The Set Within the Skull

If you want to find schizophrenia, go to a psychology department. Not among the staff (although some do seem to hear voices inaudible to the rest of us) but within the subject. It has gone from describing varieties of religious experience to censusing them, from phrenology to scanning brains and DNA, and at last—coming full circle—to explaining belief in Darwinian terms. Psychology is a journey from the arts to the sciences and back again.

How the Mind Works is a route map across the Great Divide, an ambitious attempt to explain how we act, think, and feel in terms of cognitive science. Steven Pinker believes that the voyage of discovery is more or less complete; or, at least, we have got about as far as we will. In spite of an escape clause of the kind familiar to consumers of health foods (“We don’t understand how the mind works”), his agenda is clear. It is presented in the forceful manner expected of the author of The Language Instinct. The mind works in a particular way, he says, because of evolution.

The mind is almost as hard to define as the soul. Four years after The Origin of Species, the Reverend Charles Kingsley was the first to use evolution to metaphysical ends: in The Water Babies a drowned chimney sweep is reborn, meets Darwin and Huxley, and evolves a moral sense lacking in his earthly self. After all, if evolution could produce that miracle, the Englishman, why could it not produce the greater miracle, the soul? Ethics, religion, and science were neatly reconciled.

Steven Pinker transcends the Water Babies school of brain science, but in some places only just. He is as keen on what evolution can do as was Charles Kingsley. That, in the broad sense, the mind evolved is not at all surprising. It had as little choice in the matter as did the kidney. Because of evolution, the parent of creatures as unlikely as the tree-kangaroo and the AIDS virus, the human brain does unexpected and at first sight mysterious things. Those who study it have long ignored its past: according to this book, “the study of the mind is still mostly Darwin-free, sometimes defiantly so.”

Pinker does his best to put the balance right. To demystify the mysteries of seeing, gambling, laughing, and (possibly) falling in love we need to understand the brain’s antecedents. History may not contain everything the brain does, but it defines the limits within which it is obliged to work. Take those irritating “magic eye” books that at first sight seem just a set of textured pages. Suddenly, from each a giraffe or a racing car pops out. They come from our ability to see in stereo, perhaps a relic of a life surrounded by millions of identical leaves from which a juicy insect had to be distinguished.

Is Pinker’s—notably daring—title sensible, or does it promise too much? How, for example, does television work? To a child it is obvious: press the button and it comes on. An adult has a deeper understanding, and an engineer knows how to fix it. Ask an executive and there is another response. The hard-faced men who did well out of Mrs. Thatcher understand why sports programs on British TV rake in millions when they used to be free. A producer would talk of continuity or cameras. Only a small or unduly stupid child thinks that the actors are behind the screen, but the popularity of TV and movie theme parks shows that many viewers find it hard to separate image from reality.

The Simpsons works because, inter alia, American viewers are not as stupid as advertisers once assumed, because its creator has marvelous talent, because Rupert Murdoch hyped the series in his newspapers, and because the brain can be fooled into thinking that a series of still pictures is a moving image. None of those facts alone is enough to understand its success.

How the Mind Works, though, attempts a universal exegesis of the set within the skull, a mental theory of everything. Such a doctrine may soon appear for physics (or so some physicists proclaim) but it must surely be far away for psychology. As a result How the Mind Works is two, if not more, different books. The first, an exploration of cognitive science, succeeds. The second, in which human nature—human society, indeed—is explained by natural selection, is less persuasive. It is worth remembering that Darwin himself, cautious as always, wrote in 1859: “I have nothing to do with the origin of the primary mental powers, any more than with life itself.”

Pinker is an entertaining guide to the workings of what he calls the “connectoplasm” that makes us what we are. To him, psychology is engineering in reverse: if you understand the structure of the brain, you have at least a hope of comprehending why it thinks. There is much on neural networks, on brain damage, on illusion, even on consciousness. Some is familiar, most not; and all is explained with energy and style.

