HUMAN NATURE: Deeper into the Brain

National Review, Jan 24, 2000 by Charles Murray

WE, Homo sapiens, are about to learn how to alter human nature at roughly the same time that we finally learn for sure what that nature is.

Our ignorance about the underlying truth of human nature has not been for want of trying. Philosophers took up the question as one of the very first that human beings systematically asked about themselves. But philosophers produced answers as various as Aristotle's and Rousseau's. Since the late 1900s, behavioral and social scientists too have tried to understand human nature. But while they have illuminated many useful bits and pieces, they have failed as system-builders. What is left of Freud, out of the beliefs that were so intellectually pervasive in mid century? Psychotherapy remains, in profuse variety, but only remnants of Freudianism. What is left of B. F. Skinner? Behaviorism is still a productive branch of psychology, but the Skinnerian vision of human nature that once seemed so compelling is dead. As for Marx, does anything at all survive? For more than a century, Marxism was throughout continental Europe the leading intellectual framework for thinking about how political institutions can realize the nature of man. That edifice has collapsed utterly.

How can we have expended so much of our collective genius on understanding human nature and still know so little for certain? Because up until now, we have been able to observe only behavior. People can hold very different views of human nature-man is by nature altruistic or by nature selfish; by nature amoral or by nature endowed with a moral sense- -because we observe in the human animal, in abundance, every sort of behavior. Or to put it statistically, human nature does not consist of universal human characteristics but of distributions. Is mankind altruistic or selfish? From everyday experience, we know that some people behave selfishly and some behave altruistically. When one says that human beings are by nature altruistic or selfish, one is actually saying that a distribution of the human population on the characteristic of "underlying biological propensity to altruism" will have a certain shape and median. The implications of a distribution in which, for example, the average value is "fairly selfish" has very different implications from a bell curve in which the average value is "fairly altruistic." The implications of a curve that is narrow and steep (meaning that almost all human beings are very close to the median value) are very different from those of a shape that is wide and short (meaning that human nature for this characteristic is all over the map).

The problem is that, while scientists can measure the observed shape of these behaviors, they have been stymied by the nature/nurture problem. This is not to say that we know nothing. Just as geologists know a lot about the probability of finding oil based on rock formations on the surface, psychologists have learned to infer a lot about the heritability of observed traits. But in both cases, the observer is dealing with outcroppings and probabilities, while the exact, inarguable truth lies hidden.

This situation is about to change. No one can tell how rapidly and how completely the story will unfold. A few brave souls--brave indeed to buck the consistent lesson of the last five hundred years of science--still argue that the mysteries of the human mind will forever be mysteries. But E. O. Wilson's reading of the situation in his 1998 book, Consilience, seems much more plausible. The neuroscientists, increasingly understanding how the brain works, and the molecular biologists, increasingly understanding which genes do what, are about to link up with the social sciences, according to Wilson, in a "webwork of causal explanation" that brings human behavior within the realm of rigorous investigation previously reserved for physical phenomena. And not just individual behavior. "The explanatory network now touches on the edge of culture itself," in Wilson's words--or to put it another way, we are on the edge of understanding how human nature in individuals produces social and political institutions.

What we know now is fragmentary. But the speed with which that knowledge is expanding is so fast, and accelerating, that it is reasonable to expect that we are going to know a great deal about many, many aspects of human nature and their social implications within just a few more decades. By the end of the 21st century, we will be approaching biological truth about these topics.

It will be a winding road, with many false pronouncements that will be revised a year later, as new data come to light. Even those new findings that are solidly based will seldom be exciting individually. We will not find an aggression gene or a marriage gene or an IQ gene. Instead, we will learn about complex combinations of genes and their alleles that affect a behavior, and about how they interact with the unimaginably complicated neural and hormonal processes that affect behavior. We will learn about the interaction between biology and environment.