Though theories of mate selection and reciprocal altruism are interesting, they are not the most important contribution of evolutionary psychology. The most important contribution is a new view of the human mind.
The harbinger of the breakthrough was a series of elegant experiments done in the 1960s by the psychologist John Garcia and his colleagues. The subjects were not humans but rats; the procedure was a variation on Pavlov’s. Pavlov found that it was possible to train dogs to salivate at a signal—say, the sound of a bell—by presenting the signal and then giving them food. The linkage in time between the sound of the bell and the taste of food resulted in what American psychologists called a “conditioned reflex.” The assumption that Pavlov made—and that most American psychologists never questioned—was that any arbitrary stimulus can be associated with any innate reflex to produce conditioning.
Garcia showed that Pavlov’s assumption was wrong. He demonstrated that rats quickly learn to associate a particular taste (water sweetened with saccharine) with nausea induced by exposure to X-rays, even though the X-ray-induced illness occurs hours after they drink the water. The result of this association is that the rats develop an aversion to sweetened water, despite the fact that the water was not what caused their nausea. They can also learn that when a certain light goes on, it is a warning that they’re about to receive a painful electric shock to the feet. But they do not learn to avoid the sweetened water if drinking it is followed by a shock, and they do not learn to avoid water associated with the light if drinking it is followed by an upset stomach.20
Garcia and his coauthors had a good deal of trouble getting their research published; they were turned down by journal after journal. A traditional behaviorist expressed the opinion that Garcia’s findings were “no more likely than birdshit in a cuckoo clock.”21 But the findings held up to repeated tests. Nonhuman animals, and humans too, learn certain associations more readily than others, and the associations they learn make sense. It makes sense to expect dinner when you hear the dinner bell. It also makes sense that if dinner includes some kind of food you’ve never had before, and you eat it and a little while later get sick to your stomach, you will (rightly or wrongly) associate your nausea with that food and thereafter avoid it. A single bad experience can put you off a food forever.
Garcia’s rats were just the beginning. A growing assortment of research, mostly with humans, led to the same conclusion: that the vertebrate brain is not equally disposed to perform all kinds of learning tasks. Some associations are made readily, some only with difficulty, some not at all. The human mind is poised—prepared in advance—to learn certain things with dazzling ease and speed.
The best example is language. It was Noam Chomsky who argued that language is in fact an extremely difficult thing to learn from the skimpy and imperfect examples of it that babies hear, and that in order to learn it as quickly and competently as they do, human babies must have a special aptitude for learning language. But it was Steven Pinker who turned Chomsky’s “Language Acquisition Device” (a hypothetical mechanism in the brain) into something the rest of us could understand, and who linked the theory to the brand new field—this was the early 1990s—of evolutionary psychology. Here’s what Pinker said in The Language Instinct:
Language is not a cultural artifact that we learn the way we learn to tell time or how the federal government works. Instead, it is a distinct piece of the biological makeup of our brains. Language is a complex, specialized skill, which develops in the child spontaneously, without conscious effort or formal instruction, is deployed without awareness of its underlying logic, is qualitatively the same in every individual, and is distinct from more general abilities to process information or behave intelligently. For these reasons some cognitive scientists have described language as a psychological faculty, a mental organ, a neural system, and a computational module. But I prefer the admittedly quaint term “instinct.” It conveys the idea that people know how to talk in more or less the sense that spiders know how to spin.22
Language is only one of many special abilities, some of which we share with other species, that humans are provided with. Evolutionary psychologists believe that the human mind is full of devices—mental organs or mechanisms or instincts—that were designed by evolution to perform special tasks. The mind is not like the mythical kitchen gadget that can do anything. It is a collection of specialized gadgets: one for cutting up the onions, another for frying them in, a third to keep you from burning your hand on the thing you fry them in.
Mental organs or mechanisms provide the wherewithal to accomplish jobs that, during the evolution of a species, were important to the members of that species. In many cases the devices also provide the motivation to do these jobs. Babies do not have to be rewarded, or even encouraged, to learn language: they are born wanting to learn it. They are predisposed from Day 1 to listen to human speech and to try to make sense out of it.
Another thing humans are good at is identifying individuals and telling them apart. It’s not just a matter of distinguishing males from females, or nubile females from those who are too young or too old: we recognize and remember specific people. “Humans are obsessed with individuals,” Pinker noted.23 I propose that members of our species are equipped with a mental device dedicated to this purpose and that this mental device supplies its own motivation. Just as babies are born wanting to learn the language, they are born with a tremendous interest in learning to tell people apart. From birth they stare avidly at faces; from birth—or even before—they listen avidly to voices. A very young baby can recognize his mother by looking at her face or hearing her voice.24 He can see or hear his sister, or his aunt, or the babysitter, and know that she is someone else—not his mother.
