Smarter people will tend to float into the higher strata, and their
children
will tend to stay there.
Steven-Pinker-The-Blank-Slate 1
Many examples of "plasticity" may consist o~f making the input mesh with that structure.
Anyone who has watched the Discovery Channel has seen footage of baby wildebeests or zebras falling out of the birth canal, wobbling on shaky legs for a minute or two, and then prancing around their mothers with their senses, drives, and motor control fully operational. It happens far too quickly for patterned experience to have organized their brains, so there must be genetic mechanisms capable of shaping the brain before birth. Neuroscientists were aware of this before plasticity came into vogue. The first studies of the development of the visual system by David Hubel and Torsten Wiesel showed that the microcircuitry of monkeys is pretty much complete at birth. 63 Even their famous demonstrations that the visual systems of cats can be altered by experience during a critical period of development (by being reared in the dark, in striped cylinders, or with one eye sewn shut) show only that experience is necessary to maintain the visual system and to retune it as the animal grows. They do not show that experience is necessary to wire up the brain to start with.
We know in a general way how the brain assembles itself under the guidance of the genes. 64 Even before the cortex has been formed, the neurons destined to make up different areas are organized into a"proto-map. " Each area in the proto-map is composed of neurons with different properties, molecular mechanisms that attract different input fibers, and different patterns of responses to the input. Axons are attracted and repelled by many kinds of molecules dissolved in the surrounding fluid or attached to the membranes of neighboring cells. And different sets of genes are expressed in different parts of the growing cortex. The neuroscientist Lawrence Katz has lamented that fire-together- wire-together has become a "dogma" keeping neuroscientists from exploring the full reach of these genetic mechanisms. 65
But the tide is beginning to turn, and recent discoveries are showing how parts of the brain can organize themselves without any information from the senses. In experiments that the journal Science called "heretical," Katz's team removed one or both eyes from a developing ferret, depriving the visual cortex {98} of all its input. Nonetheless, the visual cortex developed with the standard arrangement of connections from the two eyes. 66
Genetically engineered mice have provided especially important clues, because knocking out a single gene can be more precise than the conventional techniques of poisoning neurons or slicing up the brain. One team invented a mouse whose synapses were completely shut down, preventing neurons from signaling to one another. Its brain developed fairly normally, complete with layered structures, fiber pathways, and synapses in the right places. 67 (The brain degenerated quickly after birth, showing again that neural activity may be more important in maintaining the brain than in wiring it. ) Another team designed a mouse with a useless thalamus, depriving the entire cortex of its input. But the cortex differentiated into the normal layers and regions, each with a different set of turned-on genes. 68 A third study did the opposite, inventing mice that were missing one of the genes that lay down gradients of molecules that help organize the brain by triggering other genes in particular places. The missing gene made a big difference: the boundaries among cortical areas were badly warped. 69 The studies with knockout mice, then, suggest that genes may be more important than neural activity in organizing the cortex. Neural activity undoubtedly plays a role, which depends on the species, the stage of development, and the part of the brain, but it is just one capability of the brain rather than the source of its structure.
What about our own species? Recall that a recent study of twins showed that differences in the anatomy of the cortex, particularly the amount of gray matter in different cortical regions, are under genetic control, paralleling differences in intelligence and other psychological traits. 70 And demonstrations of the plasticity of the human brain do not rule out substantial genetic organization. One of the most commonly cited examples of plasticity in both humans and monkeys is that the cortex dedicated to an amputated or numbed body part may get reallocated to some other body part. But the fact that the input can change the brain once it is built does not mean that the input molded the brain in the first place. Most amputees experience phantom limbs: vivid, detailed hallucinations of the missing body part.
? ? ? ? ? ? ? ? ? ? Amazingly, a substantial proportion of people who were born with a limb missing experience these apparitions as well. 71 They can describe the anatomy of their phantom limb (for example, how many toes they feel in a nonexistent
foot) and may even feel that they are gesturing with their phantom hands during conversation. One girl solved arithmetic problems by counting on her phantom fingers! The psychologist Ronald Melzack, who documented many of these cases, proposed that the brain contains an innate "neuromatrix," distributed across several cortical and subcortical regions, dedicated to representing the body.
The impression that human brains are limitlessly plastic has also come from demonstrations that children can sometimes recover from early brain {99} damage. But the existence of cerebral palsy -- lifelong difficulties with motor control and speech caused by malformations or early damage in the brain -- shows that even the plasticity of a child's brain has severe limits. The most famous evidence for extreme plasticity in humans had been the ability of some children to grow up relatively normal even with an entire hemisphere surgically removed in infancy. 72 But that may be a special case, which arises from the fact that the primate brain is fundamentally a symmetrical organ. The typically human asymmetries -- language more on the left, spatial attention and some emotions more on the right -- are superimposed on that mostly symmetrical design. It would not be surprising if the hemispheres were genetically programmed with pretty much the same abilities, together with small biases that lead each hemisphere to specialize in some talents while letting others wither. With one hemisphere gone, the remaining one has to put all its capabilities to full use.
What happens when a child loses a part of the cortex in both hemispheres, so neither hemisphere can take over the job of the missing part in the other? If cortical regions are interchangeable, plastic, and organized by the input, then an intact part of the brain should take over the function of the missing parts. The child may be a bit slower because he is working with less brain tissue, but he should develop a full complement of human faculties. But that is not what seems to happen. Several decades ago, neurologists studied a boy who suffered a temporary loss of oxygen to the brain and lost both the standard language areas in the left hemisphere and their mirror images on the right. Though he was just ten days old when he sustained the damage, he grew into a child with permanent difficulties in speaking and understanding. 73
That case study, like many in pediatric neurology, is not scientifically pure, but recent studies on two other mental faculties echo the point that babies' brains may be less plastic than many people think. The psychologist Martha Farah and her collaborators recently reported the case of a sixteen-year-old boy who contracted meningitis when he was one day old and suffered damage to the visual cortex and to the bottom of the temporal lobes on both sides of his brain. 74 When adults sustain such damage, they lose the ability to recognize faces and also have some trouble recognizing animals, though they often can recognize words, tools, furniture, and other shapes. The boy had exactly this syndrome. Though he grew up with normal verbal intelligence, he was utterly incapable of recognizing faces. He could not even recognize pictures of the cast of his favorite television show, Baywatch, which he had seen for an hour a day for the preceding year and a half. Without the appropriate strips of brain, sixteen years of seeing faces and plenty of available cortex were not enough to give him the basic human ability to recognize other people by sight. The neuroscientists Steven Anderson, Hannah and Antonio Damasio, and their colleagues recently tested two young adults who had sustained damage to {100} their ventromedial and orbital prefrontal cortex when they were young children. 75 These are the parts of the brain that sit above the eyes and are important for empathy, social skills, and self-management (as we know from Phineas Gage, the railroad worker whose brain was impaled by a tamping iron). Both children recovered from their injuries and grew up with average IQs in stable homes with normal siblings and college-educated parents. If the brain were really homogeneous and plastic, the healthy parts should have been shaped by the normal social environment and taken oyer the functions of the damaged parts. But that is not what happened with either of the children. One, who had been run over by a car when she was fifteen months old, grew into an intractable child who ignored punishment and lied compulsively. As a teenager she shoplifted, stole from her parents, failed to win friends, showed no empathy or remorse, and was dangerously uninterested in her own baby. The other patient was a young man who had lost similar parts of his brain to a tumor when he was three months old. He too grew up friendless, shiftless, thieving, and hotheaded. Along with their bad behavior, both had trouble thinking through simple moral problems, despite having IQs in the normal range. They could not, for example, say what two people should do if they disagreed on which TV channel to watch, or decide whether a man ought to steal a drug to save his dying wife.
These cases do more than refute the doctrine of extreme plasticity. They set a challenge for the genetics and neuroscience of the twenty-first century. How does the genome tell a developing brain to differentiate into neural networks that are prepared for such abstract computational problems as recognizing a face or thinking about the interests of other people? ~
? ? ? ? ? ? ? The Blank Slate has made its last stand, but, as we have seen, its latest scientific fortifications are illusory. The human genome may have a smaller number of genes than biologists had previously estimated, but that only shows that the number of genes in a genome has little to do with the complexity of the organism. Connectionist networks may explain some of the building blocks of cognition, but they are too underpowered to account for thought and language on their own; they must be innately engineered and assembled for the tasks. Neural plasticity is not a magical protean power of the brain but a set of tools that help turn megabytes of genome into terabytes of brain, that make sensory cortex dovetail with its input, and that implement the process called learning.
