The Anatomy of Violence Page 9
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.
THE BRAINS OF MURDERERS
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 prefrontal 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.
1. At an emotional level, reduced prefrontal functioning results in a loss of control over the evolutionarily more primitive parts of the brain, such as the limbic system, that generate raw emotions like anger and rage.4 The more sophisticated prefrontal cortex keeps a lid on these limbic emotions. Take that lid off, and the emotions will boil over.
2. At a behavioral level, we know from research on neurological patients that damage to the prefrontal cortex results in risk-taking, irresponsibility, and rule-breaking.5 It’s not far to go from these behavioral changes to violent behavior.
3. At a personality level, frontal damage has been shown to result in a whole host of personality changes. These include impulsivity, loss of self-control, and inability to modify and inhibit behavior appropriately.6 Can you imagine these types of personality traits in violent offenders?
4. At a social level, prefrontal damage results in immaturity, lack of tact, and poor social judgment.7 From here we can imagine how a lack of social skills can result in socially inappropriate behavior and poorer ability to formulate nonaggressive solutions to fractious social encounters.
5. At a cognitive level, poor frontal functioning results in a loss of intellectual flexibility and poorer pro
blem-solving skills.8 These intellectual impairments can later result in school failure, unemployment, and economic deprivation, all factors that predispose someone to a criminal and violent way of life.
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.
BUSTAMANTE’S BUST HEAD—AND MONTE’S TESTIMONY
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:
I’d never seen anything like this before. I didn’t even know what a PET scan was. One of them was labeled “Bustamante” and the other was labeled “Normal.” They were obviously different. The shapes were different, the colors were different.… I don’t think it’s an excuse. From my perspective, its hocus-pocus.… I’m not sure that they had the wherewithal to say that someone hitting him with a pipe 20 years before dramatically changed an altar-boy into a killer.11
And that hocus-pocus PET scan still hangs on the wall of Joe Beard’s office as a reminder of the brain excuse that defendants increasingly ply in capital cases. A reminder of how pretty-colored pictures of the brain can be used to sway jurors’ perspectives on innocence versus guilt—on life in prison versus the death penalty.
Yes, the causal direction of the relationship between prefrontal dysfunction and violence is certainly open to question. Imaging does not demonstrate causality. There is only an association, and many possible counter-explanations. We’ll never know what Bustamante’s brain scan looked like the day before the homicide. We’ll never know if Bustamante’s poor orbitofrontal functioning caused him—in one way or another—to morph from an altar boy into a killer who beat an old man to death.
Nevertheless, let’s try to put the pieces together just as any detective or doctor would. Antonio Bustamante was as good as gold growing up, right until early adulthood. Then, at age twenty, a crowbar from hell struck the altar boy. Medical records from that time attest that it resulted in a very significant head injury. This injury likely increased Bustamante’s impulsivity and lowered his threshold for more accidents. Not long after the crow-bar injury, he was involved in a serious automobile accident that resulted in yet more head injuries.12
For the two decades that followed, Bustamante was incessantly in trouble with the law. He also had more bar brawls, which very likely resulted in further head injuries. It’s not exactly Jekyll and Hyde, but it’s not far off. At the relatively late age of twenty-two, he clocks up the first offense in his life—just after the crowbar and automobile incidents that resulted in head injury. Bustamante suddenly switches from good to evil, tumbling into a turbulent world of drugs and crime, eventually ending up at the house of his victim—and homicide. I think the order of events is telling.
Let’s put this Jekyll-and-Hyde transformation together with the medical fact that the area of the brain most susceptible to damage from head injury is the orbitofrontal cortex. Combine this with the well-known neurological fact that damage to the orbitofrontal cortex frequently results in disinhibited, impulsive behavior, poor decision-making, and a lack of emotional control.13 Blend this with Bustamante’s PET scan, revealing reduced orbitofrontal functioning. Consider that his crime was impulsive, not planned. While it was vicious, it was also very unsophisticated. His homicide was followed by disorganized, thoughtless actions. He made no attempt to cover his tracks.
You don’t have to be a Sherlock Holmes to deduce that it was the head injury at twenty—well beyond his control—that likely caused his poor prefrontal functioning and the later impulsive, violent offending. Even the plodding Doctor Watson with his nineteenth-century medical knowledge would likely have come to the same conclusion. But is this scenario true of all killers?
THE BRAIN OF A SERIAL KILLER
In striking contrast to Antonio Bustamante we have our other killer, Randy Kraft. You’ll recall from Randy’s early life history that we see nothing extraordinary. He grew up as an all-American boy in conservative Orange County in Southern California—not exactly the greatest risk factor for violence.
Would Randy have the same prefrontal impairments that we saw in Bustamante? Think about it. The selection of the victim. Working out how to orchestrate the evening beginning with friendly drinks. Being able to booze and schmooze without losing executive control over the situation. Timing the point to strike. The escalation to drugging the victim. Ensuring that he is well bound and cannot escape. All those bodies to get rid of. All that mess to clear up. Working on murder into the early hours only to show up for work the same morning and put in a hard day’s computing.
How did he do it? You can see for yourself in Randy’s brain scan. Take a good look at Figure 3.3, in the color-plate section, and focus on the three scans in a row. On the left you have the normal control, on the right you have a single murderer, and in the middle you have Randy Kraft—labeled “Multiple Murderer.” Check out the difference between Randy’s brain and the single murderer. What stands out is that he does not have reduced frontal functioning. Instead, that part of the brain is lit up like a Christmas tree.
To me, Randy is the exception that proves the rule. Here we have a man capable of killing approximately sixty-four people in a twelve-year period without getting caught. You have to have good prefrontal functioning to pull that off. He had an excellent ability to plan, to regulate his actions, to think ahead, to consider alternative plans of action, to sustain attention, and to keep on task. It’s exactly what you need to be a successful serial killer. He’s an exception in that he differs from other killers in his brain profile. He proves the rule that a lack of frontal functioning results in a lack of ability to plan, regulate, and control one’s impulses, resulting in not just homicide but early apprehension.