Why does ingroup essentialism increase prejudice against minority members?

A study with British participants (N = 90) tested a potential mediator of the effect of essentialist beliefs about the national ingroup on prejudice against immigrants. Essentialist beliefs were defined as beliefs in genetic determinism, a basic assumption that group membership is "written in the blood" and that the groups' boundaries and characteristics are determined by genetic and/or biological factors. Essentialist beliefs were expected to play an important role in the formation of prejudice. They were predicted to be associated with a reduction in the perceived possibility of immigrants' adopting the mainstream culture. Further, it was expected that essentialist beliefs would be positively associated with perceptions of intergroup threat, which in turn would be associated with a stronger demand for immigrants adopting the mainstream culture. Taken together, essentialist beliefs were predicted to be associated with a greater discrepancy between the demand for and perceived feasibility of culture adoption. This discrepancy was hypothesized to mediate the effect of essentialist beliefs on prejudice against immigrants. Structural equation modeling analysis and mediation analysis supported the hypotheses, showing that essentialism attributed to the national ingroup results in people demanding something seemingly impossible from immigrants, and that this situation in which immigrants have little chance of fulfilling majority members' expectations results in prejudice against them. Thus, results show that perceptions of the ingroup are associated with attitudes to the outgroup, and they outline an explanatory mechanism for the positive correlation between essentialism and prejudice which has been found in previous research. Theoretical and applied implications are discussed.