Words can be a window on the soul, and computers are learning to peer through that window. A new Cornell study shows that computer analyses can identify the speech patterns that psychopaths tend to use.
Psychopathic criminals tend to make identifiable word choices when talking about their crimes, the study finds. Their words reflect their personalities, showing selfishness, detachment from their crimes and emotional flatness, report Jeff Hancock, Cornell professor of communication, and colleagues at the University of British Columbia reported Sept. 11 in the online edition of the journal Legal and Criminological Psychology.
The research could lead to new tools for diagnosis and treatment, and perhaps have applications in law enforcement.
"Our paper is the first to show that you can use automated tools to detect the distinct speech patterns of psychopaths," Hancock said. This can be valuable to clinical psychologists, he said, because the approach to treatment of psychopaths can be very different.
The researchers compared stories told by 14 imprisoned psychopathic male murderers with those of 38 convicted murderers who were not diagnosed as psychopathic. Each subject was asked to describe his crime in detail; the stories were taped, transcribed and subjected to computer analysis.
A psychopath, as described by psychologists, is emotionally flat, lacks empathy for the feelings of others, and is free of remorse. Psychopaths behave as if the world is to be used for their benefit, and they employ deception and feigned emotion to manipulate others.
The words of the experimental subjects matched these descriptions. Psychopaths used more conjunctions like "because," "since" or "so that," implying that the crime "had to be done" to obtain a particular goal. They used twice as many words relating to physical needs, such as food, sex or money, while non-psychopaths used more words about social needs, including family, religion and spirituality.
Study co-author Michael Woodworth, associate professor of psychology at the University of British Columbia, prefaced the title of the paper with "Hungry Like the Wolf" to reflect the fact that psychopaths are predators and that their stories often included details of what they had to eat on the day of their crime.
Psychopaths were more likely to use the past tense, suggesting a detachment from their crimes. They tended to be less fluent in their speech, using more "ums" and "uhs." The exact reason for this is not clear, but the researchers speculate that the psychopath is trying harder to make a positive impression and needs to use more mental effort to frame the story.
The researchers caution that their analysis applies only to murderers relating the story of their own crimes, and suggest further studies of speech patterns in more neutral situations, such as telling a neutral story from the subjects' past or describing an incident shown to them on video.
In law enforcement, Hancock suggested, it might be possible to screen suspects if some social media text were available. Knowing a suspect is psychopathic could inform strategies for pursuit or interrogation, he added.
"These findings on speech begin to open the window into the mind of the psychopath, allowing us to infer that the psychopath's world view is fundamentally different from the rest of the human species," the researchers concluded.
The research was supported by the National Science Foundation and the Canadian Social Sciences and Humanities Research Council.