An interesting feature of body language is that we are often unaware of it. We usually do not consciously decide that we will smile, dilate our pupils, and move closer to someone to show our attraction. Because of this lack of awareness, people may give themselves away through nonverbal cues when they are lying. Mehrabian (1971) asked subjects to tell a lie while he studied their body language. He found that people who are telling a lie show less frequent body movement, smile more, keep a greater distance from the listener, and lean backward more than people telling the truth.