Phonological and semantic strategies in immediate serial recall

Abstract

It has been suggested that certain theoretically important anomalous results in the area of verbal short-term memory could be attributable to differences in strategy. However there are relatively few studies that investigate strategy directly. We describe four experiments, each involving the immediate serial recall of word sequences under baseline control conditions, or preceded by instruction to use a phonological or semantic strategy. Two experiments varied phonological similarity at a presentation rate of one item every 1 or 2 seconds. Both the control and the phonologically instructed group showed clear effects of similarity at both presentation rates, whereas these were largely absent under semantic encoding conditions. Two further experiments manipulated word length at the same two rates. The phonologically instructed groups showed clear effects at both rates, the control group showed a clear effect at the rapid rate which diminished with the slower presentation, while the semantically instructed group showed a relatively weak effect at the rate of one item per second, and a significant reverse effect with slower presentation. The latter finding is interpreted in terms of fortuitous differences in inter-item rated associability between the two otherwise matched word pools, reinforcing our conclusion that the semantically instructed group were indeed encoding semantically. Implications for controlling strategy by instruction are discussed.

Acknowledgements

We thank Alice F. Healy, Jean Saint-Aubin, Gerry Tehan, and Ian Neath for constructive comments on earlier versions of this article. We also thank Mercedes Cortes for her help in stimulus recording, and Lucia Colodro and Beatriz Cuevas for their assistance in data collection.

Notes

¹This advantage for lists of semantically similar lists could be seen as conflicting with the results obtained by Baddeley (1966), who found worse recall for lists of similar words. However, this discrepancy is easily explained by relevant procedural differences. Semantic similarity in the studies by Saint-Aubin and Poirier was found to have a large beneficial effect on item recall, but also a slight detrimental effect on order recall (Saint-Aubin et al., 2005). The negative effect found by Baddeley (1966) can be explained by the fact that, in contrast to Saint-Aubin and Poirier, Baddeley used closed sets of stimuli, which were, moreover, displayed during recall. It seems clear that performance in this situation was a product of order rather than item recall, with the consequence of worse recall for similar lists.

²A reverse word-length effect has also been found by Caplan and collaborators (Caplan & Waters, 1994; Caplan et al., 1992), but this effect was probably a consequence of problems with the word sets, such as differences in phonological similarity (see Baddeley & Andrade, 1994; Mueller et al., 2003).