While looming as public threats, psychopaths also stand as scientific mysteries.
Evolutionary psychologists regard psychopathy as an inherited personality style that has evolved because glib, deceitful individuals-as a minority within a larger population of trusting folk-often reproduce with much success.
Other investigators, such as neuroscientist R.J.R. Blair of the National Institute of Mental Health (NIMH) in Bethesda, Md., regard psychopathy as the result of a still-unspecified genetic disorder. The inherited defect interferes with the workings of the brain's emotion system, which is centered in the amygdala, a structure especially concerned with perceiving dangerous situations.
People with psychopathy don't modify behaviors for which they're punished and don't learn to avoid actions that harm others, Blair proposes in the September Cognition. As a result, they fail to develop a moral sense, in his view.
Blair's theory fits with previous observations that psychopaths have difficulty learning to avoid punishments, show weak physiological responses to threats, and don't often recognize sadness or fear in others.
Newman takes a different approach. He views psychopathic personalities as the product of an attention deficit. Psychopaths focus well on their explicit goals but ignore incidental information that provides perspective and guides behavior, Newman holds. Most other people, as they take action, unconsciously consult such information, for instance, rules of conduct in social settings and nonverbal signs of discomfort in those around them.
Furthermore, because psychopaths ignore peripheral information that provides context and meaning to daily situations, Newman argues, they don't appreciate music, art, or other endeavors that require depth of feeling.
In one set of studies that Newman directed, psychopathic and nonpsychopathic prisoners viewed a series of mislabeled images, such as a drawing of a pig along with the word dog. Nonpsychopathic participants found these images confusing, taking considerable time to name the objects and read the labels. Psychopathic volunteers completed these tasks much more quickly and barely noticed the discrepancies between images and labels.
Newman suspects that this narrowing of attention in psychopaths jams their mental radar for discerning other people's emotional reactions. In a study slated to appear in Psychological Science, he and his coworkers report examining people who had either a low or a high level of anxiety but weren't psychopaths. Study participants who exhibited an almost anxietyfree personality, which is one characteristic of psychopaths, showed no startle response-as measured by pronounced eye-blinks-to sudden noises that clearly surprised high-anxiety volunteers. In other words, the Wisconsin psychologist concludes, psychopaths and others who rarely or never feel anxious simply don't notice disturbing events or potential dangers in their surroundings and thus don't stop to consider them.
Unburdened by anxiety, "psychopaths respond to whims," Newman says. "This condition gets superimposed on a person's other characteristics, so a psychopath who is predisposed to violence will be violent on a whim."
