The Expression of the Emotions in Man and Animals Robert Grant's Lamarckist philosophy) ridiculed Bell's theological explanations, pointing instead to the striking similarities of human and animal biology. The meeting then ended in uproar. Forty-five years later, Darwin revisits these arguments and recruits Duchenne's (1862) unmasking of the facial mechanisms, shifting the argument from philosophical speculation to scientific discourse. Darwin's response to Bell's natural theology is discussed by Lucy Hartley (2001). In the composition of the book, Darwin drew on worldwide responses to his questionnaire (circulated in the early months of 1867) concerning emotional expression in different ethnic groups; on anthropological memories from his time on ; on conversations
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