A recent study by Brandt and Crawford shows different tendencies regarding prejudice and IQ.
Abstract: Previous research finds that lower cognitive ability predicts greater prejudice. We test two unresolved questions about this association using a heterogeneous set of target groups and data from a representative sample of the United States (N = 5,914). First, we test “who are the targets of prejudice?” We replicate prior negative associations between cognitive ability and prejudice for groups who are perceived as liberal, unconventional, and having lower levels of choice over group membership. We find the opposite (i.e., positive associations), however, for groups perceived as conservative, conventional, and having higher levels of choice over group membership. Second, we test “who shows intergroup bias?” and find that people with both relatively higher and lower levels of cognitive ability show approximately equal levels of intergroup bias but toward different sets of groups.
Is it prejudice to have poor impressions of people who are making a choice? (Do my negative feelings about ISIS, for example, count as "prejudice"?) Anyway, the study's results are interesting and may explain why Trump maintains a very loyal (albeit, insufficient) group of followers that appear impervious to logical argument.