Therefore genomics, neural networks, and neural plasticity fit into the picture that has emerged in recent decades of a complex human nature. It is not, of course, a nature that is rigidly programmed, impervious to the input, free of culture, or endowed with the minutiae of every concept and feeling. But it is a nature that is rich enough to take on the demands of seeing, moving, {101} planning, talking, staying alive, making sense of the environment, and negotiating the world of other people.
The aftermath of the Blank Slate's last stand is a good time to take stock of the case for the alternative. Here is my summary of the evidence for a complex human nature, some of it reiterating arguments from previous chapters, some of it anticipating arguments in chapters to come.
Simple logic says there can be no learning without innate mechanisms to do the learning. Those mechanisms must be powerful enough to account for all the kinds of learning that humans accomplish. Learnability theory -- the mathematical analysis of how learning can work in principle -- tells us there are always an infinite number of generalizations that a learner can draw from a finite set of inputs. 76 The sentences heard by a child, for example, can be grounds for repeating them back verbatim, producing any combination of words with the same proportion of nouns to verbs, or analyzing the underlying grammar and producing sentences that conform to it. The sight of someone washing dishes can, with equal logical justification, prompt a learner to try to get dishes clean or to let warm water run over his fingers. A successful learner, then, must be constrained to draw some conclusions from the input and not others. Artificial intelligence reinforces this point. Computers and robots programmed to do humanlike feats are invariably endowed with many complex modules. 77
Evolutionary biology has shown that complex adaptations are ubiquitous in the living world, and that natural selection is capable of evolving them, including complex cognitive and behavioral adaptations. 78 The study of the behavior of animals in their natural habitat shows that species differ innately from one another in their drives and abilities, some of them (like celestial navigation and food caching) requiring complicated and specialized neural systems. 79 The study of humans from an evolutionary perspective has shown that many psychological faculties (such as our hunger for fatty food, for social status, and for risky sexual liaisons) are better adapted to the evolutionary demands of our ancestral environment than to the actual demands of the current environment. 80 Anthropological surveys have shown that hundreds of universals, pertaining to every aspect of experience, cut across the world's cultures. 81
Cognitive scientists have discovered that distinct kinds of representations and processes are used in different domains of knowledge, such as words and rules for language, the concept of an enduring object for understanding the physical world, and a theory of mind for understanding other people. 82 Developmental psychology has shown that these distinct modes of interpreting experience come on line early in life: infants have a basic grasp of objects, numbers, faces, tools, language, and other domains of human cognition. 83
The human genome contains an enormous amount of information, both in the genes and in the noncoding regions, to guide the construction of a {102} complex organism. In a growing number of cases, particular genes can be tied to aspects of cognition, language, and personality. 84 When psychological traits vary, much of the variation comes from differences in genes: identical twins are more similar than fraternal twins, and biological siblings are more similar than adoptive siblings, whether reared together or apart. 85 A person's temperament and personality emerge early in life and remain fairly constant throughout the lifespan. 86 And both personality and intelligence show few or no effects of children's particular home environments within their culture: children reared in the same family are similar mainly because of their shared genes. 87
Finally, neuroscience is showing that the brain's basic architecture develops under genetic control. The importance of learning and plasticity notwithstanding, brain systems show signs of innate specialization and cannot arbitrarily substitute for one another. 88
In these three chapters I have given you a summary of the current scientific case for a complex human nature. The rest of the book is about its implications.
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? << {103} >>
? ? ? ? ? FEAR AND LOATHING
y the middle of the second half of the twentieth century, the ideals of the social scientists of the first half had enjoyed a well-deserved
B victory. Eugenics, Social Darwinism, colonial conquest, Dickensian policies toward children, overt expressions of racism and sexism among the educated, and official discrimination against women and minorities had been eradicated, or at least were rapidly fading, from mainstream
Western life.
At the same time, the doctrine of the Blank Slate, which had been blurred with ideals of equality and progress for much of the century, was beginning to show cracks. 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.
These developments presented intellectuals with a choice. Cooler heads could have explained that the discoveries were irrelevant to the political ideals of equal opportunity and equal rights, which are moral doctrines on how we ought to treat people rather than scientific hypotheses about what people are like. Certainly it is wrong to enslave, oppress, discriminate against, or kill people regardless of any foreseeable datum or theory that a sane scientist would offer.
But it was not a time for cool heads. Rather than detach the moral doctrines from the scientific ones, which would ensure that the clock would not be turned back no matter what came out of the lab and field, many intellectuals, including some of the world's most famous scientists, made every effort to connect the two. The discoveries about human nature were greeted with fear and loathing because they were thought to threaten progressive ideals. All this could be relegated to the history books were it not for the fact that these intellectuals, who once called themselves radicals, are now the establishment, and {104} the dread they sowed about human nature has taken root in modern intellectual life.
This part of the book is about the politically motivated reactions to the new sciences of human nature. Though the opposition was originally a brainchild of the left, it is becoming common on the right, whose spokespeople are fired up by some of the same moral objections. In Chapter 6 I recount the shenanigans that erupted as a reaction to the new ideas about human nature. In Chapter 7 I show how these reactions came from a moral imperative to uphold the Blank Slate, the Noble Savage, and the Ghost in the Machine.
<< {105} >> Chapter 6
Political Scientists
The first lecture I attended as a graduate student at Harvard in 1976 was by the famous computer scientist Joseph Weizenbaum. He was an early contributor to artificial intelligence (AI) and is best remembered for the program Eliza, which fooled people into thinking that the computer was conversing though it was just spouting canned repartee. Weizenbaum had just published Computer Power and Human Reason, a critique of artificial intelligence and computer models of cognition, praised as "the most important computer book of the past decade. " I had misgivings about the book, which was short on irgument and long on sanctimony. (For example, he wrote that certain ideas in artificial intelligence, such as a science-fiction proposal for a hybrid of nervous systems and computers, were "simply obscene. These are [applications] whose very contemplation ought to give rise to feelings of disgust in every civilized person. . . . One must wonder what must have happened to the proposers' perception of life, hence to their perceptions of themselves as part of the continuum of life, that they can even think of such a thing. ")1 Still, nothing could have prepared me for the performance in store at the Science Center that afternoon.
Weizenbaum discussed an AI program by the computer scientists Alan Newell and Herbert Simon that relied on analogy: if it knew the solution to one problem, it applied the solution to other problems with a similar logical structure. This, Weizenbaum told us, was really designed to help the Pentagon come up with counterinsurgency strategies in Vietnam. The Vietcong had been said to "move in the jungle as fish move in water. " If the program were fed this information, he said, it could deduce that just as you can drain a pond to expose the fish, you can denude the jungle to expose the Vietcong. Turning to research on speech recognition by computer, he said that the only
? ? ? ? ? ? ? ? ? conceivable reason to study speech perception was to allow the CIA to monitor millions of telephone conversations simultaneously, and he urged the students in the audience to boycott the topic. But, he added, it didn't really matter if we ignored {106} his advice because he was completely certain -- there was not the slightest doubt in his mind -- that by the year 2000 we would all be dead. And with that inspiring charge to the younger generation he ended the talk.
The rumors of our death turned out to be greatly exaggerated, and the other prophecies of the afternoon fared no better. The use of analogy in reasoning, far from being the work of the devil, is today a major research topic in cognitive science and is widely considered a key to what makes us smart. Speech-recognition software is routinely used in telephone information services and comes packaged with home computers, where it has been a godsend for the disabled and for people with repetitive strain injuries. And Weizenbaum's accusations stand as a reminder of the political paranoia and moral exhibitionism that characterized university life in the 1970s, the era in which the current opposition to the sciences of human nature took shape.
It was not how I imagined that scholarly discourse would be conducted in the Athens of America, but perhaps I should not have been surprised. Throughout history, battles of opinion have been waged by noisy moralizing, demonizing, hyperbole, and worse. Science was supposed to be a beachhead in which ideas rather than people are attacked and in which verifiable facts are separated from political opinions. But when science began to edge toward the topic of human nature, onlookers reacted differently from how they would to discoveries about, say, the origin of comets or the classification of lizards, and scientists reverted to the moralistic mindset that comes so naturally to our species.
