"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."
There is compelling evidence of an association between frontal lobe brain dysfunction and aggressive behavior. Among the most striking findings are those of Lewis and her colleagues in studies of death-row inmates. All 15 death-row inmates examined by Lewis and her colleagues (1986) had histories of severe head trauma.
The basic model for how violence arises in the brain is that the initial impulses originate in deep regions of the limbic system, or emotional brain. After that, it's the job of the prefrontal cortex to decide whether to act on these impulses or not.
At the National Institute of Neurological Disorders and Stroke, Dr. Jordan Grafman, chief of the cognitive neuroscience section, has studied wounded Vietnam veterans and found that those with penetrating head injuries that caused damage to parts of the prefrontal cortex, as shown on CT scans, were at increased risk for violent behavior.
High rates of neuropsychiatric abnormalities reported in persons with violent and criminal behaviour suggest an association between aggressive dyscontrol and brain injury, especially involving the frontal lobes. The studies reviewed support an association between frontal lobe dysfunction and increased aggressive and antisocial behaviour. Focal orbitofrontal injury is specifically associated with increased aggression.
Case studies as far back as 1835 have reported the onset of antisocial personality traits after frontal lobe injury.Such cases typically involve damage to the orbitofrontal cortex, which clinical observation has associated with “poor impulse control, explosive aggressive outbursts, inappropriate verbal lewdness, jocularity, and lack of interpersonal sensitivity.”Such gross dysregulation of affect and behaviour may occur while cognitive, motor, and sensory functioning remain relatively intact. Blumer and Benson dubbed this orbitofrontal syndrome “pseudopsychopathy,” based on similarities to psychopathy—a personality type that, as defined by reliable and valid checklist criteria, is strongly associated with violence and criminality.
Inside the Mind of a Killer.
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