George Olivo, a retired FBI special agent and senior polygraph examiner, on how polygraph tests work and their reliability.

Forensic science may be on the verge of a straighter path to exposing lies: Through functional magnetic resonance imaging (fMRI), a brain scan that maps cerebral activity by measuring blood flow. Early results of fMRI for lie detection are promising, with accuracy rates higher than 75 percent.

We've all heard that one big sign someone is lying is if they can't look you in the eye. How much truth is there to that? Apparently, none.