Stable or dynamic? Explaining the development of Muslim and non-Muslim boys’ and girls’ friendship-making across adolescence

Friendship segregation between Muslim and non-Muslim youth in Europe is well documented. However, previous network studies provide only snapshots, thus ignoring whether interreligious friendship-making changes throughout adolescence. A recent non-network study suggests increasing in-group friendships among Muslim girls and stability among Muslim boys, but it could not explain these differences and did not consider interdependence with non-Muslims’ friendship-making. To overcome these limitations, we study the trajectories of friendship-making among Muslim and non-Muslim boys and girls and assess the explanatory power of three key determinants of interreligious friendship-making dynamics: interreligious attitudes, religious norms that constrain out-group friendships, and reactions to friendship-making behavior of other groups. Addressing the methodological limitations of non-network research, we study friendship trajectories with stochastic actor-oriented models for network evolution applied to five waves of longitudinal friendship network data among 1122 Muslim and non-Muslim youth in German schools. We find that Muslim girls start out with at least as many interreligious friends as Muslim boys but that their tendency to have non-Muslim friends decreases substantially throughout adolescence. By contrast, the religious friendship-making of both Muslim boys and non-Muslims of either gender remains stable over time. We show that the increase in in-group friendships only applies to Muslim girls with high religiosity and that it is particularly strong for cross-gender friendships, suggesting that gendered religious norms can explain differences in the dynamics of Muslim boys’ and girls’ friendship-making. By contrast, interreligious attitudes and reactions to shifts in other groups’ friendship-making do not contribute to the observed friendship-making trajectories.