Delving into the divide: how ideological differences fuel out-party hostility in a multi-party context

Abstract This study investigates to what extent affective polarization, and more specifically hostility towards opposing party supporters, finds its roots in ideological differences. We look into the way out-groups are constructed when there are more than two political parties, and at the role of ideology in this process. Hereby we position ourselves in the discussion between those who argue that affective polarization finds its root more strongly in group attachments vs. those who argue that it is mostly rooted in ideological differences. We conduct our study in the context of the highly fragmented multi-party system of Belgium which enables us to analytically disentangle party label cues from ideological distance. Our findings demonstrate that affective polarization is largely rooted in ideological differences between party electorates in Belgium. Additionally, we find that this particularly holds for citizens who are more ideologically invested, namely those with higher political interest and more extreme ideological views.