Published online by Cambridge University Press: 29 January 2018
The theory has been put forward in Crime and Personality (Eysenck, 1964) that criminals are characterized by a combination of extraverted and neurotic personality traits; put in operational terms, it was suggested that compared with a control group of normal (non-criminal) subjects they would have higher scores on the N and E scales of the MPI or the EPI (Eysenck, 1959; Eysenck and Eysenck, 1964). In the second edition of the book the further hypothesis was added that prisoners would also be characterized by high P scores; the letter P refers to a third dimension of personality provisionally entitled ‘psychoticism’. Earlier investigations of the N x E hypothesis have been reviewed in the second edition of Crime and Personality (Eysenck, 1970) and by Passingham (1972); the most recent study of both hypotheses is contained in two papers dealing with the personality makeup of male prisoners (Eysenck and Eysenck, 1970, 1971). The conclusions to be drawn from an examination of the literature are as follows: (1) As far as P is concerned, prisoners undoubtedly have much higher scores than do various types of control groups. (2) As far as N is concerned, most studies show prisoners to have significantly higher scores than controls. (3) As far as E is concerned, it appears that scores sometimes do and sometimes do not separate prisoners and controls in the predicted direction; it seems that we must distinguish between the two main components of E, i.e. sociability and impulsivity (Eysenck and Eysenck, 1969). Prisoners are significantly more impulsive, but less sociable, than controls.