Can A Test Really Tell Who’s A Psychopath?

Can A Test Really Tell Who’s A Psychopath?

WBEZ brings you fact-based news and information. Sign up for our newsletters to stay up to date on the stories that matter.

In November of 2009, Robert Dixon took a test to determine whether he was a psychopath.

After 26 years in prison, he was due for a parole hearing. In California, before a “lifer” like Dixon appears before the parole board, a state psychologist must first evaluate whether he poses a risk of further violence if released. To do that, the psychologist administers a test — the PCL-R, or Psychopathy Checklist-Revised — designed to measure whether that inmate is a psychopath.

This test has incredible power in the American criminal justice system. It’s used to make decisions such as what kind of sentence a criminal gets and whether an inmate is released on parole. It has even been used to help decide whether someone should be put to death.

Many psychologists believe that psychopaths are so devoid of normal human emotion, so cold and remorseless and impulsive, that they are bound, almost by their very nature, to do harm and violence.

And so Dixon found himself sitting across a table from a no-nonsense female psychologist, answering a series of questions about his family and troubled youth.

The woman, Dixon says, didn’t look at him. Instead, she stared at the computer, methodically entering his answers, her face dimly lit by the screen.

They talked for over an hour. Then the psychologist thanked him, closed her computer and went away.

Several months later, the results came back.

“Mr. Dixon obtained a total score on the PCL-R which placed him in the high range of the clinical construct of psychopathy,” the psychologist wrote.

Basically, she’d concluded that Dixon was a psychopath – the first time he’d ever received such a diagnosis. It was suddenly extremely unlikely that Dixon would be paroled.

A Robbery Gone Wrong

The story of Dixon’s incarceration begins 28 years ago, in the winter of 1983, when Dixon and his friend John Walker decided to rob a young man they saw walking down the street in their Oakland, Calif., neighborhood.

Dixon was the lookout. He positioned himself at a distance while Walker approached the man, pulled out a gun, and asked for his belongings. The crime was supposed to be quick — grab the wallet and go — but something went wrong.

Dixon remembers hearing Walker’s gun fire, then turning to find their robbery victim lying dead on the ground.

“What I saw when I looked at my co-defendant was shock – he was in shock that he had just pulled that trigger,” Dixon says. “And so I said, you know, ‘What happened!‘”

“He looked at me and he didn’t answer me. He just ran.”

For the crime of being an accessory to murder, Dixon got 15 years to life with the possibility of parole.

A Long Criminal History

This wasn’t Dixon’s first crime.

As a teen he was convicted of date-raping one woman and beating another. Since childhood, in fact, Dixon’s life had been deeply disturbed: He tried to commit suicide at 10, and at 12 he threatened to kill himself and his father, who, according to records, often beat him. He was in and out of detention for the rest of his teens — until the robbery put him in prison.

But friends and family say that since his incarceration, they’ve seen a radical change in Robert Dixon. They all believe deeply that the man they know is transformed, and no longer a threat to anyone.

One of those true believers is Dixon’s father, Robert Dixon Sr.,whom Dixon once threatened to kill.

“I’ve seen him change in the last 10 years — drastic change in him, especially with me,” Dixon Sr. says. “He got older and he kind of slowed down.”

“Age change everybody,” he adds. “I mean, it’s a poor wind that don’t change.”

A Man Transformed?

Dixon Sr. says this transformation didn’t happen quickly. For a time even after his son went to prison, he was still hard — the kind of man who might punch you in the face if you said something that he didn’t like.

In fact, Dixon Sr. says, for some years after Robert’s incarceration, the stories he heard from his son were frequently about conflict with fellow inmates. But about 12 years ago, he says, the narrative began to shift.

“He’d tell me about a lot of incidents that would come up and he would avoid ‘em.” His son, he says, had learned to walk away.

Dixon’s friends and family argue that this change wasn’t simply a matter of the mellowing that comes with age. They say it’s the product of a very deliberate, even relentless effort on Dixon’s part.

“He knows that if he’s going to get there, he’s got to be twice as disciplined. He’s got to do things above and beyond. And quite frankly, he has,” says Bob Stuart, Dixon’s best friend.

Salvaging A Life

When we met, Stuart regaled me with stories of how Dixon had worked to transform his life. He even had a folder with copies of various certificates Dixon had earned while behind bars — business courses, self-improvement seminars — a thick stack documenting hours logged in a quest for change.

