The Expression of the Emotions in Man and Animals in the field of comparative psychology and his impact on academic psychology was muted, partly because of the widespread influence of the behaviourist school during the twentieth century. The lavish style of biological illustration was followed in work on animal locomotion by photographer Eadweard Muybridge (1830–1904)(leading to cinematography), and by the Scottish naturalist James Bell Pettigrew (1832–1908); in the extensively (and controversially) illustrated works of the evolutionary biologist Ernst Haeckel; and – to a lesser extent – in D'Arcy Thompson's "On Growth and Form" (1917). Darwin's ideas were followed up in William James' "What Is An Emotion ?" (1884); and,
Body language movement of any part of the body or the body as a whole; in layman's terms, it is the study of body language. However, Ray Birdwhistell, who is considered the founder of this area of study, never used the term "body language", and did not consider it appropriate. He argued that what can be conveyed with the body does not meet the linguist's definition of language. Birdwhistell pointed out that "human gestures differ from those of other animals in that they are polysemic, that they can be interpreted to have many different meanings depending on the communicative context in which