Research on human nature would be controversial in any era, but the new sciences picked a particularly bad decade in which to attract the spotlight. In the 1970s many intellectuals had become political radicals. Marxism was correct, liberalism was for wimps, and Marx had pronounced that "the ruling ideas of each age have ever been the ideas of its ruling class. " The traditional misgivings about human nature were folded into a hard-left ideology, and scientists who examined the human mind in a biological context were now considered tools of a reactionary establishment. The critics announced they were part of a "radical science movement," giving us a convenient label for the group. 2 Weizenbaum was repelled by the attempt within artificial intelligence and cognitive science to unify mind and mechanism, but the other sciences of human nature evoked acrimony as well. In 1971 the psychologist Richard Herrnstein published an article called "IQ" in the Atlantic Monthly. 3 Herrnstein's argument, he was the first to point out, should have been banal. He wrote that as social status becomes less strongly determined by arbitrary legacies such as race, parentage, and inherited wealth, it will become more strongly determined by talent, especially (in a modern economy) intelligence. Since differences in intelligence are partly inherited, and since intelligent people tend to marry other intelligent people, when a society becomes more just it {107} will also become more stratified along genetic lines.
Smarter people will tend to float into the higher strata, and their children will tend to stay there. The basic argument should be banal because it is based on a mathematical necessity: as the proportion of variance in social status caused by nongenetic factors goes down, the proportion caused by genetic factors has to go up. It could be completely false only if there were no variation in social status based on intellectual talent (which would require that people not preferentially hire and trade with the talented) or if there were no genetic variation in intelligence which would require that people be either blank slates or clones).
Herrnstein's argument does not imply that any differences in average intelligence between races are innate (a distinct hypothesis that had been broached by the psychologist Arthur Jensen two years earlier),4 and he explicitly denied that he was making such a claim. School desegregation was less than a generation old, civil rights legislation less than a decade, so the differences that had been documented in average IQ scores of blacks and whites could easily be explained by differences in opportunity. Indeed, to say that Herrnstein's syllogism implied that black people would end up at the bottom of a genetically stratified society was to add the gratuitous assumption that blacks were on average genetically less intelligent, which Herrnstein took pains to avoid.
Nonetheless, the influential psychiatrist Alvin Poussaint wrote that Herrnstein "has become the enemy of black people and his pronouncements are a threat to the survival of every black person in America. " He asked rhetorically, "Shall we carry banners for Herrnstein proclaiming his right to freedom of speech? " Leaflets were handed out at Boston-area universities urging students to "Fight Harvard Prof's Fascist Lies," and Harvard Square was plastered with his photograph above the caption wanted for racism and five misquotations purportedly from his article. Herrnstein received a death threat and found that he could no longer speak about his research specialty, learning in pigeons, because wherever he went the lecture halls were filled with chanting mobs. At Princeton, for example, students declared they would block the doors of the auditorium to force him to answer questions on the IQ controversy. Several lectures were canceled when the hosting universities said they could not guarantee his safety. 5 The topic of innate differences among people has obvious political implications, which I will examine in later chapters. But some scholars were incensed by the seemingly warm-and-fuzzy claim that people have innate
? ? ? ? ? ? commonalities. 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. These findings, he argued, vindicated two claims that Darwin had made in his 1872 book The Expression of the Emotions in Man and {108} Animals. One was that humans had been endowed with emotional expressions by the process of evolution; the other, radical in Darwin's time, was that all races had recently diverged from a common ancestor. 6 Despite these uplifting messages, Margaret Mead called Ekman's research "outrageous," "appalling," and "a disgrace" -- and these were some of the milder responses. 7 At the annual meeting of the American Anthropological Association, Alan Lomax Jr. rose from the audience shouting that Ekman should not be allowed to speak because his ideas were fascist. On another occasion an African American activist accused him of racism for claiming that black facial expressions were no different from white ones. (Sometimes you can't win. ) And it was not just claims about innate faculties in the human species that drew the radicals' ire, but claims about innate faculties in any species. When the neuroscientist Torsten Wiesel published his historic work with David Hubel showing that the visual system of cats is largely complete at birth, another neuroscientist angrily called him a fascist and vowed to prove him wrong. ~
Some of these protests were signs of the times and faded with the decline of radical chic. But the reaction to two books on evolution continued for decades and became part of the intellectual mainstream.
The first was E. O. Wilson's Sociobiology, published in 1975. 8 Sociobiology synthesized a vast literature on animal behavior using new ideas on natural selection from George Williams, William Hamilton, John Maynard Smith, and Robert Trivers. It reviewed principles on the evolution of communication, altruism, aggression, sex, and parenting, and applied them to the major taxa of social animals such as insects, fishes, and birds. The twenty-seventh chapter did the same for Homo sapiens, treating our species like another branch of the animal kingdom. It included a review of the literature on universals and variation among societies, a discussion of language and its effects on culture, and the hypothesis that some universals (including the moral sense) may come from a human nature shaped by natural selection. Wilson expressed the hope that this idea might connect biology to the social sciences and philosophy, a forerunner of the argument in his later book Consilience.
The first attack on Sociobiology zeroed in on its main heresy. In a book-length critique, the anthropologist Marshall Sahlins defined "vulgar sociobiology" as the challenge to Durkheim's and Kroeber's doctrine of the superorganism: the belief that culture and society lived in a separate realm from individual people and their thoughts and feelings. "Vulgar sociobiology," Sahlins wrote, "consists in the explication of human social behavior as the expression of the needs and drives of the human organism, such propensities having been constructed in human nature by biological evolution. "9 Acknowledging fear of an incursion into his academic turf, he added, "The central intellectual problem does come down to the autonomy of culture and of the {109} study of culture. Sociobiology challenges the integrity of culture as a thing-in-itself, as a distinctive and symbolic human creation. "10
Sahlins's book was called The Use and Abuse of Biology. An example of the alleged abuse was the idea that Hamilton's theory of inclusive fitness could help explain the importance of family ties in human life. Hamilton had shown how a tendency to make sacrifices for relatives could have evolved. Relatives share genes, so any gene that nudges an organism to help a relative would be indirectly helping a copy of itself. The gene will proliferate if the cost incurred by the favor is less than the benefit conferred to the relative, discounted by the degree of relatedness (one- half for a full sibling or offspring, one-eighth for a first cousin, and so on). That can't be true, Sahlins wrote, because people in most cultures don't have words for fractions. This leaves them unable to figure out the coefficients of relatedness that would tell them which relatives to favor and by how much. His objection is a textbook confusion of a proximate cause with an ultimate cause. It is like saying that people can't possibly see in depth, because most cultures haven't worked out the trigonometry that underlies stereoscopic vision.
In any case, "vulgar" wasn't the half of it. Following a favorable review in the New York Review of Books by the distinguished biologist C. H. Waddington, the "Sociobiology Study Group" (including two of Wilson's colleagues, the paleontologist Stephen Jay Gould and the geneticist Richard Lewontin) published a widely circulated philippic called "Against 'Sociobiology. '" After lumping Wilson with proponents of eugenics, Social Darwinism, and Jensen's hypothesis of innate racial differences in intelligence, the signatories wrote:
The reason for the survival of these recurrent determinist theories is that they consistently tend to provide a genetic justification of the status quo and of existing privileges for certain groups according to class, race, or sex. . . . These theories provided an important basis for the enactment of sterilization laws and restrictive immigration laws by the United States between 1910 and 1930 and also for the eugenics policies which led to the establishment of gas chambers in Nazi Germany.
? ? ? ? ? ? ? . . . What Wilson's book illustrates to us is the enormous difficulty in separating out not only the effects of environment (e. g. , cultural transmission) but also the personal and social class prejudices of the researcher. Wilson joins the long parade of biological determinists whose work has served to buttress the institutions of their society by exonerating them from responsibility for social problems. 11
They also accused Wilson of discussing "the salutary advantages of genocide" and of making "institutions such as slavery. . . seem natural in human societies because of their 'universal' existence in the biological kingdom. " In
{110} case the connection wasn't clear enough, one of the signatories wrote elsewhere that "in the last analysis it was sociobiological scholarship . . . that provided the conceptual framework by which eugenic theory was transformed into genocidal practice" in Nazi Germany. 12
One can certainly find things to criticize in the final chapter of Sociobiology. We now know that some of Wilson's universals are inaccurate or too coarsely stated, and his claim that moral reasoning will someday be superseded by evolutionary biology is surely wrong. But the criticisms in "Against 'Sociobiology'" were demonstrably false. Wilson was called a "determinist,'" someone who believes that human societies conform to a rigid genetic formula. But this is what he had written:
The first and most easily verifiable diagnostic trait [about human societies] is statistical in nature. The parameters of social organization . . . vary far more among human populations than among those of any other primate species. . . . Why are human societies this flexible? 13
Similarly, Wilson was accused of believing that people are locked into castes determined by their race, class, sex, and individual genome. But in fact he had written that "there is little evidence of any hereditary solidification of status"14 and that "human populations are not very different from one another genetically. "15 Moreover:
Human societies have effloresced to levels of extreme complexity because their members have the intelligence and flexibility to play roles of virtually any degree of specification, and to switch them as the occasion demands. Modern man is an actor of many parts who may well be stretched to his limit by the constantly shifting demands of the environment. 16
As for the inevitability of aggression -- another dangerous idea he was accused of holding -- what Wilson had written was that in the course of human evolution "aggressiveness was constrained and the old forms of primate dominance replaced by complex social skills. "17 The accusation that Wilson (a lifelong liberal Democrat) was led by personal prejudice to defend racism, sexism, inequality, slavery, and genocide was especially unfair -- and irresponsible, because Wilson became a target of vilification and harassment by people who read the manifesto but not the book. 18
At Harvard there were leaflets and teach-ins, a protester with a bullhorn calling for Wilson's dismissal, and invasions of his classroom by slogan-shouting students. When he spoke at other universities, posters called him the "Right- Wing Prophet of Patriarchy" and urged people to bring noisemakers to {111} his lectures. 19 Wilson was about to speak at a 1978 meeting of the American Association for the Advancement of Science when a group of people carrying placards (one with a swastika) rushed onto the stage chanting, "Racist Wilson, . ou can't hide, we charge you with genocide. " One protester grabbed the microphone and harangued the audience while another doused Wilson with a pitcher of water.
As the notoriety of Sociobiology grew in the ensuing years, Hamilton and Trivers, who had thought up many of the ideas, also became targets of picketers, as did the anthropologists Irven DeVore and Lionel Tiger when they :ried to teach the ideas. The insinuation that Trivers was a tool of racism and right-wing oppression was particularly galling because Trivers was himself a political radical, a supporter of the Black Panthers, and a scholarly collaborator of Huey Newton's. 20 Trivers had argued that sociobiology is, if anything, a force for political progress. It is rooted in the insight that organisms did not evolve to benefit their family, group, or species, because the individuals making up those groups have genetic conflicts of interest with one another and would be selected to defend those interests. This immediately subverts the comfortable belief that those in power rule for the good of all, and it throws a spotlight on hidden actors in the social world, such as females and the younger generation. Also, by finding an evolutionary basis for altruism, sociobiology shows that a sense of justice has a deep foundation in people's minds and need not run against our organic nature. And by showing that self-deception is likely to evolve (because the best liar is the one who believes his own lies), sociobiology encourages self-scrutiny and helps undermine hypocrisy and corruption. 21 (I will return to the political beliefs of Trivers and other "Darwinian leftists" in the chapter on politics. )
Trivers later wrote of the attacks on sociobiology, "Although some of the attackers were prominent biologists, the attack seemed intellectually feeble and lazy. Gross errors in logic were permitted as long as they appeared to give
? ? ? ? ? ? ? ? ? ? ? ? ? some tactical advantage in the political struggle. . . . Because we were hirelings of the dominant interests, said these fellow hirelings of the same interests, we were their mouthpieces, employed to deepen the [deceptions] with which the ruling elite retained their unjust advantage. Although it follows from evolutionary reasoning that individuals will tend to argue in ways that are ultimately (sometimes unconsciously) self-serving, it seemed a priori unlikely that evil should reside so completely in one set of hirelings and virtue in the other. "22
The "prominent biologists" that Trivers had in mind were Gould and Lewontin, and together with the British neuroscientist Steven Rose they became the intellectual vanguard of the radical science movement. For twenty-five years they have indefatigably fought a rearguard battle against behavioral genetics, sociobiology (and later evolutionary psychology), and the neuro-science of politically sensitive topics such as sex differences and mental
{112} illness. 23 Other than Wilson, the major target of their attacks has been Richard Dawkins. In his 1976 book The Selfish Gene, Dawkins covered many of the same ideas as Wilson but concentrated on the logic of the new evolutionary theories rather than the zoological details. He said almost nothing about humans.
The radical scientists' case against Wilson and Dawkins can be summed up in two words: "determinism" and "reductionism. "24 Their writings are peppered with these words, used not in any technical sense but as vague terms of abuse. For example, here are two representative passages in a book by Lewontin, Rose, and the psychologist Leon Kamin with the defiantly Blank Slate title Not in Our Genes:
Sociobiology is a reductionist, biological determinist explanation of human existence. Its adherents claim . . . that the details of present and past social arrangements are the inevitable manifestations of the specific action of genes. 25
[Reductionists] argue that the properties of a human society are . . . no more than the sums of the individual behaviors and tendencies of the individual humans of which that society is composed. Societies are "aggressive" because the individuals who compose them are "aggressive," for instance'. 26
The quotations from Wilson we saw earlier in the chapter show that he never expressed anything close to these ridiculous beliefs, and neither, of course, did Dawkins. For example, after discussing the tendency in mammals for males to seek a greater number of sexual partners than females do, Dawkins devoted a paragraph to human societies in which he wrote:
What this astonishing variety suggests is that man's way of life is largely determined by culture rather than by genes. However, it is still possible that human males in general have a tendency towards promiscuity, and females a tendency to monogamy, as we would predict on evolutionary grounds. Which of these tendencies wins in particular societies depends on details of cultural circumstance, just as in different animal species it depends on ecological details. 27
What exactly do "determinism" and "reductionism" mean? In the precise sense in which mathematicians use the word, a "deterministic" system is one whose states are caused by prior states with absolute certainty, rather than probabilistically. Neither Dawkins nor any other sane biologist would ever dream of proposing that human behavior is deterministic, as if people must {113} commit acts of promiscuity, aggression, or selfishness at every opportunity. 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.
So much for genetic determinism. What about "reductionism" (a concept we examined in Chapter 4) and the claim that Dawkins is "the most reductionist of sociobiologists," one who believes that every trait has its own gene?
Lewontin, Rose, and Kamin try to educate their readers on how living things really work according to their alternative to reductionism, which they call "dialectical biology":
Think, for example, of the baking of a cake: the taste of the product is the result of a complex interaction of components -- such as butter, sugar, and flour -- exposed for various periods to elevated temperatures; it is not dissociable into such-or-such a percent of flour, such-or-such of butter, etc. , although each and every component. . . has its contribution to make to the final product. 28
I will let Dawkins comment:
When put like that, this dialectical biology seems to make a lot of sense. Perhaps even / can be a dialectical biologist. Come to think of it, isn't there something familiar about that cake? Yes, here it is,
? ? ? ? ? ? ? ? ? ? in a 1981 publication by the most reductionist of sociobiologists:
". . . If we follow a particular recipe, word for word, in a cookery book, what finally emerges from the oven is a cake. We cannot now break the cake into its component crumbs and say: this crumb corresponds to the first word in the recipe; this crumb corresponds to the second word in the recipe, etc. With minor exceptions such as the cherry on top, there is no one-to-one mapping from words of recipe to 'bits' of cake. The whole recipe maps onto the whole cake. "
I am not, of course, interested in claiming priority for the cake. . . . But what I do hope is that this little coincidence may at least give Rose and Lewontin pause. Could it be that their targets are not quite the nai? vely atomistic reductionists they would desperately like them to be? 29
Indeed, the accusation of reductionism is topsy-turvy because Lewontin and Rose, in their own research, are card- carrying reductionist biologists who {114} explain phenomena at the level of genes and molecules. Dawkins, in contrast, was trained as an ethologist and writes about the behavior of animals in their natural habitat.
