To determine whether Dylan and Amber and Michael and the other adolescents we were recruiting in fact suffered from amygdala dysfunction, we needed to measure activity in this structure while they viewed fearful facial expressions. Viewing fearful expressions generally produces a robust amygdala response in healthy people. Hundreds of studies have now been conducted examining healthy adults’ brain responses to facial expressions using fMRI, and this is what they reliably show. The amygdala is more active when people view fearful expressions than when they view any other expression—backing up what studies of S.M. and other Urbach-Wiethe patients suggest, which is that the amygdala plays some special role in processing this expression.
So every time we interviewed a newly recruited adolescent for our study, Liz and I would race back to score their PCL:YV and sign up those who were eligible for a brain scan as soon as possible. Speed was imperative. We were always in a race with the unknowable, unpredictable disasters that tail kids with psychopathic traits. More than one child who cleared all our screening hurdles—getting a conduct disorder or oppositional defiant disorder diagnosis, demonstrating a normal-range IQ, receiving high psychopathy scores—became unscannable soon afterward. Several ended up hospitalized or in detention. A few of the girls got pregnant. Occasionally parents threw in the towel and sent their children to live with another relative who might be better able to manage them. We thought we were in the clear on our first attempt to scan a boy named Derek, as his scan was scheduled only a week after his interview, only to have him lope in on scanning day wearing a bulky, metal-laced monitoring bracelet on his ankle that had definitely not been there before.
“What is that?” I asked in a panic.
“It’s my monitoring bracelet,” he said. “I just got it.”
“Um… I don’t think we can put you in the scanner wearing that, Derek.”
“I can take it off.”
“No, no, no, no. Please don’t do that!” I hastened to say. “Why don’t you just come back after it’s off?”
Although MRI technology itself is quite safe, the presence of magnetic metal inside the scanning room can be catastrophic. Rarely, people have been injured or killed when loose metal oxygen tanks, scissors, or other objects were accidentally brought too near the magnet. These objects can be pulled into the bore with such force that they essentially become cannonballs in reverse, with dire consequences for anyone who happens to be inside. Even metal affixed to a person isn’t necessarily safe. A firefighter once got sucked into an MRI via the metal oxygen tank strapped to his back. He ended up pinned inside the scanner with his knees pressed so hard against his chest that he was on the verge of suffocating by the time someone quenched the magnet. The metal checks we gave each child before a scan were the stuff of a TSA supervisor’s dreams. Pockets were emptied, hair was checked and rechecked for pins and clips, jewelry was removed—even shoes, which sometimes contain a metal shank, had to come off. How quickly I came to loathe cargo pants, with their dozens of tiny pockets caching forgotten keys and safety pins.
We nearly had to cancel one scan when a subject named Brianna arrived wearing a new nose ring that she didn’t know how to remove. Putting her in with the ring was not an option. It was a great, fat steel thing, and the scanner could have torn it right through her nostril. But as luck would have it, we were running two scans that day, right next door to each other, and the other participant was Amber, who had ample experience with piercings and who offered to help when she heard Liz and me conferring.
I remember looking at Liz in alarm. I knew what both girls were capable of. They were two of our most violent participants. I half expected that just being in the same room together would cause them both to explode, like matter and antimatter colliding. But we really wanted to scan Brianna before anything else came up. (As it happened, she became pregnant not long after.) And it wasn’t like there was an explicit rule against letting participants take each other’s piercings out. True to form, they were very polite with each other. I held my breath as I watched Amber unscrew the ball at the end of the nose ring and thread the ring carefully through Brianna’s nostril. “Here you go!” she said, dropping the slightly damp ring into my palm. It was a sign of how grateful I was that it never occurred to me to be grossed out.
So, thanks to Amber, into the scanner went Brianna. Later, in went Amber. Dylan and Michael and Jamie and other teenagers like them followed. Inside the scanner, each watched through a mirror as a series of black-and-white fearful, angry, and neutral facial expressions flickered across a projection screen. I would love to know what was going through their minds as they watched. In many fMRI tasks, this is a critical question. If a participant spends the scan wondering what the task is about, the scan will be ruined—unless the researchers are trying to measure the brain activity associated with “wondering.” We were running what is called a passive viewing task. Emotional facial expressions are such primitive stimuli that people don’t need to consciously focus on them for their brains to respond. As long as their attention doesn’t get too derailed, it’s actually better if they don’t focus on what the emotion is. The simple act of labeling an emotion, whether your own or someone else’s, is actually a mild form of emotion regulation and can reduce the affective response to it. So we asked our participants to label the gender of each face instead. For over twenty minutes at a stretch, each child lay there pressing buttons to categorize over a hundred grimacing faces as male or female. It was such a deeply boring task that it’s a wonder any of them finished it. Did I mention that they had to lie perfectly still the entire time? As little as four millimeters of movement—even just a jiggling foot—could render a scan unusable. Thank goodness we could pay them. Even a child with serious behavior problems can (usually) handle twenty minutes of stock-still boredom if $75 is waiting on the other side.
