Theories of intermediate variables

Under the pressure of the three problems mentioned above — memory, motivation, and cognition, most of the creators of theories of learning supplemented the Skinner experimental analysis of environmental and behavioral variables with intermediate variables. Intermediate variables are theoretical constructs whose value is determined through their connections to various environmental variables whose total effects they are intended to summarize.

Tolman's theory of expectation

Thorndike, under the influence of Darwin's background on the continuity of the evolution of biological species, began the transition to a less mentalist psychology. John B. Watson concluded with his complete rejection of mentalist concepts. Acting along the lines of new thinking, Tolman replaced the previous speculative mentalist concepts with logically defined intermediate variables.

As for the subject of our discussion (reinforcement), here Tolman did not follow Thorndike’s example. Thorndike considered the consequences of a response as being of extreme importance in enhancing the associative relationship between stimulus and response. He called it the law of the effect, which was the forerunner of the modern theory of reinforcement. Tolman believed that the consequences of the reaction had no effect on learning as such, but only on the external expression of the processes underlying learning. The need to distinguish between learning and execution arose in the course of attempts to interpret the results of experiments on latent learning. As the theory developed, the name of the intermediate variable introduced by Tolmen, which reflects learning, changed several times, but the most appropriate name could probably be waiting. The wait depended solely on the temporal sequence - or adjacency - of events in the environment, and not on the consequences of the response.

Pavlov's physiological theory

For Pavlov, as well as for Tolman, the necessary and sufficient condition for learning was the contiguity of events. These events are physiologically represented by processes occurring in those areas of the cerebral cortex that are activated by indifferent and unconditioned stimuli. Evolutionary consequences of the learned reaction were recognized by Pavlov, but were not tested under experimental conditions, therefore their role in learning remained unclear.

Gazri's Molecular Theory

Like Tolman and Pavlov, and unlike Thorndike, Edwin R. Ghazri considered adjacency to be a sufficient condition for learning. However, coinciding events were not determined by such wide (i.e., molar) events in the environment, as Tolman claimed. Each molar environmental event, according to Ghazri, consists of a variety of molecular stimuli, which he called signals. Each molar behavior, which Gazri called "action", in turn, consists of a variety of molecular reactions, or "movements." If the signal is combined in time with the movement, this movement becomes entirely due to this signal. Learning behavioral action develops slowly only because most actions require learning to many of their constituent movements in the presence of many specific signals.

Theory of Reduction Drive Hull

The use of intermediate variables in the theory of learning has reached its widest development in the works of Clark L. Hull. Hull attempted to develop a general interpretation of behavioral changes resulting from both classical and operant procedures. Both the conjugacy of the stimulus and the reaction, as well as the reduction of the drive were included as necessary components in the Halla concept of reinforcement.

Fulfillment of learning conditions affects the formation of an intermediate variable - habits. The habit was defined by Hull as a theoretical construct that summarizes the overall effect of a number of situational variables on a number of behavioral variables. The links between situational variables and intermediate variable (habit), and further between habit and behavior were expressed in the form of algebraic equations. Despite the use in the formulation of some of their intermediate variables of physiological terms, experimental research and Hull's theory were associated exclusively with the behavioral level of analysis. Kenneth W. Spence, a Hull researcher who made a significant contribution to the development of his theory, was particularly careful in defining intermediate variables in purely logical terms.