Parietal laterality and violence.

To test whether laterality of parietal lobe cerebral functioning might relate to a history of violent behavior, a sample of 33 male and female, right-handed juvenile offenders, divided into less and more violent, each performed the Weighs Test. A lateralization index (left-hand score divided by right-hand score) formed the dependent variable. Differences for sexes and ages, but not ethnicities, required corrections. As hypothesized, poorer right- than left-parietal function related positively with the violence of past crimes. A sample of 18 additional subjects replicated the findings. The results were discussed in terms of a concept of cerebral "area-appropriateness," so that when the task-appropriate area performs less well than a less-appropriate area, we may begin to infer a dysfunction which may relate to "dyscontrol" and to violent behavior.