COMMUNICATION
Advances in DNA testing and other scientific evidence should make jurors' jobs easier. But statistics that seem black and white take on different meanings depending on how they're phrased--which could influence who we convict and who we set free.
You might think that saying "there's an 80% chance that a defendant committed a crime" is the same as saying "the proof that he did it is 80% reliable." But there's a psychological difference between the two, and a new study shows that jurors are more likely to convict in the latter case. This phenomenon, called the Wells effect, occurs because we're afraid of picking the wrong man, says Larry Messe, Ph.D., of Michigan State University.
Messe, a professor of psychology, and his team found that in the first case, people feel someone else might be responsible. But in the second scenario, only the defendant is implicated; the only unknown is how much evidence there is against him. In this situation, jurors are more willing to convict--a fact that could help the prosecution. Says Messe: "If you're an attorney and you plant in people's minds the possibility of an alternative, you could create doubt, much more than saying that something is 80% reliable."
