UNCHAINED MEMORY - ERROR PATTERNS RULE OUT CHAINING MODELS OF IMMEDIATE SERIAL-RECALL

Many models of serial recall assume a chaining mechanism whereby each item associatively evokes the next in sequence. Chaining predicts that , when sequences comprise alternating confusable and non-confusable it ems, confusable items should increase the probability of errors in rec all of following non-confusable items. Two experiments using visual pr esentation and one using vocalized presentation test this prediction a nd demonstrate that: (1) more errors occur in recall of confusable tha n alternated non-confusable items, revealing a ''sawtooth'' in serial position curves; (2) the presence of confusable items often has no inf luence on recall of the non-confusable items; and (3) the confusabilit y of items does nor affect the type of errors that follow them. These results are inconsistent with the chaining hypothesis. Further analysi s of errors shows that most transpositions occur over short distances (the locality constraint), confusable items tend to interchange (the s imilarity constraint), and repeated responses are rare and far apart ( the repetition constraint). The complete pattern of errors presents pr oblems for most current models of serial recall, whether or not they e mploy chaining. An alternative model is described that is consistent w ith these constraints and that simulates the detailed pattern of error s observed.