Time estimation and amnesia: A case study

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 su bjects 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 du rations given in chronometric units. AC's performance showed a clear dissoc iation according to the tasks and the durations. His productions of the thr ee 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 s ystematic underestimations. The results suggest that reproduction involves a long-term storage in episodic memory for durations exceeding the short-te rm memory capacity, whereas production of durations given in chronometric u nits involves semantic memory, which contains the representation of several durations, and working memory, which permits the maintenance of temporal i nformation throughout each trial.