It appears that juries that contain a diverse cultural mix are better at making decisions than homogenous groups. Well that is the conclusion of Samuel Sommers of Tufts University anyway.

Dr Sam, who happens to be white himself, conducted a study on decision making on two types of juries. The first consisting of 6 white jurers and the second where two of the jurers were black. We learn from this research that the white jurers were more objective in their assesment of the case when blacks were present. They made less errors in their recall of the evidence, took longer in their deliberation and raised more factual information. They also expressed more leniency towards the black defendant.

He seems to have missed the obvious inclusion of one containing six black jurers. Consequently we don't know how the behaviour of the black jurers alters in the presence of whites. Also it reflects America's obsession with the Black/White divide, diversity is, of course, much greater than this. Presumably he is concerned with practicality and that all black juries are a rarity, never the less from a academic perspective it seems to present less than the complete picture.

Read his research here.