Event-related potential responses of ex-combatants and war victims differ for bias stimuli

Antagonistic social identities are reflected in neurophysiological responses to implicit bias, yet empirical validation in real-life post-conflict contexts remains scarce. This cross-sectional study assessed neurocognitive responses to bias-related stimuli among 76 Colombian participants, including both victims and ex-combatants of the armed conflict. Using an Implicit Association Test combined with EEG recording and cluster-based permutation analysis, we examined group differences in event-related potentials. Results revealed differential activation patterns: a language-related N400 and an emotion-related Late Positive Potential (LPP), both showing distinct latencies and amplitudes between groups. Particularly, victims exhibited stronger LPP modulation and delayed mid-to-late components, suggesting heightened emotional processing and increased cognitive load in evaluating bias-laden content. These findings highlight how lived experiences of victimization-not merely exposure to violence-shape neurophysiological processing of intergroup bias. Our results underscore the relevance of implicit cognitive markers for informing psychosocial interventions in transitional justice and reconciliation settings.