was first theorized and discussed by the British biologist Charles Darwin (1809 - 1882) as a form of communication between individual's through non-verbal signalling through the manipulation of various facial muscles.

FACIAL EXPRESSION: "The human race is famous globally for its range and utilisation of facial expression in basic communication and day to day life."
Cite this page: N., Pam M.S., "FACIAL EXPRESSION," in PsychologyDictionary.org, May 11, 2013, https://psychologydictionary.org/facial-expression/ (accessed May 15, 2021).