research on reducing group prejudice

“A new study finds that when it comes to groups, descriptions that include positive and negative terms reduce prejudice more effectively than descriptions that include only positive terms.”
From the blog, peer reviewed by my neurons.

Abstract: In a series of five experiments, we demonstrate that exposure to information related to an out-group’s heterogeneity reduces prejudice more effectively than exposure to only positive characteristics of the out-group. We exposed participants to a poster that associated both positive and negative traits with an out-group (mixed condition), to a poster that associated only positive traits with the out-group (positive condition), or to no poster (control condition). Results revealed that participants in the mixed condition expressed less explicit prejudice (Experiments 1-2) and less implicit bias (Experiment 3-4) than participants in the other two conditions. The last experiment demonstrated that the mixed poster was more acceptable and created less reactance than the positive poster

Brauer, M., Er-rafiy, A., Kawakami, K., & Phills, C. (2011). Describing a group in positive terms reduces prejudice less effectively than describing it in positive and negative terms Journal of Experimental Social Psychology DOI: 10.1016/j.jesp.2011.11.002