Reference: Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177.

Psychology, according to behaviorists, is a purely directive experimental branch of natural science. Theoretically, its goal is to predict and control behavior. Human psychology has been a failure thus far because of the mistaken belief that introspection is the only method available to psychology and that it is the study of consciousness. Because psychology is the study of behavior, it does not require the use of conscious phenomena. As a result, animal psychology is a valid field of study in the same way that human psychology is. Animal behavior laws must be determined and evaluated independently of their applicability to other animals or humans.