or foreigner. Again, however, moral judgments remained uniformly at ceiling levels in all cases. In a final experiment (N = 78) participants were asked about how much they would be willing to personally invest in order to track down the perpetrator of various deeds. As before, people reported being willing to take more days off from work without pay to try and find the thief when a family member had been robbed (M = 12.85 days), relative to a schoolmate (M = 2.24) or a foreigner (M = 2.10). Now whether or not people would actually do these things (I don’t recall many people taking time off work to play Batman and help strangers track down thieves), people are at least expressing sentiments indicating that they think people should be punished to a greater degree for victimizing their kin, and that their kin deserve less punishment.

The results could be taken to favor either account – Dante’s or DeScioli & Kurzban’s – I feel. On the one hand, rating of morality appeared stubbornly impartial: the act was rated as being just as morally wrong, no matter the identity of the perpetrator or victim. This might suggest people were coordinating around the behavior, and not the identity of the actors. However, people were also not coordinating their behavior in the sense that what they actually wanted to see done after they had decided the act was morally wrong varied on the basis of identity. To express this tension in a different context, we might consider the following: imagine that most people agree with the statement, “freedom is a good thing”; good for America. However, that certainly does not mean that most people would be in agreement when it came to what precisely that sentence is supposed to mean: that is, what limits are to be put in place, and how those limits should be enacted?

Just exercising his freedom to pepper-spray protesters.

That said, the paper by Lieberman & Linke (2007) doesn’t exactly get at what Dante was proposing: Dante didn’t, as far as I know, anyway, say that lust was any better or worse when a family member does it. After all, everyone is someone’s family member, or friend, or foreigner. Instead, what Dante appeared to be proposing is that the relationship of the perpetrator to the victim is the crucial variable. As I’ve discussed previously, some initial research has tentatively borne out Dante’s hypothesis: while acts are rated as morally worse than omissions between strangers, this difference is reduced when the interaction occurs between friends, and the act is rated as more morally wrong overall. A more formal test of these competing hypotheses appears to await data. I’ll be sure to get right on that personally; just as soon as I’m done being addicted to this game in the next three or four years.

References: DeScioli, P. & Kurzban, R. (2013). A solution to the mysteries of morality. Psychological Bulletin, 139, 477-496.

Lieberman, D. & Linke, L. (2007). The effect of social category on third party punishment. Evolutionary Psychology, 5, 289-305.

When Are Equivalent Acts Not Equal?

There’s been an ongoing debating in the philosophical literature on morality for some time. That debate focuses on whether the morality of an act should be determined on the basis of either (a) the act’s outcome, in terms of its net effects on people’s welfare, or (b) whether the morality of an act is determined by…something else; intuitions, feelings, or what have you (i.e. “Incest is just wrong, even if nothing but good were to come of it”). These stances can be called the consequentialist and nonconsequentialist stances, respectively, and it’s at topic I’ve touched upon before. When I touched on the issue, I had this to say:

There are more ways of being consequentialist than with respect to the total amount of welfare increase. It would be beneficial to turn our eye towards considering strategic welfare consequences that likely to accrue to actors, second parties, and third parties as a result of these behaviors.

In other words, moral judgments might focus not only on the acts per se (the nonconsequentalist aspects) or their net welfare outcomes (the consequences), but also on the distribution of those consequences. Well, I’m happy to report that some very new, very cool research speaks to that issue and appears to confirms my intuition. I happen to know the authors of this paper personally and let me tell you this: the only thing about the authors that are more noteworthy than their good looks and charm is how humble one of them happens to be.

Guess which of us is the humble one?

The research (Marczyk & Marks, in press) was examining responses to the classic trolley dilemma and a variant of it. For those not well-versed in the trolley dilemma, here’s the setup: there’s an out-of-control train heading towards five hikers who cannot get out of the way in time. If the train continues on it’s part, then all five wills surely die. However, there’s a lever which can be pulled to redirect the train onto a side track where a single hiker is stuck. If the lever is pulled, the five will live, but the one will die (pictured here). Typically, when asked whether it would be acceptable for someone to pull the switch, the majority of people will say that it is. However, in past research examining the issue, the person pulling the switch has been a third party; that is, the puller was not directly involved in the situation, and didn’t stand to personally benefit or suffer because of the decision. But what would happen if the person pulling the switch was one of the hikers on one of the tracks; either on the side track (self-sacrifice) or the main track (self-saving)? Would it make a difference in terms of people’s moral judgments?

