Liars can't completely suppress facial expressions - A new report

in biology, education

A new study reports that although liars can reduce facial actions when under scrutiny, they can't completely suppress them.  The lead author spent two decades studying the faces of people lying when in high-stakes situations and arrived at this conclusion, potentially valuable to security experts.

To date research has not shown whether deceivers can suppress elements of their facial expression as a behavioral countermeasure. The study authored by Carolyn M. Hurley and  Mark G. Frank at the University of Buffalo was published in the recent issue of Journal of Nonverbal Behavior.

The results are derived from frame-by-frame coding of facial movements filmed during an interrogation in which participants, some lying, some telling the truth, were asked to suppress specific parts of facial expressions. Hurley and Frank found that these actions can be reduced, but not eliminated, and that instructions to the subjects to suppress one element of expression resulted in reduction of all facial movement, regardless of their implications for veracity.

The interesting aspect of the study results is that the majority of the 60 study participants reported believing that they had controlled all facial movement and had remained "poker faced" during the interview/interrogation, though they did not!

"Behavioral countermeasures," says Frank, "are the strategies engaged by liars to deliberately control face or body behavior to fool lie catchers. Until this study, research had not shown whether or not liars could suppress elements of their facial expression as a countermeasure.

"As a security strategy," he says, "there is great significance in observing and interpreting nonverbal behavior during an investigative interview, especially when the interviewee is trying to suppress certain expressions."

"Although these facial movements are not necessarily guaranteed signs of deception," says Frank, "expression suppression -- regardless of its validity as a clue to deception -- is clearly one of the more popular strategies used by liars to fool others. What we didn't know was how well individuals can do this when they are lying or when they are telling the truth.

Source article: Executing Facial Control During Deception Situations. J Nonverbal Behav (2011) 35:119–131 DOI 10.1007/s10919-010-0102-1.

Link to Mark Frank Faculty Website

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