The Nonverbal Dictionary Of Gestures, Signs & Body Language Cues by David B. Givens:

“Items in this Dictionary have been researched by anthropologists, archaeologists, biologists, linguists, psychiatrists, psychologists, semioticians, and others who have studied human communication from a scientific point of view.”.

From Proxemics:

“I have learned to depend more on what people do than what they say in response to a direct question, to pay close attention to that which cannot be consciously manipulated, and to look for patterns rather than content.”.
(Edward T. Hall, 1968)