Most people look for "shifty eyes" or nervousness. These are myths. Real deception detection is about spotting structural flaws in a story.
Liars rehearse their stories in strict chronological order (A -> B -> C). Truth-tellers remember in emotional clusters. The Test: Ask them to tell the story backwards. A liar's cognitive load will spike, and the story will crumble.
Liars subconsciously distance themselves from the lie. They will use fewer first-person pronouns
("I", "me", "my") and more passive voice.
"The car was driven to the store" vs "I drove the car to the store."
A truth-teller wants to convey information. They are helpful and will admit gaps in memory ("I'm not sure about the time"). A liar wants to convince you. They are often overly specific about irrelevant details to "prove" their honesty, but vague on the core event.
In a genuine reaction, the emotion appears on the face before or simultaneously with the words. In a lie, the words often come first, followed by a forced expression. If they say "I'm so angry!" and then frown, it's a performance.
These techniques are just the basics. The full Lieproof Mind protocol covers micro-expressions, statement analysis, and interrogation techniques.