Though logically distinct, methodological, psychological, and analytical behaviorisms often are found in one behaviorism. Skinner's radical behaviorism combines all three forms of behaviorism. It follows analytical strictures (at least loosely) in paraphrasing mental terms behaviorally, when or if they cannot be eliminated from explanatory discourse. In Verbal Behavior (1957) and elsewhere, Skinner tries to show how mental terms can be given behavioral interpretations. In About Behaviorism (1974) he says that when mental terminology cannot be eliminated it can be “translated into behavior” (p. 18, Skinner brackets the expression with his own double quotes).
Radical behaviorism is concerned with the behavior of organisms, not with internal processing. So, it is a form of methodological behaviorism. Finally, radical behaviorism understands behavior as a reflection of frequency effects among stimuli, which means that it is a form of psychological behaviorism.