When we say to someone that we "got their message", more often we are referring to either a written or a spoken message. But there are other sources of information. When we interact with others,we receive a stream of nonverbal information. Part of this is "body language"-- the gestures, eye movements, head movements,shifts in posture, and movements of the arms, hands, and legs that give us messages about the emotions and motives of another person.
Let's assume nonverbal communication in the detection of lying and deception. A person may try to cover up a shady past in applying for a job,a patient in a patient in a mental hospital may try to deceive the staff in order to gain release, or a student may lie about cheating on an examination. Paul Ekman and Wallace Friesen made a number of observations indicating that as Freud said, the deception may "leak out" in behavior. Although the face is the most expressive part of the body, Ekman and Friesen say that it is also the most easily controlled when trying to deceive someone. Not so easy to control are gestures of the hands, feet and legs. For instance, while a person is smiling in a relaxed way,the tension and anxiety the individual is feeling may be shown by clutching the knee tightly, digging into the cheek with the fingers,pressing the fingers tightly together, or tense positions of the limbs. Anger may "leak out" in a clenched fist, a tense posture, a rapid drumming of the fingers on the table, or kicks of the foot.
Recent years have seen a number of body-language articles in newspapers and magazines; several popular books have also been written on the subject. Using phrases such as #your-body-doesn't-know-how-you-lie and #body-gestures-project-your-most-hidden-thoughts, these popular articles and books probably claim too much for nonverbal communication. As Morton Wiener and his colleagues have pointed out,the accurate interpretation of gestures is very difficult. A major problem is separating gestures which communicate nonverbal emotional or motivational messages from those which do not. Many gestures do not communicate anything. For example, a woman walking down the street may display a hip sway that some men interpret as a 'sexy' message when,in fact,it is only a characteristic nature of the way she walks. Furthermore, Wiener and his colleagues warn against associating any specific movement with one particular meaning: "Similar movements may serve different functions and different movements may serve different functions."
We need reliable guides to tell us what movements, under what circumstances, communicate emotional and motivational messages. Research continues, but the accurate interpretation of body language remains an art in which some people are more skilled than others.