Crime Library: Criminal Minds and Methods

Dr. Robert Hare: Expert on the Psychopath


"When I was working on my Ph.D.," Hare recalls, "I was interested in the effects of punishment on human behavior.  My dissertation looked at the frequency, intensity, duration, and delay effects of punishment.  Of course, I needed to start thinking about people who were resistant to the effects of punishment, so I started reading up on the psychopath.  Hardly any empirical research on psychopathy was going on, so I started to publish some of my own results in 1965."

That led to an opportunity.  At John Wiley & Sons, Inc., Brendan Maher was putting together a series of books on behavior pathology.  He was impressed with Hare's work and asked him to write one of the books, so in 1970, Hare published Psychopathy: Theory and Research, which set forth some ideas that would guide much of the research on psychopaths over the next two decades.  Just the year before, he had received a large grant from the Canadian Mental Health Association, and this provided funds to increase his research efforts.

He noticed throughout the early 1970s that other researchers in the same area were using different classification systems to address psychopathy, such as categories based on the Minnesota Multiphasic Personality Inventory and the California Psychological Inventory.  That was a problem, however, because these were self-report inventories, and it's not difficult for clever psychopaths to figure out the test structures and to lie.  Aside from that, researchers were going in too many different directions.

"Nothing was consistent," Hare says.  "The results were all over the place.  I began to realize that if you can't measure the concept, you can't study it."

He decided to experiment with different systems of assessment and measurement, using ratings based on clinical accounts, such as the detailed case descriptions of psychopaths that he had read in The Mask of Sanity.  "Cleckley was the one who put it all together for me," Hare affirmed.

He and his assistant went through numerous files and did many interviews, trying to determine what makes one person a psychopath and another person not.  He came up with a three-point rating system, and then a seven-point one. Yet neither satisfied him, and journal editors did not understand what he was actually measuring.  Then, as with most discoveries, perseverance and the constant grind of trying different things finally paid off. 

"One day," Hare remembers, "a research assistant who had been with me for a dozen years and I decided to quantify what we thought went into our assessments.  First, we listed all the characteristics we thought are important.  We had about a hundred different features and characteristics.  Then we started to score these on people on whom we already had done the seven-point assessment.  We were able to cut the list down to twenty-two items that we thought were useful for discriminating a psychopathic criminal from a non-psychopathic criminal."

Hare's first published work on this 22-item research scale for the assessment of psychopathy appeared in 1980.

That was the same year that the DSM-III came out.

Then the field began to divide.

Hare was acquainted with people who were on the DSM-III work committees and had some input into their discussions about the criteria they were devising for what they were calling antisocial personality disorder.  However, he diverged significantly from American ideas about the disorder.

Dr. Lee Robins, an eminent sociologist whom Hare knew, was working to focus the antisocial diagnosis strictly on behavior.  Hare recalls that it was her contention that clinicians cannot reliably measure personality traits such as empathy, so it was best just to drop them from the list of criteria and include only overt behaviors.

Hare saw a draft of what the committee was proposing and he spotted real problems.  Of the list of 10 items, which consisted primarily of violations of social norms, a person needed to manifest only a few to be diagnosed with antisocial personality disorder.  To his mind, that would encompass the entire prison population.  Not only that, it would not be congruent with his understanding of a psychopath.  He made suggestions for changes to bring antisocial personality disorder a little closer to psychopathy, but for the most part the committee members went forward with their own ideas.

The DSM-IV Manual

With some adjustments, these criteria were continued over the next two decades in the DSM-III-R and the DSM-IV.  Accordingly, clinicians who use these manuals look for symptoms in people over 18 and not otherwise psychotic who since age 15 have shown a pervasive pattern of disregard for, and violation of, the rights of others.  Among these behaviors, the person has done at least three of the following:

  • failure to conform to lawful social norms
  • deceitfulness
  • impulsivity or failure to plan ahead
  • irritability and aggressiveness, as indicated by repeated physical fights or assaults
  • reckless disregard for safety of self or others
  • consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations
  • lack of remorse, as indicated by being indifferent about having hurt, mistreated, or stolen from another


So while there was now a list of explicit criteria for clinicians to use, APD (Antisocial Personality Disorder) proved to be unworkable for those who were researching psychopathy.  Hare points out, In forensic populations, diagnoses of APD have far less utility with respect to treatment outcome, institutional adjustment, and predictions of post-release behavior than do careful assessments of psychopathy based on the traditional use of both behaviors and inferred personality traits.   While most psychopaths may fit the criteria for APD, the majority of people with APD are not psychopaths.  In other words, there were now two different diagnostic instruments to assess two different populations that shared some but not all traits in common.

The PCL-R Manual, Second Edition

Hare had continued his work with the assessment scale, eventually called the Psychopathy Checklist, and in 1985, he revised it to include only twenty items.  It was now known as the Psychopathy Checklist-Revised (PCL-R), and was completed on the basis of a semi-structured interview with the people being assessed, along with information from files.  Person by person, each trait on the scale was rated on a scale from 0, meaning the person did not manifest it, to 2, meaning he or she definitely did.  The total score was 40, and a person was diagnosed as a psychopath if his or her score fell between 30 and 40. (In some places, a cut-off score of 25 is useful.)

To help others with scoring, Hare put together a brief informal manual consisting of about twenty pages, and this was passed around.  As more people used the scale and sent Hare their ideas and results, the manual grew in thickness.  Finally in 1991, Hare formally published it with Multi Health Systems, which currently distributes it to qualified professionals.  Throughout the rest of the decade, more researchers affirmed the PCL-R's reliability and validity with male forensic populations, and some branched off into work with adolescents and with females.  Cross-cultural studies showed that the concept of psychopathy, as measured by the PCL-R, was generalizable. 

According to Hare in an article published in 1998, Psychopathy is one of the best validated constructs in the realm of psychopathology. The PCL-R generated a dramatic increase in basic research on the nature of psychopathy and on the implications of the disorder for the mental health and criminal justice systems.

Once it was clear that the PCL-R yielded such solid results, it was time to reach a larger audience than professional diagnosticianspeople who might be the victims.