In Johnston, Newman and Velez (2015), we examine how personality traits related to uncertainty aversion moderate the effect of local ethnic change on perceived cultural threat from immigrants and on immigration-related policy preferences. In two studies—one observational and one experimental—we find that ethnic change increases perceptions of threat and decreases support for immigration among uncertainty-averse citizens but has the opposite effect for the uncertainty tolerant. Neither study finds evidence for similar associations with levels of ethnic diversity.