How to spot a liar

A liar's words will give him away, if you know what to look for.

Telltale signs may include running of the mouth, an excessive use of third-person pronouns, and an increase in profanity, according to Deepak Malhotra, a Harvard Business School professor.

He and two colleagues at the University of Wisconsin-Madison set up an experimental negotiation to see what behaviors indicated a less than truthful participant. The observed strategic cues of lying -- a conscious strategy to reduce the likelihood of the deception being detected -- and nonstrategic cues -- an emotional response, which people aren't usually aware that they're doing.

In terms of strategic cues, the researchers discovered the following:

• Bald-faced liars tended to use many more words during the ultimatum game than did truth tellers, presumably in an attempt to win over suspicious receivers. Associate Professor Lyn M. Van Swol dubbed this "the Pinocchio effect." "Just like Pinocchio's nose, the number of words grew along with the lie," she says.
• Allocators who engaged in deception by omission, on the other hand, used fewer words and shorter sentences than truth tellers.

Among the findings related to nonstrategic cues:

• On average, liars used more swear words than did truth tellers—especially in cases where the recipients voiced suspicion about the true amount of the endowment. "We think this may be due to the fact that it takes a lot of cognitive energy to lie," Van Swol says. "Using so much of your brain to lie may make it hard to monitor yourself in other areas."
• Liars used far more third-person pronouns than truth tellers or omitters. "This is a way of distancing themselves from and avoiding ownership of the lie," Van Swol explains.
• Liars spoke in more complex sentences than either omitters or truth tellers.

An interesting application: The team is investigating the linguistic differences between lying in person and lying via email. Results regarding the latter may be increasingly useful as a larger portion of business is now being conducted via email, and such communications leave a transcript that can be analyzed carefully—and at leisure—by suspicious counterparts. "People detect lies better over the computer than they do face-to-face," Van Swol says.