The Anatomy of Violence (25 page)

Let’s face it, findings come and go. Our study was the first to demonstrate a structural brain abnormality in any antisocial group. But perhaps it was just a fluke. We therefore conducted a meta-analysis that pooled together the findings of all anatomical brain-imaging studies conducted on offender populations—twelve in all—and found that this specific area of the brain is indeed structurally impaired in offenders.
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Since this meta-analysis, yet more studies have observed prefrontal structural abnormalities in offenders.
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The findings are not a fluke.

To make better sense of what we found, and to understand more fully the
implications of this specific structural brain abnormality, we need to take a quick trip to a neurologist’s clinic in Iowa. As it happens, it is the clinic of the neurologist who consulted in the pretrial hearing of Herbert Weinstein—
Antonio Damasio.

I have briefly mentioned earlier how Damasio, then at the University of Iowa and now at the
University of Southern California, made truly groundbreaking contributions to our knowledge of how the brain works. A lot of this knowledge has come from the study of unfortunate individuals who, for one reason or another, have suffered a
head injury resulting in brain damage. The silver lining to these clouds, from a scientific standpoint, is that by taking together all the clinical patients with damage to one specific brain region, and by comparing them to patients with lesions in different areas, we can draw conclusions on the critical functions of that brain region. Together with his equally brilliant wife,
Hanna Damasio, and other colleagues, Antonio has made fascinating deductions from these patients about the functions of some areas of the pre
frontal cortex and related regions, including the
amygdala.

One group of patients had lesions localized to the
ventral prefrontal cortex, the lower region of frontal cortex. It includes the orbitofrontal cortex, which sits right above your eyes, and the ventromedial prefrontal cortex, which is in line with your nose. The patients showed a striking pattern of cognitive,
emotional, and behavioral features that set them apart not just from normal controls, but also from patients with lesions outside of this brain area.
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First, at an emotional level, while their electrodermal response system is otherwise intact and responsive, patients with ventral prefrontal damage do not give
skin-conductance responses to socially meaningful pictures such as disasters and mutilations. The ventral prefrontal cortex is involved in coding social-emotional events. It connects to the limbic system and other brain areas to generate appropriate emotional responses within a social context, measured here by a
sweat response. Without that neural system in place, the individual is emotionally blunted—and we saw earlier that psychopaths and those with antisocial personality disorder are similarly emotionally blunted and
lacking in empathy.

Second, at a cognitive level, such neurological patients make bad
decisions. In a psychological test called the
Iowa gambling task, which was developed by the neurologist
Antoine Bechara, subjects have to
sort cards into one of four piles. Depending on which pile they place their card in they get monetary rewards or punishments. Unbeknownst to the subject, the decks are loaded. If they pick decks A or B, they might initially get large rewards, but eventually they are hit by even larger losses. Decks C and D give smaller rewards but they also yield much smaller punishments. Over the course of one hundred card plays, normal subjects learn about halfway through to avoid the high-reward/high-loss decks A and B. They instead persist in picking decks C and D, which ultimately give them the best payoff. They show good decision-making in the face of competing rewards and punishments. Patients with ventral prefrontal lesions don’t. They instead keep making bad decisions by picking the bad decks.
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Even more interesting is what normal individuals show in terms of their sweat responses during the task. About halfway through the task they become cognitively aware of which decks are bad, and which are good. Just prior to that, when they are consciously unaware of the good and bad decks, they contemplate picking from a bad deck. What Antoine Bechara saw on the polygraph was a skin-conductance response (a
somatic marker), a bodily alarm bell warning them that they were about to embark on a risky move. Subconsciously, their body knows that bad news is just around the corner, and that they should hold back on their response—but consciously their brain does not. Very soon after this somatic alarm bell rings, normal individuals change their strategy and switch to the good decks—and they become cognitively aware of what’s going on. The ventromedial lesion patients? No alarm bell. So they continue to pick cards from the bad decks.

It’s not surprising, then, that psychopaths make bad decisions and mess up their own lives as well as those unfortunate enough to be within their social circle. As we saw in
chapter 4
, the lack of autonomic,
emotional responsivity results in an inability to reason and decide advantageously in risky situations. This in turn is very likely to contribute to the impulsivity, rule-breaking, and reckless, irresponsible behavior that make up four of the seven traits of
antisocial personality disorder. So we can understand how structural abnormalities to the prefrontal cortex could later result in antisocial personality—they could be the cause of the functional autonomic abnormalities we documented in the last chapter.

