How good are you at picking out fibbers from a crowd? According to a new paper from researchers at the University of Rochester, New York, there are particular (involuntary) quirks and facial movements that give us away – whether we like it or not.
The team used a combination of big data, machine learning technology, and automated facial feature analysis software to identify differences in facial and verbal cues between people who are lying and people who are telling the truth.
Volunteers were recruited from Amazon Mechanical Turk and split into pairs. In total, there were 151 couples and 1.3 million frames of expressions for the team to analyze.
One person was given the job of "interrogator", the other was the "describer". Before getting into the gist of the experiment, the interrogator asked the describer a series of baseline questions (which the describers were expected to answer truthfully). For example, "what did you wear yesterday?" or "What is 14 x 4?" These mundane questions were to capture individual differences in behavior when being truthful and were then used to build a model personalized to each and every describer.
Next, the describers were handed pictures to examine and memorize, which they later had to describe to the interrogator – only some people were instructed to tell the truth and others were told to lie.
Automated facial feature analysis software was used to pick out certain actions, say a raised eyebrow. Then with machine learning, the researchers clustered certain behaviors so that they could spot patterns in the facial cues of truth-tellers and liars, and, essentially, work out who was telling porkies and who was not.
And what did they find?
“It told us there were basically five kinds of smile-related ‘faces’ that people made when responding to questions,” Tay Sen, a PhD student, said in a statement.
The most indicative of fibbers was what they dub the "Duchenne smile" (beautifully demonstrated by Neil Patrick Harris below). This is when both sets of eye and mouth muscles contract and is consistent with the "Duping delight" theory, the researchers say. That is, the liar is delighting in fooling someone.
The team also noticed that people who were telling the truth tended to contract their eyes slightly – probably because they were concentrating hard on remembering all the details – and unlike the fabricators, their mouth muscles did not also contract.
However, these findings won't make you a better liar (though it might make you better at working out who is). The Duchenne smile involves “a cheek muscle you cannot control,” Ehsan Hoque, an assistant professor of computer science, explained.
How do you think you stack up? See for yourself with the video below.