Seeking the Roots of Violence

Apr. 19, 1993

The search for biological clues to crime is igniting a brutal political controversy

By ANASTASIA TOUFEXIS--With reporting by Hannah Bloch/New York and Dick Thompson/Washington

It's tempting to make excuses for violence. The mugger came from a broken home and was trying to lift himself out of poverty. The wife beater was himself abused as a child. The juvenile murderer was exposed to Motley Crue records and Terminator movies. But do environmental factors wholly account for the seven-year-old child who tortures frogs? The teenager who knifes a teacher? The employee who slaughters workmates with an AK-47? Can society's ills really be responsible for all the savagery that is sweeping America? Or could some people be predisposed to violence by their genes?

Until recently, scientists had no good way to explore such questions--and little incentive: the issue was seen as so politically inflammatory that it was best left alone. But advances in genetics and biochemistry have given researchers new tools to search for biological clues to criminality. Though answers remain a long way off, advocates of the work believe science could help shed light on the roots of violence and offer new solutions for society.

But not if the research is suppressed. Investigators of the link between biology and crime find themselves caught in one of the most bitter controversies to hit the scientific community in years. The subject has become so politically incorrect that even raising it requires more bravery than many scientists can muster. Critics from the social sciences have denounced biological research efforts as intellectually unjustified and politically motivated. African-American scholars and politicians are particularly incensed; they fear that because of the high crime rates in inner cities, blacks will be wrongly branded as a group programmed for violence.

The backlash has taken a toll. In the past year, a proposed federal research initiative that would have included biological studies has been assailed, and a scheduled conference on genetics and crime has been canceled. A session on heredity and violence at February's meeting of the American Association for the Advancement of Science turned into a politically correct critique of the research; no defenders of such studies showed up on the panel. "One is basically under attack in this field," observes one federal researcher, who like many is increasingly hesitant to talk about his work publicly.

Some of the distrust is understandable, given the tawdry history of earlier efforts to link biology and crime. A century ago, Italian physician Cesare Lombroso claimed that sloping foreheads, jutting chins and long arms were signs of born criminals. In the 1960s, scientists advanced the now discounted notion that men who carry an XYY chromosome pattern, rather than the normal XY pattern, were predisposed to becoming violent criminals.

Fresh interest in the field reflects a recognition that violence has become one of the country's worst public-health threats. The U.S. is the most violent nation in the industrialized world. Homicide is the second most frequent cause of death among Americans between the ages of 15 and 24 (after accidents) and the most common among young black men and women. More than 2 million people are beaten, knifed, shot or otherwise assaulted each year, 23,000 of them fatally. No other industrialized nation comes close: Scotland, which ranked second in homicides, has less than one-fourth the U.S. rate.

This cultural disparity indicates that there are factors in American society--such as the availability of guns, economic inequity and a violence-saturated culture--that are not rooted in human biology. Nevertheless, a susceptibility to violence might partly be genetic. Errant genes play a role in many behavioral disorders, including schizophrenia and manic depression. "In virtually every behavior we look at, genes have an influence--one person will behave one way, another person will behave another way," observes Gregory Carey, assistant professor at the University of Colorado's Institute for Behavioral Genetics. It stands to reason that genes might contribute to violent activity as well.

Some studies of identical twins who have been reared apart suggest that when one twin has a criminal conviction, the other twin is more likely to have committed a crime than is the case with fraternal twins. Other research with adopted children indicates that those whose biological parents broke the law are more likely to become criminals than are adoptees whose natural parents were law-abiding.

No one believes there is a single "criminal gene" that programs people to maim or murder. Rather, a person's genetic makeup may give a subtle nudge toward violent actions. For one thing, genes help control production of behavior-regulating chemicals. One suspect substance is the neurotransmitter serotonin. Experiments at the Bowman Gray School of Medicine in North Carolina suggest that extremely aggressive monkeys have lower levels of serotonin than do more passive peers. Animals with low serotonin are more likely to bite, slap or chase other monkeys. Such animals also seem less social: they spend more time alone and less in close body contact with peers.

