The Anatomy of Violence (12 page)

In September 1986, three years after Randy Kraft’s arrest, Bustamante
burglarized a home. He did not find cash, but did uncover traveler’s checks. Things were looking good until he was surprised by the eighty-year-old occupant, who had returned from a nearby grocery store. Bustamante was six feet two inches tall and weighed in at 210 pounds. You’d think that it would not be too hard to get away from an eighty-year-old man, but Bustamante’s fight-or-flight system decided to fight instead of take flight. Bustamante beat the defenseless old man to death with his fists. According to the prosecution, blood was splattered everywhere in the apartment.

Bustamante was a messy and disorganized killer. He’d left his fingerprints everywhere at the crime scene. He hadn’t even bothered to clean himself up. When he went to cash the traveler’s checks they had blood on them. In an even more remarkable oversight, he was still wearing his bloody clothes when arrested by the police.

Two distinct types of killers: the cool, calculating Kraft, and the
bungling, bullheaded Bustamante. Divergent home backgrounds. Different ethnic backgrounds. Dissimilar criminal backgrounds. Distinct modi operandi. A very disparate number of victims. If you could look inside the minds of these men, what would you see? Would the brain scan of a murderer look like yours? Where exactly in the brain would the difference be? How would the brain functioning of serial killers like Randy Kraft differ from those of less memorable but more common-variety one-off killers like Antonio Bustamante? And how do any of us—who presumably have not killed—fit into the picture?

Not that long ago, such questions were the province of pulp fiction. In
Jonathan Demme’s movie
Silence of the Lambs
the serial killer Hannibal
Lecter scolds
FBI agent Clarice
Starling for trying to dissect him with a paper-and-pencil questionnaire, what he termed a “blunt little tool.” But today brain-imaging technology is giving us a much sharper instrument to probe the anatomy of violence. It’s giving us tangible visual evidence that there is something wrong with how such killers’ brains function. While these studies are still coming of age and have their limitations, they not only provide a basis upon which future research may build, but also raise provocative and important questions about
free will,
blame, and
punishment that we’ll return to in
chapter 10
.

But before getting to these complex ramifications, let’s look at the scientific evidence showing that murderers have a mind to crime; we can now bear witness to that fact by studying their brain functioning.

We’ve come a long, long way in our understanding of the brain.
Aristotle thought the organ was a radiator to cool blood.
Descartes thought it was an antenna for the spirit to communicate with the body. The phrenologist
Franz Gall believed that bumps on the skull revealed an individual’s personality. Now we know that this three-pound lump of gray matter is behind everything we do—seeing, hearing, touching, moving, speaking, tasting, feeling, thinking, and of course book reading. And if all actions and behaviors stem from the brain, then why not violent behavior? Why not homicide?

Before 1994, I’d never done a brain-imaging study of murderers. Neither had anyone else. It’s not too surprising, given the difficulty of recruiting and testing a substantial number of the minuscule proportion
of us who commits homicide—less than one in 20,000 in any one year in the United States.

But one reason I emigrated from England to California in 1987 was that in addition to the good weather, there were plenty
of
murderers who could be recruited into my research studies. Credit for recruiting the unusual sample I studied goes to my colleague
Monte Buchsbaum, who was just down the road from me at the University of California in
Irvine. We identified the subjects through referrals from defense attorneys. Because California has the
death penalty, their clients would die unless mitigating circumstances like
brain abnormalities could be documented. We were able to build up a unique and sizable research sample.

So, complete with shackles and chains, and flanked by guards, our forty-one murderers trooped into the brain-scanning facility. They looked pretty formidable, intimidating, and ominous. Yet in reality they were very cooperative. We forget that for 99.9 percent of their lives, murderers are just like me and you. That’s why they always come across as your next-door neighbor. Tragic actions in a few fleeting moments set murderers apart from the rest of us. As we shall see, their brain functioning also sets them apart.

The technique we used to scan their brains was
positron-emission tomography—PET for short. It allows us to measure the metabolic activity of many different regions of the brain at the same time, including the prefrontal cortex—the very front part of the brain, which sits right above your eyes and immediately behind your forehead. We used the
continuous performance task to activate or “challenge” the prefrontal cortex. The subject had to press a response button every time they saw the figure “0” flashed on a computer screen. This went on for thirty-two minutes. Believe me, it’s very boring. But the task requires sustaining
attention for a long period, and the prefrontal cortex plays an important role in maintaining vigilance. It’s this part of the brain that is active in you now and that has gotten you to reach this point in the book. After the task, the murderer was taken to the PET scanner, which measured
glucose metabolism occurring during the earlier task, rather than afterward in the scanner. The higher the glucose metabolism, the more that part of the brain was working during the cognitive task.

