The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (60 page)

of genetic indeterminism did not have the influence they deserved in evolutionary theory.

The logic of proteanism is simple. If a rabbit fleeing from a fox always chose the single apparently shortest escape route, the consistency of its behavior would make its escape route more predictable to the fox, its body more likely to be eaten, and its genes less likely to replicate. Predictability is punished by hostile animals capable of prediction. Instead of fleeing in a straight line, rabbits tend to zigzag erratically—a protean escape behavior that makes rabbits much harder to catch. Like the moth, the rabbit probably evolved special brain mechanisms to randomize its escape path.

Protean escape is probably the most widespread and successful adaptation against being eaten by predators, and is used by virtually all mobile animals on land, under water, and in the air. Proteanism explains why it is harder to predict the movements of a common housefly for the next ten seconds than the orbit of Saturn for the next ten million years. Yet there is more to proteanism than escape behavior. The effectiveness of almost any behavior can be enhanced by making its details unpredictable to evolutionary opponents. For example, predators also use proteanism to confuse prey. When a weasel is stalking a vole, it may do a "crazy dance." The weasel jumps about like a mad thing, chases its tail, shakes its head, licks its feet, all the while positioning itself closer and closer to its bemused prey. The seemingly pointless series of weird actions baffles the vole. The vole is caught in a web of confusion. Australian aborigine hunters did similar wild dances to mesmerize the kangaroos they hunted. Perhaps our hominid ancestors did too.

Animal play behavior also reveals the importance of proteanism. Most animal play is play-chasing and play-fighting. At the level of movement patterns, play is a way of practicing pursuit and evasion. But at the psychological level, it is a way of practicing prediction and proteanism.

Unpredictability can be useful at many levels. When threatened, octopuses and cuttlefish use "color convulsions."

Their pigmented skin cells, which are under direct control of the nervous system, display an unpredictable series of color patterns to confound the perceptual expectations of predators. One moment the cuttlefish has black stripes, the next it has red spots, which makes it hard for predators to keep in mind what they're supposed to be chasing. The lesson of proteanism is very general: whenever one animal benefits from being able to predict something about another animal's behavior or appearance, the second animal might benefit from making its behavior or appearance unpredictable.

Proteanism Versus Science

Proteanism may be one reason why the behavioral sciences are so much better at description than prediction. We can sometimes explain behavior after the fact, and can often make statistical predictions about average future behavior. But it is almost impossible to predict whether a particular rabbit in a particular situation will hop left or right.

The physical sciences offer many examples of unpredictability, but it is usually there by accident, not design. Quantum theory accepted the "noisiness" of elementary particles. But it did not assume that the randomness was put there just to frustrate physicists. Chaos theory showed that the behavior of many systems is very sensitive to the starting conditions. Many systems that unfold deterministically over the short term become unpredictable over the long term. But chaos theory does not attribute any strategic intention to chaotic systems. The behavioral sciences have tried to follow the physical sciences in this regard, viewing unpredictability as noise. If the same animal in the same situation does different things on different occasions, this is usually considered to be behavioral "noise." Yet that is exactly what moths and rabbits evolved to do—avoiding predators through unpredictability Psychology's favorite brand of statistics, called the analysis of variance, assumes that all behavior can be explained as the interaction of environmental determinants and random, non-adaptive noise. There is no place for proteanism in the analysis of

variance, because analysis of variance does not distinguish between random errors and adaptive unpredictability.

Proteanism does not fit into this framework of scientific explanation. It is both adaptive and noisy both functional and unpredictable—like human creativity. The difficulty of predicting animal behavior may be much more than a side-effect of the complexity of animal brains. Rather, the unpredictability may result from those brains having been selected over evolutionary history to baffle and surprise all of the would-be psychologists who preceded us. To appreciate why psychology is hard, we have to stop thinking of brains as physical systems full of quantum noise and chaos, or as computational systems full of informational noise and software bugs. We have to start thinking of brains as biological systems that evolved to generate certain kinds of adaptive unpredictability under certain conditions of competition and courtship. If you're not looking for proteanism, you won't find it.

How Proteanism Works

Proteanism does not imply that all of your brain cells are firing randomly in total cortical anarchy. The randomness is injected into your behavior at a particular level appropriate to the situation. If you are fleeing "randomly," your trajectory through the environment may be unpredictable. But you are still maintaining order at many other levels: coordinated nerve firings to activate muscles, coordinated muscle movements to power limbs, coordinated limb movements to maintain an efficient gait, and eye-foot coordination to avoid obstacles. Proteanism implies the strategic ability to use randomness just when it is needed to make yourself unpredictable. It does not imply a masochistic enslavement to Fortuna, the pagan goddess of chance. Here proteanism foreshadows human creativity, since creativity implies the strategic use of novelty to achieve a social effect, not the random combination of random ideas in a chaotic style.

A capacity for proteanism in one situation does not imply an ability to act like a random number generator in all situations.

Psychologists have tested human capacities for "randomness" since the 1950s, but they have usually given paper-and-pencil tests that do not tap into natural proteanism abilities. For example, when people are asked to write down a random series of "heads" or "tails" on paper, they fail statistical tests of randomness: they alternate too much (heads, tails, heads, tails) and do not produce enough long runs (heads, heads, heads, heads). By the mid-1970s, after dozens of experiments on the generation of random series, psychologists came to believe that people are hopelessly bad at randomizing their responses.

However, these tests did not usually provide any incentives to behave randomly. When incentives are provided, people do rather better. In the 1980s, psychologist Alan Neuringer found that rats and people can produce almost perfectly random sequences when given good feedback and good incentives for performance. Also, the social situation matters. Amnon Rapoport and David Budescu found that when people play Matching Pennies for real money, they get very good at randomizing very quickly. You do not even have to tell them to randomize. They just do it naturally, to be unpredictable.

