Abstract
It has been suggested in many studies and reviews that the form of aggressive behaviour displayed differs between the two genders. Studies that take on a developmental focus argue that the prevalence of aggression in general and relational/indirect aggression in particular varies over the developmental course of boys and girls with regard to its different function in children's and adolescents' biopsychosocial development. A closer look at the results on gender-specific expression of aggression reveals an ambiguous picture, however. Thus, the aim of this present paper is to discuss first results of a meta-analysis on studies that deal with questions regarding gender and age differences in relational and indirect aggression. Our results on 30 effect sizes from 23 primary studies on relational and indirect aggression revealed that there is sparse evidence for gender differences and for age differences in relational/indirect aggression, supporting a gender similarities hypothesis as opposed to a gender differences hypothesis. Further analyses are needed to investigate whether these differences are expression of developmental variances or the results of an underlying moderator effect of information source or other moderators.