Introduction

A distinct feature of the positive school of criminology is its concern with the individual criminal rather than with the phenomenon of crime. The focal issue is why, under similar environmental conditions, one person becomes a criminal, whereas the other does not. To confront this issue, research on criminal behavior must be directed toward the study of the personal characteristics of individual criminals rather than toward the analysis of criminal acts. Since personal characteristics are based partly on biological processes, these processes must be taken into consideration if criminal behavior is to be understood.

With this notion in mind, Lombroso (1874), the founder of the positive school of criminology, devoted much effort to the study of what he thought was the criminal's inadequacy and degeneracy as manifested by physical characteristics, or stigmata. Among the numerous stigmata that Lombroso investigated, two indicated lateral asymmetries, namely, abnormal asymmetry of the face and imbalance of the cerebral hemispheres. Subsequently, Talbot (1898) reported three lateral abnormalities among criminals: atypical asymmetries of the bulk and gyral development of the cerebral hemispheres and defective development of the great interhemispheric commissures. Finally, cranial asymmetries in violent criminals were reported by Lydston (1904).

Because, according to phrenological theory, structure determined function and the exterior of the skull conformed to the interior and to the shape of the brain (Vold, 1958/1979; pp. 51, 53), it was thought that cranial asymmetry might represent hemispheric asymmetry.