Anyone who has watched the Discovery Channel has seen footage of baby wildebeests or zebras falling out of the birth canal, wobbling on shaky legs for a minute or two, and then prancing around their mothers with their senses, drives, and motor control fully operational. It happens far too quickly for patterned experience to have organized their brains, so there must be genetic mechanisms capable of shaping the brain before birth. Neuroscientists were aware of this before plasticity came into vogue. The first studies of the development of the visual system by David Hubel and Torsten Wiesel showed that the microcircuitry of monkeys is pretty much complete at birth. 63 Even their famous demonstrations that the visual systems of cats can be altered by experience during a critical period of development (by being reared in the dark, in striped cylinders, or with one eye sewn shut) show only that experience is necessary to maintain the visual system and to retune it as the animal grows. They do not show that experience is necessary to wire up the brain to start with.
We know in a general way how the brain assembles itself under the guidance of the genes. 64 Even before the cortex has been formed, the neurons destined to make up different areas are organized into a"proto-map. " Each area in the proto-map is composed of neurons with different properties, molecular mechanisms that attract different input fibers, and different patterns of responses to the input. Axons are attracted and repelled by many kinds of molecules dissolved in the surrounding fluid or attached to the membranes of neighboring cells. And different sets of genes are expressed in different parts of the growing cortex. The neuroscientist Lawrence Katz has lamented that fire-together- wire-together has become a "dogma" keeping neuroscientists from exploring the full reach of these genetic mechanisms. 65
But the tide is beginning to turn, and recent discoveries are showing how parts of the brain can organize themselves without any information from the senses. In experiments that the journal Science called "heretical," Katz's team removed one or both eyes from a developing ferret, depriving the visual cortex {98} of all its input. Nonetheless, the visual cortex developed with the standard arrangement of connections from the two eyes. 66
Genetically engineered mice have provided especially important clues, because knocking out a single gene can be more precise than the conventional techniques of poisoning neurons or slicing up the brain. One team invented a mouse whose synapses were completely shut down, preventing neurons from signaling to one another. Its brain developed fairly normally, complete with layered structures, fiber pathways, and synapses in the right places. 67 (The brain degenerated quickly after birth, showing again that neural activity may be more important in maintaining the brain than in wiring it. ) Another team designed a mouse with a useless thalamus, depriving the entire cortex of its input. But the cortex differentiated into the normal layers and regions, each with a different set of turned-on genes. 68 A third study did the opposite, inventing mice that were missing one of the genes that lay down gradients of molecules that help organize the brain by triggering other genes in particular places. The missing gene made a big difference: the boundaries among cortical areas were badly warped. 69 The studies with knockout mice, then, suggest that genes may be more important than neural activity in organizing the cortex. Neural activity undoubtedly plays a role, which depends on the species, the stage of development, and the part of the brain, but it is just one capability of the brain rather than the source of its structure.
What about our own species? Recall that a recent study of twins showed that differences in the anatomy of the cortex, particularly the amount of gray matter in different cortical regions, are under genetic control, paralleling differences in intelligence and other psychological traits. 70 And demonstrations of the plasticity of the human brain do not rule out substantial genetic organization. One of the most commonly cited examples of plasticity in both humans and monkeys is that the cortex dedicated to an amputated or numbed body part may get reallocated to some other body part. But the fact that the input can change the brain once it is built does not mean that the input molded the brain in the first place. Most amputees experience phantom limbs: vivid, detailed hallucinations of the missing body part.
? ? ? ? ? ? ? ? ? ? Amazingly, a substantial proportion of people who were born with a limb missing experience these apparitions as well. 71 They can describe the anatomy of their phantom limb (for example, how many toes they feel in a nonexistent
foot) and may even feel that they are gesturing with their phantom hands during conversation. One girl solved arithmetic problems by counting on her phantom fingers! The psychologist Ronald Melzack, who documented many of these cases, proposed that the brain contains an innate "neuromatrix," distributed across several cortical and subcortical regions, dedicated to representing the body.
The impression that human brains are limitlessly plastic has also come from demonstrations that children can sometimes recover from early brain {99} damage. But the existence of cerebral palsy -- lifelong difficulties with motor control and speech caused by malformations or early damage in the brain -- shows that even the plasticity of a child's brain has severe limits. The most famous evidence for extreme plasticity in humans had been the ability of some children to grow up relatively normal even with an entire hemisphere surgically removed in infancy. 72 But that may be a special case, which arises from the fact that the primate brain is fundamentally a symmetrical organ. The typically human asymmetries -- language more on the left, spatial attention and some emotions more on the right -- are superimposed on that mostly symmetrical design. It would not be surprising if the hemispheres were genetically programmed with pretty much the same abilities, together with small biases that lead each hemisphere to specialize in some talents while letting others wither. With one hemisphere gone, the remaining one has to put all its capabilities to full use.
What happens when a child loses a part of the cortex in both hemispheres, so neither hemisphere can take over the job of the missing part in the other? If cortical regions are interchangeable, plastic, and organized by the input, then an intact part of the brain should take over the function of the missing parts. The child may be a bit slower because he is working with less brain tissue, but he should develop a full complement of human faculties. But that is not what seems to happen. Several decades ago, neurologists studied a boy who suffered a temporary loss of oxygen to the brain and lost both the standard language areas in the left hemisphere and their mirror images on the right. Though he was just ten days old when he sustained the damage, he grew into a child with permanent difficulties in speaking and understanding. 73
That case study, like many in pediatric neurology, is not scientifically pure, but recent studies on two other mental faculties echo the point that babies' brains may be less plastic than many people think. The psychologist Martha Farah and her collaborators recently reported the case of a sixteen-year-old boy who contracted meningitis when he was one day old and suffered damage to the visual cortex and to the bottom of the temporal lobes on both sides of his brain. 74 When adults sustain such damage, they lose the ability to recognize faces and also have some trouble recognizing animals, though they often can recognize words, tools, furniture, and other shapes. The boy had exactly this syndrome. Though he grew up with normal verbal intelligence, he was utterly incapable of recognizing faces. He could not even recognize pictures of the cast of his favorite television show, Baywatch, which he had seen for an hour a day for the preceding year and a half. Without the appropriate strips of brain, sixteen years of seeing faces and plenty of available cortex were not enough to give him the basic human ability to recognize other people by sight. The neuroscientists Steven Anderson, Hannah and Antonio Damasio, and their colleagues recently tested two young adults who had sustained damage to {100} their ventromedial and orbital prefrontal cortex when they were young children. 75 These are the parts of the brain that sit above the eyes and are important for empathy, social skills, and self-management (as we know from Phineas Gage, the railroad worker whose brain was impaled by a tamping iron). Both children recovered from their injuries and grew up with average IQs in stable homes with normal siblings and college-educated parents. If the brain were really homogeneous and plastic, the healthy parts should have been shaped by the normal social environment and taken oyer the functions of the damaged parts. But that is not what happened with either of the children. One, who had been run over by a car when she was fifteen months old, grew into an intractable child who ignored punishment and lied compulsively. As a teenager she shoplifted, stole from her parents, failed to win friends, showed no empathy or remorse, and was dangerously uninterested in her own baby. The other patient was a young man who had lost similar parts of his brain to a tumor when he was three months old. He too grew up friendless, shiftless, thieving, and hotheaded. Along with their bad behavior, both had trouble thinking through simple moral problems, despite having IQs in the normal range. They could not, for example, say what two people should do if they disagreed on which TV channel to watch, or decide whether a man ought to steal a drug to save his dying wife.
These cases do more than refute the doctrine of extreme plasticity. They set a challenge for the genetics and neuroscience of the twenty-first century. How does the genome tell a developing brain to differentiate into neural networks that are prepared for such abstract computational problems as recognizing a face or thinking about the interests of other people? ~
? ? ? ? ? ? ? The Blank Slate has made its last stand, but, as we have seen, its latest scientific fortifications are illusory. The human genome may have a smaller number of genes than biologists had previously estimated, but that only shows that the number of genes in a genome has little to do with the complexity of the organism. Connectionist networks may explain some of the building blocks of cognition, but they are too underpowered to account for thought and language on their own; they must be innately engineered and assembled for the tasks. Neural plasticity is not a magical protean power of the brain but a set of tools that help turn megabytes of genome into terabytes of brain, that make sensory cortex dovetail with its input, and that implement the process called learning.
