Performs work requiring application of a professional knowledge of behavior, capacities, traits, interests and activities of human and animal organisms. Work may involve any one or a combination of the following functions: experimenting with or systematically observing organisms to develop scientific principles or laws concerning the relationship of behavior to factors of environment, experience, or physiology, or to develop practical applications of findings; applying professional knowledge of psychological principles, theories, methods, or data to practical situations and problems; and providing consultative services or training in psychological principles, theories, methods, and techniques to advance knowledge of them and their appropriate use.