The Expression of the Emotions in Man and Animals allows cultural factors only an auxiliary role in the shaping of expression. This biological emphasis leads to an appreciation of the universal nature of expression, with its implication of a single origin for the entire human species; and Darwin points to the significance of emotional communication with children in their psychological development. Darwin sought out the opinions of some leading British psychiatrists, notably James Crichton-Browne, in the preparation of the book which forms his main contribution to psychology. Amongst the innovations with this book are Darwin's circulation of a questionnaire (probably inspired by his cousin, Francis Galton) in his preparatory
The Expression of the Emotions in Man and Animals initial correspondence with the psychiatrist James Crichton-Browne Darwin set aside his material concerning emotional expression in order to complete "The Descent of Man", which covered human ancestry and sexual selection. Darwin concluded work on "The Descent of Man" on 15 January 1871. Two days later, he started on "The Expression of the Emotions" and, on 22 August 1872, he finished work on the proofs. In this book, Darwin brings his evolutionary theory into close approximation with behavioural science, although many Darwin scholars have remarked on a kind of spectral Lamarckism haunting the text of the "Emotions". Universal Nature of Expression: