The Psychopath Whisperer: The Science of Those Without Conscience (14 page)

One summer I was hiking with my fellow whale research colleague Michael on the Pacific Crest Trail in California. We were hiking just south of Yosemite National Park. We had been out for over a week and we were trying to finish our hike by exiting at the Kings Canyon National Park some ten miles away. My two black female German shepherds, Andi (short for Andes mountains) and Alaya (short for Himalaya mountains), were along for the trek. Andi and I were in front of our group, Alaya behind me, with Michael pulling up the rear. As we were hiking along, Andi and I heard a funny noise coming from the trail ahead of us. It sounded like a bird fluttering under a rock. Andi’s ears perked up, and I recall thinking to myself at the time that we had both just had a P3 novelty response.

Andi proceeded to go over and investigate the rock from where the sound was emanating. When she was about a foot away, she froze and then leaped straight back up in the air. Attached to her backpack was a baby rattlesnake. I quickly flicked the snake off Andi’s backpack with my trekking pole, and we watched it slither away down the hill. We just looked at each other. We all had big P3s as a result of that baby snake, but everyone was okay. It turned out that the baby snake’s tail was not fully formed, and it did not make the distinctive rattle with which we were all familiar.

About a quarter mile later we heard the same sound again. However, this time our brain had prepared us for the target sound. All of us, canines and humans, immediately jumped back out of the way. P3 again.

We can translate this experience into the laboratory by simply requiring participants to press buttons for auditory stimuli we designate as important or salient. A robust P3 can be elicited by the salient stimuli.

Why does the brain respond like this? Well, it’s adaptive to respond quickly to important stimuli in our environment. If our brain did not permit us to learn quickly, Andi and I might have been killed by that baby rattlesnake, and our bodies would be decomposing on the side of a hiking trail in Kings Canyon National Park.

Scientists believe that the brain has a reflex that engages anytime a stimulus is potentially important. By engaging this brain reflex, we are preparing our minds to process and adapt to important stimuli. This is the essence of the P3.

My laboratory has shown that the Oddball Task elicits activity from more than thirty-five regions of the brain. The synchronous activity of these thirty-five or so regions results in the waveform we record on the scalp as the P3. Any abnormalities in the thirty-five regions of the brain responsible for the P3 will result in alterations in the amplitude, latency, or topography of the component. When we find that a mental health disorder is associated with some alteration in the P3, we have to figure out what brain regions might be causing the abnormality. In this way the P3 can serve as a probe for what’s going wrong in these thirty-five or so regions of the brain.
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I had Shock Richie complete the Oddball Task, and I took the data home for processing. As I analyzed the brain wave data that night, I noticed something very odd about Richie’s P3. Not only was it reduced in amplitude relative to other (nonpsychopathic) inmates over the front part of the brain, but it went hugely negative right after the P3. I stared at that waveform for a long time that evening.

I collected Oddball Task data from forty more psychopaths in addition to Shock Richie. I also collected brain wave data from forty inmates who scored low on the Psychopathy Checklist. The latter subjects constitute the nonpsychopathic control group (see
Figure 2
).

Figure 2
. Event-related brain response (ERP) from a frontal brain site for forty psychopaths (gray line) compared to forty nonpsychopaths (black line) for the auditory oddball stimuli. Note the prominent difference between the psychopaths and nonpsychopaths starting at about 400 milliseconds and extending out to 800 milliseconds. This is the abnormal brain wave response of psychopaths. Units on the x-axis are in microvolts with negative amplitude plotted up; units on the y-axis are in milliseconds following the onset of the oddball stimuli. Data from Kiehl, K.A., et al. (2006). Brain potentials implicate temporal lobe abnormalities in criminal psychopaths.
Journal of Abnormal Psychology
, 115, 443–453.

I printed out the eighty-one inmates’ brain responses to the Oddball Task. I assigned a random number to each case and removed any details about whether the plot was a psychopath or not. I asked a research assistant to sort the brain wave plots based on the presence or absence of the weird P3. The assistant correctly sorted forty out of forty-one psychopaths. None of the nonpsychopaths were put in the wrong group. In other words, the weird P3 was literally diagnostic of psychopathy. Ninety-seven percent of the psychopaths showed this weird brain wave response, and none of the nonpsychopaths showed any evidence of it. It was a fascinating result.

Over the course of the next year, my lab collected hundreds of additional control subjects who were not in prison, studying their oddball responses to see if we could find any indications of the weird P3 in anyone other than a psychopath.

One morning an excited research tech came into the lab to show me a plot of a brain wave response he had recently collected. I assumed it was from a new psychopath since this tech had just
been trained to collect ERPs at the prison. I reviewed the plot and concluded that it matched the template we had created for the psychopathic brain. I congratulated him on his first psychopathic brain wave.

All at once the blood drained from the tech’s face.

“What is the matter?” I asked.

“Y—you don’t understand,” he stammered. “That plot isn’t from an inmate. It’s from my roommate.”

My first thought was my assistant better get a new roommate as soon as possible. My second thought was that we couldn’t disclose anything about this plot to his roommate; it would be a serious breach of ethics.

