Research by University of Oxford economist Evan Soltas and Stanford political scientist David Broockman suggests that voters act upon racially discriminatory tastes. A 2018 study in "Public Opinion Quarterly" found that whites, in particular those who had racial resentment, largely attributed Obama's success among African-Americans to his race, and not his characteristics as a candidate and the political preferences of African-Americans. A 2018 study in the journal "American Politics Research" found that white voters tended to misperceive political candidates from racial minorities as being more ideologically extreme than objective indicators would suggest; this adversely affected the electoral chances for those candidates. A 2018 study in the "Journal of Politics" found that "when a white candidate makes vague statements, many voters project their own policy positions onto the candidate, increasing support for the candidate. But they are less likely to extend black candidates the same courtesy... In fact, black male candidates who make ambiguous statements are actually punished for doing so by racially prejudiced voters."