Identifying violent offenders using a video measure of interpersonal distance (I.P.D.)

Abstract

The purpose of this study was to see if violent offenders, as had previously been reported, preferred to maintain a greater Interpersonal Distance (I.P.D.) than non-violent offenders; and if they did, to assess the extent to which violent offenders could be identified by using an I.P.D. measure. A detailed review of the literature revealed that there were considerable inadequacies in the measures of I.P.D. that had been used, and that were available. As accurate measurement was essential, the first experiment was devoted to evaluating I.P.D. measures in order to select the best measure. The I.P.D. measures used were: three pencil and paper procedures, chosen because some psychometric data were available on them and because they had been used in previous I.P.D. studies; a measure previously used in studies of I.P.D. and violence; and a Video measure developed by the author. Fifty subjects took part. The results demonstrated that the Video procedure was the best measure of I.P.D. It overcame methodological problems associated with the other measures, was superior psychometrically in several ways, including reliability and validity, and was also practical to use. The Video measure of I.P.D. was administered to 73 prisoners of whom 24 were classified as violent and 49 were non-violent. The results showed that violent offenders did prefer to maintain a greater I.P.D. than non-violent offenders (p > .005). However, I.P.D. only accounted for approximately 12% of the variance of violence and, therefore, by itself could not be used to correctly identify violent offenders. A Discriminant Function Analysis was computed using I.P.D. and seventeen other variables, such as number in family, number of previous convictions, age and I.Q., most of which had previously been shown to be related to violence. By using the discriminant function that was obtained it was possible to correctly identify 92% of the violent and 92% of the non-violent offenders. The best predictor variable of violence was Current Offence (11 of the 24 violent offenders had a violent current offence) and the next best predictor was the Video measure of I.P.D.