Reciprocal escalation of violent extremism: Experimental and longitudinal evidence from Denmark.

Recent surges in intergroup conflict across racial, religious, and national lines highlight how mutual perceptions of threat can lead to escalating cycles of hostility. These cycles are believed to be driven by interconnected psychological, sociopolitical, and cultural mechanisms, with each group responding aggressively to perceived hostility from the other. Yet, systematic exploration of the psychological mechanisms behind reciprocally escalating violence and negativity remains limited. This research uniquely integrates experimental and longitudinal methodologies to provide novel, causal insights into these dynamics by being the first to demonstrate reciprocal violent intentions over time between majority and minority groups. This research uniquely integrates experimental and longitudinal methodologies to provide novel, causal insights into these dynamics. Using intergroup tensions in Denmark as a case in point, we investigated escalating reciprocal violent intentions between members of a majority group and a marginalized minority. In wave 1, experiments 1A and 2A showed that both groups expressed stronger endorsement of violent extremism against the other group when they perceived hostility from that group. In wave 2, experiments 1B and 2B provided evidence of a stronger effect and a reciprocal dynamic, demonstrating how intergroup conflict can escalate in tandem toward mutual hostility.