March 27, 2008

Lie Detection

Stupid Question ™
Nov. 4, 1999
By John Ruch
© 1999

Q: The movie “True Romance” says the Sicilians have an ancient technique for detecting liars, based on 17 specific body movements. Is it true?
—Il Duce

A: In this 1993 Quentin Tarantino-penned film, a Sicilian mobster, played by Christopher Walken, is trying to gain information from a security guard (Dennis Hopper) who’s playing dumb.

Walken tells Hopper that “Sicilians are great liars,” indicating that this also makes them great lie-detectors.

Walken then says that his father taught him “the pantomime. Now, there are 17 different things a guy can do when he lies to give him away. A guy has 17 pantomimes. A woman’s got 20, but a guy’s got 17. And if you know ’em like you know your own face, they beat lie detectors to hell.”

He then says he can tell Hopper is lying, and suggests he tell the truth.

Tarantino apparently invented this “pantomime” method of lie-detection. I can find no mention of such a thing in literature on the Mafia, Sicilian culture or pantomime (which isn’t even Italian, though it was influenced by the commedia dell’arte).

Of course, there’s a widespread notion that various body movements and tics (known collectively as “kinesics”) give away a liar. But in experimental situations, people do no better than chance at catching liars by these methods.

While most of these experiments seem flawed in design, there’s still a basic problem with all lie-detection methods—kinesics, polygraph machines (which measure pulse rate, respiration and sweating), whatever. They can only tell you that someone is emotionally agitated. They can’t tell you why. There is no known physiological reaction unique to lying.

Interpretation of results is highly subjective, and usually based on the faulty premise that all people react to guilt (or lack thereof) in the same way. In fact, as any champ poker player knows, you have to know an individual’s particularly reactions before you can read their bluffs. (This is also why it’s far easier to catch a friend lying than a stranger.)

The one thing common to all lie-detection methods is that when they do work, it’s because the subjects believe they will work.

A major function of the pre-polygraph exam interview is to fool subjects into believing the machine is infallible. And a literally textbook police interrogation tactic is to tell the subject that kinesics are giving them away, whether that’s true or not.

Watch “True Romance” again, and you’ll see that Walken’s character is pulling this exact same trick. We never actually see him use the “pantomime” (at most, he exhibits one shrewd glance); he’s really just psyching Hopper out, convincing him he can’t get away with a lie.

Plus, he tortures him, which is a time-honored technique itself.

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