Testing the Idea of Distinct Storage Mechanisms in Memory

Abstract

This paper sets out quantitative foundations for testing the idea that memory is served by two distinct storage mechanisms, a short‐term and a separate long‐term store, using data from the single‐trial free‐recall experiment by Murdock and Okada (1970). In single‐trial free recall one can observe which word is recalled next and how long that recall takes, but that is all. So justification for two separate stores must turn either on the probabilities of recall, or on the latencies, for particular serial positions in the stimulus list.(a) Nearly one‐third of all recalls after the first are successors (Word n+1 immediately following recall of Word n). So recall is dominated, not by absolute serial position (as a short‐term store would require), but by position relative to the preceding recall.(b) To a first approximation, all first recalls have the same latency distribution except for Word 1. A common latency distribution is compatible with a single store. An explanation is offered why Word 1 should take longer, in which Word 1 is the second retrieval from a common store.The idea of two separate stores appears to lack experimental support.