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Case No. 4: Detecting a Lie
We've all heard how to catch liars in the act: An upward glance to the right means they're dishonest. That's false, found a study led by the psychologist Richard Wiseman at the U.K.'s University of Hertfordshire. This time-honored tactic didn't detect liars accurately in any setting—when viewing videos of shifty-eyed volunteers or actual news cases.

Try instead: Look for the "Pinocchio effect": bald-faced liars tend to talk more (their word count "grows"), and their sentences become more complex, found a study by the University of Wisconsin and Harvard Business School. (Watch out: Wordy liars were mistakenly perceived as more trustworthy than their laconic peers.) Liars also swore more than truth-tellers—their tongues loosened by cognitive overload—and made fewer "I" statements.