The human brain is about nine times larger, relative to body size, than that of a typical mammal. Why do we have such big brains? A number of explanations have been offered; many of them probably contain at least a grain of truth. Though possessing a big brain has some serious disadvantages, being smart has some even more serious advantages. Homo sapiens didn’t colonize the earth and become the master of most of its other species through brute force. In the brute force department, humans, taken singly, are pathetic. Richard III died, according to Shakespeare, because he didn’t have a horse.
Robin Dunbar, a British evolutionary psychologist, believes that brains got larger during hominid evolution because of the need to collect and store social information. Most species of monkeys and apes (orangutans are the notable exception) are highly social animals; they live in groups. Living in groups enabled them to survive in a hostile environment, even though, taken singly, most primates are pathetic in the brute force department. Our ancestors made a point of not being taken singly. Those who didn’t do well in groups didn’t become our ancestors.
But for a primate, doing well in groups involves more than sticking together for protection against predators. Within a primate group, there is a complex network of coalitions and enmities, of paid and unpaid obligations and affronts. Living successfully in a group means being aware of who is friends with whom, who is enemies with whom, who can beat up whom. If Clyde gets mad at you, not only do you have to watch out for Clyde—you also have to watch out for Clyde’s friend Jake. You are less likely to get beaten up by Clyde and Jake if you can enlist the aid of an ally who ranks higher in the pecking order than they do.
The bigger the group, the more individuals and relationships between individuals you have to keep track of. Dunbar discovered that there is a strong correlation between the size of a primate’s group—the typical group size for a given species—and the size of the neocortex for that species. The neocortex, the layer of brain cells just beneath the skull, is, as Dunbar put it, “what you might call the ‘thinking’ part of the brain.”25 With a few exceptions (the orangutan again), primates that have larger neocortices tend to associate in larger groups.
Armed with this correlation, Dunbar went on to calculate the natural group size
for humans, based on the average size of the human neocortex. The answer he got was 150.
Today humans are found almost everywhere on our planet, in great numbers in some places. But until quite recently, Homo sapiens was a relatively uncommon species. Until our ancestors invented agriculture—a mere ten thousand years ago, only yesterday in evolutionary time—they lived a catch-as-catch-can existence as hunters and gatherers. It takes a lot of land to support a hunting and gathering lifestyle, so their groups tended to be smallish and thinly spread. For hundreds of thousands of years, our human and prehuman hominid ancestors lived and traveled together in small groups. Based on what we know from studies of surviving hunter-gatherer and tribal peoples, these groups were probably somewhat unstable. Small groups would coalesce, perhaps temporarily; larger ones would split in two. Individuals or families would occasionally switch from one group to another.
As Dunbar explained, hunter-gatherer and tribal societies are organized in tiers. At the bottom are temporary “overnight” groups of 30 or 35 people who travel together for a while. At the top is the tribe, a linguistic group that speaks the same language or dialect and typically numbers about 1,500 to 2,000 people. In between is the clan, which averages about 150. This, Dunbar believes, is the natural group size for humans, and he found other examples to support his claim. The villages of the earliest farmers. The optimal size for business organizations or church congregations or military fighting units. The maximum size of Hutterite communities. The Hutterites (a religious group that practices communal farming) divide their communities in two when their size exceeds 150 people. According to Dunbar, they’ve found that above this number it becomes more difficult to maintain compliance to the sect’s rules.26
The inhabitants of a community of 150 or less all know one another. They know everyone’s name and face; they can recite everyone’s ancestry and life history. And they have opinions about everyone’s personality. The members of an Eskimo group in northwest Alaska told an anthropologist that in the old days incorrigible troublemakers were quietly pushed off the ice.27 The opinion that a man is an incorrigible troublemaker is an opinion about his personality. It is also a prediction about his future behavior: this man will continue to make trouble if somebody doesn’t stop him.
Among the special-purpose devices with which evolution has provided our species is a face-recognition module. Neuroscientists found it fairly easy to demonstrate that this device is modular because most of its wiring happens to be located in one place in the brain. There is no necessity for a brain mechanism that performs a particular task to be localized in one small area of the brain—some mental mechanisms have widespread components—but localized mechanisms are easier to study. Did you ever hear of the man who mistook his wife for a hat? His face-recognition module was so badly damaged that he couldn’t even tell the difference between a human face and an object.28 More commonly, damage to the face-recognition area of the brain results in recognizing that something is a human face but not knowing whose face it is. A person with this disability, called prosopagnosia, doesn’t ordinarily mistake his wife for a hat: he mistakes her for a stranger. Even his own face in the mirror is unfamiliar to him. He hasn’t only forgotten faces he already knew: he is unable to learn new ones.29
One of the remarkable things about the neurologically intact human brain is how many new faces it is able to learn. “The human features and countenance, although composed of but some ten parts or little more, are so fashioned that among so many thousands of men there are no two in existence who cannot be distinguished from one another,” said Pliny the Elder, back in the days when thousands seemed like a large number.30 Pliny wasn’t claiming that he himself could distinguish each of these thousands of men from all the others, but he clearly felt that he could do so, given the opportunity.
