Source: Management Today
Date: October 2006 

TELL-TALE SIGNS

Ten research-based tips for detecting liars from their demeanour (your results may vary)

1 Remind the subject that the stakes are high. If they have something serious to gain or lose, they are more likely to give away their true emotions.

2 Establish a baseline. Observe their demeanour when they are in a stressful situation but telling the truth, and watch for changes.

3 Look for lots of signs of lying, not just one or two.

4 Do not tell them what you know. You need them to struggle to invent a story that won't contradict what they think you know.

5 Listen for detail in their story. You want unexpected, irrelevant information and snippets of dialogue.

6 Listen to the pitch of their voice. Does it rise when answering certain questions?

7 Are they pausing to think before answering? They may be inventing, not remembering.

8 Do their smiles reach their eyes? True emotions affect the upper portion of the face, and those muscles are much harder to control.

9 Practise, and give yourself feedback on your successes and failures. Skill in lie-detection comes with experience.

10 Do not over-estimate your ability to catch liars. It's a lot harder than it looks.