Therefore genomics, neural networks, and neural plasticity fit into the picture that has emerged in recent decades of a complex human nature. It is not, of course, a nature that is rigidly programmed, impervious to the input, free of culture, or endowed with the minutiae of every concept and feeling. But it is a nature that is rich enough to take on the demands of seeing, moving, {101} planning, talking, staying alive, making sense of the environment, and negotiating the world of other people.
The aftermath of the Blank Slate's last stand is a good time to take stock of the case for the alternative. Here is my summary of the evidence for a complex human nature, some of it reiterating arguments from previous chapters, some of it anticipating arguments in chapters to come.
Simple logic says there can be no learning without innate mechanisms to do the learning. Those mechanisms must be powerful enough to account for all the kinds of learning that humans accomplish. Learnability theory -- the mathematical analysis of how learning can work in principle -- tells us there are always an infinite number of generalizations that a learner can draw from a finite set of inputs. 76 The sentences heard by a child, for example, can be grounds for repeating them back verbatim, producing any combination of words with the same proportion of nouns to verbs, or analyzing the underlying grammar and producing sentences that conform to it. The sight of someone washing dishes can, with equal logical justification, prompt a learner to try to get dishes clean or to let warm water run over his fingers. A successful learner, then, must be constrained to draw some conclusions from the input and not others. Artificial intelligence reinforces this point. Computers and robots programmed to do humanlike feats are invariably endowed with many complex modules. 77
Evolutionary biology has shown that complex adaptations are ubiquitous in the living world, and that natural selection is capable of evolving them, including complex cognitive and behavioral adaptations. 78 The study of the behavior of animals in their natural habitat shows that species differ innately from one another in their drives and abilities, some of them (like celestial navigation and food caching) requiring complicated and specialized neural systems. 79 The study of humans from an evolutionary perspective has shown that many psychological faculties (such as our hunger for fatty food, for social status, and for risky sexual liaisons) are better adapted to the evolutionary demands of our ancestral environment than to the actual demands of the current environment. 80 Anthropological surveys have shown that hundreds of universals, pertaining to every aspect of experience, cut across the world's cultures. 81
Cognitive scientists have discovered that distinct kinds of representations and processes are used in different domains of knowledge, such as words and rules for language, the concept of an enduring object for understanding the physical world, and a theory of mind for understanding other people. 82 Developmental psychology has shown that these distinct modes of interpreting experience come on line early in life: infants have a basic grasp of objects, numbers, faces, tools, language, and other domains of human cognition. 83
The human genome contains an enormous amount of information, both in the genes and in the noncoding regions, to guide the construction of a {102} complex organism. In a growing number of cases, particular genes can be tied to aspects of cognition, language, and personality. 84 When psychological traits vary, much of the variation comes from differences in genes: identical twins are more similar than fraternal twins, and biological siblings are more similar than adoptive siblings, whether reared together or apart. 85 A person's temperament and personality emerge early in life and remain fairly constant throughout the lifespan. 86 And both personality and intelligence show few or no effects of children's particular home environments within their culture: children reared in the same family are similar mainly because of their shared genes. 87
Finally, neuroscience is showing that the brain's basic architecture develops under genetic control. The importance of learning and plasticity notwithstanding, brain systems show signs of innate specialization and cannot arbitrarily substitute for one another. 88
In these three chapters I have given you a summary of the current scientific case for a complex human nature. The rest of the book is about its implications.
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? << {103} >>
? ? ? ? ? FEAR AND LOATHING
y the middle of the second half of the twentieth century, the ideals of the social scientists of the first half had enjoyed a well-deserved
B victory. Eugenics, Social Darwinism, colonial conquest, Dickensian policies toward children, overt expressions of racism and sexism among the educated, and official discrimination against women and minorities had been eradicated, or at least were rapidly fading, from mainstream
Western life.
At the same time, the doctrine of the Blank Slate, which had been blurred with ideals of equality and progress for much of the century, was beginning to show cracks. 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.
These developments presented intellectuals with a choice. Cooler heads could have explained that the discoveries were irrelevant to the political ideals of equal opportunity and equal rights, which are moral doctrines on how we ought to treat people rather than scientific hypotheses about what people are like. Certainly it is wrong to enslave, oppress, discriminate against, or kill people regardless of any foreseeable datum or theory that a sane scientist would offer.
But it was not a time for cool heads. Rather than detach the moral doctrines from the scientific ones, which would ensure that the clock would not be turned back no matter what came out of the lab and field, many intellectuals, including some of the world's most famous scientists, made every effort to connect the two. The discoveries about human nature were greeted with fear and loathing because they were thought to threaten progressive ideals. All this could be relegated to the history books were it not for the fact that these intellectuals, who once called themselves radicals, are now the establishment, and {104} the dread they sowed about human nature has taken root in modern intellectual life.
This part of the book is about the politically motivated reactions to the new sciences of human nature. Though the opposition was originally a brainchild of the left, it is becoming common on the right, whose spokespeople are fired up by some of the same moral objections. In Chapter 6 I recount the shenanigans that erupted as a reaction to the new ideas about human nature. In Chapter 7 I show how these reactions came from a moral imperative to uphold the Blank Slate, the Noble Savage, and the Ghost in the Machine.
<< {105} >> Chapter 6
Political Scientists
The first lecture I attended as a graduate student at Harvard in 1976 was by the famous computer scientist Joseph Weizenbaum. He was an early contributor to artificial intelligence (AI) and is best remembered for the program Eliza, which fooled people into thinking that the computer was conversing though it was just spouting canned repartee. Weizenbaum had just published Computer Power and Human Reason, a critique of artificial intelligence and computer models of cognition, praised as "the most important computer book of the past decade. " I had misgivings about the book, which was short on irgument and long on sanctimony. (For example, he wrote that certain ideas in artificial intelligence, such as a science-fiction proposal for a hybrid of nervous systems and computers, were "simply obscene. These are [applications] whose very contemplation ought to give rise to feelings of disgust in every civilized person. . . . One must wonder what must have happened to the proposers' perception of life, hence to their perceptions of themselves as part of the continuum of life, that they can even think of such a thing. ")1 Still, nothing could have prepared me for the performance in store at the Science Center that afternoon.
Weizenbaum discussed an AI program by the computer scientists Alan Newell and Herbert Simon that relied on analogy: if it knew the solution to one problem, it applied the solution to other problems with a similar logical structure. This, Weizenbaum told us, was really designed to help the Pentagon come up with counterinsurgency strategies in Vietnam. The Vietcong had been said to "move in the jungle as fish move in water. " If the program were fed this information, he said, it could deduce that just as you can drain a pond to expose the fish, you can denude the jungle to expose the Vietcong. Turning to research on speech recognition by computer, he said that the only
? ? ? ? ? ? ? ? ? conceivable reason to study speech perception was to allow the CIA to monitor millions of telephone conversations simultaneously, and he urged the students in the audience to boycott the topic. But, he added, it didn't really matter if we ignored {106} his advice because he was completely certain -- there was not the slightest doubt in his mind -- that by the year 2000 we would all be dead. And with that inspiring charge to the younger generation he ended the talk.
The rumors of our death turned out to be greatly exaggerated, and the other prophecies of the afternoon fared no better. The use of analogy in reasoning, far from being the work of the devil, is today a major research topic in cognitive science and is widely considered a key to what makes us smart. Speech-recognition software is routinely used in telephone information services and comes packaged with home computers, where it has been a godsend for the disabled and for people with repetitive strain injuries. And Weizenbaum's accusations stand as a reminder of the political paranoia and moral exhibitionism that characterized university life in the 1970s, the era in which the current opposition to the sciences of human nature took shape.
It was not how I imagined that scholarly discourse would be conducted in the Athens of America, but perhaps I should not have been surprised. Throughout history, battles of opinion have been waged by noisy moralizing, demonizing, hyperbole, and worse. Science was supposed to be a beachhead in which ideas rather than people are attacked and in which verifiable facts are separated from political opinions. But when science began to edge toward the topic of human nature, onlookers reacted differently from how they would to discoveries about, say, the origin of comets or the classification of lizards, and scientists reverted to the moralistic mindset that comes so naturally to our species.
