The Blank Slate: The Modern Denial of Human Nature

by Steven Pinker

For the most part I will try not to advocate particular policies or to advance the agenda of the political left or right. I believe that controversies about policy almost always involve tradeoffs between competing values, and that science is equipped to identify the tradeoffs but not to resolve them. Many of these tradeoffs, I will show, arise from features of human nature, and by clarifying them I hope to make our collective choices, whatever they are, better informed.

Until the studies are redone with adopted children (who get only their environment, not their genes, from their parents), the data are compatible with the possibility that genes make all the difference, the possibility that parenting makes all the difference, or anything in between. Yet in almost every instance, the most extreme position—that parents are everything—is the only one researchers entertain.

Though many of my arguments will be coolly analytical—that an acknowledgment of human nature does not, logically speaking, imply the negative outcomes so many people fear—I will not try to hide my belief that they have a positive thrust as well. “Man will become better when you show him what he is like,” wrote Chekhov, and so the new sciences of human nature can help lead the way to a realistic, biologically informed humanism. They expose the psychological unity of our species beneath the superficial differences of physical appearance and parochial culture. They make us appreciate the wondrous complexity of the human mind, which we are apt to take for granted precisely because it works so well. They identify the moral intuitions that we can put to work in improving our lot. They promise a naturalness in human relationships, encouraging us to treat people in terms of how they do feel

They offer a touchstone by which we can identify suffering and oppression wherever they occur, unmasking the rationalizations of the powerful. They give us a way to see through the designs of self-appointed social reformers who would liberate us from our pleasures. They renew our appreciation for the achievements of democracy and of the rule of law. And they enhance the insights of artists and philosophers who have reflected on the human condition for millennia.

“Every man, wherever he goes, is encompassed by a cloud of comforting convictions, which move with him like flies on a summer day.”

Most Victorian gentlemen could not have imagined that the coming century would see a nation-state forged by Jewish pioneers and soldiers, a wave of African American public intellectuals, or a software industry in Bangalore. Nor could they have anticipated that women would lead nations in wars, run huge corporations, or win Nobel Prizes in science. We now know that people of both sexes and all races are capable of attaining any station in life.

Both psychology and the other social sciences, then, denied that the minds of individual people were important, but they set out in different directions from there. Psychology banished mental entities like beliefs and desires altogether and replaced them with stimuli and responses. The other social sciences located beliefs and desires in cultures and societies rather than in the heads of individual people. The different social sciences also agreed that the contents of cognition—ideas, thoughts, plans, and so on—were really phenomena of language, overt behavior that anyone could hear and write down. (Watson proposed that “thinking” really consisted of teensy movements of the mouth and throat.) But most of all they shared a dislike of instincts and evolution.

The doctrine of the superorganism has had an impact on modern life that extends well beyond the writings of social scientists. It underlies the tendency to reify “society” as a moral agent that can be blamed for sins as if it were a person. It drives identity politics, in which civil rights and political perquisites are allocated to groups rather than to individuals. And as we shall see in later chapters, it defined some of the great divides between major political systems in the twentieth century.

The unification of our understanding of life with our understanding of matter and energy was the greatest scientific achievement of the second half of the twentieth century.

The division was built into each of the doctrines of the official theory: the blank slate given by biology versus the contents inscribed by experience and culture, the nobility of the savage in the state of nature versus the corruption of social institutions, the machine following inescapable laws versus the ghost that is free to choose and to improve the human condition.

But as soon as one starts to think seriously about what kind of computation enables a system to see, think, speak, and plan, the problem with blank slates becomes all too obvious: they don’t do anything. The inscriptions will sit there forever unless something notices patterns in them, combines them with patterns learned at other times, uses the combinations to scribble new thoughts onto the slate, and reads the results to guide behavior toward goals.

Leibniz repeated the empiricist motto “There is nothing in the intellect that was not first in the senses,” then added, “except the intellect itself.”

Once one starts to think about mental software instead of physical behavior, the radical differences among human cultures become far smaller, and that leads to a fourth new idea: Universal mental mechanisms can underlie superficial variation across cultures.

