Using experimental designs to understand the development of peer relations

In the past decades, tremendous advances have been made in our understanding of peer relations. A description is emerging of how peer relations develop. Surprisingly, though, we know less about why peer relations develop as they do. Experimental designs provide opportunities to learn about causal processes in peer relations, yet they have not been used frequently in this field. The aim of this paper is to encourage greater use of experimental designs to unravel causal processes that shape the development of peer relations. To this end, limitations of causal inferences from longitudinal studies are presented, it is demonstrated how expe000350125300001rimental designs and experiments nested in longitudinal studies can be used to test causal mechanisms, and intervention trials as real-life experiments are discussed.