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Science of Lying

By Sean Henahan, Access Excellence

psychiatryWashington, DC (4/20/99)- Humans practicing mendacity, otherwise known as lying, exhibit numerous physical and verbal cues that can be objectively measured, researchers reported at the annual meeting of the American Psychiatric Association.

Researchers at the Smell & Taste Treatment Research Foundation in Chicago, IL reviewed 64 peer-reviewed articles and 20 books on mendacity. From these they derived an index of 23 clinically practical physical and verbal signs of dissimulation. Many of the books used in the project are standard texts for the FBI and other law enforcement agencies involved in interrogating suspects.

Physicals cues believed to be associated with lying include an increased incidence of leaning forward, licking the lips, touching the nose, averting the gaze and handling objects. An insincere smile, characterized by lack of movement of the wrinkle lines around the eyes is another well know indicator of lying. People who are lying also often reveal themselves verbally. Verbal cues include the increased use of verbal qualifiers or modifiers, the use of expanded contractions (e.g. I did not rather than I didn't), stuttering, throat clearing and speech errors.

To test the validity of these measurements, the investigators carefully reviewed videotapes of President Bill Clinton's testimony to the grand jury in which he denied any relationship with the intern Monica Lewinsky, a denial he later admitted was false. The researchers studied the tape over and over again, looking for the verbal and physical cues believed to be associated with lying. They studied the preliminary section of the president's testimony in which he gave his name etc., along with a tape of a fundraiser before a friendly crowd, as controls.

The now well known lying incident was associated with a remarkable increase in 20 of the 23 verbal and nonverbal signs measured in the study. Half of the signs increased more than 100%. Using both controls, 100% of the verbal indicators demonstrated changes consistent with deception, reported Alan R. Hirsch, MD, neurological director of the Smell and Taste Treatment Research Foundation.

The comparison of the president's known truthful (e.g. name) and nontruthful answers showed a 100% increase in leaning, a 355% increase in drinking and swallowing, a 250% increase in hand to face touching, a 219% increase in averting the gaze and a 268% reduction in blinking. When compared with the fundraiser before the friendly audience, there was a 402% increase in the use qualifiers and modifiers, a 117% increase in expanded contractions, a 63% increase in denials, a 1733% increase in speech errors and a 1444% increase in stuttering, said Dr. Hirsch.

"We watched these videos repeatedly, carefully measuring each change. The differences were apparent even when we first watched the video without the audio. The increased incidence of of leaning forward and nose touching was immediately apparent, " Dr. Hirsch noted.

The raising of the hand to the nose has been reported in many cultures as a movement associated with lying. This may be related to the fact that the nose contains erectile tissues that engorge when a person is lying. For this reason Dr. Hirsch calls the physical changes associated with mendacity the "Pinnochio Effect".

This research may have practical application in the field of psychiatry. In some psychiatric disorders it can be very difficult to determine if the patient is telling the truth.

"This exercise demonstrates the utility of using formalized veracity measures in the videotaped and scripted interview situation. With practice, the same technique can be used contemporaneously during an actual psychiatric interview, " Dr. Hirsch said.

The approach would not be useful in every situation. For example, in some types of psychoses, the patient truly believes what he is saying, even though it is patently false. If a patients really believes something is true then it is true as far as this sort of analysis is concerned, he added.

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