The brain is the ultimate lying machine. Television, whatever its weaknesses, is at least honest. Switch it on, and it bursts into color. We all know that those myriad hues are based on three simple pigments, red, blue and green. Together, that makes white—elementary physics. Where, though, do the black parts of the picture come from? The screen, switched off, is dim gray, not coal black. The brain copes, Pinker explains, by telling fibs: it fills in black instead of gray where it expects it to be.

Having a dishonest body part leads to both problems and opportunities. The brain is immeasurably more complex than anything made by man (as indeed is the tongue). No computer could list the facts we know without noticing: that when Edna goes to church, her head goes with her, or that zebras in the wild never wear underwear. No computer has common sense: if there’s a bag in your car with a gallon of milk in it, there’s a gallon of milk in your car, but if you—with your gallon of blood—were to get in, it would seem odd to you (but not to the most advanced analytical engine) to say that there is a gallon of blood in the driver’s seat.

Pinker’s book ranges widely in its search for the nature of thought. Fossils, artificial intelligence, Dr. Strangelove, binocular vision, literature, kibbutzim, all (perhaps too much) human life is there. Most of it, it seems, is explainable by Darwin. On the way through the neural jungle, Pinker comes up with an endless series of extraordinary facts. We find crumpled balls of paper to be the same, although their shapes are very different, but faces to be different, although their shapes are almost the same. A simple calculation based on the average numbers of words per sentence and the number of choices that could sensibly be made for each word shows that there are a hundred times more meaningful sentences than the number of seconds since the beginning of the universe. Altruism is simple: in the absence of refrigerators, the best place for a hunter to store meat is in the bodies of other hunters, who will then be able to kill, and share, the next meal. Sixty-two percent of toddlers will eat imitation dog feces crafted from peanut butter and odorous cheese.

The strength of How the Mind Works is in its deconstruction of the mechanism of the brain from the evidence of what it can and cannot do. Much of it is straight science. The explanation of the mind’s eye—three-dimensional vision—is the clearest I know, but pulls few punches. Why is turning a photograph upside down immediately apparent, while switching it left to right is scarcely noticed? Read this book (with considerable concentration) to find out.

In any discussion of the mind, the arts faculty gets a say. It is odd that physics and chemistry make do with scientists, while psychology needs Thinkers. Steven Pinker, quite rightly, sees himself as among the former group; but in his book the thinkers get a look-in. In general, they are not much help. Pinker uses humor (much of it Jewish and all of it funny) to illustrate his more ticklish points. Another story comes to mind. Two American Jews go into a nightclub in Tel Aviv to find a comic making cracks in Hebrew to an appreciative audience. One of the Americans breaks into uproarious laughter. The other asks him—as neither speaks He-brew—why he is laughing. “Why not?” he answers. “I trust these people.”

That is the essence of science. Even though I do not understand quantum mechanics or the nerve cell membrane, I trust those who do. Most scientists are quite ignorant about most sciences, but all use a shared grammar that allows them to recognize their craft when they see it. The motto of the Royal Society of London is Nullius in verba: trust not in words. Observation and experiment are what count, not opinion and introspection. The study of the mind has been invaded by both. Few working scientists have much sympathy for those who try to interpret nature in metaphysical terms. For most wearers of white coats, philosophy is to science as pornography is to sex: it is cheaper, easier, and some people seem, bafflingly, to prefer it. Outside psychology it plays almost no part in the functions of the research machine.

Brain scientists—Steven Pinker included—are defensive about their flirtation with the mystics. They know that they cannot afford a relationship with their subject as austere as that of the physicist Lord Rutherford with his; he claimed that “if your experiment needs statistics, you should have done a better experiment.” Even biologists see that as unfair; in the messy world of real life, statistics reveal the general through the mists of the particular. Psychologists, with minds of their own to deal with, may need yet another level of explanation. The cynical view that if their science needs philosophy they should do better science is less than reasonable. It may mean, though, that large parts of their enterprise are for the time being beyond the limits of science altogether.