Well, the nonconsequentist account would say, “no; it shouldn’t matter”, because the behavior itself (redirecting a train onto a side track where it will kill one) remains constant; the welfare-maximizing consequentialist account would also say, “no; it shouldn’t matter”, because the welfare calculations haven’t changed (five live; one dies). However, this is not what we observe. When asked about how immoral it was for the puller to redirect the train, ratings were lowest in the self-sacrifice condition (M = 1.40/1.16 on a 1 to 5 scale in international and US samples, respectively), in the middle for the standard third-party context (M = 2.02/1.95), and highest in the self-saving condition (M = 2.52/2.10). In terms of whether or not it was morally acceptable to redirect the train, similar judgments cropped up: the percentage of US participants who said it was acceptable dropped as self-interested reasons began to enter into the question (the international sample wasn’t asked this question). In the self-sacrifice condition, these judgments of acceptability were highest (98%), followed by the third-party condition (84%), with the self-saving condition being the lowest (77%).

Participants also viewed the intentions of the pullers to be different, contingent on their location in this dilemma: specifically, the more one could benefit him or herself by pulling, the more people assumed that was the motivation for doing so (as compared with the puller’s motivations to help others: the more they could help themself, the less they were viewed as intending to help others). Now that might seem unsurprising: “of course people should be motivated to help themselves”, you might say. However, nothing in the dilemma itself spoke directly to the puller’s intentions. For instance, we could consider the case where a puller just happens to be saving their own life by redirecting the train away from others. From that act alone, we learn nothing about whether or not they would sacrifice their own life to save the lives of others. That is, one’s position in the self-beneficial context might simply be incidental; their primary motivation might have been to save the largest number of lives, and that just so happens to mean saving their own in the process. However, this was not the conclusion people seemed to be drawing.

*Side effects of saving yourself include increased moral condemnation.

Next, we examined a variant of the trolley dilemma that contained three tracks: again, there were five people on the main track and one person on each side track. As before, we varied who was pulling the switch: either the hiker on the main track (self-saving) or the hiker on the side track. However, we now varied what the options of the hiker on the side track were: specifically, he could direct the train away from the five on the main track, but either send the train towards or away from himself (the self-sacrifice and other-killing conditions, respectively). The intentions of the hiker on the side track, now, should have been disambiguated to some degree: if he intended to save the lives of others with no regard for his own, he would send the train towards himself; if he intended to save the lives of the hikers on the main track while not harming himself, he would send the train towards another individual. The intentions of the hiker on the main track, by contrast, should be just as ambiguous as before; we shouldn’t know whether that hiker would or would not sacrifice himself, given the chance.

What is particularly interesting about the results from this experiment is how closely the ratings of the self-saving and other-killing actors matched up. Whether in terms of how immoral it was to direct the train, whether the puller should be punished, how much they should be punished, or how much they intended to help themselves and others, ratings were similar across the board in both US and international samples. Even more curious is that the self-saving puller – the one whose intentions should be the most ambiguous – was typically rated as behaving more immorally and self-interestedly – not less – though this difference wasn’t often significant. Being in a position to benefit yourself from acting in this context seems to do people no favors in terms of escaping moral condemnation, even if alternative courses of actions aren’t available and the act is morally acceptable otherwise.

One final very interesting result of this experiment concerned the responses participants gave to the open-ended questions, “How many people [died/lived] because the lever was pulled?” On a factual level, these answers should be “1″ and “5″ respectively. However, our participants had a somewhat different sense of things. In the self-saving condition, 35% of the international sample and 12% of the US sample suggest that only 4 people were saved (in the other-killing condition, these percentages were 1% and 9%, and in the self-sacrifice condition they were 1.9% and 0%, respectively). Other people said 6 lives had been saved: 23% and 50% in the self-sacrifice condition, 1.7% and 36% in the self-saving condition, and 13% and 31% in the (international and US respectively). Finally, a minority of participants suggested that 0 people died because the train was redirected (13% and 11%), and these responses were almost exclusively found in the self-sacrifice conditions. These results suggest that our participants were treating the welfare of the puller in a distinct manner from the welfare of others in the dilemma. The consequences of acting, it would seem, were not judged to be equivalent across scenarios, even though the same number of people actually lived and died in each.

