The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature (61 page)

Random Brains

Social proteanism may have provided a set of brain mechanisms for randomizing that could have been modified to play an important role in human creativity. Proteanism depends on the capacity for the rapid, unpredictable generation of highly variable alternatives. Creativity researchers agree that creativity depends on exactly this sort of mechanism, though they disagree about whether to call it "divergent thinking," "remote association," or something else. As far back as 1960, psychologist Donald Campbell insisted on the importance of randomness in creativity. He saw an analogy between creative thought and genetic evolution: both work through an interplay between "blind variation'
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and "selective retention." It is fairly clear how the brain might do the "selective retention" using well-studied aspects of judgment, evaluation, and memory. But how could the brain produce large numbers of "mutant" ideas when creativity is demanded?

Perhaps brain areas that originally evolved for proteanism were modified in the service of creativity. Instead of randomizing escape plans and social strategies, these brain areas might have been re-engineered to randomly activate and recombine ideas. As with all forms of proteanism, this random activation would happen at the appropriate level of behavior. If one is improvising jazz music, one might activate random melody fragments and very quickly sort through them using various unconscious filters. One would not activate random memories of life events, random limb movements, or random moral ideals.

It is hard to test such a theory at the moment, but it will become easier with advances in neuroscience and behavior genetics. The theory that creativity derives from proteanism suggests that some of the same brain systems should be active in playing Matching Pennies and in doing various creative tasks. It also suggests that some of the same genes associated with high randomization abilities in strategic games should also predict high creativity (after controlling for general intelligence, of course). However, this random-brain theory is not very satisfying, because it does not

identify what selection pressures favored creativity. To do that, we have to ask why evolution would favor amplified displays of the brain systems used in proteanism.

Creativity as a Display of Proteanism

A second way to connect proteanism to creativity is through indicator theory. If proteanism was important to survival and reproduction among our group-living ancestors, then mate choice would have created the usual incentives to pay attention to it. In particular, individuals who showed better social proteanism abilities should have been favored as sexual partners, because their offspring would inherit these abilities, which would confer social benefits. Once sexual selection started focusing on proteanism as a criterion for mate choice, reliable indicators of proteanism might evolve. Any social behavior that clearly demonstrated randomization ability would tend to be included in courtship.

Some forms of everyday creativity, especially humor, could be viewed as proteanism displays. They harness randomization abilities in the service of courtship, not competition. When your train of thought proves fascinatingly unpredictable to a potential mate, perhaps you are also showing that your social strategies can be devastatingly unpredictable to your social competitors. Creativity displays make unpredictability attractive, not intimidating. Perhaps creativity evolved through sexual selection as a reliable indicator of social proteanism ability.

This idea makes some of the same predictions as the first hypothesis about brain systems for randomization. It suggests that individuals who are poor at social proteanism should be poor at creativity However, I don't find this idea completely satisfactory, because social proteanism abilities may have been less important than other abilities. Given a choice between an individual good at randomizing when he attacks and a very strong individual capable of winning any attack, mate choice may favor the strong over the random. The pressures of social competition may have been strong enough to favor good proteanism abilities, but it is not clear

that they were so strong that sexual selection would have favored specific indicators of proteanism. Let's consider a third possible way to connect proteanism to creativity.

Playfulness as a Youth Indicator

Most mammals start out cute, playful, and innovative, and gradually become grim, pragmatic, and habit-ridden. Ashley Montagu and many others have observed that humans retain some aspects of juvenile playfulness longer into adulthood. This has been considered one of the prime symptoms of human "neoteny," the slowing-down of behavioral maturation relative to physical maturation. The traditional explanation for human neoteny is that slower cognitive development might permit a longer period of useful learning. Certainly there may have been good reasons for specific kinds of social learning to persist longer into adulthood over hominid evolution. But I see no reason why this would generalize into the sort of playfulness that we see in adult humans but not in adult chimpanzees.

Playfulness has large time and energy costs. Indeed, biologists struggled for a long time to identify what possible benefits could offset the costs of play behavior, even for young animals. A consensus has emerged that most animal play is practice. Play-fighting, play-chasing, and play-fleeing are ways of practicing some of the most important skills that adult animals need for competing, eating, and avoiding being eaten. But once these basic skills are mastered, what possible selection pressure could favor the retention of playfulness into adulthood?

One clue is that adult human playfulness is not uniform across all situations. When human hunter-gatherers are foraging, they do not walk playfully like John Cleese in the Monty Python "Ministry of Silly Walks" sketch. They walk along with the silent, steady efficiency of any other adult mammal making its living. But when they are socializing in a group—especially a mixed-sex group— they may very well hop, skip, jump, and do the Chicken Walk.

Playful, creative behaviors could function as indicators of

youthfulness. Their persistence into human adulthood may be not a side-effect of neoteny, but a result of direct sexual selection for youth indicators. We have already seen how large human breasts may have evolved as youth indicators. The same reasoning would work here for playfulness and creativity: if playfulness usually decreases from juveniles to older adulthood for all mammals, then playfulness may be a reliable cue of youthfulness, health, and fertility.

