There are numerous ways in which a person’s body language can give you clues as to whether or not they are telling lies. Members of police departments and security experts use these clues to catch out criminals during interrogation. Research has shown that people lie every four minutes of every day. They may not even be aware that they are doing it and it may be an unconscious reaction.

One of the biggest signs that a person is telling lies is that they avoid eye contact during conversation. They may also touch their face continuously, very often covering their mouth with their hand. Touching or scratching the nose is also said to be a sign of distraction to cover up lies. A person who is lying may be trying to make you focus on their actions rather than their words.

When a person tells lies, their physical expression is often very stiff and limited. If a person is smiling as they lie, only the mouth will move. A real smile involuntarily causes movement of the mouth, eyes, forehead, cheeks and jaw.

The liar's hand, leg and arm movements are toward his own body; the liar takes up little space. The liar’s body language is not open. Liars do not look relaxed, even though they may be trying to give the impression that they are.

When a person is telling lies, she has a variety of ways to distract you from the lie. Liars may move around the room and place objects between you and them, such as a book or coffee cup. A liar will feel uncomfortable facing and looking directly at you when talking and may turn his head and body away from yours. An innocent person will go on the offensive, while a guilty person will get defensive.

When explaining something, a liar may put into the conversation more detail than is necessary. She will not be comfortable with pauses or silences. The person telling lies may speak softly or in garbled words. However, a very accomplished liar is able to speak directly and with confidence; salespeople are great at this technique.

If you suspect someone of telling lies, change the topic of conversation abruptly. The liar will willingly change topics with you and become more relaxed. A person who is telling the truth will become confused by this sudden change. Another sign of someone telling a lie is yawning. The liar may try and look as relaxed as possible during the lie, and yawing and stretching are ways of achieving this.