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Does the Brain’s Geography Reveal Criminal Predispositions?

April 15, 2011

Over the past 10 years, research scientists have made illuminating discoveries about the geography of the typical criminal mind. Recently in one such study, scientists observed a group of 21 people, all of whom were characterized as having “antisocial personality disorder,” a condition often found in criminals. People with the disorder are described as those who “may often violate the law and the rights of others,” and “typically have no regard for right and wrong.” When compared with a control group of individuals who did not have a personality disorder, brain scans of the antisocial group showed on average, an 18% and 9% reduction in the volume of two particular frontal brain lobes.

Though intriguing, this is not a ground-breaking discovery. In 2009, another study compared the brain scans of 27 psychopaths, people who have severe antisocial personality disorder, to the brain scans of 32 control individuals who did not exhibit psychopathic tendencies. [In 1980, the Diagnostic and Statistical Manual of Mental Disorders (DSM III) changed the term psychopath to “antisocial personality disorder,” but essentially the terms characterize the same behavior; an abnormal lack of empathy, extreme egocentricity, irresponsible and impulsive conduct and an ability to appear outwardly normal.] The study revealed that the individuals with severe antisocial behavior had deformations in their amygdala, the part of the brain linked to motivation and emotions such as fear and pleasure. The psychopaths showed an average of 18% volume reduction and dramatic thinning of the cortex.

In 2005, Adrian Raine Ph.D, former professor of psychology at the University of Southern California and current chair of the Department of Criminology at the University of Pennsylvania, conducted a study that compared the MRI (magnetic resonance imaging) data of a sampling of 52 individuals that yielded similar results. Raine and his coworkers used five Los Angeles area temporary employment agencies to seek out subjects for the study. In order to determine whether the subjects demonstrated any psychopathic tendencies, and if so, to what degree, they administered various tests including the Psychopathy Checklist–Revised, Structured Clinical Interview for the DSM-IV Mental Disorders (SCID I), and SCID Axis II Personality Disorders (SCID II). Guaranteeing confidentiality, the researchers also sought to compile information about the criminal history of each subject by way of interviews and criminal records searches. Eventually the researchers ended up with a group of 52 individuals. 13 of the 52 demonstrated high psychopathy scores and had been determined to have escaped detection for their crimes, while 16 had high psychopathy scores and had been convicted for their criminal acts. The remaining 23 served as control subjects. The MRI data indicated that volume of prefrontal matter, a region of the brain involved in judgment, planning, and decision making, was on average 22% less in unsuccessful psychopaths than in the control subjects. The prefrontal cortex of psychopaths who had avoided criminal detection was slightly smaller than those who had been detected but the difference was not nearly as significant.

The studies can be characterized as improving understanding of criminal behavior but their increased presence in scientific publications raises the question, “how should we use this information?” The results pose serious questions, the answers of which transcend mere issues of predicting and minimizing criminal behavior. If we can in fact, identify, study and predict criminal behavior, how should we integrate this information into our foundational beliefs surrounding the application of guilt and conviction? Criminal law has taught us that in order to be guilty of some particularly heinous crimes, the requisite mens rea is intent. For inherently dangerous crimes, especially those that demonstrate intent and premeditation, we as a society punish people who in theory, were aware of the gravity of their actions, but committed the crimes regardless. However, these studies indicate that certain individuals with predisposition for criminal behavior have reduced capacity for judgment and decision making. Is it appropriate to convict these individuals when we know they may not have the capacity to make the intentional decisions we accuse them of making?

The ALI Penal Code dictates that a person is not responsible for their criminal conduct if at the time of such conduct as a result of mental disease or defect he lacks the substantial capacity either to appreciate the wrongfulness of his conduct, or to conform their conduct to the requirement of the law. A strong argument can be made that this definition is on point in describing a psychopath and their behavior. In one illustrative case, a convicted murderer struck a plea bargain in which the sentence for killing his wife was reduced to only 11 years based on brain scans that revealed a large cyst that was thought to compromise his cognitive abilities. “Imaging was used to reduce his culpability, to reduce his responsibility,” said Raine. “Yet is that not a slippery slope to Armageddon where there’s no responsibility in society?”

However, if we are hesitant to convict those who do not understand the gravity of their actions, how do we protect an innocent society from the danger their behavior poses? As future law makers and advocates, these studies pose endless ethical questions and the dilemma is anything but new. Consider Cesare Lombroso, a man who was convinced that physical anomalies and physiognomy could lead to predictions about criminal behavior. He supposed that people were simply born criminals. His theories of criminology were echoed by Hitler as a basis for genocide. It is crucial that we tread carefully when applying the results of these studies.