Beliefs about aggression: a trial of the revised EXPAGG and the Aggression questionnaire with New Zealand student and offender populations

Abstract

Beliefs about aggression were examined using a scale designed to measure instrumental and expressive beliefs (the Revised EXPAGG) with New Zealand male students and male violent and non-violent offenders. Scores on the Revised Expagg were compared with scores on a self-report measure of aggression, the Aggression Questionnaire, and compared to previous findings by Archer and Haigh (1997) with British students and offenders. In contrast to previous findings, there was no significant difference between violent and non-violent offenders on either the expressive or instrumental scale of the Revised EXPAGG. Offenders had significantly higher scores on the instrumental scale than students, but there was no difference between the two groups on the expressive scale. The present study was also unable to replicate the four-factor structure of the Aggression Questionnaire found in previous studies. Overall, these findings cast doubt on the construct validity of the expressive scale of the Revised EXPAGG, and also suggest that subscales of the Aggression Questionnaire should be interpreted with caution. However, as found in previous studies, the instrumental scale of the Revised EXPAGG was highly correlated with scores on the Aggression Questionnaire.