Both genetic and environmental factors contribute to individual differences in aggression. Catechol-O-methyltransferase Val158Met (COMT), a common, functional polymorphism, has been implicated in aggression and aggression traits, as have childhood experiences of adversity. It is unknown whether these effects are additive or interactional and, in…

This study investigated the normative use and developmental course of physical aggression (PA), defined as use of physical force such as hitting, biting, and kicking, from 8 to 26 months and predictors thereof. We used data from the Behavior Outlook Norwegian Developmental Study, comprising 1,159 children (559 girls and 600 boys). Both mothers and…

This study aims to conceptualize disobedient pupil behavior within the more general framework of antisocial behavior and to reveal how two forms of aggressiveness are related to disobedience. Disobedience, in the context of this article, covers disruptive pupil behavior or discipline problems when the pupil is aware of breaking a standard set by…