A to Z Health Guide 2007

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Why We Turn Bad
With so many redundant moral systems to keep us in line, why do we so often fall out of ranks? Sometimes we can't help it, as when we're suffering from clinical insanity and behavior slips the grip of reason. Criminal courts are stingy about finding such exculpatory madness, requiring a disability so severe, the defendant didn't even know the crime was wrong. That's a very high bar that prevents all but a few from proving the necessary moral numbness.

Things are different in the case of the cool and deliberate serial killer, who knows the criminality of his deeds yet continues to commit them. For neuroscientists, the iciness of the acts calls to mind the case of Phineas Gage, the Vermont railway worker who in 1848 was injured when an explosion caused a tamping iron to be driven through his prefrontal cortex. Improbably, he survived, but he exhibited stark behavioral changes—becoming detached and irreverent, though never criminal. Ever since, scientists have looked for the roots of serial murder in the brain's physical state.

A study published last year in the journal NeuroImage may have helped provide some answers. Researchers working through the National Institute of Mental Health scanned the brains of 20 healthy volunteers, watching their reactions as they were presented with various legal and illegal scenarios. The brain activity that most closely tracked the hypothetical crimes—rising and falling with the severity of the scenarios—occurred in the amygdala, a deep structure that helps us make the connection between bad acts and punishments. As in the trolley studies, there was also activity in the frontal cortex. The fact that the subjects themselves had no sociopathic tendencies limits the value of the findings. But knowing how the brain functions when things work well is one good way of knowing where to look when things break down.

Fortunately, the overwhelming majority of us never run off the moral rails in remotely as awful a way as serial killers do, but we do come untracked in smaller ways. We face our biggest challenges not when we're called on to behave ourselves within our family, community or workplace but when we have to apply the same moral care to people outside our tribe.

The notion of the "other" is a tough one for Homo sapiens. Sociobiology has been criticized as one of the most reductive of sciences, ascribing the behavior of all living things—humans included—as nothing more than an effort to get as many genes as possible into the next generation. The idea makes sense, and all creatures can be forgiven for favoring their troop over others. But such bias turns dark fast.

Schulman, the psychologist and author, works with delinquent adolescents at a residential treatment center in Yonkers, New York, and was struck one day by the outrage that swept through the place when the residents learned that three of the boys had mugged an elderly woman. "I wouldn't mug an old lady. That could be my grandmother," one said. Schulman asked whom it would be O.K. to mug. The boy answered, "A Chinese delivery guy." Explains Schulman: "The old lady is someone they could empathize with. The Chinese delivery guy is alien, literally and figuratively, to them."

This kind of brutal line between insiders and outsiders is evident everywhere—mobsters, say, who kill promiscuously yet go on rhapsodically about "family." But it has its most terrible expression in wars, in which the dehumanization of the outsider is essential for wholesale slaughter to occur. Volumes have been written about what goes on in the collective mind of a place like Nazi Germany or the collapsing Yugoslavia. While killers like Adolf Hitler or Slobodan Milosevic can never be put on the couch, it's possible to understand the xenophobic strings they play in their people.

"Yugoslavia is the great modern example of manipulating tribal sentiments to create mass murder," says Jonathan Haidt, associate professor of psychology at the University of Virginia. "You saw it in Rwanda and Nazi Germany too. In most cases of genocide, you have a moral entrepreneur who exploits tribalism for evil purposes."

That, of course, does not take the stain of responsibility off the people who follow those leaders—a case that war-crimes prosecutors famously argued at the Nuremberg trials and a point courageous people have made throughout history as they sheltered Jews during World War II or refuse to murder their Sunni neighbor even if a militia leader tells them to.

For grossly imperfect creatures like us, morality may be the steepest of all developmental mountains. Our opposable thumbs and big brains gave us the tools to dominate the planet, but wisdom comes more slowly than physical hardware. We surely have a lot of killing and savagery ahead of us before we fully civilize ourselves. The hope—a realistic one, perhaps—is that the struggles still to come are fewer than those left behind.
—With reporting by Tiffany Sharples and Alexandra Silver / New York