The third striking characteristic of these patients, at a behavioral level, is that they exhibit psychopathic-like behavior. A classic example
of this, which took place more than 150 years ago and highlights the intricate link between
brain and personality, is the case of
Phineas Gage. It’s an unusual story that has been told before in neuroscience circles, but it is well worth retelling here.

Gage was a well-respected, well-liked, industrious, and responsible foreman working for the Great Western Railway. The fateful day was September 13, 1848. He was organizing the destruction of a large boulder lying in the path of the projected railway track. The work team had chiseled a hole into the boulder for the gunpowder and sand. The gunpowder was then poured into the hole. It was four-thirty in the afternoon.
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The next step should have been an apprentice pouring sand on top of the gunpowder. Gage was standing by with a metal tamping rod that was three feet seven inches long and one and a quarter inches in diameter. He was on the verge of using the rod to tamp down and compress the sand on top of the gunpowder to potentiate the explosion. At that critical moment, Gage was distracted by a conversation with his co-workers. After a few seconds he turned back to the boulder, believing that sand had been placed on top of the gunpowder. It had not. He tamped down with the rod right on top of the exposed gunpowder. The metal rod rubbed against the rock and created a spark that ignited the gunpowder. It transformed the tamping rod into a lethal spear that blasted its way right through the
head of Phineas Gage.

Gage had been stooped over the hole as he tamped down with his hand. The rod entered his lower left cheek and exited from the top-middle part of his head, creating an open flap of bone on the top of his skull. You can see this flap in
Figure 5.2
and the bone-shattering damage the rod created. The deadly missile flew through the air, landing eighty feet away, while Gage was hurled to the ground.

Understandably, all the railway workers thought Gage was as dead as a doornail. But after a couple of minutes he began to twitch and groan, and they realized that he was still alive. They put him into an oxcart and took him to the nearest town. He was carried upstairs into a hotel room and a doctor was summoned. What was the treatment in the nineteenth century when you had a tamping rod blown through your brain? Rhubarb and castor oil.

Figure 5.2
   Skull of Phineas Gage

You would not think
Gage stood a snowball’s chance in hell of surviving. But what a miraculous remedy rhubarb and castor oil turned out to be! Gage lost his left eye, but in no less than three weeks, he was out of bed and back on his feet. Within a month Gage was walking around town creating a new life for himself. And it truly was a new life. For in the words of his friends, acquaintances, and employers, he was “no longer Gage”:

We see here, very clearly, that
Gage had been transformed from a well-controlled, well-respected railway worker into a
pseudo-psychopath—an individual with psychopathic traits. Like many patients with frontal-lobe damage, he was impulsive, irresponsible, and was reputed to have been sexually promiscuous and a drunkard.
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He was fired by his employer because he was unreliable. He took on a series of jobs and moved around, switching from one job to another. Eventually he went on tour with the tamping rod and appeared in
Barnum’s American Museum in
New York and other public shows (see
Figure 5.3
). Among his many jobs he worked at an inn in Hanover, New Hampshire, in 1851, looking after horses. A spirited,
risk-taking adventurer, he even spent several years in Chile as a stagecoach driver before traveling to California, where he worked on a series of farms until his premature death on May 21, 1860, after a series of
epileptic seizures. Despite a most remarkable recovery from what should have been a mortal wound, that tamping rod he carried with him for the remainder of his life eventually got the better of him.

The case was such a remarkable one that medical doctors at the time scoffed at the idea that anyone could survive such an injury, and viewed it as a hoax. It could not possibly be true. While it was indeed a true case, could it nevertheless be unique? Can accidental damage to the pre
frontal cortex really transform an otherwise normal, law-abiding
individual into a capricious, psychopathic–like,
antisocial individual?

Figure 5.3
   Phineas Gage at Barnum’s American Museum holding the tamping rod that destroyed his prefrontal cortex

The answer can be found back in
Antonio Damasio’s and others’ laboratories. A large body of evidence has now convincingly shown that adults suffering
head injuries that damage the prefrontal cortex—especially the lower,
ventral region—do indeed show disinhibited, impulsive, antisocial behavior that does not conform to the norms of society.
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But you could counter that adults have brains that are relatively fixed. What about children, whose developing brains show much greater plasticity? Does damage to the prefrontal cortex in youngsters also lead to antisocial behavior? Overwhelmingly, studies of the behavioral changes that follow head injuries in children find that
conduct disorder and externalizing behavior problems are common.
^17
,
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While some other children develop internalizing behavior problems like anxiety and depression,
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there is little doubt overall that head injuries in children predispose them to impulsive, dysregulated behavior.
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