As Pinker says, to interpret the brain too literally from the behavior of its owners would be to argue that rocks are smarter than cats because rocks always go away when you kick them. Some questions of the mind remain unanswered and perhaps unanswerable. When it comes to “What is it like to be a bat?” or (as much debated by those who believe in things called qualia, subjective experiences of, for instance, color) “Might your experience of red be the same as my experience of green?” Pinker is refreshingly frank—he admits that it “beats the heck out of me.” If others wish to coin words to describe things of that kind, so what? That is what the arts faculty is for.

Pinker has a tendency to overreact to the mass of sterile verbiage which once surrounded (or constituted) his subject. As a result he has a matching inclination to overbiologize the human race. The Freudian claim that the incest taboo arises from an unconscious desire to mate with a relative is a classic example of trusting in words: there is no evidence of any kind that it is true. Pinker’s own claim, that it is a Darwinian evolutionary strategy to avoid the birth of damaged children, is itself a gene too far. Humans are not particularly prone to inbreeding or much subject to its dire effects. We are, of course, all related. Even Mrs. Thatcher and John Major, never close friends, are fifth cousins. Both descend from John Crust, an eighteenth-century Lincolnshire farmer (the present Mr. Crust is a country and western singer whose “I’ve Burned All My Bridges on the Road to No Return” made it to the charts). In Europe, the average marriage is between sixth cousins.

The genetic effects of close liaison are small. The increase in the death rate of offspring of cousins compared to that of unrelated parents is only 4 percent, of sibs perhaps twice as much. In an age when most children died of disease or starvation anyway, that would scarcely be noticed. Incest taboos extend much further than can be explained by biology. In the eleventh century, the Church stretched the ban to include fifth cousins. Their agenda was not scientific, but social. Many people were forced to stay celibate (giving rise to the proverb that “Even the Devil disapproves of unnatural vice, except in Alsace”) and to leave their wealth to their Church rather than to their children.

And does Steven Pinker really believe that the biggest influence that parents have on their children is at the moment of conception, through a coalition of two lengths of DNA? If he does, he is unique among the middle classes who, in spite of their trust in genes, IQ, and The Bell Curve, insist on sending their offspring to private schools. His claim comes from the finding that identical twins (who share all their genes) are more similar in personality than are nonidentical twins, who hold only half their DNA in common. It seems simple. But, because they may share a placenta, identicals have a tougher existence before birth. This pushes them away from the norm in many ways, which means that, for environmental rather than genetic reasons, they become similar, neatly fooling those who believe that personality lies in the cell nucleus.

Pinker treats the mind as other biologists treat the kidney. His thesis is clear: “The mind is a system of organs of computation designed by natural selection to solve the problems faced by our ancestors in their foraging way of life.” Perhaps it is, but to treat thought as an upbeat version of making water runs into the problems that haunt those who work on less pretentious organs. Evolution has a grammar of its own which applies to whatever structure is being studied. Any argument that is—like Pinker’s—based on comparing different creatures must defer to it.

His book makes much of the fact that the mind works in a certain way because for 99 percent of our evolution we were hunter-gatherers. That seems fair but is not, because when speculating about the past you have to know which 99 percent to choose. At one point in How the Mind Works, a female student interjects into a tutorial on sex roles the heartfelt statement that “Men are slime!” Well, for 99 percent of their evolution they—and women, and ostriches, and cacti—were. Our pedigree began not a hundred thousand years ago when one lineage was defined to be human, but at the origin of life four thousand million years before that. Why pick on the hunter-gatherers? Without other evidence one could as well say that human evolution began with the appearance of the cell membrane or the printing press and fit a hypothesis around those milestones instead.

To understand how far a body part—a kidney, perhaps—has come, one needs to know where it started from. For the mind that is not possible. It is for cell membranes, for kidneys, gills, breasts, or opposable thumbs, because some creatures have them and some do not. Their pattern—shared by groups who descend from a common ancestor and not by others—is a map through the past. “Shared derived characters,” as they are known, untangle the hierarchy of evolution.

The mind is different. More ethno-linguistic humor suggests why: A man goes into a Szechuan restaurant in Aberystwyth (a doggedly Welsh-speaking town) and is served by a Chinese waiter who speaks perfect Welsh. Beckoning the proprietor, the customer asks where he found this prodigy. The reply: “Keep your voice down, boyo, he thinks he’s learned English!”

