Mark Frank has spent two decades studying the faces of people lying when in high-stakes situations and has good news for security experts.
"Executing Facial Control During Deception Situations," a new study he co-authored with former graduate student Carolyn M. Hurley, PhD, reports that although liars can reduce facial actions when under scrutiny, they can't suppress them all.
Frank, PhD, a professor of communication at the University at Buffalo, supervised and co-wrote the study with lead author Hurley, now a research scientist at the U.S. Transportation Security Administration.
Published earlier this year in the Journal of Nonverbal Behavior, the study examined whether subjects could suppress facial actions like eyebrow movements or smiles on command while under scrutiny by a lie catcher.
It turns out subjects could to a degree, but not completely and not always.
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.