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
The Descent of Man, and Selection in Relation to Sex to the forces of sexual selection. While debates on the subject continues, in January 1871 Darwin started on another book, using left over material on emotional expressions, which became "The Expression of the Emotions in Man and Animals". In recent years controversy also involved the peacock tail, the most famous symbol of the principle of sexual selection. A seven-year Japanese study of free-ranging peafowl came to the conclusion that female peafowl do not select mates merely on the basis of their trains. Mariko Takahashi found no evidence that peahens expressed any preference for peacocks with more elaborate trains, such as