The human body's mental and physical actions are linked; one cannot usually act without the other responding in kind. When a person chooses mentally to tell a lie, there are small physical movements in the body that can give the liar away. A trained eye can tell when he is being lied to if he is able to identify these markers.

Note whether or not the accused liar is trying to change the subject. Those who have begun to lie and wish not to talk about it anymore will very adamantly attempt to change the topic of discussion, while innocent people will not care about moving on.

Attempt to touch the accused liar in a platonic way on the arm to see if she jerks back or not. Those people who might be lying may wish to avoid physical contact with those to whom they are lying.

Watch the placement of items on the table between you and the accused liar. A liar may try to put an object between himself and you to create a physical barrier in order to try to keep you away.

Ask questions that will require the liar to elaborate on his story quickly. Rapidly fire several questions in succession at the potential liar to check if he is able to answer them without great hesitation. Someone who knows the truth will be able to answer genuinely without second thought, but a liar may need time to get his story straight.

Be aware of the pose the liar has chosen to position himself in. If he is sitting with his arms crossed and moving his limbs very little, he may be lying.

Identify whether the liar's voice has been raised in pitch. This is a natural occurrence that happens when an individual becomes stressed or tense. Vocal chords stretch and the voice becomes higher in tone.

Note whether a liar is faking a smile by moving only the corners of his lips in an upward direction. A genuine smile requires the movement of cheek and eye muscles, as well.

Ask the potential liar a "yes" or "no" question. If the liar's head movement does not agree with his answer, he is possibly lying.