For years Liz and I spent every other Sunday under the glare and buzz of the fluorescent lights in the NIH basement collecting MRI scans of these children, as well as scans of matched healthy control children to whom we could compare them. All this work was of course in part aimed at reaching our own goals—our findings ultimately were published in prestigious psychiatry journals, which helped us later attain faculty positions, research funding, and invitations to conferences. But we were also strongly motivated by the broader gains our work could yield. Our studies were the first effort to directly measure brain dysfunctions that might contribute to psychopathic traits in children and adolescents and would represent an important step toward understanding the roots of psychopathy, which might lead to better ways of identifying and treating such children in the future.
Such steps are desperately needed. Children with conduct disorder and oppositional defiant disorder are every bit as mentally ill as children with bipolar disorder or anxiety or autism, but much less is known about the origins of their disorders because only a tiny fraction of available public and private research resources are devoted to understanding them—far, far less than the resources spent on relatively less prevalent and severe disorders. Given this, it’s a small wonder that so few effective therapies—either pharmaceutical or behavioral—exist to treat them. This fact makes life worse for everyone: certainly for affected children and their families, but also for their friends, teachers, and other community members whose lives are negatively affected by the untreated aggressive and disruptive children in their midst. Despite how difficult and occasionally dispiriting it can be to study these children, the urgent need of these children and their families and communities remains a constant motivator.
At last we collected usable data from twelve non-pregnant, non-institutionalized, non-jiggly children with psychopathic traits and twenty-four matched controls (twelve of whom were healthy and the other twelve of whom had only ADHD). Subsequent analyses of the data took weeks because of the enormous amount of information that a whole-brain fMRI scan collects and the number of transformations the data must be subjected to before they can be analyzed. At the e
nd of this long process, I finally conducted the statistical test comparing activation in the amygdala across the three groups of children while they viewed fearful expressions. When the analysis finished running, I opened up the image that would show me whether our hypotheses were confirmed: whether children with psychopathic traits fail to show appropriate elevations in amygdala activity when looking at these expressions. I scrolled through the image, the whorls of the cortex unfolding as my cursor moved deep into the temporal lobe, holding my breath until I got to the amygdala, hoping that it would show a cluster of differential activation—and there it was! A little glowing red blob signifying differences in activity across the groups of children, right where it should be.
On average, our psychopathic children showed no activation—zero—in the right amygdala when they viewed the face of someone experiencing intense fear as compared to a neutral face. The sight of another person in distress made no mark on this part of their brains. This was quite unlike what we saw in the healthy children and the children with ADHD, who, on average, showed reliable increases in amygdala activity, just as most adults do. Our finding, which has now been reproduced several times by researchers from different laboratories, helps explain why children with psychopathic traits have so much difficulty recognizing fear in other people—why the sight of the distress that their violence and threats cause others has so little power to inhibit their cruelty. It is because the region of the brain that is critical for accurately identifying and responding to these expressions is defective; as a result, these children literally struggle to understand what they are looking at.
More insight into this pattern of results emerged from the results of one of the cognitive tests that Liz and I had also been conducting with the children along the way. The test was aimed at evaluating the children’s subjective experiences of different emotions. First we asked the children to recall times in their lives when they had experienced strong emotions themselves, including anger, disgust, fear, happiness, and sadness. Next, they were to describe details of each event and how it made them feel, in terms of both body sensations and psychological experiences. People who are psychopathic are known not to show strong physiological responses, like changes in sweating and heart rate, in response to images or sounds that most people find frightening. But no one had yet systematically inquired whether children with psychopathic traits feel fear psychologically in the same way as other children. As we discovered, they don’t.
Overall, the children with psychopathic traits reported that they felt fear only infrequently and weakly. When asked, for example, how often they felt fear on a scale from 1 to 7, the average response for healthy children was a little over 4. Michael and Amber both circled “1” (“never”). Their responses echoed the stories we’d heard during our interviews. Michael was forever hurting himself when attempting physical stunts like riding his bicycle off the roof of his school; Amber’s mother recounted in wonder that when Amber was in preschool she would sometimes run off and her mother would find her playing alone in the pitch-dark, spooky basement of their building. Some of the children with psychopathic traits reported that they had felt fear when, for example, they found themselves on a roller coaster that got stuck, or saw a falling tree narrowly miss their house during a hurricane. But when we queried them on how this fear felt, they reported not feeling the same intense physical changes as the healthy children, like muscle tension, shaking, or breathing changes. Two of the psychopathic children we queried claimed that they had never felt fear in their entire lives, whereas no healthy children said this.
This might be my favorite response to a question about fearfulness in the children I’ve worked with. This child, a thirteen-year-old girl, embellished her response to a survey question about fear with the comment: “(Nothing scares me!) #Nothing”:
The response of a thirteen-year-old girl with psychopathic traits and serious conduct problems when asked to indicate whether she agreed with the statement “What scares others doesn’t scare me.” She checked off “applies very well,” and so that there would be no mistake about it, added, “(Nothing scare’s me!) #Nothing.” Abigail Marsh.