What did the study of forty-one murderers and forty-one age- and sex-matched normal controls reveal? Our key finding is illustrated in
Figure 3.1
, in the color-plate section, which shows the brain scan of a normal control on the left and the brain scan of a murderer on the right. It shows a horizontal slice through the brain, so you are looking down on it with a bird’s-eye view. The
prefrontal region is at the top, and the
occipital cortex—the back part of the brain, where vision is controlled—is at the bottom. The warm colors—red and yellow—indicate areas of high glucose metabolism while cool colors like blue and green indicate low brain functioning.

If you look at the normal control, on the left, you can see strong activation in the pre
frontal cortex as well as the occipital cortex (at the bottom). The murderer, on the right, shows strong activation in the occipital cortex, just like the normal control. There’s nothing wrong with his visual system. In stark contrast to the normal control, however, the murderer shows a striking lack of activation in the prefrontal cortex. Overall, the forty-one murderers showed a significant reduction in prefrontal glucose metabolism compared with the controls.
³

Why should poor prefrontal functioning predispose one to violence? What can help us to form a bridge between a bad brain and bad behavior? And what happens after
impairment to the prefrontal cortex? These questions can be answered at different conceptual levels.

It’s not just one level of analysis but five—five reasons we might expect that poor prefrontal functioning could predispose a person to violent behavior. It’s not surprising, therefore, that poor prefrontal functioning is the best-replicated correlate of antisocial and violent behavior.
⁹

Fact or artifact? Is there a true relationship between poor prefrontal functioning and homicide, or is it explained instead by some methodological artifact? We think fact. Group differences in brain functioning could not be explained away by group differences in age, sex, handedness, history of head injury, medications, or illegal drug use prior to scanning. Furthermore, the murderers could do the task—their performance was just as good as the controls’, possibly because the behavioral
occipital cortex was
more
activated in the murderers than in the controls.
¹⁰
The murderers likely recruited this visual brain area into action to help them perform the visual task and to compensate for their poorer prefrontal functioning. Prefrontal dysfunction in murderers is fact, and not artifact.

Our study constituted the first brain-imaging evidence to show that the brains of a large sample of murderers are functionally different from those of the general population. Nevertheless we must be cautious. Violence is enormously complex, and prefrontal dysfunction doesn’t apply to all murderers.

To illustrate this further, let’s return to Antonio and
Randy and delve further into their murderous minds.
Antonio Bustamante, as you will recall, was an
impulsive criminal who had for years been spiraling
downhill until he finally hit rock bottom in an unplanned, impulsive killing of a defenseless old man during a botched
burglary. As the prosecution attorney
Joseph Beard argued, it was a vicious and needless attack motivated by greed and money. He inevitably sought the
death penalty.

Bustamante had been charged by the police no fewer than twenty-nine times prior to his arrest for homicide. His crimes included theft, breaking and entering, drug offenses, strong-arm
robbery, and unlawful flight to avoid prosecution. His background and pattern of offending was typical of many lifelong recidivistic
criminals. He was your typical thug.

With one curious exception. Looking closely at his records, I see that his offending did not start until he was nearly twenty-two. That’s simply not typical of your recidivistic violent offender, whose
antisocial behavior typically starts much earlier—often in childhood and certainly by early adolescence. And yet by all accounts Bustamante was a well-behaved teenager. So what gives?

The defense team, led by
Christopher Plourd, looked over his history and the circumstances of the homicide. Something seemed strange to them too. Bustamante had been very messy and disorganized in stealing and cashing the traveler’s checks. There was blood all over them. He’d left his fingerprints everywhere at the crime scene. He was still in his bloody clothes when he was arrested. Does this sound like a well-oiled, efficient killing machine to you? Probably not. Maybe this particular killing machine had a screw loose.

Plourd discovered that his client had suffered a head injury from a crowbar at the age of twenty. By all accounts Bustamante’s personality
changed radically afterward, transforming him from a well-regulated individual into a recklessly impulsive and emotionally labile renegade. Believing that this history of head injury was significant, Plourd had his client’s brain scanned. It was at this point that
Monte Buchsbaum, a world-leading schizophrenia expert and brain-imaging researcher, became involved. He testified at trial that Bustamante was suffering from dysfunction to the
prefrontal cortex.

Antonio Bustamante was one of the forty-one murderers whose brains we had scanned, and his scan was telling. If you were sitting on the jury, what would you yourself think? Could the injury have turned Bustamante into a monster of a man unable to regulate and control his actions and emotions? Would you buy the neurological evidence
that damage to the orbitofrontal cortex impairs
decision-making and releases the brakes on emotion regulation, and that the brain scan provided objective evidence for this?

Take a good look at
Figure 3.2
, in the color-plate section and you can bear witness yourself. You can see the brain impairment to Antonio Bustamante, on the right-hand side. The orbitofrontal cortex is at the top. It’s a cool-colored green compared with the big blotch of red in the normal control on the left. Bustamante’s brain is not normal. At least, that’s what the jury believed—they spared Bustamante the
death penalty.

The prosecution was flabbergasted. As prosecution attorney Joseph Beard said: