A Proactive Restatement of the Law of Effect
Although theoretical accounts of learning exist in abundance few psychologists would doubt the validity of the empirical law of effect. Behavior which produces some reward does come to predominate over behavior that does not. Both the circularity of the law of effect and its teleological implications have been commented upon from time to time and explained away (Mowrer, 1952; Postman, 1947). It is also widely thought that larger rewards are more effective than smaller ones in 'strengthening' the behavior that produces them. However detailed examinations of the function of both primary and secondary reward have pointed to its proactive, rather than its retroactive, effects in consolidating beha~ior .~ Several methods of estimating the strength of a response have been proposed and utilized, but so far there is scant evidence showing how these measures co-vary. Skinner (1938, 1950) has argued for probability of occurrence, or rate of performance, as the most satisfactory gauge of response strength, and it is this measure that is utilized herein. It is understood that the response under discussion is that which produces a reward. The particular topography of that response is not our immediate concern. Consider the following experiment. An human S is instructed that if he presses a key, E say, a light will occasionally come on, and that pressing another key, C, in the presence of the light will activate a counter giving S a score. His task is to obtain as high a score as he can. One hand only can be used and the keys are placed so that they cannot be manipulated simultaneously. Designations E and C refer to effective and consmmatory activity, respectively. That is, a response to key E is effective in producing a reward, and a key C response 'consumes' it. These are analogous to bar pressing and eating in the typical operant experiment. Suppose each response to key E turns on the light, and each depression of key C turns it off and gives S 1 point. Then key E responses may be said to be reinforced 100% of the time. Key C responses, being consummatory, are typically ignored, but under the conditions specified the two responses co-vary exactly. Suppose we now increase the amount of reward given for each depression of key E. That is, the light remains on long enough for S to make several responses to key C. Notice that we have given a larger reward for the E response, but that it is the C response that increases in rate. Responses to key E