ABSTRACT
Behaviorism developed as a reaction to the subjective introspection of the structuralists (e.g., Titchener). With behaviorism came not only objective data-based research which emphasized control of extraneous variables, but also an attempt to describe all behavior in terms of external (i.e., observable) stimulus and response events. Even when they were forced to retreat into the organism, behaviorists such as Hull (1943) postulated mechanisms that were potentially observable (e.g., the fractional anticipatory goal response). Occasionally the behaviorist mantle was adopted by someone like Tolman (1932) who felt comfortable with purely internal, stimulus-stimulus associations, but this was the exception rather than the rule.
