Hot-headed or cold-blooded? Towards a clear distinction between reactive and proactive aggression in youth

The current dissertation touches on the distinction between reactive and proactive aggression. Reactive aggression is a reaction to a presumed threat which is associated with anger. This type of aggression is driven by frustration and anger and is instigated by provocation. The function of this kind of behavior is to defend oneself against or to undo an event believed to be threatening or unjust. Proactive aggression, on the other hand, is planned cold-blooded behavior. The function of this type of behavior is to take possession of things or to dominate or intimidate. Aim of the present dissertation was to provide a detailed investigation of the discriminant validity – that is, the distinctness - of reactive and proactive aggression. There is much promise in the distinction between reactive and proactive aggression; although there were some mixed findings, both are associated with different empirically tested unique correlates in the biological, personal, socio-cognitive, and environmental domains (Chapter 2). However, some have argued that both constructs are too highly related to speak of them as distinct concepts. A multi-trait multi-informant approach (Chapter 3) and a meta-analysis (Chapter 4) indeed showed that current questionnaires are not very capable of distinguishing between reactive and proactive aggression because both concepts are found to be highly related. There is reason to believe that the supposedly high correlation between reactive and proactive aggression is actually an artifact of the measures used in most research. Most questionnaires that measure reactive and proactive aggression do not exclusively focus on the function of aggression but confound the function with the form of aggression. This may explain the lack of discriminant validity associated with these questionnaires. Items in widely used measures of reactive and proactive aggression simultaneously ask for the frequency of a specific form of behavior and a function. For instance, a proactive item in a widely used measure is “uses physical force to dominate”, and a reactive item “when teased, strikes back”. Both items demonstrate an overt (physical) form, however, the first item concerns a proactive function, whereas the second item deals with a reactive function. Different functions may not be distinguished by respondents if they tend to focus on the form (which may be the same for reactive and proactive items). Such emphasis on forms of behavior may result in high correlations between reactive and proactive aggression, because forms of aggression are generally highly correlated. The meta-analytic review showed that some measures are capable of making a clear distinction. These studies either used behavioral observations or used questionnaires that kept apart the forms and functions of aggression. In the current dissertation we developed a questionnaire that kept apart the forms and functions of aggression. The functions of aggression were intra-individually consistent across forms of aggression (Chapter 5). With the new IRPA questionnaire we found good discriminant, convergent, and construct validity for reactive and proactive functions of aggression (Chapter 6). We conclude that reactive and proactive aggression can be distinguished clearly if they are conceptualized as functions of aggressive behavior. The distinction between reactive and proactive aggression was found to contribute to a clearer understanding of the motivations for aggressive behavior