Take these signs with a grain of salt. You want to watch the gestures that accompany these signs or you will erroneously assume that everyone who scratches their nose is lying to you.
If someone uses these gestures while talking to you, it may indicate lying or withholding of information. If they do these gestures while you are talking to them, it may indicate they are skeptical of what you are saying. Either way, these are important gestures to watch for.
If they are deceit signs, generally you will see the gestures accompanied by some of the following: squirming, breaking eye contact, shifting of eyes, shifting of body, turning the body away from you, voice level rising in volume and pitch. In a negotiation this lets you know whether they are serious about the offer or if they are going to just keep pressing you to give in more.
Eye Rub. According to Desmond Morris, if it is a big lie, a woman will rub lightly and look at the ceiling. A man will rub vigorously and look at the floor. Either way, the gesture is intended to avoid eye contact with the other person.
Nose Touching. Look for a slow rub by one finger just under the nose.
Ear Rub. This may be a finger behind the ear, in the ear or rubbing the back of the ear.
Collar Pull. This signifies that the person suspects they will be caught.
Neck Scratch. When a person lies a tingling sensation may pass up the spine so a person will scratch exactly five times to relieve the itch.