Psychopaths are not cold-blooded, but have attention deficit

AN ATTENTION deficit, rather than an inability to feel emotion, may be what makes psychopathic individuals seem fearless. It's a finding that challenges the common characterisation of such people as cold-blooded predators.

"A lot of their problems may be a consequence of something that's almost like a learning difficulty," says Joseph Newman, a psychologist at the University of Wisconsin-Madison who investigated how prisoners with psychopathic personalities react when anticipating pain.

Previous experiments have suggested such people may not feel fear, while brain imaging studies have found abnormalities in the amygdala, a region that processes fear and other emotions. This has encouraged the perception that they are "emotionally shallow", Newman says. "People call them cold-blooded predators." But he questioned whether this was the whole story.

To tease apart why such people behave the way they do, Newman's team recruited 125 male prisoners convicted of serious crimes and scored them on traits characteristic of a psychopathic personality, including narcissism, impulsivity and callousness. About 20 per cent scored highly enough to be described as psychopathic - a proportion typical for criminals but well above the 1 per cent expected in the general population.

The researchers then hooked each prisoner up to a device that measures how strongly they blink - an indication of how afraid they are - and placed a screen in front of them. The subjects were warned that during tasks in which letters flashed on the screen, an electric shock would sometimes follow a red letter, but never a green one.

When instructed to push buttons to indicate whether letters were green or red, subjects with marked psychopathic characteristics flinched in response to red letters with the same strength as other subjects.

Yet when they were told to indicate whether letters were capitals or lower-case, the psychopathic prisoners barely blinked upon seeing red letters, while the others continued to anticipate the mild shock (Biological Psychiatry, DOI: 10.1016/j.biopsych.2009.07.035).

This suggests that psychopathic individuals sense fear as much as anyone, and only seem fearless because they find it harder to pay attention to what is scary and what is not, says Newman, who hopes his hypothesis can be used to discourage psychopathic repeat offenders. "They're famous for being difficult if not impossible to treat," he says.

Donald Hands, director of psychology at the Wisconsin Department of Corrections, is working with Newman to design a pilot treatment programme. Reminding psychopathic lawbreakers of the immediate consequences of their actions, such as getting arrested and sent back to prison, might help to dissuade them from reoffending, he says.

Newman's finding may also persuade prison authorities to treat psychopathic individuals differently. "I think this shows that there's some humanity there," Hands says. "It challenges the belief that they are robots."