“Thanks to the guy who was hit by the train, no one had to die!”

In sum, the experiments seemed to demonstrate that these questions of morality are not to be limited to considerations of just actions and net consequences: to whom those consequences accrue seems to matter as well. Phrased more simply, in terms of moral judgments, the identity of actors seems to matter: my benefiting myself at someone else’s expense seems to have much different moral feel than someone else benefiting me by doing exactly the same thing. Additionally, the inferences we draw about why people did what they did – what their intentions were – appear to be strongly affected by whether that person is perceived to have benefited as a result of their actions. Importantly, this appears to be true regardless of whether that person even had any alternative courses of action available to them. That latter finding is particularly noteworthy, as it might imply that moral judgments are, at least occasionally, driving judgments of intentions, rather than the typically-assumed reverse (that intentions determine moral judgments). Now if only there was a humble and certainly not self-promoting psychologist who would propose some theory for figuring out how and why the identity of actors and victims tends to matter…

References: Marczyk, J. & Marks, M. (in press). Does it matter who pulls the switch? Perceptions of intentions in the trolley dilemma. Evolution and Human Behavior.

Who’s Blaming The Victim?

One phrase – or some variant of it – that seems to crop up in discussions of sexual assault more frequently than almost all others is “blaming the victim” (though I imagine “rape culture” and “patriarchy” are probably in the running for most commonly-used term as well). Coined in the early 1970s, the phrase has been nothing but gaining in popularity if Google’s N-gram viewer is any indication. The way I’ve seen the term used, “blaming the victim” appeared to amount to any suggestion that sexual assault might be reduced through any behavioral modifications on the part of victims of the act; in other words, any suggestion that people bear some responsibility for ensuring their own safety. Now, of course, sexual assault victims are no more at moral fault for the crime they suffer than robbery victims are at fault for being robbed (which is to say not morally at fault at all). The responsibility for the criminal act lies at the feet of the criminal. Nevertheless, one might also responsibly suggest that precautions might be taken to minimize the frequency of such acts, in much the same way that criminals are at fault for stealing bikes, but one might suggest that people lock their bikes up so as to make theft more difficult.

“Good idea, but your execution of it leaves something to be desired.”

The recent Slutwalks were one of the more notable outcomes of such a suggestion: specifically, the suggestion that women might be able to minimize their risks of being sexually assaulted by dressing less provocatively. While I have no data on hand bearing on the plausibility of such a suggestion, I happen to have some other interesting research on the topic of victim blaming in the case of sexual assault. What’s unique about the current study by Perilloux et al (2014) is the examination of how different parties assign responsibility for a sexual assault: more precisely, how victims of a completed or attempted sexual assault assign responsibility, relative to third parties who were not assaulted themselves, but know a friend that was. The questions of interest here were (a) whether these three groups differ in terms of how much responsibility they assign to various parties, and (b) whether these groups also perceive the motivations of the attacker differently as well.

The sample included 49 women who self-reported experiencing a completed sexual assault after puberty, 91 women who reported an attempted sexual assault, and 152 women who reported knowing someone who was the victim of an assault. The participants were asked to assign blame (totaling 100%) for the assault to six potential sources: the perpetrator, the victim, the situation, the victim’s family, friends, or other categories. They were then asked to response in an open-ended fashion as to why they had assigned blame the way they did. The participants were also asked what they thought the perpetrators hoped to gain from the assault.

The results found some interesting disconnects between the perceptions of these groups. For the most part, the three groups – completed, attempted, and third parties – were in agreement over how much blame the situation, friends, family members, and other factors shared for the assault (approximately 7%, 2%, 1%, and 1%, respectively; so about 10% of the overall blame). Where these groups differed primarily was with respect to how much blame the victim of the assault and perpetrator share. Those women who were the victims of a completed or attempted assault suggested the perpetrator bore about 70% of the blame while they – the victim – were about 19% responsible. Third parties – those women who were not assaulted but knew someone who said they were – reported a different pattern: the third parties suggested the victim (their friends) was only about 9% responsible, while the perpetrator was 82% responsible. In other words, the victims themselves seemed to be doing about twice as much of the victim blaming than their friends were.

