Judging juries

YOU DON’T HAVE TO BE A social scientist to realize that racially diverse juries might engage in more give-and-take than homogeneous ones. Still, it’s reassuring to learn that a study by a psychologist has concluded that multiracial juries are more deliberative than all-white panels. The study by professor Samuel R. Sommers of Tufts University should give impetus to a lonely campaign by a member of the U.S. Supreme Court to make it easier to impanel juries that are more reflective of the community.

It seems obvious that adding African Americans to a jury will often bring a broader range of viewpoints to deliberations. The twist in the Sommers study -- published in the Journal of Personality and Social Psychology -- is that a jury that includes at least some African Americans changes the way white jurors even think about the case, at least when the defendant is black.

Sommers’ experiment, which involved a mock trial of an African American man on charges of sexual assault, also tested the effect of asking jurors if they harbored racial prejudices against the defendant. Sommers found that 47% of jurors who weren’t asked about their racial attitudes voted to convict the defendant, compared with only 34% of those who were asked race-related questions.

Still, it’s Sommers’ conclusion about the value of a diverse jury that is likely to reverberate. It has been 20 years since the Supreme Court ruled that it was unconstitutional for lawyers to use so-called peremptory challenges -- those requiring no stated reason -- to exclude potential jurors because of their race.

Unfortunately, as Justice Stephen G. Breyer has observed, prosecutors have been able to circumvent the decision by offering a nonracial reason, however trivial, for a peremptory challenge actually motivated by race. A prosecutor who wants to strike an African American from a jury will say it’s not the man’s skin color he finds bothersome -- it’s that he has a beard.

Breyer took note of such absurdities in an opinion last year in the case of a Texas prisoner who was sentenced to death after prosecutors used peremptory challenges to remove 10 of 11 African Americans in the jury pool. Then he offered a simple solution: Abolish peremptory challenges, as courts in Britain have done. Lawyers could then exclude someone from a criminal jury only “for cause” -- such as evidence of prejudice or ties to a witness or defendant.

Peremptory challenges long have been criticized as a form of racial discrimination. If Sommers’ study is correct, such challenges also make it less likely that jurors will work their hardest to arrive at the truth.