When I give talks on protean behavior, I usually ask two members of the audience to play Matching Pounds. This is like Matching Pennies, but played for higher stakes: British £1 coins. I give the players ten pounds each, and they can walk away with whatever they win after they have played ten rounds. The chance to win as much as £10 in five minutes concentrates the minds of British academics wonderfully. The resulting drama of prediction, counterprediction, greed, fear, frustration, and incredulity is something to behold. I do not instruct the players to behave randomly; they just figure out that they had better do so. Those who alternate too predictably between heads and tails quickly lose
£3
or
£4
to their opponents. Most players learn that it is much easier just to randomize than to try to out-predict one's opponent. Our innate capacities for proteanism reveal themselves only in strategic situations where unpredictability becomes important to behavior.

Normal people can randomize pretty well, but autistic people cannot. Psychologist Simon Baron-Cohen found that people with autism are very poor at randomizing their strategies in games like Matching Pennies. He suggested this was because they lack the "theory of mind" that ordinary people use to understand the beliefs and desires of other people. Autistic people seem unable to realize that other people can form predictions about what they will do next, so they usually alternate heads and tails in a totally predictable way. Randomizing your strategies in new situations seems to require the ability to understand that opponents are trying to predict your moves. Of course, rabbits don't need to understand fox minds in order to zigzag unpredictably, because the rabbits evolved brain circuits dedicated to playing the evolutionarily ancient game of pursuit and evasion. They do not need a theory of mind in order to zigzag when frightened. A theory of mind may be required for proteanism only when we are playing evolutionarily novel games such as Matching Pennies.

Protean Primates Versus Machiavellian Mind-Readers

In the 1990s primate researchers became enthusiastic about the idea of Machiavellian intelligence—the ability that apes and humans have evolved for predicting and manipulating the behavior of other individuals. Apes and humans live in social groups where one's survival and reproduction prospects depend on one's social relationships. Once primatologists understood evolution from the selfish-gene viewpoint, they saw social interaction in a new light. Before, social behavior was thought to be for "pair-bonding" and "group cohesion." Now, it became viewed as a strategic game of politics, alliances, reciprocity, kinship, aggression, and peacemaking. A key to success in these strategic games is the ability to predict the behavior of other individuals. The Machiavellian intelligence theory suggests that great apes evolved larger brains and higher intelligence to better predict one another's behavior.

Suppose this view is right. Would evolution stop there, with everyone able to predict and manipulate everyone else's

behavior? Or would counter-strategies evolve? In a society of Machiavellian psychoanalysts, individuals that are harder to predict and manipulate would have the usual protean advantages.

In their important 1984 paper on "mind-reading and manipulation," John Krebs and Richard Dawkins identified only two defenses an animal might use against having its actions predicted by an opponent: concealment and deception. You can try to hide your intentions (the poker-face strategy), or you can create a false impression about your intentions (the bluffing strategy). However, they overlooked the classic third option: randomness. The protean strategy. Doubtless each of these strategies is useful under particular conditions, and in a species with high Machiavellian intelligence, all of them would evolve. However, the protean strategy has one big advantage: it stops prediction dead in its tracks. The poker-face and bluffing strategies remain vulnerable to the evolution of better intention-sensing and deception-foiling abilities. But there is no way to improve prediction when you meet genuine randomness.

The Mad Dog Strategy

Despots throughout history have often used a form of social proteanism to maintain power. They have unpredictable rages that terrify subordinates. Caligula, Hitler, and Joan Crawford were all alleged to have increased their power over underlings through this "mad dog strategy," which keeps subordinates in line by imposing stressful levels of uncertainty on them.

Imagine a despot who had a fixed threshold for getting angry. Subordinates could quickly learn that threshold and do anything just below the anger threshold with impunity. If King Arthur only got upset by knights actually having sex with Queen Guinevere, the knights could still court her, kiss her, and plot with her. But if Arthur's anger-threshold was a random variable that changed every day, subordinates could never be sure what they could get away with. Maybe he was happy for them to carry her flag at the joust yesterday, but maybe he will chop off their heads for even looking at her today.

Against the mad dog strategy, any insult, however slight, risks retaliation. But mad dog despots don't incur the time and energy costs of having a fixed low anger threshold—the uncertainty does most of the work of intimidating subordinates. Despotism is the power of
arbitrary
life and death over subordinates. If a despot can't kill people at random, he isn't a real despot. And if he doesn't kill people at random, he probably can't retain his despotic status. Social proteanism lies at the root of despotic power.

The mad dog strategy is just the most dramatic example of how unpredictability can bring social benefits. The advantages of an unpredictable punishment threshold also apply to sexual jealousy, group warfare, and moralistic aggression to punish antisocial behavior. Fickleness, moodiness, inconstancy, and whimsy may be other manifestations of social proteanism. However, we need more research on human and ape capacities for adaptively unpredictable social behavior. Given the importance of mixed strategies in game theory, and the fact that many social interactions can be interpreted as games, it would be surprising if randomized behaviors did not play a large role in human social interaction.

If great apes differ from monkeys in having better social prediction abilities, it seems likely that they would also have evolved better social proteanism abilities to avoid being predictable. How does this relate to human creativity? The mad dog strategy sounds sexually repulsive, not the sort of behavior that sexual choice might favor. Yet I shall argue that the same capacities for strategic randomization that underlie the mad dog strategy were transformed, through sexual selection, into our human capacities for creativity, wit, and humor. There are at least three ways that social proteanism may have smoothed the way for human creativity to evolve. One has to do with the brain mechanisms underlying creativity, the second with sexually selected indicators of proteanism ability, and the third with playfulness as an indicator of youthfulness.