Body language is a form of non-verbal communication that allows visual cues that transmit messages without speaking. Gestures are movement that are made with the body: arms, hands, facial, etc. Authors Barbara Pease and Allan Pease, of "The Definitive Book of Body Language" concluded that everyone does a shoulder shrug, a gesture signifying that the person is not comprehending what they are supposed to be understanding. Also, that showing the palms of both hands to show a person is not hiding anything, and raising the eyebrows to indicate a greeting.