When participants were in diverse company, their answers were 58 percent more accurate. The prices they chose were much closer to the true values of the stocks. As they spent time interacting in diverse groups, their performance improved. In homogeneous groups, whether in the United States or in Asia, the opposite happened. When surrounded by others of the same ethnicity or race, participants were more likely to copy others, in the wrong direction. Mistakes spread as participants seemingly put undue trust in others’ answers, mindlessly imitating them. In the diverse groups, across ethnicities and locales, participants were more likely to distinguish between wrong and accurate answers. Diversity brought cognitive friction that enhanced deliberation. - www.nytimes.com