Fig. I. An incomplete conceptual diagram of information flow in immediate memory tasks. No reference whatever to locations or pathways in the nervous system isimplied.
PRELIMINARY DESCRIPTION OF THE MODELThe overall schema in which we are operating is given in Fig. I. Our preliminary assumptions are based on a clear distinction between information which has been categorized (i.e., identified or perceived) and information which has not been categorized. Like Tulving (1968) we see no defensible reason for distinguishing between perception and learning, with respect to individual elements. Once categorization has argument is, on the contrary, that PAS bears important qualitative similarities to the comparable precategorical storage system in vision (Sperling, 1963) though the relevant time parameters appear to be of different order of magnitude. While other writers (e.g., Mackworth, 1965;Neisser, 1967) have previously considered the existence of an acoustic-equivalent to the visual sensory store (and have suggested longer duration in the case of audition than in vision) there has been no comprehensive attempt to make explicit the properties of such a store. In considering these properties, our main objective has been to give an explanation for various serial position data which have been reported in immediate memory. Although the system is in this sense ad hoc it leads readily to a number of testable implications, two of which were confirmed in the experiments reported herein. We shall first describe the PAS system and its properties; second, review the evidence in its favor from both our laboratory and others'; and finally, suggest the relation of the model to a general approach to memory theory.