The Expression of the Emotions in Man and Animals the issues at play, writing: "The force of language is much aided by the expressive movements of the face and body" - hinting at a neurological intimacy of language with psychomotor function (body language),and underscoring the social value of expression. Darwin's Sources on Emotional Expression: Darwin had listened to a discussion about emotional expression at the Plinian Society in December 1826 when he was a medical student at Edinburgh University. This had been prompted by the publication of Sir Charles Bell's "Anatomy and Philosophy of Expression"; and in his presentation, the phrenologist William A.F. Browne (in a spirited account of
Body language postural expressions of emotions such as anger/aggression, happiness, and fear. These similarities support the evolution argument that social animals (including humans) have a natural ability to relay emotional signals with one another, a notion shared by several academics (Chevalier-Skolnikoff, 1974; Linnankoski, Laakso, Aulanko, & Leinonen, 1994). Where Darwin notes similarity in expression among animals and humans, the Cultural Equivalence Model notes similarity in expression across cultures in humans, even though they may be completely different. One of the strongest pieces of evidence that supports this model was a study conducted by Ekman and Friesen (1971), where members of a preliterate