Previous NSF-supported research by Hintzman has shown that a simple theory of human memory, based on a few core assumptions, can account for a surprising number of empirical phenomena uncovered in experiments on human learning and memory. The basic assumptions of the theory have been formalized in computer programs, which have been tested on learning and memory tasks analogous to those given to humans participanting in experiments. Such simulation work is a valuable aid in the development of theories of cognition, particularly theories involving factors such as parallel processing and variability, whose consequences are difficult to anticipate intuitively. The basic assumptions of the Hintzman simulation model, for example, concern processes underlying the operation of just two fundamental variables, repetition and similarity. However, the model accounts for several phenomena that previously had been thought to be unique, and to require their own ad hoc explanations. The research will consist of three types of activity: (a) The simulation model will be expanded in two ways. First, the present model, which has so far been applied primarily to memory for distinct events and the learning of abstract categories, will be applied to the domains of associative learning and recall. Second, different versions of the model will be developed to handle problems for which the present model is inadequate. These include retrieval of the meaning of a word from memory, and the facilitative effect of prior familiarity on learning. (b) Several experiments will test new predictions made by the model concerning the learning of abstract categories, the effects of repetition and similarity on recognition of previously encountered items, and memory retrieval latencies. (c) Comparisons will be made between the present memory model and other models in the literature. Interest will focus primarily on determining whether a simple model of the "connectionist" type exists whose behavior is essentially the same as that of the current model. This is important because an advantage claimed for connectionist models by some is that they are anatomically or physiologically plausible. The theory has broad implications for learning, memory, and cognitive processes. As such, it could yield practical insights in the fields of education and training, memory improvement, treatment of memory defects, and the reliability of judgments based on memory.
