Evidence for alternative strategies of sentence retention

Measurements of pupil size were taken while subjects listened to sentences and either tried to repeat them (R) or answered a question about them (QuA), after either a 3 or 7 sec retention interval. Pupil dilations were larger for R than for QuA, both towards the end of presentation and during the retention interval. Similar results were obtained by Kahneman and Wright (1971) when comparing total and partial recall of word lists. They attributed the differences in pupil dilations to differences in rehearsal strategy. However, the interaction between recall condition and retention interval was less convincing with sentential material, and an alternative explanation is suggested in terms of the level of abstraction at which the sentences are processed. This interpretation is supported by other evidence relating to the existence of alternative sentence retention strategies.

Pupil dilations failed to reveal phrase juncture phenomena, although two levels of ambient illumination were used in the hope of detecting such effects. In a modified question condition (QuB), where the question was given before the sentence, pupil dilations varied as a function of the part of the sentence providing the answer. These data indicated that people did not begin to frame their answer until they encountered in the sentence those words used in the question.