My assistant was shaking. He started babbling about the behavior of his roommate he had met on Craigslist. The guy seemed nice enough, was very talkative, and, although he smoked a lot of marijuana, there didn’t seem to be anything wrong with him on the surface.

In the end, my assistant decided that it was probably a good idea for him to move out. That’s the best way to avoid being a victim of a psychopath—trust your gut.

A couple weeks later my assistant told me he had some interesting news. First, he had moved back in with his parents and felt a lot better. But he said that before he had moved out, his roommate had confided in him that his father had been convicted of murder.

Interesting. Would our quest to figure out the psychopath’s weird P3 response lead us to conclude there is a genetic component to the abnormalities in the brain?

Determined to figure out the psychopaths’ weird P3
brain riddle, I studied thousands of scientific articles published on the brain wave known as the P3. In parallel, I presented my unusual P3 findings on psychopaths at scientific meetings. I designed a poster describing the results and put the brain waves up in big colored graph plots so everyone could see. But nobody had a clue what the weird P3 meant.

Next, I printed out a smaller version of my poster and went to conferences to ask other scientists who studied ERPs to take a look at my plots. Again, nothing.

I started taking my data to other scientists’ presentations, asking them to look at my plots. I made friends with graduate students from all the laboratories that did ERP studies. None of them had ever seen anything like my weird P3 results. In fact, most of the graduate students initially thought my results were artifacts. But when I told them about the consistency of the results, they would often ask to see the plots again and would just stare at them for a while. Then they would look up and apologize; nobody recognized the weird brain wave.

After about a year of taking my plots around with me and finding no answers, I was getting frustrated. And I was a little scared
that I might not get my PhD if I did not have a solution to this riddle.

Then I received an invitation to give a lecture at a European conference in Budapest, Hungary. Maybe somebody in Europe could help solve the riddle of the psychopaths’ odd brain waves. I accepted the invitation and flew over to give my talk on the psychopaths’ weird P3 responses.

The audience found my results fascinating, but nobody had an answer about what they might mean. In attendance at that conference was Dr. Robert Knight, a neurologist whom I knew from my UC Davis days. Bob had published studies showing that the P3 is abnormal in patients with brain damage to the frontal lobes. But the abnormality wasn’t the same as what we were seeing in psychopaths. Nevertheless, I asked Bob about my psychopathic plots.

We went to an outdoor bar that overlooked the city and ordered a couple beers. Bob suggested I apply for a faculty position at the University of California, Berkeley, where he had just relocated from UC Davis. I was very interested in the faculty position, but I told him that I wasn’t likely to graduate anytime soon if I didn’t figure out a good interpretation of the strange P3 in psychopaths.

“Let me see that plot again,” he said.

He stared at it for a while. I had been trained to use the same software Bob used, so he was very familiar with the custom plots and the layout of my findings. After a while, he looked up at me and said, “I think I have seen this before. But I don’t remember where.” He dropped the plot back on the table. “I’ll send you a list of my papers. You can look through them to see if this plot shows up in any of them.”

Bob sent me the list of more than two hundred papers he had published.

I went to the library and spent a fortune to photocopy all his papers. I scoured every paper. Nothing. I double-checked and, again, found nothing. I became an expert in Bob Knight’s career.

I e-mailed Bob and told him that I did not find anything similar to my plots, but thanked him for sending me the list of all his publications. He wrote back that I should check the book chapters he had written. Sometimes his group published brain wave results in them.

Scientists are usually concerned only with peer-reviewed publications, where two or more scientists critique manuscripts anonymously and provide feedback to help the journal editor decide to accept or reject the scientist’s manuscript. Most good journals publish only 10 to 20 percent of the articles they receive, so it’s quite difficult to get a manuscript published by peer review. Book chapters, on the other hand, are often invited by the person organizing the book, and they are typically not peer reviewed. In academia, book chapters aren’t viewed as highly as peer-reviewed articles.

Bob had authored over fifty book chapters. Back to the library I went, to spend another fortune on photocopies.

The list of book chapters was organized alphabetically by the surname of the lead author. I placed the photocopies of the chapters in a stack on my kitchen table in the same order. As I ate dinner, I flipped through the chapters one by one, looking at the brain wave plots. As I worked my way through the pile of book chapters, I slowly drained a bottle of wine.

I got to the last book chapter, written by Yamaguchi and Knight, published in 1993.
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It was a study of the P3 in patients who had brain damage to the lateral and medial temporal lobe. I turned the page and when I looked down on the plot before me, I gasped (see
Figure 3
).

There it was. Patients with brain damage to the lateral and medial temporal lobe have the same weird P3 response as psychopaths. I could not believe it. I memorized the chapter.

From time to time I see Bob at conferences. At a recent meeting he was giving a lecture when someone in the audience asked him about the results from one of his older papers. He looked over at me and said to the audience: “I don’t remember, but Kent Kiehl does.”

The audience laughed, and I took the microphone Bob handed me and told them of the results from the 1993 paper by Yamaguchi and Knight.