We might all be equipped with a program that responds to an affront to our interests or our dignity with an unpleasant burning feeling that motivates us to punish or to exact compensation. But what counts as an affront, whether we feel it is permissible to glower in a particular setting, and what kinds of retribution we think we are entitled to, depend on our culture.

Before the revolution, commentators invoked enormous black boxes such as “the intellect” or “the understanding,” and they made sweeping pronouncements about human nature, such as that we are essentially noble or essentially nasty. But we now know that the mind is not a homogeneous orb invested with unitary powers or across-the-board traits. The mind is modular, with many parts cooperating to generate a train of thought or an organized action.

More generally, the interplay of mental systems can explain how people can entertain revenge fantasies that they never act on, or can commit adultery only in their hearts. In this way the theory of human nature coming out of the cognitive revolution has more in common with the Judeo-Christian theory of human nature, and with the psychoanalytic theory proposed by Sigmund Freud, than with behaviorism, social constructionism, and other versions of the Blank Slate.

Behavior is not just emitted or elicited, nor does it come directly out of culture or society. It comes from an internal struggle among mental modules with differing agendas and goals.

When a patch of brain tissue dies, a part of the mind can disappear: a neurological patient may lose the ability to name tools, recognize faces, anticipate the outcome of his behavior, empathize with others, or keep in mind a region of space or of his own body. (Descartes was thus wrong when he said that “the mind is entirely indivisible” and concluded that it must be completely different from the body.)

Similarly, if the patient’s left hemisphere is shown a chicken and his right hemisphere is shown a snowfall, and both hemispheres have to select a picture that goes with what they see (each using a different hand), the left hemisphere picks a claw (correctly) and the right picks a shovel (also correctly). But when the left hemisphere is asked why the whole person made those choices, it blithely says, “Oh, that’s simple. The chicken claw goes with the chicken, and you need a shovel to clean out the chicken shed.”32 The spooky part is that we have no reason to think that the baloney-generator in the patient’s left hemisphere is behaving any differently from ours as we make sense of the inclinations emanating from the rest of our brains.

Sigmund Freud immodestly wrote that “humanity has in the course of time had to endure from the hands of science three great outrages upon its naïve self-love”: the discovery that our world is not the center of the celestial spheres but rather a speck in a vast universe, the discovery that we were not specially created but instead descended from animals, and the discovery that often our conscious minds do not control how we act but merely tell us a story about our actions.

These gross features of the brain are almost certainly not sculpted by information coming in from the senses, which implies that differences in intelligence, scientific genius, sexual orientation, and impulsive violence are not entirely learned.

Identical twins are far more similar than fraternal twins, whether they are raised apart or together; identical twins raised apart are highly similar; biological siblings, whether raised together or apart, are far more similar than adoptive siblings.

“Virtual twins” are the mirror image of identical twins raised apart: they are unrelated siblings, one or both adopted, who are raised together from infancy. Though they are the same age and are growing up in the same family, the psychologist Nancy Segal found that their IQ scores are barely correlated.44 One father in the study said that despite efforts to treat them alike, the virtual twins are “like night and day.”

The slate cannot be blank if different genes can make it more or less smart, articulate, adventurous, shy, happy, conscientious, neurotic, open, introverted, giggly, spatially challenged, or likely to dip buttered toast in coffee.

An eye for beauty, for example, locks onto faces that show signs of health and fertility—just as one would predict if it had evolved to help the beholder find the fittest mate.59 The emotions of sympathy, gratitude, guilt, and anger allow people to benefit from cooperation without being exploited by liars and cheats.60 A reputation for toughness and a thirst for revenge were the best defense against aggression in a world in which one could not call 911 to summon the police.61 Children acquire spoken language instinctively but written language only by the sweat of their brow, because spoken language has been a feature of human life for tens or hundreds of millennia whereas written language is a recent and slow-spreading invention.