We didn’t find the same pattern for any of the other emotions we asked about, all of which psychopathic and healthy children generally reported experiencing in similar ways. Ours was not the only study to find these effects; several other labs have since produced similar findings confirming that psychopathic children show drastically muted physiological and subjective fear responses.
These findings also beautifully parallel previous findings in S.M., who similarly shows no physiological or subjective fear in response to things that most people find scary. Even attempts to induce extreme fear in her by taking her through a haunted house or handing her pet snakes have yielded no fear response at all—only curiosity. Similar fearlessness has been observed in other patients with severe amygdala lesions, as well as in animals whose amygdalas have been experimentally lesioned. It appears, then, that amygdala damage, whether in association with psychopathy or as a result of Urbach-Wiethe, can result in two unusual and specific impairments: difficulty recognizing others’ fear, and a muted personal experience of fear.
To me, this suggested a possibility that goes somewhat beyond what the VIM model and other models of psychopathy propose, which is that amygdala dysfunction in psychopaths impairs not only their behavior but their fundamental ability to empathize with others’ fear.
It is widely agreed that an intact amygdala is important for coordinating the array of physiological and subjective processes that result in the experience of fear. This is not the amygdala’s only role by a mile, but it is one of its core functions. When an external threat is detected, the sensory cortex conveys detailed information about the nature of that threat to your amygdala: Is it a snake? A gun? The edge of a cliff? The amygdala—which has been described as the most densely interconnected structure in the cerebrum—then rallies the neuronal troops to respond. Messages are conveyed to ancient subcortical brain structures that govern low-level behavioral and hormonal responses to any danger, like the hypothalamus and the brain stem. These structures dutifully ratchet up your heart rate and blood pressure, maximize your air intake, rev up adrenaline production, drive blood into your muscles and away from your core, even pump sugar into your bloodstream for energy. The amygdala also conveys information about the specific threat to various regions of the cortex that enable you to register that a problem has been detected and to alter your ongoing behavior to prevent injury. Without an intact amygdala, none of these processes work very well. The various independent regions all still work, but they cannot be marshaled in the same coordinated way in response to danger.
More, it is thought that the amorphous subjective feeling of fear somehow emerges from the confluence of all this coordinated brain activity, and that too is largely lost in both amygdala lesion patients and highly psychopathic individuals. As one psychopathic sex offender interviewed by the renowned psychopathy researcher Robert Hare responded when asked why he failed to empathize with his victims, “They are frightened, right? But, you see, I don’t really understand it. I’ve been scared myself, and it wasn’t unpleasant.”
I think we can agree that this is not the statement of someone who really understands what it means to feel fear.
And if someone doesn’t understand what it means to feel fear, how can they possibly be expected to empathize with this emotion in others? In fact, as our accumulated data suggested, they can’t. Without a normally functioning amygdala, psychopathic adolescents—and presumably adults as well—don’t recognize others’ fear for what it is, they don’t understand how a frightened person is feeling, and they don’t, as a consequence, appreciate what is wrong with making someone feel this way. More recent studies I have conducted with my student Elise Cardinale show that, unlike most people, those with psychopathic traits think it is fine to cause others fear by using threats like, “I could easily hurt you,” or, “You better watch your
back.” In an fMRI study, we demonstrated that these aberrant judgments correspond to reduced amygdala activity as these individuals arrive at their judgments.
When Amber hissed threats of arson and violence at her parents, when Dylan held up a knife to his mother and threatened to cut her, when Brianna vowed to beat her schoolmates to a pulp, they did so because they had learned that threatening violence was a useful tool that would help them get their way, but they had no deep appreciation of the emotional suffering these threats caused. Dysfunction in the amygdala and the network of brain regions to which it’s connected had robbed them of an essential form of empathy, which is the simple ability to understand another person’s experience of fear. They might have had difficulty labeling the emotion their threats caused as “fear,” and they almost certainly would not have been able to accurately describe how it felt or truly understand why it was wrong to cause it.
* To protect the anonymity of individual participants, case study details have been combined to create composites, and names and identifying details have been changed.
4
THE OTHER SIDE OF THE CURVE
IN 2008, AFTER more than four years at NIMH, I wrapped up my postdoctoral position. The Department of Psychology at Georgetown University, a few miles to the south in Washington, DC, had advertised a tenure-track position for a cognitive neuroscience researcher specializing in social and affective processes, with a focus on child development. It was an enormous stroke of good fortune. The odds of a PhD landing any tenure-track professorship are low. To snag one requires luck and good timing—a university where you’d like to work must be looking for someone with your particular research focus and skills the same year that you are looking for a position. Then you just need to beat out another hundred or so applicants for it. That year, both luck and timing were on my side, and I was offered the spot at Georgetown, where I have been ever since. But my research program has expanded considerably to include research with individuals who are as unlike psychopaths as you could possibly imagine.
The Fear Factor Page 10
