Frequent repeat offending among people with psychopathy suggests that punishment does not modify their behavior.
The study, published in Lancet Psychiatry, shows that abnormalities can be found in the areas of the brain associated with learning from punishment. These abnormalities were not found in the brains of non-psychopathic violent offenders or non-offenders.
"One in five violent offenders is a psychopath," states study author Prof. Sheilagh Hodgins. "They have higher rates of recidivism and don't benefit from rehabilitation programs. Our research reveals why this is and can hopefully improve childhood interventions to prevent violence and behavioral therapies to reduce recidivism."
Researchers typically use the term "psychopath" to refer to individuals who display "moral depravity" or "moral insanity," despite exhibiting outwardly normal behavior.
Dr. Nigel Blackwood, co-author of the study, explains that psychopathic offenders are different from regular criminal in a variety of ways. While regular criminals are respond to threat swiftly and are quick-tempered and aggressive, psychopaths have a low response level to threats, act cold and their aggression is premeditated.
"Evidence is now accumulating to show that both types of offenders present abnormal, but distinctive, brain development from a young age," he adds. The identification of neural mechanisms in their brains behind persistent re-offending is key to the development of effective programs of rehabilitation and further crime prevention.
A comparison of brains
The researchers examined brain structure and functioning among a sample of violent offenders and healthy non-offenders in the UK utilizing magnetic resonance imaging (MRI).
From the British probation service, the team recruited 12 violent offenders with antisocial personality disorder and psychopathy and 20 violent offenders with antisocial personality but not psychopathy. Their brains were compared to those of 18 healthy non-offenders.
Among the participants with psychopathy, reductions in gray matter volume were found in the areas of the brain associated with empathy, moral reasoning and the processing of emotions such as embarrassment and guilt. The team also observed specific abnormalities that are associated with a lack of empathy considered typical of psychopathy.
While their brains were being scanned, participants completed an image-matching task designed to evaluate their ability to alter their behavior when they received positive or negative responses to their actions.
When previously rewarded responses were punished, the researchers observed that violent offenders with psychopathy displayed abnormal responses in certain areas of the brain in comparison with the non-offenders and the violent offenders without psychopathy.
"These results suggest the violent offenders with psychopathy are characterized by a distinctive organization of the brain network that is used to learn from punishment and from rewards," says Dr. Blackwood.
Learning-based interventions could 'significantly reduce violent crime'
Decision-making typically involves the weighing up of potential positive and negative outcomes of possible actions. Prof. Hodgins believes that offenders with psychopathy may only consider the positive consequences of their actions, failing to take account of any potential negative outcomes:
"Consequently, their behavior often leads to punishment rather than reward as they had expected. Punishment signals the necessity to change behavior. Clearly, in certain situations, offenders have difficulty learning from punishment to change their behavior."
The findings of the study give new insight into the neural mechanics behind the actions of violent offenders with psychopathy. The difference observed by the team between violent offenders with antisocial personality disorder with and without psychopathy could influence future treatment programs for these conditions.
This research could also serve as a foundation for further research into the abnormal development of violent offenders, which Dr. Blackwood believes could be tested in studies of children.
"Since most violent crimes are committed by men who display conduct problems from a young age, learning-based interventions that target the specific brain mechanisms underlying this behavior pattern and thereby change the behavior would significantly reduce violent crime," Prof. Hodgins suggests.
Recently, Medical News Today reported on a study suggesting a link between severe childhood neglect and structural changes to white matter in the brain.