In the first textbook of physiological psychology, written by Wilhelm Wundt (1910) at the end of the 19th century, Wundt defined the task of physiological psychology as the analysis of the physiological bases of consciousness and subjective experience. In the textbook of physiological psychology which I used when a student, written by Morgan and Stellar (1950) in the middle of the 20th century, physiological psychology was defined as the study of the physiological bases of behavior. The word consciousness does not even appear in the index of the latter volume, nor have I encountered it anywhere in the text.