How group processes push excluded people into a radical mindset: An experimental investigation

Social exclusion is a condition that seems to allow terrorism to flourish. Since radicalization is argued to occur mostly in the context of group identification and accompanying processes, we hypothesized that these may contribute to pushing excluded individuals toward radicalism. To investigate this, we performed four studies. In Studies 1 to 3, we conducted experiments in which we manipulated exclusion (vs. inclusion), created new in-groups, and measured radicalism intentions in the context of eco- or animal rights extremism. In Study 4, we tested the focal variables in a reanalysis of coded qualitative data on an Islamist sample. In Study 1, the exclusion–radicalism link revealed to be mediated by in-group sympathy as opposed to out-group antipathy. Studies 2 to 4 specifically identified perceived group threat as a driver of radicalism in the aftermath of exclusion. This work provides first experimental evidence for the catalyzing power of relationships in the exclusion–radicalism link.