A similar chemical variation appears to exist in humans. Studies at the National Institute on Alcohol Abuse and Alcoholism conclude that men who commit impulsive crimes, such as murdering strangers, have low amounts of serotonin. Men convicted of premeditated violence, however, show normal levels. As for aggressive behavior in women, some researchers speculate that it might be tied to a drop in serotonin level that normally occurs just before the menstrual period. Drugs that increase serotonin, researchers suggest, may make people less violent.

Scientists are also trying to find inborn personality traits that might make people more physically aggressive. The tendency to be a thrill seeker may be one such characteristic. So might "a restless impulsiveness, an inability to defer gratification," says psychologist Richard Herrnstein of Harvard, whose theories about the hereditary nature of intelligence stirred up a political storm in the 1970s. A high threshold for anxiety or fear may be another key trait. According to psychologist Jerome Kagan, also of Harvard, such people tend to have a "special biology," with lower-than-average heart rates and blood pressure.

Findings like these may be essential to understanding--and perhaps eventually controlling--chronic wrongdoers, argue proponents of this research. "Most youth or adults who commit a violent crime will not commit a second," observes Kagan. "The group we are concerned with are the recidivists--those who have been arrested many times. This is the group for whom there might be some biological contribution." Kagan predicts that within 25 years, biological and genetic tests will be able to pick out about 15 children of every thousand who may have violent tendencies. But only one of those 15 children will actually become violent, he notes. "Do we tell the mothers of all 15 that their kids might be violent? How are the mothers then going to react to their children if we do that?"

It is just such dilemmas that have so alarmed critics. How will the information be used? Some opponents believe the research runs the danger of making women seem to be "prisoners of their hormones." Many black scholars are especially concerned. "Seeking the biological and genetic aspects of violence is dangerous to African-American youth," maintains Ronald Walters, a political science professor at Howard University. "When you consider the perception that black people have always been the violent people in this society, it is a short step from this stereotype to using this kind of research for social control."

The controversy began simmering more than a year ago, when Louis Sullivan, then Secretary of Health and Human Services, proposed a $400 million federal research program on violence; 5% of the budget would have been devoted to the study of biochemical anomalies linked to aggressive behavior. The program was shelved before being submitted to Congress, and one reason may have been the reaction to an unfortunate statement by Dr. Frederick Goodwin, then director of the Alcohol, Drug Abuse and Mental Health Administration. Commenting about research on violence in monkeys, Goodwin said, "Maybe it isn't just the careless use of the word when people call certain areas of certain cities `jungles.' " African Americans were outraged. The ensuing furor forced Goodwin to resign, though Secretary Sullivan then appointed him to head the National Institute of Mental Health, a job he still holds.

Soon after that episode, the federally endowed Human Genome Project agreed to provide the University of Maryland with $78,000 for a conference on violence. When the program's organizers announced that the session would look at genetic factors in crime, opponents torpedoed the meeting. "A scandalous episode," charges Harvard's Herrnstein. "It is beneath contempt for the National Institutes of Health to be running for cover when scholars are trying to share their views."

Dr. Peter Breggin, director of the Center for the Study of Psychiatry in Bethesda, Maryland, who led the opposition that scuttled the conference, has no apologies. "The primary problems that afflict human beings are not due to their bodies or brains, they are due to the environment," he declares. "Redefining social problems as public health problems is exactly what was done in Nazi Germany."

Some critics see the current interest in heredity as part of an ugly political trend. ``In socially conservative times," argues political scientist Diane Paul of the University of Massachusetts at Boston, "we tend to say crime and poverty are not our fault and put the blame not on society but on genes."

Even staunch believers in heredity's influence do not discount environment. In fact, the two are intimately entwined, and separating cause and effect is not easy. Biology may affect behavior, but behavior and experience also influence biology. Serotonin levels, for example, are not only controlled by genes but, according to research in monkeys, they can be lowered by regular exposure to alcohol. By the same token, says Kagan, a child with a fearless personality may turn into a criminal if reared in a chaotic home, but given a stable upbringing, "he could well become a CEO, test pilot, entrepreneur or the next Bill Clinton."

No one thinks that discovering the roots of violence will be simple. There may be as many causes as there are crimes. The issue is whether to explore all possibilities--to search for clues in both society and biology.

Copyright (c) TIME Magazine, 1995 TIME Inc. Magazine Company; (c) 1995 Compact Publishing, Inc.

Go Back to Shy David's Domestic Violence Page.