That doesn't make it any easier for people to sort out fact from fiction. Studies have shown that people can identify lies only about 50 percent of the time, or about the same as chance. To be sure, researchers have been able to figure out some clues to uncovering deception. When people tell a significant lie, for instance, they typically gesture less and their arms may appear stiff. People telling lies also might have dilated pupils because they feel nervous about spinning an untruth.
Even with the development of such research, there's no surefire way to catch a liar. But someone with a known track record of lying is likely to pay a price. "Lies add up," says Feldman. "The more you know that someone is not telling you the truth, the less trustworthy they are. They're just telling you stuff you want to hear, and you won't listen to them anymore."
Corrected on 5/20/09: Richard Gramzow's study involved students from Northeastern University and not, as an earlier version of this article stated, Northwestern University.