Playfulness is also a general fitness indicator. The energy and time costs of play were sufficient to make biologists wonder why play could ever have evolved even in young animals. These costs do not go away for adults—if anything, they increase. Juveniles have to compete only for survival, but sexually mature adults also have to compete sexually and take care of offspring. The costs of playfulness for adults with so many demands on their time and energy may be higher than the costs for juveniles. And as adults grow older, the relative energy costs of playfulness must keep increasing. Middle-aged and older adults often revert to the playfulness of youth if they fall in love again with someone new, though their playfulness does not usually show the same incandescent physical energy as that of young adults. Thus, the costs of playfulness generally increase as age increases, and this makes playfulness a potentially reliable indicator of youth, fertility, energy, and fitness.

Still, creativity is a mental capacity, whereas play is a physical manifestation of creativity. It is easy to see how running around and acting playful for several hours could be favored by sexual selection as a fitness indicator. It is less clear how the quieter forms of creativity could be favored. They are not necessarily manifest in whole-body movements. They may be displayed mostly in verbal courtship, which has low energy costs. Creativity may also be displayed in art or music, which only have moderate performance costs.

However, there is good evidence that even less physical forms of creativity can work as energy indicators. Psychologist Dean Keith Simonton found a strong relationship between creative

achievement and productive energy. Among competent professionals in any field, there appears to be a fairly constant probability of success in any given endeavor. Simonton's data show that excellent composers do not produce a higher proportion of excellent music than good composers—they simply produce a higher total number of works. People who achieve extreme success in any creative field are almost always extremely prolific. Hans Eysenck became a famous psychologist not because all of his papers were excellent, but because he wrote over a hundred books and a thousand papers, and some of them happened to be excellent. Those who write only ten papers are much less likely to strike gold with any of them. Likewise with Picasso: if you paint 14,000 paintings in your lifetime, some of them are likely to be pretty good, even if most are mediocre. Simonton's results are surprising. The constant probability-ofsuccess idea sounds very counterintuitive, and of course there are exceptions to this generalization. Yet Simonton's data on creative achievement are the most comprehensive ever collected, and in every domain that he studied, creative achievement was a good indicator of the energy, time, and motivation invested in creative activity.

Creativity and Intelligence

People's scores on psychological tests of creativity are correlated with their scores on standard intelligence tests. The correlation is moderate, but not perfect. In particular, high intelligence appears to be a necessary but not sufficient condition for high creativity. Many creativity researchers believe that people who become famous for their "creativity" usually have an IQ of at least 120. The evidence from psychological testing implies that creativity is a rather good indicator of general intelligence, not just an indicator of youthfulness and proteanism ability.

A similar story comes from behavior genetics. The heritability of creativity is fairly modest, much lower than that of general intelligence. In studies that look at both creativity and intelligence together, the heritability of creativity appears to be carried almost

entirely by the heritability of intelligence. In this respect, creativity is like vocabulary size: it looks heritable in its own right, but it is probably heritable only because it depends so strongly on general intelligence, which is highly heritable.

So, what is this "general intelligence"? I have mentioned intelligence repeatedly throughout this book as an important criterion of mate choice, but I have not discussed it explicitly in much detail. There are two reasons for this. First, intelligence research remains controversial. A few vocal critics who do not understand modern intelligence research have had an undue influence on public opinion. Despite the fact that more is known about the nature, importance, and genetics of intelligence than about almost anything else in psychology, I did not want to get side-tracked into such debates. Perhaps my ideas are already controversial enough. Second, I am still thinking about the relationships between intelligence, fitness, genes, and sexual selection. I can make some plausible guesses about how they may have interacted during human evolution, but these guesses should be taken as provisional speculations.

Perhaps what psychologists call "general intelligence" or "the
g
factor" will turn out to be a major component of biological fitness. If so, the high heritability of general intelligence may reflect, in part, the heritability of fitness itself. There are a few pieces of evidence that support a link between general intelligence and biological fitness. A recent study at the University of New Mexico found a 20 percent correlation between performance on an intelligence test and a compound measure of body symmetry. Body symmetry is often used as a proxy for heritable fitness, so this result suggests that there is a relationship between general intelligence and heritable fitness. Intelligence is also known to correlate positively with body height, physical health, longevity, and social status. These intercorrelations may arise because all these traits tap into biological fitness to some extent. Much more research needs to be done to address this question, however.

If the correlation between intelligence and fitness holds up, then any intelligence indicator may work as a reliable fitness

indicator. If that is true, then any creative behavior that depends on intelligence can work as a fitness indicator too. Cyrano's creativity may have evolved for the same reason as his vocabulary size: to advertise his fitness to potential mates.

Neophilia

Creativity may have evolved as a sexually selected indicator of

proteanism ability, youthful energy and intelligence, but that still does not explain what is distinctive about creativity. Creative

people are delightful because they are full of surprises. They produce novelty. They are unpredictable, but in a good way. To account for creativity's psychological appeal, perhaps we should consider the charms of novelty.

Neophilia, an attraction to novelty, runs deep in animal brains. Brains are prediction machines. They run an internal model of

what is happening in the world, and pay attention when the world deviates from their model. Violations of expectation attract

attention. Attention guides behavior to adjust the world to one's desires, or guides learning to adjust one's world-model to reality. Both functions of attention are crucial to the effectiveness of nervous systems as behavior-control systems, and both depend on registering violations of expectation. Sensitivity to violations of expectation can be shown even in very small, primitive nervous systems.