How to Spot a Lie: The 3 Channels Experts Watch - a segment from a podcast I was on a year ago. It's a common question, in life, negotiations, and business: How do we know if someone is lying to us? Having worked as a human lie detector in the polygraph unit and as a seasoned interrogator trained in lie detection, here are a few things to look out for. Lie detection is both an "art" and a science that requires observing three means of communication working in sync: words, tone of voice, and body language. If all three channels are not working together, something is "off", and you'd better be paying attention. 3 Key Ways to Detect Deception (The "Off" Signs): 1. Evasion, Not an Answer: When asked a simple "yes or no" question (e.g., "Did you steal that money?"), the first thing to come out of an innocent person's lips should be "no". It's a 'yes' or 'no' question. A deceptive response often involves telling a story, shifting the topic, or giving reasons instead of a direct answer ...