Not All Political Topics Are Created Equal: How Issue Polarization Shapes Partner Selection in Informal Political Discussion

Informal political conversations are vital for the functioning of liberal democracies, especially when they involve individuals with differing political views. While prior research suggests that incidental and non-political factors may guide individuals’ choice of discussion partners and outweigh strictly political ones, this article argues that these dynamics may shift depending on the topic of discussion. Drawing on original personal network data from the highly polarized context of Catalonia, Spain (65 citizens reporting on 663 social relationships), we compare discussion partner selection across three topics: general politics, Catalan independence (high polarization), and climate change (low polarization). We examine: (1) the extent to which political and non-political interpersonal factors facilitate or inhibit political discussion, and (2) whether their influence varies by issue polarization. Contrasting previous findings, our results reveal that opinion similarity is the strongest predictor of discussion partner selection across all topics, even when controlling for interaction opportunities, highlighting the role of purposeful partner selection. Selection on non-political factors such as tie strength, structural proximity, and socio-demographic similarity also occurs, but their influence varies depending on the issue being discussed. Tie strength and network centrality were more powerful predictors for discussion on the more polarized issue. Overall, the findings reveal that individuals selectively activate ties for political talk, and that issue polarization amplifies this selectivity, thus linking topic-alter dependence in informal political discussion networks with the growing literature on affective polarization.