Peer Effects on Aggressive Behavior in Norwegian Child Care Centers

The purpose is to investigate whether levels of peers’ physical aggression and the number of externalising peers can help to predict physically aggressive behaviour in children in Norwegian kindergartens. The study will test the effect of exposure from peers in a sample of children at Norwegian kindergartens.

The main finding was that physical aggression and externalising behaviour among peers can contribute in predicting the level of children’s physical aggression. The finding is more robust for boys. The authors believe that the findings as a whole support the knock-on effect hypothesis and suggest that the affect of aggressive behaviour on processes between peers is already present in the kindergarten years. The findings show that having two or more externalising peers in the same kindergarten group predicts an increase in physical aggression for the children, especially for boys. The effect of peers seems to predict changes in children’s physical aggression exceeding normative changes, and most clearly in children aged 2-3 years old.

The findings mainly apply to kindergartens and are based on data from kindergarten teachers. The study finds no significant effect of peers’ behaviour on physical aggression reported by parents.

According to the authors, the results of the study point to the importance of avoiding the placement of several problematic children, especially boys, in the same kindergarten group.

The study’s sample of respondents is taken from a larger longitudinal study. This study uses demographic data on the children from interviews with parents when the children were 6 months old, and parent and kindergarten teacher reported data from the ages of 2, 3 and 4 years old.

Kindergarten teachers reported the frequency of physically aggressive behaviour in kindergarten contexts by ranking 8 categories when the children were 2, 3 and 4 years old. The categories were part of a set of surveys sent to kindergartens around the children’s birthdays, requesting the teacher who knew the child best to conduct the survey. The parents carried out a computerised version of the corresponding ranking scale. In addition, teachers were also asked to indicate other children in the same group with behavioural challenges that could affect the other children.

Ribeiro, L. A. & Zachrisson, H. D. (2019). "Peer Effects on Aggressive Behavior in Norwegian Child Care Centers". Child Development, 90(3):876-893.