As sex scandals involving powerful men seem to be getting increasingly commonplace (Edwards, Lee, Schwarzenegger, Strauss-Kahn, Weiner, etc.), many have been asking: Why are men so much more likely than women to cause these scandals? Why, in other words, are men so much more willing than women to risk losing their careers and families in order to pursue new mating opportunities?

Darwin's theories of natural and sexual selection provide a deeply compelling framework for understanding the sex difference in this compulsion to pursue new mates. And while much of the general public may be willing to accept, on some level, that this sex difference has evolutionary biological roots, there is still a lot of fear and misunderstanding out there about what the implications of this fact may be.

This fear and misunderstanding is evident in recent articles about why men cause more scandals than women. In a New York Times piece Sheryl Stolberg says, "It would be easy to... dismiss" the sex difference "as a testosterone-induced, hard-wired connection between sex and power." Stolberg goes on to explain her view that the difference is the product not of biology, but of the fact that women in power are more serious about their jobs (a view for which there doesn't seem to be much evidence). And in a post for Slate, Amanda Marcotte commends Stolberg for "manag[ing] to avoid the trap of trying to establish some dramatic differences between male and female sexuality." She goes on to offer her own preferred explanations: men cause more scandals because there are more men in power (a view debunked in this article), and because women would be more harshly punished for such behavior (which doesn't explain why the severe punishments faced by males in these scandals—e.g., loss of career—haven't done much to deter them).

The language that Stolberg and Marcotte use implies fear of the idea that the sex difference is biological. Stolberg says that to accept this fact would be to "dismiss" the behavior. It seems odd to regard the evolutionary view as a dismissal rather than an explanation for the behavior, but I suppose she fears that if it's biological then we must just accept it as "natural" because there's nothing we can do to change it. And Marcotte regards the evolutionary view not as an explanation but as a "trap," suggesting that accepting it would be freedom-restricting in some way.

These fears illustrate beautifully the kind of flawed assumptions about evolutionary psychology that I discussed in my last post, "Mental evolution and the freedom to change." Instead of regarding evolved mental adaptations as the mechanisms which make behavior possible, these authors see biology as something which oppresses and constrains behavior. But if you're serious about understanding the causes of behavior, in a way that would give you some power to change that behavior (in yourself or others), then their approach is exactly the wrong one to take. Efforts to pretend that these sex differences aren't rooted in biology, and to offer relatively superficial alternative explanations that strenuously avoid the truth because they see it as a trap, are ultimately a road to nowhere.

Before I go further, let me review the evolutionary logic for why men are on average more interested than women in acquiring new sex partners. Evolutionary success is mainly about success in reproductive competition, and how you achieve this success depends on how much you are obligated to invest in the production of offspring. This "parental investment" can take many forms, including the investment of one's own bodily reproductive capacity. In general, female mammals must make a large minimum investment in order to reproduce (e.g. in ancestral humans, nine months of gestation and years of lactation), whereas male mammals can reproduce with a much smaller minimum investment (i.e. a few minutes of time and an easily replenished amount of sperm). This does not mean that males don't often benefit their offspring in essential ways by investing beyond this bare minimum. However, it does mean that because the obligatory costs of reproduction are (in most species) much lower for males than for females, there are significant differences in the mating strategies that males and females evolve.

The typical pattern--and the one that applies to humans--is that females evolve to be relatively choosy about who they mate with, and relatively low in "sociosexuality" (i.e., relatively uninterested in promiscuous, uncommitted sex). Males, on the other hand, have more to gain and less to lose from having large numbers of sexual partners, and they evolve to be less choosy and higher in sociosexuality. A simple way to understand this logic is to imagine what an ancestral man and woman could have gained reproductively from having 100 sex partners, as opposed to just one partner, in one year. The woman could produce exactly one child, whether she had one or 100 partners, and so would gain little from those 99 extra partners. For the man, on the other hand, 99 extra partners could in theory mean 99 extra kids.

This sex difference in the desire for new mates doesn't mean that men aren't interested in long-term, committed sexual relationships; on the contrary, most men strive for such relationships and value them deeply. But it does mean that even when he is involved in such a relationship, the average man will regard opportunities to mate with new partners as being more compelling than would the average woman. And the strength of this temptation will generally be proportional to his social status, because the higher his status, the more women will be attracted to him (again, for basic evolutionary reasons), and the more opportunities he will have.

So the high status man will often face a dilemma. While some evolved modules in his brain—let's call them his "long-term interest" modules—are coaching him to act in ways that will benefit his family, career and reputation, other evolved modules—his "mating" modules—are urging him to pursue new sexual opportunities. And these mating modules, besides being insistently persuasive in their own right, may even actively sabotage the influence of the long-term interest modules, by causing the man to underestimate and discount the risks involved (to family, career and reputation) in the pursuit of sexual thrills. Thus the man may be compelled to pursue these thrills in ways that, to other people, seem surprisingly reckless and stupid. ("Why on earth would he think he'd be able to get away with that?")

It's hard to see how anyone could truly accept the theory of evolution without also accepting that when the sexes differ in obligatory parental investment, they're going to evolve divergent mating strategies. Nevertheless, it's a non sequitur to say that because this fact applies to humans, we must see "scandalous" male behavior as "natural," condonable or inevitable. Cross-culturally (and again, for elementary evolutionary reasons), men are much more likely than women to commit murder, but thankfully, people in most modern societies don't think that it's "natural," condonable or inevitable for men to murder.

If you're a man who wants to avoid wrecking your life for the sake of pursuing new mating opportunities, your best hope is to recognize that when these opportunities present themselves, your brain's mating modules will know precisely what they want you to do, and you may feel like they're making a heroic effort to get you to do it. They may even cause you to badly underestimate the damage that your actions could cause to your family and career, and to overestimate your chances of getting away with it or of being forgiven. To avoid doing something you may regret, recognize your mating modules for what they are, and be aware of what they're trying to persuade you to do. This knowledge will increase your power to ignore them, and to listen more to the parts of your brain that evolved to serve you in the long term.

(A version of this article appeared in the author's "Natural Law" column in the banking magazine Global Custodian, Summer plus 2011 issue).

Copyright Michael E. Price 2011. All rights reserved.

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