WEDNESDAY, July 20 (HealthDay News) -- Liars can control certain
facial expressions when facing scrutiny, but they can't suppress
them completely or every time, a new study shows.
The researchers noted the findings could have an impact in
In conducting the study, scientists randomly asked 60 people to
either lie or be truthful to an interrogator about taking a pair of
movie tickets from an envelope. While being interviewed, the
participants were told to attempt behavioral countermeasures, or
suppress certain facial expressions, such as raising their eyebrows
"Behavioral countermeasures are the strategies engaged by liars to deliberately control face or body behavior to fool lie catchers," study co-author Mark Frank, a professor of communication at the University at Buffalo, said in a news release.
Meanwhile, the participants were told they would be rewarded if
they could convince the interrogator they were telling the truth.
They also said anyone found to be lying would be punished.
The interviews were taped so researchers could analyze the
participants' facial expressions frame-by-frame. They found that
although the liars could minimize their facial movements when under
scrutiny, they were unable to suppress them all.
"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," added Frank, "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."
Moreover, the study authors found that in instructing the
participant to suppress one specific facial movement, all of their
facial movements were reduced. The researchers noted this response
is typically greater when a person is lying because being dishonest
raises a person's cognitive load, inhibiting their ability to
interact with others successfully and naturally.
Despite these findings, the majority of participants believed
they effectively controlled their expressions during their
"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," concluded Frank, "the findings of this study have important implications for security settings."
The study's findings were published earlier this year in the
Journal of Nonverbal Behavior.
The American Psychology Association provides more information on