This research demonstrates a common psychology of outgroup hostility driven by perceived intergroup threat among three groups and seven cultural contexts: non‐Muslim Westerners, Muslims in Western societies, and Muslims in the Middle East. In Study 1, symbolic, but not realistic and terroristic threats, predicted non‐Muslim Norwegians' intentions to join anti‐Islamic movements. In Study 2, symbolic and realistic, but not terroristic threat, predicted non‐Muslim Americans' willingness to persecute Muslims. In Studies 3 and 4, symbolic threat predicted support and behavioral intentions against the West among Swedish and Turkish Muslims. Finally, in Study 5, a comparison demonstrated that symbolic and realistic threats had the same effects on violent intentions among non‐Muslim and Muslim Danes, and Muslims in Afghanistan. Meta‐analysis showed that symbolic threat was most strongly associated with intergroup hostility. Across studies, participants with high religious group identification experienced higher levels of threat. Implications for intergroup research and prejudice reduction are discussed.

Islamist extremism is often explained by the suffering endured by Muslims in Islamic countries as a result of Western‐led wars. However, many terrorist attacks have been carried out by European Muslims with no personal experiences of war. Across two studies among Danish Muslims, we tested if what we call “victimization‐by‐proxy processes” motivate behavioral intentions to commit acts of violence. We used Muslim identification, perceived injustice of Western foreign policies, and group‐based anger to predict violent and nonviolent behavioral intentions. More importantly, we compared path models of Danish Muslims from conflict zones with those without direct personal experience of Western‐led occupation. We found similar effects among the participants in each category, that is, vicarious psychological responses mimicked those of personally experienced adversity. In fact, participants born in Western Europe were, on average, more strongly identified with Muslims, more likely to perceive Western foreign policy as more unjust, reported greater group‐based anger, and were more inclined to help Muslims both by nonviolent and violent means.

Humans are a coalitional, parochial species. Yet, extreme actions of solidarity are sometimes taken for distant or unrelated groups. What motivates people to become solidary with groups to which they do not belong originally? Here, we demonstrate that such distant solidarity can occur when the perceived treatment of an out-group clashes with one’s political beliefs (e.g., for Leftists, oppressive occupation of the out-group) and that it is driven by fusion (or a feeling of oneness) with distant others with whom one does not share any common social category such as nationality, ethnicity or religion. In Study 1, being politically Leftist predicted European-Americans’ willingness to engage in extreme protest on behalf of Palestinians, which was mediated by fusion with the out-group. Next, in Study 2, we examined whether this pattern was moderated by out-group type. Here, Norwegian Leftists fused more with Palestinians (i.e., a group that, in the Norwegian context, is perceived to be occupied in an asymmetrical conflict) rather than Kurds (i.e., a group for which this perception is less salient). In Study 3, we experimentally tested the underlying mechanism by framing the Kurdish conflict in terms of an asymmetrical occupation (vs. symmetrical war or control conditions) and found that this increased Leftist European-Americans’ fusion with Kurds. Finally, in Study 4, we used a unique sample of non-Kurdish aspiring foreign fighters who were in the process of joining the Kurdish militia YPG. Here, fusion with the out-group predicted a greater likelihood to join and support the Kurdish forces in their fight against ISIS, insofar as respondents experienced that their political orientation morally compelled them to do so (Study 4). Together, our findings suggest that politically motivated fusion with out-groups underpins the extreme solidary action people may take on behalf of distant out-groups. Implications for future theory and research are discussed.

Although jihadist threats are regarded as foreign, most Islamist terror attacks in Europe and the United States have been orchestrated by Muslims born and raised in Western societies. In the present research, we explored a link between perceived deprivation of Western Muslims and endorsement of extremism. We suggest that Western-born Muslims are particularly vulnerable to the impact of perceived relative deprivation because comparisons with majority groups’ peers are more salient for them than for individuals born elsewhere. Thus, we hypothesized that Western-born, compared with foreign-born, Muslims would score higher on four predictors of extremism (e.g., violent intentions), and group-based deprivation would explain these differences. Studies 1 to 6 ( Ns = 59, 232, 259, 243, 104, and 366, respectively) confirmed that Western-born Muslims scored higher on all examined predictors of extremism. Mediation and meta-analysis showed that group-based relative deprivation accounted for these differences. Study 7 ( N = 60) showed that these findings are not generalizable to non-Muslims.