A successful engineer, Stuart met Dixon through a mutual friend who thought Dixon could use a mentor. But 16 years later, it’s clear that relationship has evolved.

“I consider him my best friend,” says Stuart. “Hard to believe that someone inside prison would be, but he’s a person I trust absolutely.”

Dixon’s goal, Stuart told me, was not just to get out of prison on parole. Once out, he wanted to do good.

Dixon says the same.

“I’m not proud of my life,” he told me when I visited him in a maximum security prison in Vacaville, Calif. “I’ve hurt people. I’ve disappointed myself. I’ve ruined my life. And I’m doing everything I can to salvage some part of the second half of my life.”

So who is the real Robert Dixon — the one the test sees, or the one his friends and family see?

Born Bad? The Rise Of The Psychopath Test

Canadian psychologist Robert Hare began studying psychopaths in the 1960s, and it’s easy to forget now — in part because Hare’s work has made the concept of the psychopath so commonplace — but a half-century ago, research on psychopaths was considered both obscure and largely irrelevant to understanding crime.

Back then, Hare says, there was a very clear consensus about where crime came from: Criminals were made, not born.

“In those days, social factors, environmental factors were the explanation for all crime,” Hare says. “When you’re born, you’re a blank slate, and I can train you to be anything you want — a doctor, a dentist.”

Hare, for one, didn’t fully buy this. He thought inborn personality was important. He says that as a psychologist, when he looked at people, he just saw incredible differences in temperament: differences in impulsivity, differences in the capacity for empathy, for feeling guilt.

“We have individual differences in intelligence,” Hare says. “Well, we should have individual differences in the personality traits that are responsible or related to crime.”

Predisposed To Crime?

Hare set out to dissect the personality traits that might predispose people to criminality. To do this, he recruited the help of inmates at a prison some 30 miles down the road from his office at the University of British Columbia.

“The offenders in those days had hardly ever been studied,” Hare says, “and they were very interested in what I was doing. They would all volunteer. And in fact, one of the head inmates there — the one at the top of the heap — actually held a public address (because in those days they could congregate in groups of four or five hundred) and said, ‘Look, this sounds interesting, I’m in.’ And then everybody else said, ‘I’m in, too.‘”

Hare set up a lab and started pumping out studies on the prisoners.

In one experiment, he placed the prisoners in chairs and told them that in 30 seconds he was going to zap them with an intense electrical shock. Then Hare measured their heart rate to see if that information bothered them. Most of the prisoners were bothered, but a small subset weren’t.

“Most people show lots of emotional arousal, anticipatory fear, anxiety, while they’re waiting for the shock to occur,” Hare says. “Psychopaths, hardly any.”

Another time, Hare showed prisoners both highly emotional and totally neutral pictures — a picture of a rape, say, versus one of a table. And again, he measured their physical response.

He found that for most prisoners, the emotional pictures prompted a very different reaction than the pictures of a table or chair.

“But with psychopaths, there’s no difference,” Hare says. “They treat these horrific pictures as if they were neutral pictures — no difference whatsoever between them.”

Ultimately, this work led Hare to theorize that people with psychopathic personalities were essentially emotionally deaf. They simply did not have the capacity to feel, in a first-hand way, emotions like empathy and love and remorse.

“It’s sort of like trying to explain to a color-blind person what the color red is,” Hare says. “Can we teach a color blind person how to see red, what red is? You can have all the dictionary definitions you want, but the person will never quite get it.”

The Measure Of A Psychopath

While Hare was making progress in his research on psychopathic personality, his work was still regarded as marginal, in part because the field of psychopath research in general was in chaos.

One major problem: the lack of a clear and standardized way to identify who was a psychopath and who was not. There was no way to measure psychopathy, as it’s known.

Hare says it’s hard to overestimate just how large an issue this is for a community of scientists.

“Science cannot progress without reliable and accurate measurement of what it is you are trying to study,” he says. “The key is measurement, simple as that.”

And so Hare decided to make a way to measure: a test for psychopaths.

Hare sat down with his research assistant and together they wrote down all the personality traits they’d consistently seen in the psychopaths they’d studied. Things like lack of empathy, lack of remorse, manipulation, egocentricity, impulsivity, superficial charm, psychological lying.

For each of these qualities, Hare wrote up a description so it would be clear what he meant by, say, lack of empathy.

Psychologists using the test were supposed to ask the prisoners a series of questions to determine whether the trait was present. If it was there, the prisoner got two points; if it wasn’t, zero; if the psychologist couldn’t tell, one point was awarded.

