Looking someone in the eye and lying to them is apparently much easier than Hollywood films and politicians have led us to believe.
Researchers who watched hundreds of hours of video footage of lying criminals in high-profile court cases have found that fibbers share a surprising selection of common tells.
A team at the University of Michigan discovered that far from averting their gaze, people actually make more eye contact when they lie.
Being dishonest also makes people scowl and use their hands more.
The study found people share these traits when lying:
- Move their hands a lot
- Scowl or grimace their whole face
- Use fillers such as "um," "uh" and "ah"
- Try to sound more certain
- Look their questioners in the eye more often than those telling the truth
"People are poor lie detectors," says study leader Dr Rada Mihalcea, professor of computer science and engineering. "This isn't the kind of task we're naturally good at."
"There are clues that humans give naturally when they are being deceptive, but we're not paying close enough attention to pick them up," she adds. "We're not counting how many times a person says 'I' or looks up. We're focusing on a higher level of communication."
The team examined footage from witnesses and defendants in 120 court cases and based their honesty on the outcomes of the trials. They have now developed the first lie-detecting software that examines words and gestures and doesn't require hooking people up to machines.
In tests, the software correctly identified when people were lying in 75% of cases, while humans can generally catch out lies only 50% of the time.
While previous findings have indicated that people tend to look away when they lie, Dr Mihalcea says it's difficult to motivate study participants to truly lie in a laboratory setting. She says her team's research is based on "real world" dishonesty where there is true motivation to deceive.