Clark Hull
Clark Hull developed an extensive overall psychological system that covered not just learning, but motivation, incentives, and, through the work of associates such as Dollard and Miller, applications in social psychology and psychotherapy. In this discussion, we shall focus on a creative idea of his: the fractional anticipatory (antedating) goal response. The fractional anticipatory goal response (rg) is part of a mechanism which can explain (in stimulus-response terms) how, say, a rat might learn that turning right in a T-maze will lead to a reward. Notice that the phrase that a rat “learns that X will lead to Y” has a natural cognitive interpretation, namely, in terms of expectations. After a number of repetitions through the maze, the rat seems to develop a number of “if I do X, then Y will happen” beliefs. How does a behaviorist combat such notions? With the help of rg.
When a rat eats its reward, it salivates, chews, etc. After a number of trials, it starts salivating and/or chewing (and/or other component behaviors of eating) before it gets to the food---- these are fractional antedating goal responses. Just as stimuli present in a maze can become conditioned to the actual response RG (eating), those stimuli can also become conditioned stimuli that produce an rG. Since the rG’s are actual movements, they will produce internal stimulation, for example, the sense of movement of muscles and tendons. The sense of movement of these muscles and tendons produces internal stimuli: so-called movement-produced or proprioceptive stimuli sG. So, rG’s produce sG’s. The sG’s then lead to an overt response (progressing through the maze) that leads the organism to experience the next SD (discriminative stimulus), which produces the next rG, which leads to the next sG, which produces the next overt response, which starts the sequence all over again; until the organism makes its way from the starting point to the reinforcing stimulus in the goal box. It is very much a mechanical view (each step is completely determined by the preceding step) of a sequence of behaviors.
Yes, this is a wildly complex explanation for what seems like a simple sequence of behaviors. But, Hull is providing a deterministic step by step sequence of events that leads the rat from start to finish on a maze running trial.