Oct. 27, 2002 -- Joel Rifkin strangled 17 prostitutes in four years, at random and without remorse. But years after New York police caught him in 1994, he still said he had no idea why he killed.
"It was just something that happened and, you know, I had no plans to repeat it," Rifkin said in an interview from prison, where he is serving a life sentence. "Am I just evil? Am I brain-damaged? I mean, these are questions I want answered."
So do a lot of scientists. Using imaging techniques that allow them to map the brain with growing precision, they have found subtle but similar patterns in the brain activity of people who commit violent crimes.
The Frontal Lobe
In the 1990s a research team — led by Adrian Raine of the University of Southern California and Monte Buchsbaum, now at Mount Sinai School of Medicine in New York — did brain scans of 25 convicted murderers.
They found that many of the killers had abnormalities in the front sections of the brain — the so-called frontal lobes.
"In the normal person the frontal lobe is one of the most highly active areas of the brain," says Buchsbaum, calling up an image on his computer.
He points at a brightly colored cross-section of a man's brain on the screen. "In this individual, who carried out a murder, we can see that the frontal lobe is quite inactive."
Why does that matter? Because scientists have found that parts of the frontal lobes seem to be involved in planning and organizing, and — perhaps most important to the understanding of violent crime — impulse control.
"The frontal lobes are the part of the brain that put a brake on impulses and drives," says Dr. Jonathan Pincus, a psychiatrist at Georgetown University in Washington. "It's the part of the brain that allows us to say, 'Don't do that! Don't say that! It's not appropriate! There are going to be consequences!'"
Pincus has examined brain scans of more than 100 killers, including some of Rifkin. He says Rifkin matches many other offenders he's seen: "His frontal lobes were very, very seriously damaged."
Understanding Criminal Urges
That brain deficiency alone is not enough to make a person violent. Researchers say people with poor impulse control may simply seem poorly organized, or socially inept. Researchers cite a myriad of other factors — ranging from schizophrenia to severe abuse in childhood — that may play roles.
If a person was badly abused, says Pincus, there may be anger waiting to be released. If the person also has frontal lobe deficiency, he says, "then you have a very dangerous combination of impulses and drives that cannot be easily controlled by the damaged frontal lobes."
Buchsbaum warns against reading too much into this. Research has moved gradually, partly because doctors do not want to create a false impression that they are looking for ways to excuse violence. Researchers also agree it is far too early to say anything about the serial sniper slayings in Maryland, Virginia and Washington, D.C.
"We can't specifically say, 'This person will be a sniper and at age 30 will carry out such-and-such a crime.' That is fundamentally impossible," Buchsbaum says. "What we can do is understand the underlying dimensions of impulse control — how the brain stops behavior — and perhaps we can learn to strengthen this, with educational strategies, or with drugs."
Meanwhile, Joel Rifkin concedes that if he were ever set free, he is not sure he could prevent himself from killing again.