The test listed 20 traits to check and so Hare called it the Psychopath Checklist. Scores were totaled at the end — 40 was the highest score, but anything over 30 certified the test taker as a psychopath.

Hare next tested his test to make sure that it was “scientifically reliable” — that two people using the test on the same person would reach the same conclusion about whether that person was a psychopath. In research settings, the PCL-R’s reliability appeared astonishingly good.

Voila! The test was born. It was 1980.

The Psychopath Test Meets The Criminal Justice System

For about five years, Robert Hare’s test did exactly what he wanted it to do: make the science of psychopathy better. Psychopathy researchers from around the world bombarded Hare’s lab with requests to use the PCL-R. They published study after study on their findings.

Then in the mid-’80s, one of Hare’s students, an undergraduate named Randy Kropp, decided to conduct a different kind of study using the PCL-R.

Kropp selected a group of prisoners with high, low and moderate scores on the PCL-R, then followed them after their release from prison. He wanted to see whether prisoners with high scores were more likely to commit crimes than those with low scores once they were out on parole. About a year later, he published his findings.

“Those who had low scores on the PCL-R, about 20 to 25 percent would be re-convicted within four or five years,” says Hare. “In the high group, it was about 80 percent.”

So a parolee who scored high had an 80 percent chance of committing another offense within the next five years. Low scorers had just a 20 percent chance of recidivism.

Predictive Power

These results were shocking at a time when most researchers believed criminal behavior was primarily the result of poor environments. A number of very famous psychological experiments had help created this impression: There was the Stanford prison experiment, and Stanley Milgram’s obedience to authority study (in which normal people gave electrical shocks to a person they couldn’t see because someone in a white coat told them to), as well as B. F. Skinner’s work on conditioning.

Suddenly, the PCL-R — a personality test used only in marginal academic research — appeared to identify the world’s most serious chronic criminals. The research community was stunned, says Stephen Hart, a former student of Hare’s who is now a leader in the field of psychopathy research.

“Here we are using a diagnosis of personality disorder to predict criminal behavior,and it’s working!” says Hart. “An old psychologist Jacob Cohen called this the intra-ocular effect, like it just really hit you between the eyes.”

Its predictive ability made the test potentially useful outside the lab. Shortly after Kropp’s finding went public, Hart recalls, Hare’s lab got a visit from Canada’s National Parole Board. They wanted the test:

“They said quite literally, ’ What we want to do is give everybody this test, and then have the test score written in big red numbers on the front of the file. No parole board should be able to make a decision without having some knowledge of whether or not somebody is psychopathic!“’

Potential For Misuse

But at least initially, Hare was deeply concerned about letting people in the criminal justice system use the PCL-R. He feared that the test, created purely for research purposes, might be used incorrectly in the real world and could hurt people.

He was particularly worried, Hare says, because by that point, the test had become widely respected as a scientifically reliable instrument.

“The potential for misuse of an instrument that has solid scientific credentials is very great,” Hare says. “And the reason is people say, ’ Well, it’s got solid scientific credentials — it’s really, really good. It must be good.’ So my apprehensions were there from the very, very beginning.”

For years, Hare made it clear to his students that he would not give the test out to anyone working in the criminal justice system, according to Hart.

“He said, ‘I’m never giving the checklist to people who work in the criminal justice system. I’m just going to give it to scientists who do nothing, as opposed to people who actually try to make decisions,’” Hart recalls. “And we actually had a lot of value or moral discussions about that. About whether we should actually restrict that information to certain kinds of scientists who promised not to do anything useful with it.”

According to Hart, Hare’s students argued that scientists don’t really have the right to withhold knowledge once that knowledge exists. Ultimately, Hare agreed, and published his test officially so that anyone could use it.

Which is how the test ended up being used in the criminal justice system in America, on people like Robert Dixon.

Why Robert Dixon’s Score Will Likely Keep Him In Prison

Charles Carbone, Dixon’s lawyer, is a small, wiry man with an intense gaze and perfect diction. He tells me that two years ago, when Dixon’s psychological evaluation arrived in the mail, he was devastated.

“I remember reading the report and feeling heartbroken,” Carbone says, “because I knew no matter how hard I worked from that day forward, that when I brought him back to the board, we were going to get denied.”

In California, the governor, along with the parole board, must sign off on every parole granted. Carbone says there’s just no benefit — and considerable risk — associated with being seen as soft on crime. And, he points out, there’s no political cover if the prisoner re-offends.

