Mark Frank has been studying the faces of people lying when the stakes are high for over two decades, being one of the leading authorities in this matter; now, he has some good news for the good guys. According to his latest research, entitled “Executing Facial Control During Deception Situations” people lying can suppress most of their betraying facial expressions, but they cannot suppress all of them.

Frank, PhD, a professor of communication at the University at Buffalo, supervised and wrote the study with former graduate student Carolyn M. Hurley, PhD, and published it in the Journal of Nonverbal Behavior. The study analyzed whether subjects can fully eliminate facial actions like smiles or eyebrow movements when they are telling a lie.

Some of the participants in the study were asked to tell the truth, and some were asked to lie, but regardless of this fact, all 60 of them believed they had fully concealed whether they were lying or not and had a perfect pokerface.

However, Hurley and Frank found that these actions can be reduced, but not eliminated, even though the subjects had been told to hide every expression they could.

“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.”

The people involved in the study were 33 female and 27 male undergraduate subjects who were instructed to hide their expresions as much as possible.

“Based on the research literature on the nature of facial expressions of emotion, the neuroanatomy of the face, emotional suppression research and IPT research,” he says, “we correctly predicted that in interrogations in which deception is a possibility, individuals would be able to significantly reduce their rate and intensity of smiling and brow movements when requested to do so, but would be able to do so to a lesser degree when telling a lie.

Of course, some parts of the face are easier to conceal than the others, and if you’re in this line of work, you know where to search for answers.

“And, since the lower face (and smile in particular) is easier to control than the upper face, we predicted that our subjects would more greatly reduce their rate of smiling, compared to their rate of brow movement, when requested to suppress these actions,” he says, “and that turned out to be the case as well. We can reduce facial movements when trying to suppress them but we can’t eliminate them completely. “Whether we are dealing with highly skilled and motivated liars who have practiced their nonverbal expression in high-stakes scenarios, or untrained individuals who learn from a television program about a particular brow or lip movement that is allegedly a telltale sign of deception,” Frank says, “the findings of this study have important implications for security settings.”

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