When it comes to fibbing, it takes one to know one. Some research suggests accomplished liars are better at detecting lies. They may also be good actors, and lack emotions such as guilt.
Vrij's research steers away from using traditional lie detectors because similar results can occur in people who are lying and those who are just anxious. The polygraph measures skin conductance, heart rate, respiration, blood pressure and finger temperature -- which all rise when under pressure, whether you're lying or not.