I must admit that this surprised me. I've personally never noticed a connection.
Study Links Religion and Racism
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A meta-analysis of 55 independent studies carried out in the United States with more than 20,000 mostly Christian participants has found that members of religious congregations tend to harbor prejudiced views of other races.
In general, the more devout the community, the greater the racism, according to the authors of the analysis, led by Wendy Wood, Provost Professor of Psychology and Business at USC College and the USC Marshall School of Business. The study appears in the February issue of Personality and Social Psychology Review.
“Religious groups distinguish between believers and non-believers and moral people and immoral ones,” Wood said. “So perhaps it’s no surprise that the strongly religious people in our research, who were mostly white Christians, discriminated against others who were different from them — blacks and minorities.”
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http://uscnews.usc.edu/university/study_links_religion_and_racism.html?view=full