They may covet their neighbor’s spouse, eat themselves into an early grave, explode over minor slights, fail to love their stepchildren, rev up their bodies in response to a stressor that they cannot fight or flee, exhaust themselves keeping up with the Joneses or climbing the corporate ladder, and prefer a sexy and dangerous partner to a plain but dependable one. These personally puzzling drives have a transparent evolutionary rationale, and they suggest that the mind is packed with cravings shaped by natural selection, not with a generic desire for personal well-being.

This shared way of thinking, feeling, and living makes us look like a single tribe, which the anthropologist Donald Brown has called the Universal People, after Chomsky’s Universal Grammar.63 Hundreds of traits, from fear of snakes to logical operators, from romantic love to humorous insults, from poetry to food taboos, from exchange of goods to mourning the dead, can be found in every society ever documented.

When unwitting subjects are surrounded by confederates of the experimenter who have been paid to do something odd, many or most will go along.

Cows really should be sacred in India, he points out; they supply food (milk and butter), fuel (dung), and power (by pulling plows), so the customs protecting them thwart the temptation to kill the goose that laid the golden egg.

In the same way, our understanding of ourselves and our cultures can only be enriched by the discovery that our minds are composed of intricate neural circuits for thinking, feeling, and learning rather than blank slates, amorphous blobs, or inscrutable ghosts.

I should say at the outset that I find these latest-and-best blank-slate theories highly implausible—indeed, barely coherent. Nothing comes out of nothing, and the complexity of the brain has to come from somewhere. It cannot come from the environment alone, because the whole point of having a brain is to accomplish certain goals, and the environment has no idea what those goals are.

To one species, a snatch of human speech is a warning to flee; to another, it is an interesting new sound to incorporate into its own vocal repertoire; to a third, it is grist for grammatical analysis. Information in the world doesn’t tell you what to do with it.

If you don’t believe this, consider the roundworm Caenorhabditis elegans, which has about 18,000 genes. By the logic of the genome editorialists, it should be twice as free, be twice as diverse, and have twice as much potential as a human being.

Take the development of the body. The genes that build a femur cannot specify the exact shape of the ball on top, because the ball has to articulate with the socket in the pelvis, which is shaped by other genes, nutrition, age, and chance. So the ball and the socket adjust their shapes as they rotate against each other while the baby kicks in the womb. (We know this because experimental animals that are paralyzed while they develop end up with grossly deformed joints.)

The doctrine of extreme plasticity has used the plasticity discovered in primary sensory cortex as a metaphor for what happens elsewhere in the brain. The upshot of these two sections is that it is not a very good metaphor. If the plasticity of sensory cortex symbolized the plasticity of mental life as a whole, it should be easy to change what we don’t like about ourselves or other people.

Take a case very different from vision, sexual orientation. Most gay men feel stirrings of attraction to other males around the time of the first hormonal changes that presage puberty. No one knows why some boys become gay—genes, prenatal hormones, other biological causes, and chance may all play a role—but my point is not so much about becoming gay as about becoming straight. In the less tolerant past, unhappy gay men sometimes approached psychiatrists (and sometimes were coerced into approaching them) for help in changing their sexual orientation. Even today, some religious groups pressure their gay members to “choose” heterosexuality. Many techniques have been foisted on them: psychoanalysis, guilt mongering, and conditioning techniques that use impeccable fire-together-wire-together logic (for example, having them look at Playboy centerfolds while sexually aroused). The techniques are all failures.52 With a few dubious exceptions (which are probably instances of conscious self-control rather than a change in desire), the sexual orientation of most gay men cannot be reversed by experience. Some parts of the mind just aren’t plastic, and no discoveries about how sensory cortex gets wired will change that

As the new sciences of human nature began to flourish, it was becoming clear that thinking is a physical process, that people are not psychological clones, that the sexes differ above the neck as well as below it, that the human brain was not exempt from the process of evolution, and that people in all cultures share mental traits that might be illuminated by new ideas in evolutionary biology.

In the late 1960s the psychologist Paul Ekman discovered that smiles, frowns, sneers, grimaces, and other facial expressions were displayed and understood worldwide, even among foraging peoples with no prior contact with the West.

