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Pants on fire: Scientifically proven ways to catch a liar

Was traffic really that bad, or did he just leave late (again)? Did her phone battery truly die, or did she forget to call? And do you actually look as fat in those pants as you suspected?

Overly suspicious people, meet R. Edward Geiselman. He's a professor of psychology at UCLA -- and he's spent the last several years studying the best ways to catch a liar. Geiselman and three former UCLA undergrads believe that -- after analyzing 60 studies on detecting deceit and conducting their own research -- they've pinpointed the best ways to catch even the most fabulous of fabulists.

Their findings were published this week in the American Journal of Forensic Psychiatry. Geiselman's work is tailored for law enforcement officers, but "anyone ... could use our techniques," he says. We spoke to the human lie detector about the best ways to spot the liars in your life. (Geiselman would like us to note here that these are all simply red flags, not surefire indicators that someone isn't telling the truth.)

They offer only the bare bones of a story. This is somewhat counterintuitive, Geiselman admits. (The lady doth protest too much, etc.) But as Geiselman explains, "Most liars do not like to tell you too much," in part, because they know they'll have to remember those fabrications later. And some liars fear that if they told an elaborate story, it would make the person listening assume they'd made it up, he explains.

They offer unsolicited details about the little they've shared.  If they tell you what they were wearing, or drinking, or driving, but you didn't ask -- you may be justified in raising an eyebrow.

They answer your question with a question. Question: "Where were you last night?" Answer: "Where was I last night?" Geiselman explains that other tells are starting to answer slowly, then speeding up their speech (once they've got their story straight in their own head). They also may hesitate, speak in sentence fragments, or stop and start repeatedly. "Either they're tired, or they're being deceptive," he says.

They press their lips together and look away. "Reliably, that indicates something going on," Geiselman explains. "It means they have to think really hard about the answer." Liars also tend to gesture inward -- as in, fiddling with their clothes or their hair.

What's the biggest lie you've ever told? Did you get away with it?

Follow Melissa Dahl on Twitter @melissadahl.