The inhabitants of modern industrialized nations are given that opportunity. They live, work, and go to school in places where there are hundreds of people. Every time they change schools or jobs or residences, they meet a whole new set. Television, movies, newspapers, magazines, books, and the Internet bring them still more faces. They can remember and identify an amazing number of them. If the students who took part in the experiment with the nice or nasty grad student met her in the supermarket a month later, most of them would recognize her.
If our brains were constructed to enable us to live in groups of 150, how come so much storage space was provided? There appears to be no limit to how many new faces we can learn. No limit to our ability to collect and store other information to go with those faces—their names, or where you encountered them, or whether they are nice or nasty.
Unlike the language acquisition device, which did its best work before your twelfth birthday and then rested on its laurels, your people-information acquisition device will keep chugging away all through your life. I am sixty-seven years old and in poor health; often a week will go by in which the only people I see in person are my husband and the woman who cleans our house. But about five years ago I developed an interest in watching professional golf tournaments on TV. Today I printed out a list of the top two hundred of the world’s male golfers and found that I can mentally call up a face for at least seventy of them, including twenty-three of the top twenty-five. I can also tell you other things about many of them. This one spends long hours on the practice range; that one is lazy. This one just got married; that one has two kids. This one wears his emotions on his sleeve; that one keeps them well buttoned up.
What’s the point of learning all this stuff? Why am I wasting my brain cells on this useless information? I’m never going to run into Tiger Woods or Ernie Els in the supermarket!
But I’ve found it enjoyable to acquire this useless information and in this respect I’m by no means unusual. It is to serve this acquisitive drive that magazines fill their pages with articles about people and photographs of their faces, and bookstores load their shelves with biographies and autobiographies of real people and novels about fictional ones. In the “A” Is for Alibi series, detective Kinsey Millhone reveals a little more about herself in each new mystery; she keeps her readers coming back for more. In The Daughter of Time, Alan Grant spends hours in his hospital bed gazing at a portrait of Richard III. “I want to know,” he explains, “what made him tick.”31
I’ve seen that portrait; it’s reproduced in a little book I own, The Kings and Queens of Britain, by Sir George Bellew. To me, Richard looks worried and a little sad, as though he already had an inkling that his cry for a horse would go unanswered. But according to Sir George, “This portrait gives more than a hint of the unscrupulous nature of Richard III.”32
Not to me it doesn’t, and not to Alan Grant. Grant thought Richard looked like a saint. But remembering faces is a lot easier than deciphering them. “There’s no art,” said Shakespeare, “to find the mind’s construction in the face.”33 Shakespeare didn’t mean that it’s easy to read people’s minds by looking at their faces; he meant just the opposite. Those words are spoken in Macbeth by a character expressing his dismay that someone he trusted had turned out to be a traitor.
We want to know what makes people tick. Not just people in general: we want to know what makes particular people tick, because people don’t all tick alike. We are fascinated by the differences among people because our brains are built that way. And they’re built that way for a reason: during the evolutionary history of our species it paid off to know what makes particular individuals tick, because it made it easier to predict their behavior. To decide whether to share with them, to mate with them, to trust them, to fear them. The proposal—not the only one I will make in this book—that the human brain contains a specialized mechanism for collecting people-information is consistent with the principles of evolutionary psychology.
The people-information acquisition device not only does the work of collecting the information: it also provides the motivation to do so. It makes collecting people-information something we do without effort or training and w
ithout the expectation of reward: doing it is its own reward. The face-recognition module is one component of this mechanism, but not an essential component. We store information about people even if we don’t have a face to attach it to. I have no mental image of Kinsey Millhone’s face. Nor do you, I daresay, but you may nonetheless remember that she runs to keep fit, lives in California, and is currently unattached.
Though the people-information acquisition device is part of our innate equipment, its innateness doesn’t imply that we’re all exactly alike in this respect. Just as the desire to engage in sex, or take care of a baby, or learn the meaning of a new word varies from one individual to another, so does the interest in acquiring people-information. There are individuals—the journalist Malcolm Gladwell calls them “Connectors”—who are champion collectors of people-information. But even ordinary people possess huge stores of such information. Gladwell has devised a test that he has given to hundreds of people. The test consists of a list of about 250 surnames, some common, some rare. Here are the first 50 names on the list:
Algazi, Alvarez, Alpern, Ametrano, Andrews, Aran, Arnstein, Ashford, Bailey, Ballout, Bamberger, Baptista, Barr, Barrows, Baskerville, Bassiri, Bell, Bokgese, Brandao, Bravo, Brooke, Brightman, Billy, Blau, Bohen, Bohn, Borsuk, Brendle, Butler, Calle, Cantwell, Carrell, Chinlund, Cirker, Cohen, Collas, Couch, Callegher, Calcaterra, Cook, Carey, Cassell, Chen, Chung, Clarke, Cohn, Carton, Crowley, Curbelo, Dellamanna.34
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