Charles Darwin and Psychology at the Bicentennial and Sesquicentennial.

This article provides an introduction to the special issue on Darwin and psychology at the bicentennial of his birth and the sesquicentennial of his publication of On the Origin of Species. His core contributions, as viewed today, were his theory of natural selection, his naturalistic philosophy, and his mass of evidence for evolutionary change. A brief summary of Darwin `s life is also presented. Among Darwin's contributions to psychology were his demonstration of the continuity of species, a model for the study of instinct, a book on the expression of the emotions, and a baby biography. Previous celebrations of Darwin and the changing perceptions of his work since its publication are described. Darwin's theory remains an important part of psychology. [ABSTRACT FROM AUTHOR]