Research on human nature would be controversial in any era, but the new sciences picked a particularly bad decade in which to attract the spotlight. In the 1970s many intellectuals had become political radicals. Marxism was correct, liberalism was for wimps, and Marx had pronounced that "the ruling ideas of each age have ever been the ideas of its ruling class. " The traditional misgivings about human nature were folded into a hard-left ideology, and scientists who examined the human mind in a biological context were now considered tools of a reactionary establishment. The critics announced they were part of a "radical science movement," giving us a convenient label for the group. 2 Weizenbaum was repelled by the attempt within artificial intelligence and cognitive science to unify mind and mechanism, but the other sciences of human nature evoked acrimony as well. In 1971 the psychologist Richard Herrnstein published an article called "IQ" in the Atlantic Monthly. 3 Herrnstein's argument, he was the first to point out, should have been banal. He wrote that as social status becomes less strongly determined by arbitrary legacies such as race, parentage, and inherited wealth, it will become more strongly determined by talent, especially (in a modern economy) intelligence. Since differences in intelligence are partly inherited, and since intelligent people tend to marry other intelligent people, when a society becomes more just it {107} will also become more stratified along genetic lines.
Smarter people will tend to float into the higher strata, and their children will tend to stay there. The basic argument should be banal because it is based on a mathematical necessity: as the proportion of variance in social status caused by nongenetic factors goes down, the proportion caused by genetic factors has to go up. It could be completely false only if there were no variation in social status based on intellectual talent (which would require that people not preferentially hire and trade with the talented) or if there were no genetic variation in intelligence which would require that people be either blank slates or clones).
Herrnstein's argument does not imply that any differences in average intelligence between races are innate (a distinct hypothesis that had been broached by the psychologist Arthur Jensen two years earlier),4 and he explicitly denied that he was making such a claim. School desegregation was less than a generation old, civil rights legislation less than a decade, so the differences that had been documented in average IQ scores of blacks and whites could easily be explained by differences in opportunity. Indeed, to say that Herrnstein's syllogism implied that black people would end up at the bottom of a genetically stratified society was to add the gratuitous assumption that blacks were on average genetically less intelligent, which Herrnstein took pains to avoid.
Nonetheless, the influential psychiatrist Alvin Poussaint wrote that Herrnstein "has become the enemy of black people and his pronouncements are a threat to the survival of every black person in America. " He asked rhetorically, "Shall we carry banners for Herrnstein proclaiming his right to freedom of speech? " Leaflets were handed out at Boston-area universities urging students to "Fight Harvard Prof's Fascist Lies," and Harvard Square was plastered with his photograph above the caption wanted for racism and five misquotations purportedly from his article. Herrnstein received a death threat and found that he could no longer speak about his research specialty, learning in pigeons, because wherever he went the lecture halls were filled with chanting mobs. At Princeton, for example, students declared they would block the doors of the auditorium to force him to answer questions on the IQ controversy. Several lectures were canceled when the hosting universities said they could not guarantee his safety. 5 The topic of innate differences among people has obvious political implications, which I will examine in later chapters. But some scholars were incensed by the seemingly warm-and-fuzzy claim that people have innate
? ? ? ? ? ? commonalities. 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. These findings, he argued, vindicated two claims that Darwin had made in his 1872 book The Expression of the Emotions in Man and {108} Animals. One was that humans had been endowed with emotional expressions by the process of evolution; the other, radical in Darwin's time, was that all races had recently diverged from a common ancestor. 6 Despite these uplifting messages, Margaret Mead called Ekman's research "outrageous," "appalling," and "a disgrace" -- and these were some of the milder responses. 7 At the annual meeting of the American Anthropological Association, Alan Lomax Jr. rose from the audience shouting that Ekman should not be allowed to speak because his ideas were fascist. On another occasion an African American activist accused him of racism for claiming that black facial expressions were no different from white ones. (Sometimes you can't win. ) And it was not just claims about innate faculties in the human species that drew the radicals' ire, but claims about innate faculties in any species. When the neuroscientist Torsten Wiesel published his historic work with David Hubel showing that the visual system of cats is largely complete at birth, another neuroscientist angrily called him a fascist and vowed to prove him wrong. ~
Some of these protests were signs of the times and faded with the decline of radical chic. But the reaction to two books on evolution continued for decades and became part of the intellectual mainstream.
The first was E. O. Wilson's Sociobiology, published in 1975. 8 Sociobiology synthesized a vast literature on animal behavior using new ideas on natural selection from George Williams, William Hamilton, John Maynard Smith, and Robert Trivers. It reviewed principles on the evolution of communication, altruism, aggression, sex, and parenting, and applied them to the major taxa of social animals such as insects, fishes, and birds. The twenty-seventh chapter did the same for Homo sapiens, treating our species like another branch of the animal kingdom. It included a review of the literature on universals and variation among societies, a discussion of language and its effects on culture, and the hypothesis that some universals (including the moral sense) may come from a human nature shaped by natural selection. Wilson expressed the hope that this idea might connect biology to the social sciences and philosophy, a forerunner of the argument in his later book Consilience.
The first attack on Sociobiology zeroed in on its main heresy. In a book-length critique, the anthropologist Marshall Sahlins defined "vulgar sociobiology" as the challenge to Durkheim's and Kroeber's doctrine of the superorganism: the belief that culture and society lived in a separate realm from individual people and their thoughts and feelings. "Vulgar sociobiology," Sahlins wrote, "consists in the explication of human social behavior as the expression of the needs and drives of the human organism, such propensities having been constructed in human nature by biological evolution. "9 Acknowledging fear of an incursion into his academic turf, he added, "The central intellectual problem does come down to the autonomy of culture and of the {109} study of culture. Sociobiology challenges the integrity of culture as a thing-in-itself, as a distinctive and symbolic human creation. "10
Sahlins's book was called The Use and Abuse of Biology. An example of the alleged abuse was the idea that Hamilton's theory of inclusive fitness could help explain the importance of family ties in human life. Hamilton had shown how a tendency to make sacrifices for relatives could have evolved. Relatives share genes, so any gene that nudges an organism to help a relative would be indirectly helping a copy of itself. The gene will proliferate if the cost incurred by the favor is less than the benefit conferred to the relative, discounted by the degree of relatedness (one- half for a full sibling or offspring, one-eighth for a first cousin, and so on). That can't be true, Sahlins wrote, because people in most cultures don't have words for fractions. This leaves them unable to figure out the coefficients of relatedness that would tell them which relatives to favor and by how much. His objection is a textbook confusion of a proximate cause with an ultimate cause. It is like saying that people can't possibly see in depth, because most cultures haven't worked out the trigonometry that underlies stereoscopic vision.
In any case, "vulgar" wasn't the half of it. Following a favorable review in the New York Review of Books by the distinguished biologist C. H. Waddington, the "Sociobiology Study Group" (including two of Wilson's colleagues, the paleontologist Stephen Jay Gould and the geneticist Richard Lewontin) published a widely circulated philippic called "Against 'Sociobiology. '" After lumping Wilson with proponents of eugenics, Social Darwinism, and Jensen's hypothesis of innate racial differences in intelligence, the signatories wrote:
The reason for the survival of these recurrent determinist theories is that they consistently tend to provide a genetic justification of the status quo and of existing privileges for certain groups according to class, race, or sex. . . . These theories provided an important basis for the enactment of sterilization laws and restrictive immigration laws by the United States between 1910 and 1930 and also for the eugenics policies which led to the establishment of gas chambers in Nazi Germany.