“The headline will be: Well, The Psychologist Told You So. There is no political upside,” Carbone says. “They only have something to lose by allowing these lifers to go home.”

Which is why few people with Dixon’s test scores ever do go home.

Still, Carbone is trying to fight it. He hired Peter Bradlee, a forensic psychologist, to evaluate Dixon. Like Dixon’s friends and family, Bradlee concluded that Dixon is not a psychopath.

“I concluded that he has developed, among other things, a sense of caring, an ability to be compassionate with other people, that he’s matured in that way,” Bradlee says.

Obviously, Bradlee and Dixon’s friends and family could be wrong: Dixon could be a psychopath.

But in recent years, use of the PCL-R in the criminal justice system has come under more intense criticism. Among the critics: its creator, Robert Hare.

Real-World Reliability And A Researcher’s Second Thoughts

Hare says he’s come to feel that some of his initial fears about the test’s potential for misuse have come to pass. “I feel ambivalent about it,” Hare says.

While Hare remains a strong believer that his test works well for the kind of basic science research that it was originally designed for, he and others have begun to wonder if it does as good a job outside the lab.

“Once you get into the real world, there does seem to be some lessening of reliability,” says Daniel Murrie, a professor at the University of Virginia who has studied what happens when psychological tests are taken from a rarefied research environment and transferred to the rough and tumble world of criminal justice.

About four years ago, Murrie decided to study the PCL-R to look at what happened when a psychologist hired by the prosecution gave Hare’s test to the same prisoner as a psychologist hired by the defense.

Did those two psychologists give the same score to the same person?

The answer, says Murrie, was no. “Ten,15, even 20-point score differences we found,” he says, ” And overall there was about an eight-point difference in scores.”

The question is why. One possibility, Murrie argues, is that the psychologists using the test in prisons and courts might not be well-trained.

“We don’t know if the people giving the test in the field have gotten formal, rigorous training, or if they’ve just sort of bought the manual and maybe read a couple of papers and just decided to start using it,” Murrie says.

But Murrie thinks it’s also something else. He says that in his study, psychologists hired by the prosecution consistently gave higher scores than psychologists employed by the defense.

Probably, Murrie says, because they’re being paid for those opinions, and that money influences them.

‘It Shouldn’t Work That Way’

As for Hare, he sees both this bias and the lack of training as a problem. It really seems to bother him.

“I’m very concerned about the inappropriate use of this instrument for purposes that have serious implications for individuals and for society,” Hare says. “It shouldn’t work that way.”

In fact, Hare says, he is so disturbed by some of what he has seen as he has traveled through America training psychologists on use of the PCL-R, that he sometimes has trouble focusing on the way his test could be affecting people’s lives.

“I think about this periodically, and I probably try to suppress it,” Hare says. “I do disassociate myself from it. I mean, if I thought about every potential use or misuse of the instrument, I probably wouldn’t sleep at all.”

Of course, Dixon’s family is convinced that there has been a misuse of Bob Hare’s test, and convinced, too, that this error will somehow, miraculously, be corrected. They even have a home waiting for Dixon when that correction finally happens.

When I went to visit Robert’s father at his home, he took me down a hallway and showed me a neatly prepared, fully equipped second bedroom. It was, he told me, for his son.

For most of their lives, these two men had serious difficulties. But somehow that conflict, Dixon Sr. says, has passed.

“We put more value on each other,” he tells me. “We found a need for us.”

Robert Dixon will have a new parole hearing in 2014. If he goes to that hearing with the psychological evaluation that he currently has — which he’s slated to do — it’s very likely he will be denied.

Meanwhile, use of the PCL-R continues to spread; it’s now mandated by statue in several states.

And the test has helped cause a shift in our ideas about where crime comes from as well.

The idea that criminal behavior is primarily a product of poor environments has much less power today, in part because Hare’s work seemed to teach us that crime resides inside the person. Inborn personality traits, like empathy, can influence whether people participate in crime.

When you think about criminals this way — as people who are almost genetically predisposed to crime — you are much less likely to invest in their rehabilitation than if you saw their acts as the product of unfortunate environmental circumstances.

This is why it’s so important to figure out if bias and bad training are affecting Hare’s test to the point that it is potentially mislabeling people.

After all, once someone is labeled as a psychopath, what can you do with him?

Nothing but lock him away.

Copyright 2011 National Public Radio. To see more, visit