A novel EEG-based paradigm to measure intergroup prosociality. An intergenerational study in the aftermath of the genocide in Rwanda

Studying how intergroup prosociality evolves in war-torn societies is critical for understanding better the perpetuation of conflict. Rwanda is a unique example of how two groups that were in conflict in the past have to reconcile and manage their intergroup biases. In the present study, we used a novel Intended Prosociality Task to measure intergroup prosociality between former perpetrators, survivors and their children in Rwanda. In the task, participants had to decide between different individuals representing their own ingroup or their outgroup, who would be the recipient of their prosocial intentions. We measured how frequently they selected the ingroup or outgroup individuals and to what extent choosing each individual induced a cognitive conflict, as measured with reaction times (RT) and mid-frontal theta activity (FMθ). Results indicated that survivors and their children selected less frequently former perpetrators and their offspring as the recipient of their prosocial intentions. Further, nonetheless selecting them involved a higher cognitive conflict preceding their decision, as indexed by longer RT and a higher FMθ, compared to choosing their own ingroup. For the group composed of former perpetrators and their children, we observed a dissociation. They selected more frequently the outgroup individuals, perhaps as a compensating behavior for their past wrongdoings. Nonetheless, selecting the outgroup individuals involved a higher cognitive conflict preceding their decision, as indexed by longer RT when they were free to choose and higher FMθ, than selecting their own ingroup. Results are important to understand how past conflicts influence the intergroup prosociality bias and to what extent this bias is diffused to the next generation individuals.