? ? ? ? ? ? ? . . . What Wilson's book illustrates to us is the enormous difficulty in separating out not only the effects of environment (e. g. , cultural transmission) but also the personal and social class prejudices of the researcher. Wilson joins the long parade of biological determinists whose work has served to buttress the institutions of their society by exonerating them from responsibility for social problems. 11
They also accused Wilson of discussing "the salutary advantages of genocide" and of making "institutions such as slavery. . . seem natural in human societies because of their 'universal' existence in the biological kingdom. " In
{110} case the connection wasn't clear enough, one of the signatories wrote elsewhere that "in the last analysis it was sociobiological scholarship . . . that provided the conceptual framework by which eugenic theory was transformed into genocidal practice" in Nazi Germany. 12
One can certainly find things to criticize in the final chapter of Sociobiology. We now know that some of Wilson's universals are inaccurate or too coarsely stated, and his claim that moral reasoning will someday be superseded by evolutionary biology is surely wrong. But the criticisms in "Against 'Sociobiology'" were demonstrably false. Wilson was called a "determinist,'" someone who believes that human societies conform to a rigid genetic formula. But this is what he had written:
The first and most easily verifiable diagnostic trait [about human societies] is statistical in nature. The parameters of social organization . . . vary far more among human populations than among those of any other primate species. . . . Why are human societies this flexible? 13
Similarly, Wilson was accused of believing that people are locked into castes determined by their race, class, sex, and individual genome. But in fact he had written that "there is little evidence of any hereditary solidification of status"14 and that "human populations are not very different from one another genetically. "15 Moreover:
Human societies have effloresced to levels of extreme complexity because their members have the intelligence and flexibility to play roles of virtually any degree of specification, and to switch them as the occasion demands. Modern man is an actor of many parts who may well be stretched to his limit by the constantly shifting demands of the environment. 16
As for the inevitability of aggression -- another dangerous idea he was accused of holding -- what Wilson had written was that in the course of human evolution "aggressiveness was constrained and the old forms of primate dominance replaced by complex social skills. "17 The accusation that Wilson (a lifelong liberal Democrat) was led by personal prejudice to defend racism, sexism, inequality, slavery, and genocide was especially unfair -- and irresponsible, because Wilson became a target of vilification and harassment by people who read the manifesto but not the book. 18
At Harvard there were leaflets and teach-ins, a protester with a bullhorn calling for Wilson's dismissal, and invasions of his classroom by slogan-shouting students. When he spoke at other universities, posters called him the "Right- Wing Prophet of Patriarchy" and urged people to bring noisemakers to {111} his lectures. 19 Wilson was about to speak at a 1978 meeting of the American Association for the Advancement of Science when a group of people carrying placards (one with a swastika) rushed onto the stage chanting, "Racist Wilson, . ou can't hide, we charge you with genocide. " One protester grabbed the microphone and harangued the audience while another doused Wilson with a pitcher of water.
As the notoriety of Sociobiology grew in the ensuing years, Hamilton and Trivers, who had thought up many of the ideas, also became targets of picketers, as did the anthropologists Irven DeVore and Lionel Tiger when they :ried to teach the ideas. The insinuation that Trivers was a tool of racism and right-wing oppression was particularly galling because Trivers was himself a political radical, a supporter of the Black Panthers, and a scholarly collaborator of Huey Newton's. 20 Trivers had argued that sociobiology is, if anything, a force for political progress. It is rooted in the insight that organisms did not evolve to benefit their family, group, or species, because the individuals making up those groups have genetic conflicts of interest with one another and would be selected to defend those interests. This immediately subverts the comfortable belief that those in power rule for the good of all, and it throws a spotlight on hidden actors in the social world, such as females and the younger generation. Also, by finding an evolutionary basis for altruism, sociobiology shows that a sense of justice has a deep foundation in people's minds and need not run against our organic nature. And by showing that self-deception is likely to evolve (because the best liar is the one who believes his own lies), sociobiology encourages self-scrutiny and helps undermine hypocrisy and corruption. 21 (I will return to the political beliefs of Trivers and other "Darwinian leftists" in the chapter on politics. )
Trivers later wrote of the attacks on sociobiology, "Although some of the attackers were prominent biologists, the attack seemed intellectually feeble and lazy. Gross errors in logic were permitted as long as they appeared to give
? ? ? ? ? ? ? ? ? ? ? ? ? some tactical advantage in the political struggle. . . . Because we were hirelings of the dominant interests, said these fellow hirelings of the same interests, we were their mouthpieces, employed to deepen the [deceptions] with which the ruling elite retained their unjust advantage. Although it follows from evolutionary reasoning that individuals will tend to argue in ways that are ultimately (sometimes unconsciously) self-serving, it seemed a priori unlikely that evil should reside so completely in one set of hirelings and virtue in the other. "22
The "prominent biologists" that Trivers had in mind were Gould and Lewontin, and together with the British neuroscientist Steven Rose they became the intellectual vanguard of the radical science movement. For twenty-five years they have indefatigably fought a rearguard battle against behavioral genetics, sociobiology (and later evolutionary psychology), and the neuro-science of politically sensitive topics such as sex differences and mental
{112} illness. 23 Other than Wilson, the major target of their attacks has been Richard Dawkins. In his 1976 book The Selfish Gene, Dawkins covered many of the same ideas as Wilson but concentrated on the logic of the new evolutionary theories rather than the zoological details. He said almost nothing about humans.
The radical scientists' case against Wilson and Dawkins can be summed up in two words: "determinism" and "reductionism. "24 Their writings are peppered with these words, used not in any technical sense but as vague terms of abuse. For example, here are two representative passages in a book by Lewontin, Rose, and the psychologist Leon Kamin with the defiantly Blank Slate title Not in Our Genes:
Sociobiology is a reductionist, biological determinist explanation of human existence. Its adherents claim . . . that the details of present and past social arrangements are the inevitable manifestations of the specific action of genes. 25
[Reductionists] argue that the properties of a human society are . . . no more than the sums of the individual behaviors and tendencies of the individual humans of which that society is composed. Societies are "aggressive" because the individuals who compose them are "aggressive," for instance'. 26
The quotations from Wilson we saw earlier in the chapter show that he never expressed anything close to these ridiculous beliefs, and neither, of course, did Dawkins. For example, after discussing the tendency in mammals for males to seek a greater number of sexual partners than females do, Dawkins devoted a paragraph to human societies in which he wrote:
What this astonishing variety suggests is that man's way of life is largely determined by culture rather than by genes. However, it is still possible that human males in general have a tendency towards promiscuity, and females a tendency to monogamy, as we would predict on evolutionary grounds. Which of these tendencies wins in particular societies depends on details of cultural circumstance, just as in different animal species it depends on ecological details. 27
What exactly do "determinism" and "reductionism" mean? In the precise sense in which mathematicians use the word, a "deterministic" system is one whose states are caused by prior states with absolute certainty, rather than probabilistically. Neither Dawkins nor any other sane biologist would ever dream of proposing that human behavior is deterministic, as if people must {113} commit acts of promiscuity, aggression, or selfishness at every opportunity. 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.
So much for genetic determinism. What about "reductionism" (a concept we examined in Chapter 4) and the claim that Dawkins is "the most reductionist of sociobiologists," one who believes that every trait has its own gene?
Lewontin, Rose, and Kamin try to educate their readers on how living things really work according to their alternative to reductionism, which they call "dialectical biology":
Think, for example, of the baking of a cake: the taste of the product is the result of a complex interaction of components -- such as butter, sugar, and flour -- exposed for various periods to elevated temperatures; it is not dissociable into such-or-such a percent of flour, such-or-such of butter, etc. , although each and every component. . . has its contribution to make to the final product. 28
I will let Dawkins comment:
When put like that, this dialectical biology seems to make a lot of sense. Perhaps even / can be a dialectical biologist. Come to think of it, isn't there something familiar about that cake? Yes, here it is,
? ? ? ? ? ? ? ? ? ? in a 1981 publication by the most reductionist of sociobiologists:
". . . If we follow a particular recipe, word for word, in a cookery book, what finally emerges from the oven is a cake. We cannot now break the cake into its component crumbs and say: this crumb corresponds to the first word in the recipe; this crumb corresponds to the second word in the recipe, etc. With minor exceptions such as the cherry on top, there is no one-to-one mapping from words of recipe to 'bits' of cake. The whole recipe maps onto the whole cake. "
I am not, of course, interested in claiming priority for the cake. . . . But what I do hope is that this little coincidence may at least give Rose and Lewontin pause. Could it be that their targets are not quite the nai? vely atomistic reductionists they would desperately like them to be? 29
Indeed, the accusation of reductionism is topsy-turvy because Lewontin and Rose, in their own research, are card- carrying reductionist biologists who {114} explain phenomena at the level of genes and molecules. Dawkins, in contrast, was trained as an ethologist and writes about the behavior of animals in their natural habitat.
