Tim Roth discusses how his character Dr. Cal Lightman, from Lie to Me, detects deception by studying facial expressions and body language.Tim Roth discusses how his character Dr. Cal Lightman, from Lie to Me, detects deception by studying facial expressions and body language.Tim Roth discusses how his character Dr. Cal Lightman, from Lie to Me, detects deception by studying facial expressions and body language.