Simulation of expert memory using EPAM IV.

EPAM is a theory of the processes of human perception and memory, first programmed for a computer by E. A. Feigenbaum in 1959, that has shown an excellent fit to experimental data from a wide variety of psychological tasks. Over the years, it has been progressively extended to new domains without essential change in its central mechanisms. This article examines EPAM IV, a version extended to account for expert memory, especially the work in recent years by Chase and Ericsson (1981, 1982) and Staszewski (1988a, 1988b, 1990). EPAM IV has also been adapted to deal with numerous other short-term and long-term memory tasks, which will be reported elsewhere. The main modifications of EPAM that are relevant to the serial recall task examined in this article are a schema in long-term memory (called a retrieval structure) created by the expert's learning and the addition of an associative search process in long-term memory. These new components operate in close interaction with the other EPAM structures to match the observed behavior. EPAM IV reproduces all of the phenomena explained previously by EPAM III and in addition gives an accurate detailed account of the performance (studied by Staszewski) of an expert recalling long sequences of digits. The theory substantially revises, improves, and extends Chase and Simon's earlier "chunking" explanation of expert memory.