Can the PCL-R test developed by Canadian psychologist Robert Hare tell who's a psychopath?

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."

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.

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.

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.

Hare was particularly worried, he 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.


Link:
http://www.npr.org/2011/05/26/136619689/can-a-test-really-tell-whos-a-psychopath?sc=emaf