> Do those studies explain why it relates to productivity? Correlation studies... Sommers showed causation. The presence of black subjects in the heterogenous

> Do those studies explain why it relates to productivity? Correlation studies... Sommers showed causation. The presence of black subjects in the heterogenous group caused the white subjects in that group to behave more conscientiously/objectively, increasing the performance of that group compared to the control. Others like Ellison/Mullin discuss performance in relation to social capital. Homogenous groups tend to find it easier to build more social capital, so feel more comfortable, but more easily succumb to groupthink.