Intergroup conflict, also called civil conflict, is one of the world’s most serious problems, as warfare has shifted from the battlefield toward something enmeshed within civilian life. The constant exposure to high-stress conflict situations affects everyone, but it may have an outsized influence on developing adolescent brains. A recent study published in PNAS found that adolescents who grow up in protracted civil conflicts end up more empathetic and cognitively attuned to the people within their own group and less sensitive to pain felt by others.

The researchers who conducted this study recruited 85 adolescents from a conflict-ridden region in Israel. They categorized the participants as identifying either as Arab-Palestinian or Jewish-Israeli. The participants were shown a set of well-validated photographs of other people who clearly belonged to one of these groups, either in painful or non-painful conditions. During this task, each participant's brain activity was measured using MEG (magnetoencephalography), a functional neuroimaging technique that tracks the magnetic effects of currents moving through neurons to visualize brain activity.

The authors found that adolescents from both groups (Arab and Jewish) responded differently to ingroup and outgroup images. All the subjects showed significant brain activation in pain-empathy regions when the pain images contained in-group characters. But when an outgroup figure was shown, there was no difference in the response, regardless of whether that figure was experiencing pain. So all participants could have an empathetic response, but only to members of their own group

The group of Palestinian adolescents also showed significant similarities in terms of their brain region activation they exhibited while looking at photographs of other in-group members. This wasn't seen in the Israeli teens. The authors suspect this results from different levels of ethnocentric identification between these two groups—Arab-Palestinian adolescents were more likely to report that they identified with their own ethnic group very strongly. This may produce the similar responses in brain activity seen among the Arab-Palestinian teens.

The authors also looked at the social behavior of the participants when they interacted with teens from the other ethnic group. They found that both groups of adolescents showed moderate levels of intergroup hostility and a low willingness for intergroup compromise. They also found that the teens showed less empathic behavior, measured in verbal patterns within conflict and non-conflict conversations, toward adolescents from the other ethnic group than they did toward in-group members.

This study demonstrates that adolescents’ exposure to prolonged conflict can significantly affect the way that they related to people who are on the other side of that conflict. These adolescents’ brains no longer exhibit the typical response to the pain of other people if they are outgroup members. These findings suggest that interventions to prevent the perpetuation of intractable conflicts could involve promoting compassionate encounters between teens on opposing sides.

PNAS, 2016. DOI: 10.1073/pnas.1612903113 (About DOIs).