Ekman's interest in nonverbal communication led to his first publication in 1957, describing how difficult it was to develop ways of empirically measuring nonverbal behaviour.He chose the Langley Porter Neuropsychiatric Institute, the psychiatry department of the University of California Medical School, for his clinical internship partly because Jurgen Ruesch and Weldon Kees had recently published a book called Nonverbal Communication (1956).
Ekman then focused on developing techniques for measuring nonverbal communication. He found that facial muscular movements that created facial expressions could be reliably identified through empirical research. He also found that human beings are capable of making over 10,000 facial expressions; only 3,000 relevant to emotion.Psychologist Silvan Tomkins convinced Ekman to extend his studies of nonverbal communication from body movement to the face, helping him design his classic cross-cultural emotion recognition studies.Interestingly enough, Tomkins also supervised Carroll Izard at the same time, fostering a similar interest in emotion through cross-cultural research.
