Abstract
<p>Social exclusion has been proposed as a key driver of radicalization, yet experimental evidence linking exclusion with support for extremist action remains inconsistent. We investigated whether the effect of exclusion on radicalism depends on whether perceived control is preserved. To do this, we compared own-group exclusion with vicarious exclusion – that is, exclusion directed at an outgroup – an experimental condition we expected to preserve perceived control. Across two preregistered online experiments with U.S. participants (N = 466), we experimentally induced feelings of social rejection targeting the U.S. and Palestine using the RateME paradigm. While both own-group and vicarious exclusion increased hostility, only vicarious exclusion increased radicalism outcomes among participants highly fused with the outgroup. To explain these differences, we focused on psychological needs: while own-group exclusion reduced all psychological needs, including perceived control, vicarious exclusion preserved perceived control. Critically, direct comparison between both types of exclusion using moderated mediation analyses revealed that reductions in perceived control following own-group exclusion suppressed radicalism, whereas this suppression was absent after vicarious exclusion. These findings suggest that hostility following exclusion is insufficient to increase radicalism unless individuals also perceive themselves as capable of acting, suggesting that perceived control may be a pre-requisite rather than a motivation goal of extremist action.</p>