Time estimation and amnesia: A case study

Abstract

The present experiment investigates the ability of an amnesic patient (AC) to estimate three durations (5, 14 or 38 s) in two different temporal tasks (reproduction and production). In the reproduction task, AC and control subjects first had to encode one of the three durations and then to reproduce it. In the production task, they were asked to produce one of the three durations given in chronometric units. AC's performance showed a clear dissociation according to the tasks and the durations. His productions of the three durations and his reproductions of 5 s did not differ from those of the controls, whilst his reproductions of longer durations (14 and 38 s) were systematic underestimations. The results suggest that reproduction involves a long-term storage in episodic memory for durations exceeding the short-term memory capacity, whereas production of durations given in chronometric units involves semantic memory, which contains the representation of several durations, and working memory, which permits the maintenance of temporal information throughout each trial.