The Expression of the Emotions in Man and Animals Darwin notes the universal nature of expressions in the book, writing: "the young and the old of widely different races, both with man and animals, express the same state of mind by the same movements." This connection of mental states to the neurological organization of movement (as the words "motive" and "emotion" suggest) is central to Darwin's understanding of emotion. Darwin himself displayed many biographical links between his psychological life and locomotion, taking long, solitary walks around Shrewsbury after his mother's death in 1817, in his seashore rambles near Edinburgh with the Lamarckian evolutionist Robert Edmond Grant in 1826/1827, and
The Expression of the Emotions in Man and Animals the actor Henry Siddons in his "Practical Illustrations of Rhetorical Gesture and Action" (1807) and by the anatomist Robert Knox in his "Manual of Artistic Anatomy" (1852) – but abandoned them as unreliable, although the text of "The Expression" is littered with quotations from Shakespeare. Darwin opens the book with three chapters on "the general principles of expression", introducing the rather Lamarckist phrase "serviceable associated habits". With this phrase, Darwin seeks to describe the initially voluntary actions which come together to constitute the complex expressions of emotion. He then invokes a principle of "antithesis", through which opposite states of mind