The Better Angels of Our Nature: Why Vio - By Steven Pinker Page 0,314

they cannot afford to smack each other around indefinitely, let alone kill each other. Among primates whose interests are not bound up in any of these ways, adversaries are unforgiving, and violence is likelier to escalate. Chimpanzees, for example, reconcile after a fight within their community, but they never reconcile after a battle or raid with members of a different community.107 As we shall see in the next chapter, reconciliation among humans is also governed by the perception of common interests.

The metaphor of competitive distance urination suggests that the gender with the equipment best suited to competing is the gender that is most likely to participate in contests of dominance. Though in many primate species, including humans, both sexes jockey for preeminence, usually against members of their own sex, it seems to loom larger in the minds of men than in the minds of women, taking on a mystical status as a priceless commodity worth almost any sacrifice. Surveys of personal values in men and women find that the men assign a lopsided value to professional status compared to all the other pleasures of life.108 They take greater risks, and they show more confidence and more overconfidence.109 Most labor economists consider these sex differences to be a contributor to the gender gap in earnings and professional success.110

And men are, of course, by far the more violent sex. Though the exact ratios vary, in every society it is the males more than the females who play-fight, bully, fight for real, carry weapons, enjoy violent entertainment, fantasize about killing, kill for real, rape, start wars, and fight in wars.111 Not only is the direction of the sex difference universal, but the first domino is almost certainly biological. The difference is found in most other primates, emerges in toddlerhood, and may be seen in boys who (because of anomalous genitalia) are secretly raised as girls.112

We have already seen why the sex difference evolved: mammalian males can reproduce more quickly than females, so they compete for sexual opportunities, while females tilt their priorities toward ensuring the survival of themselves and their offspring. Men have more to gain in violent competition, and also less to lose, because fatherless children are more likely to survive than motherless ones. That does not mean that women avoid violence altogether—Chuck Berry speculated that Venus de Milo lost both her arms in a wrestling match over a brown-eyed handsome man—but they find it less appealing. Women’s competitive tactics consist in less physically perilous relational aggression such as gossip and ostracism.113

In theory, violent competition for mates and violent competition for dominance needn’t go together. One doesn’t have to invoke dominance to explain why Genghis Khan inseminated so many women that his Y chromosome is common in Central Asia today; it’s enough to observe that he killed the women’s fathers and husbands. But given that social primates regulate violence by deferring to dominant individuals, dominance and mating success in practice went hand in hand during most of our species’ history. In nonstate societies, dominant men have more wives, more girlfriends, and more affairs with other men’s wives.114 In the six earliest empires, the correlation between status and mating success can be quantified precisely. Laura Betzig found that emperors often had thousands of wives and concubines, princes had hundreds, noblemen had dozens, upper-class men had up to a dozen, and middle-class men had three or four.115 (It follows mathematically that many lower-class men had none—and thus a strong incentive to fight their way out of the lower class.) Recently, with the advent of reliable contraception and the demographic transition, the correlation has been weakened. But wealth, power, and professional success still increase a man’s sex appeal, and the most visible clue to physical dominance—height—still gives a man an edge in economic, political, and romantic competition.116

Whereas instrumental violence deploys the seeking and calculating parts of the brain, dominance deploys the system that Panksepp calls Intermale Aggression. It really should be called Intrasexual Competition, because it is found in women too, and the human habit of male parental investment means that women as well as men have an evolutionary incentive to compete for mates. Still, at least one part of the circuit, a nucleus in the anterior preoptic portion of the hypothalamus, is twice as large in men as it is in women.117 And the entire system is studded with receptors for testosterone, which is about five to ten times more plentiful in the bloodstream of men than of women. The hypothalamus, recall, controls the