Passage difficulty, speech rate, and age differences in memory for spoken text: speech recall and the complexity hypothesis

Memory for speech in young and elderly adults was studied by varying speech rate and average predictability of prose passages (measured by a "cloze" procedure). Increased speech rate and decreased predictability yielded poorer memory performance on three retention measures (free recall, cued recall, and multiple-choice recognition), confirming passage predictability as a good predictor of empirical difficulty of a speech passage. Older adults recalled less than young adults on all three measures, with increasing speech rates producing special difficulty for the elderly subjects relative to the young. Although there was a suggestion that elderly subjects were less able to take advantage of passage predictability than the young in recall of very rapid speech, neither age group showed an interaction between passage predictability and speech rate. Results are discussed in terms of a simple extension of the complexity hypothesis to speech recall.