In other words, from a Chinese speaker’s point of view, Welsh and English are just dialects of each other, both equally easy or difficult to understand. As members of the Indo-European family of languages, all descended from a common ancestor, this is of course true. Although English tourists find Welsh impenetrable (which is why it stays alive), the only way of testing how different it really is is to put the language into evolutionary context, with Chinese as an “outgroup” with which Welsh and its presumed relative can be compared. This shows that, bizarre though it might sound to those who cannot speak it, there is nothing special about Welsh. The pattern of shared derived characters proves that the language broke away from what became English long after Chinese separated from the Ursprache. The romantic languages split off even later (to Dumas, after all, English was just French badly pronounced). Literary fragments—fossil speech—and a few daring assumptions about the rate at which words change with time can date the separation of what became each of those tongues.

But what if there were only one world language—how would we know when it began? It would be impossible. That is the trouble with the mind. You can guess when it appeared but evolution won’t tell you; there is no outgroup, no creature possessing measurably more or less mind than us available for comparison. Did it start before the chimps broke off from the human lineage (on the way losing what little mind they had), or with the first ground-dwellers, the hunter-gatherers, the first to speak, the inventors of the printing press, or (ask any teenager) with television itself? Without an outgroup with which to compare ourselves we face the Chinese Waiter’s Paradox: we cannot know.

It took a long time for biology to wake up to that dilemma. Now it has a statistical machine to sort it out, based on the objective measurement of the affinities of different creatures. Cladistics, as it is called, has come up with some suprises. It shows that a group such as “reptiles” is unnatural: it contains lizards and crocodiles, but crocodiles are closer to birds than to their supposed companions. Shared features in cows and worms prove that the great forms of life supposed to have burst into existence during the Cambrian Explosion five and a half million years ago were born long before that. The mind, though, has no relatives and leaves no fossils. It may look like the sort of mind that would be useful to a hunter-gatherer, but without the evidence we cannot be sure.

There is another problem with the argument from evolution. Darwin’s key phrase is that “the present is the key to the past”; that the events of today—mutation, natural selection, accidental change—explain the course of biological history. That is why the first pages of The Origin are not about universals but about pigeons. Indeed, one publisher’s reader suggested that most of his manuscript should be dropped and it be turned into a book entirely on pigeon breeding: “Everyone is interested in pigeons…. The book would be reviewed in every journal in the kingdom, and would soon be on every library table.”

Darwin’s interest came from the fact that different breeds could be seen to descend from a shared ancestor through the daily efforts of fanciers. That present process could, he thought, explain not just the origin of pigeon stocks but how the birds themselves began.

There is a great snare awaiting those who use Darwinism to understand the modern world: that of reversing his formula. It is fatally easy to assume that the past must be the key to the present. That is simply not true, for the mind or anything else. Most evolutionary arguments turn on events which are enormously powerful over vast lengths of time but cannot be measured or even perceived over the instant in which we live our lives. I once released a million fruit flies into Death Valley in the hope of measuring the difference in fitness between two forms of a certain enzyme. The idea was absurd. To see any real effect needed hundreds of times as many flies for perhaps thousands of generations.

Evolution has a speedometer. It is read in Darwins, a measure of the rate of change over time. In fossil mammals, one of the most rapidly evolving of all groups, the average velocity over the past few million years was at a Darwin or so. A tiny average difference in fitness—the length of a giraffe’s neck changing by a fraction of a millimeter a generation—led to the vast diversity of mammals that surrounds us. To look for such differences among living giraffes would be a waste of time. Not to find them would say little about why they have long necks (or, for that matter, philosophers great minds). The mind, like the neck, may have evolved through something quite invisible to experimental science.

There is a matching problem. It arises from the fact that evolution has wonderful tactics but no strategy. Although there may be a long-term trend, the driver of the Darwinian machine often throws his charge into reverse. The direction in which it travels at any instant says little about what it might do in the future. What is advantageous over centuries may be harmful on a scale of decades.