Or remember to always make accusations with all five fingers. Problem solved.

That wasn’t the only avenue along which these perceptions diverged, though: the three groups also differed in terms of how they perceived the attacker’s motivation (i.e. why the assaulter did what they did). In the completed assault group, 65% of women nominated “sex” as the primary motivation for the assault, while 22% suggested power was the motivation. These percentages were similar to the attempted group (71% and 18%, respectively). However, the third party women saw things rather differently: only 48% suggested sex was the motivation for the action, while 27% suggested power was driving the act. So the friends of the assault victims appeared to feel the assault was less about sex, relative to the women who were actually assaulted.

Finally, the analysis turned to only the perceptions of the completed and attempted groups. Perilloux et al (2014) examined the most common reasons listed for self-blame: (1) putting oneself in a bad situation, (2) being intoxicated, (3) not resisting enough, (4) sending mixed messages, and (5) being too trusting. Perhaps unsurprisingly, completed assault victims were more likely to list “not resisting enough” (25%) relative to attempted victims (11%), owing to the probability that resistance likely serves as a deterrent, and how much resistance is “enough” is assessed by whether or not the assault was stopped, or when it was. More completed victims (29%) also listed their own intoxication as a reason for their blame, relative to attempted victims (19%), and the completed group also reported more intoxication at the time of the assault. Again, this is might well be related to the resistance factor: intoxicated people could be less capable or willing to resist.

So, the good news from this research should be that, by in large, people seem to overwhelming place the blame for sexual assault on the perpetrator rather than the victim. The blame given to the perpetrator tended to be three- to nine-times that of the blame assigned to the victim. This appears to be true regardless of whether it’s the victim or the victim’s friend. The most interesting finding seems to be the disconnect between the responses of third parties and victims, however: most of the victim blame came from the victims themselves, and these victims tended to see the motivation for sex on the part of perpetrator as playing a more primary role than third parties did. There is, of course, the possibility that other, more socially-distant, third parties would assign more blame to the victims, relative to current groups, but that much remains to be seen. In any case, the question to consider is why these perceptions differ.

*Warning: point of view might not match well to reality.

One possibility is that the victims might have greater insight to what factors increased their risks for the assault, relative to third parties, owing to the fact that they were direct witnesses to the event. This certainly seems like a reasonable suggestion, and should give pause to those who claim that rape is primarily and act of violence or domination, rather than sex. Another, not mutually-exclusive suggestion, that I would advance would be to consider what signals these perceptions of victim blame might be sending. Since there’s no objective truth to the question, “how much blame does party X deserve”, these perceptions are likely to be reflecting something else.

Here are two possible alternatives as to what that something else might be: the first is that “who deserves how much blame?” might be interpreted as “whose side would you take in a dispute between the victim and the perpetrator?” In placing very little blame on the victim, third parties could be signaling a strong willingness to take their friend’s side on the matter. Another (also non-mutually exclusive) potential is that the question about who deserves blame might be interpreted as, “how much did the behavior of this individual increase their probability of being assaulted?” In this case, victims, through their self-blame, might be signaling that they recognize some potential for minimizing their future risk of being assaulted. This recognition could, in turn, make the victim look like a better social ally. Friends who consistently expose themselves to costly risks are, all else being equal, more costly to consistently support and side with than friends who suffer fewer costs. Accordingly, a friend who suggests they will behave more cautiously next time might appear to be at a lower risk for suffering costs, and a better social investment.

If third parties and victims interpret the notion of “blame” somewhat differently, then, this would lead to the following prediction: when rating one’s own blame for sexual assault, victims should rate their own blame higher, relative to third parties, as they did in the current study. However, there’s another prediction we could make: when rape victims are rating another victim’s blame for their sexual assault, the former group should not differ from non-victimized third parties. That is, victims of sexual assault should not both blame themselves and other victims equally; how much blame they assign to themselves or others should vary strategically.

References: Perilloux, C., Duntley, J., & Buss, D. (2014). Blame attribution in sexual victimization. Personality and Individual Differences, 63, 81-86.