Narrator: This is Science Today. Law enforcement officers depend on their ability to know when people are telling the truth. So in order to improve their skills, some agencies have solicited help from Doctor Paul Ekman, a psychology professor at the University of California, San Francisco.
Ekman: We try to teach people what are the various clues in the voice and in the speech itself that can give them a better sense of how the person they're dealing with is feeling at the moment and where they need to ask more questions, where there are signs that they're not getting the full story.
Narrator: Ekman says officers often have poor judgment.
Ekman: Our studies of police interrogators show that most of them can't tell from demeanor - from how someone behaves - whether they're telling the truth or not.
Narrator: : But Ekman says after just 12 hours of training, officers can dramatically improve their abilities. But repetition, he says, is key.
Ekman: You can benefit from reading about it, just like you can learn a lot about the game of tennis by reading about it. But you're not going to get the ball over the net without practice.Narrator: For Science Today, I'm Larissa Branin.