Take the famous finches of the Galapagos. Fossils show that each species, with its characteristic large or small beak, has persisted more or less unchanged for thousands of years. That makes evolutionary sense since the islands have not changed much either. Experiments with marked birds, though, show that at any moment there is within each species strong selection—at a thousand Darwins and more—for one extreme of beak size or the other. In dry years (such as those that follow El Niño, the climatic shift that leads to drought and is about to break out again) birds with large beaks do better since they can crack the hard seeds that survive. In wet years, those with slender bills are favored. In most years, one form or its opposite is at a great advantage and the hopeful biologist is sure to find a difference between them. In the long term, though, as the fossils show, that is quite irrelevant and everything stays the same. A calm (or at least inconsistent) past is no key to the evolutionary turbulence of today.

For “big beak,” substitute “rape” or “cognitive thinking.” At any moment in history rape may have been biologically advantageous and cognitive thinking a disaster (or vice versa). However, this moment is not that. Even if in past ages either practice made a difference to the job of passing on the genes, that fact tells us almost nothing about their value now. We may be—we are—in an El Niño of the soul, a time against the trend, when what was once good is now bad. What once explained human behavior in evolutionary terms simply need not apply to the modern world.

Toward the end of its 565 pages, How the Mind Works begins to wander. Steven Pinker does not like socialist utopias or “the conventional wisdom of Marxists, academic feminists and café intellectuals,” and evolution gives him a reason why. He is well aware of the naturalistic fallacy that what happens in nature is right; but he veers toward its libertarian equivalent, that what is natural cannot be helped. At its worst, the book degenerates into fortune cookie mottoes. “Liking is the emotion that initiates and maintains an altruistic partnership…. Gratitude calibrates the desire to reciprocate according to the costs and benefits of the original act…. Sympathy, the desire to help those in need, may be an emotion for earning gratitude…. The love of kin comes naturally; the love of non-kin does not.” And so on.

Evolution can be as accommodating as an expensive courtesan. Having learned that personality is set at conception, we go on to hear that children in a family are different because the first- and second-born compete for attention. War arose through a desire for rape; but it is not much of a feature of modern armies because rape has been outlawed. The 44-page final chapter falls into a frenzy of over-explanation, in which art, music, fiction, politics, friendship, and religion are construed in terms of a kind of evolved phosphorescence of the brain.

All this detracts from a book which is otherwise a model of scientific writing; erudite, witty, and clear. In the rush toward reason, psychology is in danger of falling into a post-Freudian trap. In its early days it was intrigued by the idea—ludicrous in retrospect—that human society arose from the unconscious desire of sons to sleep with their mothers. Now there is a more subtle temptation; that the mind works the way it does because their great grandmothers gathered berries. They did, and that helped to form us, but the claim that it defines what we are is, like most universal explanations, unlikely to stand the test of time.

The study of the mind is still in the suburbs of science, uncertain whether to join the brutal city of experiment or to retire to the groves of comfortable dialectic. In George Eliot’s tale of provincial life, Middlemarch, set thirty years before The Origin, are two opposed characters who try, like Pinker, to produce a unitary theory of existence. The desiccated Casaubon, with his huge and unfinished Key to All Mythologies, is convinced that introspection will do the job. Dr. Lydgate represents the modern age. He knows of Bichat, the inventor of the word “tissue,” and is determined to discover its ultimate constituent. To understand that will be to comprehend everything. Dr. Lydgate would have been very happy with a DNA-sequencing machine and this book.

Lydgate was a scientist before the word was invented. For him, to understand “the basic tissue” (the connectoplasm, perhaps) was to find the key to “The Meaning of Life” (the title of Pinker’s last chapter). Casaubon had a different view. “He thought that he should prefer not to know the sources of the Nile, and that there should be some unknown regions preserved as hunting-grounds for the poetic imagination.” In spite of Steven Pinker’s excellent book, when it comes to understanding how the mind works, that imagination will be needed for some time yet.