انگیختگی ادراکی ایجاد حافظه های جدید اپیزودیک را بهبود می بخشد

Previous studies that operationalized reactive aggression using behavioral observations in general populations have not taken into account the type of stimulus that elicits reactive aggression. In the present study we define a specific form of reactive aggression, i.e., reactive aggression in response to neutral behavior of a peer, which we will call unprovoked reactive aggression. We were specifically interested in children with severe aggressive behavior problems, since they may respond with reactive aggression even though the opponent did not clearly provoke them, but instead showed neutral behavior. Children with a disruptive behavior disorder (DBD) and normal control (NC) children participated in separate play sessions in which they played with a normal peer (NP). Children with DBD showed more unprovoked reactive aggression than NC children, during a cooperative game. Moreover, for children with DBD, unprovoked reactive aggressive behavior in this game correlated with parent-rated reactive aggression. Results of this study suggest that an unprovoked reactive form of aggression can be identified in children with DBD.

The clinical population of aggressive children diagnosed as having either an oppositional defiant disorder (ODD) or a conduct disorder (CD) is heterogeneous, both with respect to behavior and aetiology. Therefore, a unitary construct of aggression does not suffice to qualify the behaviors of children with ODD or CD, together referred to as disruptive behavior disorders (DBD). Moreover, theories of aggressive behavior (Berkowitz, 1989 and Bandura, 1973) suggest the existence of different forms of aggression. In this respect, a distinction in children's aggressive behavior between reactive and proactive aggression (Dodge and Coie, 1987 and Dodge, 1991; for review see Kempes et al., 2005) is of importance. Over the past years a growing body of research has been dedicated to the distinction between reactive aggression and proactive aggressive behavior (Vitaro et al., 2006, Kempes et al., 2005 and Dodge, 1991). In contrast to proactive aggression, which is defined as behavior that anticipates a reward, reactive aggression has its roots in the frustration–aggression model of Berkowitz (Berkowitz, 1989). It is described as an aggressive response to a perceived threat or provocation. An abundance of studies on reactive and proactive aggression have focused on questionnaires. It was found that reactive and proactive aggression as measured by teacher-rating scales are indeed a two-dimensional phenomenon (Poulin and Boivin, 2000). The two types of aggression are related to different kinds of variables, i.e. social information processing, peer status, developmental history, in ways that are consistent with their definitions (for reviews see Kempes et al., 2005, Merk et al., 2005 and Vitaro et al., 2006). Nevertheless, correlations found between teacher-rated reactive and proactive aggression are substantial (Dodge and Coie, 1987 and Brown et al., 1996). In addition to studies using questionnaires, some studies investigated the distinction between reactive and proactive aggression by using behavioral observations of play-group interactions between peers in laboratory settings (see for example Dodge and Coie, 1987, Price and Dodge, 1989 and Schwartz et al., 1998). Not only were observed reactive and proactive aggression highly correlated with each other, but correspondence between teacher-rated and observed measures of reactive and proactive aggression was also low, with correlation coefficients ranging from 0.16 to 0.27 (Dodge and Coie, 1987 and Price and Dodge, 1989). These results raise the question whether observed and teacher-rated reactive and proactive aggression represent the same phenomena. A factor that might underlie the high correlations between reactive and proactive aggression and the low correlations between teacher-rated and observed measures is the operationalization of reactive aggression. Most observation studies that investigated children's aggressive behavior considered reactive aggression as a homogeneous category of behavior, with the emphasis lying on the impulsive and highly aroused nature of this form of aggression, and do not discriminate between factors that incite aggression. When we consider reactive aggression as an impulsive response to the behavior of an opponent, we can distinguish between different instigators. That is, aggression, provocation, or anger of a peer. However, so far researchers have mainly focused on samples from a general population. Children with severe aggressive behavior problems such as children with disruptive behavior disorders (DBD) may respond with reactive aggression even though the opponent did not clearly provoke them, but showed neutral behavior. This form of unprovoked reactive-aggressive behavior may be rooted in a hostile misinterpretation of the peer's intent (for a meta-analysis see Orobio de Castro et al., 2002). In the present study we aimed to investigate the above described form of reactive aggression, i.e., reactive aggression in response to neutral behavior, in DBD children. We conducted a dyadic play session in which normal children (NC) and DBD children played aggression-facilitating games. Previous research showed that the type of interactive partner (a DBD child or a normal peer) plays a role in the generation of antisocial behavior of DBD children (Matthys et al., 1995a) and that acquaintance with the interactive partner influences the generation of antisocial behavior (Matthys et al., 1995b). Therefore, in the present study, both NC and DBD children played with the same unacquainted normal peer (NP). We used a theory-derived criterion, i.e., latency between the action of a peer and the reaction of the focal child, to define reactive aggression as quick aggressive behavior. Thus, reactive aggression in this study was narrowed down to quick aggression in response to neutral behavior of the peer. In this definition of reactive aggression the interaction partner does not clearly provoke the aggression shown by the focal child. To examine external validity, we related observed unprovoked reactive aggression to parent-rated reactive and proactive aggression. We expected that observed unprovoked reactive aggression would be positively related to parent-rated reactive aggression, but negatively or unrelated to parent-rated proactive aggression. To investigate whether the observed unprovoked reactive aggression was related to a possible misinterpretation of the peer's intent we also included a measure of interpretation of the peer's intent.