Lie still

Polygraphs apparently have an 80% to "no better than chance" range when it comes to lie detecting. So it's probably a good thing that there's another option - magnetic resonance imaging machines. Initial research (reported on the Wired website) reports MRI machines have a 90% success rate. They show that more blood flows to the parts of the brain associated with anxiety and impulse when people lie. In the research, at the Medical University of South Carolina, questions were projected onto a screen while participants were in the MRI and they pressed a button for their yes/no answers. Unfortunately the test doesn't work if the subject doesn't lie still!