In search of the M-Gram: The structure of organization in free recall

This paper reviews three major classes of structural models of episodic and semantic memory which have been proposed to describe the organization of permanent memory. Although semantic memory workers have developed methods for obtaining representations of these models from empirical data, students of episodic memory generally have not. A method is presented for extracting representations of memory structure using output order information from a free recall learning task. It is shown that this method can be embedded within each of the three general models of memory structure to produce graphic representations of those structures. These representations may be obtained for individuals or for group data, and in some cases the nature and extent of individual differences in organizational structure can be characterized. A final section of the paper demonstrates the validity of the method using both real and simulated data, shows that the method is sensitive even to small differences in organizational structure, and illustrates the utility of this approach with an analysis of part-whole transfer.