Although sudden cracks in facial expression could give away subtle clues to deception, one researcher found that tiny movements in facial muscles -- such as the zygo maticus major and the orbicularis oculi -- can unmask liars.
Social psychologist Mark Frank used computer technology to analyze facial expressions, following a large body of research "about the evolutionarily-derived nature of emotion and its expression," according to a press release on EurekAlert!.
Micro-expressions in subjects' faces, such as tics, smiles, frowns and wrinkles, essentially serve as accurate windows into the emotions, even if the person being interrogated is trying to suppress his or her feelings.
Frank's system can be used not only to uncover potential criminals, but also even reveal terrorist threats. Frank, however, is quick to point out that his system only provides investigators with "very good clues" and "not proof of anything."