Introduction

Immediate memory capacity for lists is usually estimated at around 5–6 words, whereas for sentences, Miller and Self ridge (1950) found that 20-word sentences can be produced with nearly 100% recall, a finding replicated by Craik and Masani (1969). In a more recent study, Butterworth, Campbell and Howard (1986) presented subjects with 40 sentences 15–21 words long for immediate recall. Undergraduate subjects recalled about 25 of them perfectly. Most of the errors were omissions and word substitutions, not word order errors (less than 3% of all errors). There were significant serial position effects, with the first two words and the last word recalled better than the others. “Running memory span” tasks (where subjects are allowed to choose the segment to report) show accurate recall for segments up to and exceeding 20 words; in general, about 88% of the words are recalled (discounting order) irrespective of the segment length (Wingfield & Butterworth, 1984, Experiment 1).

Why is immediate serial recall of sentences better than lists? A number of probable solutions will doubtless spring to mind. Sentences encourage chunking; the meaning of a sentence can be stored in long-term memory (LTM) and thence retrieved in recall; sentences are meaningful; sentences have structure; sentence materials utilize quite different memorial systems; and so on. Various authors have made suggestions along one or other of these lines (e.g., Miller & Selfridge, 1950; Craik, 1971; Shallice, 1979; Butterworth et al., 1986; McCarthy & Warrington, 1987a).

It has frequently been argued that a verbatim record of sentence input is held in some limited-capacity store while the construction of a higher-level representation is carried out.