Born criminal? Differences in structural, functional and behavioural lateralization between criminals and noncriminals.

Over 100 years ago Lombroso [(1876/2006). Criminal man. Durham: Duke University Press] proposed a biological basis for criminality. Based on inspection of criminals' skulls he theorized that an imbalance of the cerebral hemispheres was amongst 18 distinguishing features of the criminal brain. Specifically, criminals were less lateralized than noncriminals. As the advent of neuroscientific techniques makes more fine-grained inspection of differences in brain structure and function possible, we review criminals' and noncriminals' structural, functional, and behavioural lateralization to evaluate the merits of Lombroso's thesis and investigate the evidence for the biological underpinning of criminal behaviour. Although the body of research is presently small, it appears consistent with Lombroso's proposal: criminal psychopaths' brains show atypical structural asymmetries, with reduced right hemisphere grey and white matter volumes, and abnormal interhemispheric connectivity. Functional asymmetries are also atypical, with criminal psychopaths showing a less lateralized cortical response than noncriminals across verbal, visuo-spatial, and emotional tasks. Finally, the incidence of non-right-handedness is higher in criminal than non-criminal populations, consistent with reduced cortical lateralization. Thus despite Lombroso's comparatively primitive and inferential research methods, his conclusion that criminals' lateralization differs from that of noncriminals is borne out by the neuroscientific research. How atypical cortical asymmetries predispose criminal behaviour remains to be determined.