Among the radical scientists and the many intellectuals they have influenced, “determinism” has taken on a meaning that is diametrically opposed to its true meaning. The word is now used to refer to any claim that people have a tendency to act in certain ways in certain circumstances. It is a sign of the tenacity of the Blank Slate that a probability greater than zero is equated with a probability of 100 percent. Zero innateness is the only acceptable belief, and all departures from it are treated as equivalent.

The decimation of native Americans by European disease and genocide over five hundred years is indeed one of the great crimes of history. But it is bizarre to blame the crime on a handful of contemporary scientists struggling to document their lifestyle before it vanishes forever under the pressures of assimilation.

Self-appointed “advocates” who link the survival of native peoples to the doctrine of the Noble Savage paint themselves into a terrible corner. When the facts show otherwise they either have inadvertently weakened the case for native rights or must engage in any means necessary to suppress the facts.

One is that in the twentieth century the Blank Slate became a sacred doctrine that, in the minds of its defenders, had to be either avowed with a perfect faith or renounced in every aspect. Only such black-and-white thinking could lead people to convert the idea that some aspects of behavior are innate into the idea that all aspects of behavior are innate, or convert the proposal that genetic traits influence human affairs into the idea that they determine human affairs.

Only if the mind is required to be a scraped tablet could anyone be outraged by the claim that human nature makes us smile, rather than scowl, when we are pleased.

The idea of “biological determinism”—that genes cause behavior with 100 percent certainty—and the idea that every behavioral trait has its own gene, are obviously daft (never mind that Wilson never embraced them). So Gould’s dichotomy would seem to leave “biological potentiality” as the only reasonable choice. But what does that mean? The claim that the brain is “capable of a full range of human behaviors” is almost a tautology: how could the brain not be capable of a full range of human behaviors? And the claim that the brain is not predisposed to any human behavior is just a version of the Blank Slate. “Predisposed to none” literally means that all human behaviors have identical probabilities of occurring. So if any person anywhere on the planet has ever committed some act in some circumstance—abjuring food or sex, impaling himself with spikes, killing her child—then the brain has no predisposition to avoid that act as compared with the alternatives, such as enjoying food and sex, protecting one’s body, or cherishing one’s child.

So while Gould, Lewontin, and Rose deny that they believe in a blank slate, their concessions to evolution and genetics—that they let us eat, sleep, urinate, defecate, grow bigger than a squirrel, and bring about social change—reveal them to be empiricists more extreme than Locke himself, who at least recognized the need for an innate faculty of “understanding.”

The issue is not whether our species is “evil and destructive” but whether we house evil and destructive motives, together with the beneficent and constructive ones. If we do, one can try to understand what they are and how they work.

But if the “we” is an imperfect product of evolution—limited in knowledge and wisdom, tempted by status and power, and blinded by self-deception and delusions of moral superiority—then “we” had better think twice before constructing all that history. As the chapter on politics will explain, constitutional democracy is based on a jaundiced theory of human nature in which “we” are eternally vulnerable to arrogance and corruption. The checks and balances of democratic institutions were explicitly designed to stalemate the often dangerous

The other moral doctrine (which is found in some, but not all, Christian denominations) is that the soul enters the body at conception and leaves it at death, thereby defining who is a person with a right to life. The doctrine makes abortion, euthanasia, and the harvesting of stem cells from blastocysts equivalent to murder.

Biologists reject Behe’s argument for a number of reasons.32 His specific claims about the “irreducible complexity” of biochemistry are unproven or just wrong. He takes every phenomenon whose evolutionary history has not yet been figured out and chalks it up to design by default. When it comes to the intelligent designer, Behe suddenly jettisons all scientific scruples and does not question where the designer came from or how the designer works. And he ignores the overwhelming evidence that the process of evolution, far from being intelligent and purposeful, is wasteful and cruel.

It is not clear whether these worldly thinkers are really convinced that Darwinism is false or whether they think it is important for other people to believe it is false.