A person with a psychopath personality disorder is a person who is wholly consumed by their own self-interest and has profound emotional deficits, including the inability to empathize with people and feel guilt or remorse for their actions. In other words, a psychopath is someone who lacks a conscience. While many psychopaths are not criminals (and in unique circumstances can even use their ruthlessness to successfully climb corporate ladders), some inevitably turn to crime. When they do, there is potential risk that their escapades will result in monstrous offenses that include the serial killings by Ted Bundy, Paul Bernardo, and Robert Pickton.

As psychopaths can be incredibly destructive within society, any information on their unique thought patterns and how they behave could help improve how they are identified within the public or treated with mental health services.

To improve the information available on psychopath murderers, Dr. Hancock of Cornell University and Dr. Woodworth and Dr. Porter of the University of British Columbia published an article in Legal and Criminological Psychology which investigated the speech patterns or murderers.

Past research indicated that speech patterns can reveal important details about psychological functioning and reasoning. With this in mind, the researchers conducted a study which compared the speech patterns of convicted psychopath murderers versus non-psychopath murderers in hopes of identifying unique speech patterns which could be used to differentiate between them.

To identify these speech patterns, the researchers interviewed over 50 murderers from Canadian prisons and asked them to describe in detail the crimes that they committed. They differentiated between psychopaths and non-psychopaths using the Psychopathy Checklist Revised, a psycho-diagnostic tool used to assess psychopathy.

The researchers hypothesized that psychopaths would use vocabulary such as because, so that, and since more often than non-psychopaths because psychopaths are thought to see the world and its occupants as instruments for manipulation and domination. It was also thought that psychopaths were more likely than non-psychopaths to use more words describing basic physiological needs (such as sex, money, and shelter) versus higher-order needs such as family, relationships and spirituality when describing their crime. Lastly, they predicted that psychopaths would use less emotional terminology and speak more in the past tense in comparison to non-psychopaths because of their psychological detachment and emotional deficits.

Using the Wmantrix Linguistic Analysis Tool and the Dictionary of Affect and Language Tool, the transcripts of the interviews were analyzed. The results indicated that psychopath murderers do indeed use significantly more words that: support an instrumental orientation towards the world; are more focused on basic physiological needs; are less interested on higher-order needs; speak more in the past tense; and use less emotional terminology versus non-psychopath murderers. The results largely support the researchers’ hypotheses.

While the results are interesting and reveal unique ways in which psychopaths perceive the world, opposed to those who do not have the personality disorder, the project can be pushed further in the future. For example, research should examine whether a model based on the results of this project could be used to help identify psychopaths based on the way they speak alone. Predictive validity of the results would help corroborate the findings and perhaps even allow practical application of the research in the criminal justice system.