Cumulative Record. Chapter 23: Current Trends in Experimental Psychology. Quote 28

The most important contribution that psychology can make today is a workable theory of behavior in the present sense—a conception of man which is in accord with all the facts of human behavior and which has been crucially tested in the experimental laboratory. Only an effective and progressive theory of behavior can bring about the proper change in attitude which will make it possible to apply the methods of science to human affairs in every field. (p. 358)