Psychopathic serial killers may one day be unmasked by a simple 10-minute test, British psychologists propose in Thursday’s issue of Nature.
Psychopaths are dangerous people who are remorseless and without a conscience, yet are often highly skilled at lying and charming and at faking the emotions they lack. Their suave patina of sanity means psychopathic murderers, driven by a relentless thirst to kill, can sometimes evade detection for years.
That was notoriously the case in the American serial killers Ted Bundy and Jeffrey Dahmer, and in Britain’s ”doctor of death,” Harold Shipman, who between them took more than 200 lives before they were finally snared.
A group led by Nicola Gray of Cardiff University believe murderous psychopaths can be swiftly spotted because they lack emotional attachment to the meaning of words.
The team have adapted a procedure called the Implicit Association Test (IAT), a standard psychology test which is used to detect whether an individual secretly harbours prejudices about homosexuality, race or gender.
The modified test uses words which flash up on a screen, one after another. The individual has to classify each word as either ”pleasant” or ”unpleasant” and either ”violent” or ”peaceful”.
There are two buttons available, each with two labels. When the labels are ”pleasant” and ”peaceful” on one button, and ”violent” and ”unpleasant” on the other, the classification task is easy.
For instance, ”kill” is easily considered violent, while ”vomit” is considered unpleasant.
But if the labels are swapped around — so that one button is used, say, for ”pleasant” and ”violent” and the other for ”peaceful” and ”unpleasant” — things start to get complicated.
For instance, if ”blood” or ”peace” flashes up, ordinary people take more time, for they have to think more about the concept of the word, before choosing which button to press.
It is that relative time difference, between the tests on the congruent and incongruent labels, that makes the big difference.
”With psychopathic murderers, there’s almost no difference between whether we put the ‘violent’ words with ‘pleasant’ (ones), or the ‘violent’ words with ‘unpleasant’ ones, they are just as fast,” said co-author Robert Snowden an interview.
The Gray team carried out the test on 121 male convicts, 13 of whom were psychopathic murderers; 17 were non-psychopathic murderers; 39 were psychopaths who had committed offences other than murder; and the remaining 52 were non-psychopaths who had committed offences other than murders.
The telltale rapid response shown by psychopathic murderers can probably be pinned to their ”abnormal social beliefs” about violence, the authors say.
”Psychopathic murderers have diminished negative reactions to violence compared with non-psychopathic murders and other offenders.”
The study points out that not all psychopaths are murderers and some non-psychopathic murderers, too, can be remorseless about taking life.
The test could be useful for distinguishing those psychopaths who have a taste for extreme violence from the majority of psychopaths who do not, it suggests.
Snowden said that there is already a standard psychopathy test, but it takes between three to five hours to administer and has to be followed an assessment, lasting about eight hours, that has to be conducted by a trained interviewer with access to the subject’s full case history.
The modified IAT takes ”about five to 10 minutes,” and could be conducted by police investigators probing a suspect, although the results would need analysis by a psychologist, Gray said.
Psychopaths are considered to have an extreme personality disorder and have the appearance of sanity.
In contrast, psychotics, who have delusions such as schizophrenia or suffer from manic depression, are considered to have a mental illness. They only rarely commit acts of violence.
On the other hand, 90% f serial murderers are psychopathic, previous research has found. – Sapa-AFP