Time estimation: does the reference memory mediate the effect of knowledge of results?

This study presents evidence for the role of knowledge of results (KR) in the estimation of medium time intervals (4-12 s durations). Experiment 1 tested the hypothesis that KR operates at the same stage of temporal processing as attention. The absence of an interaction of attention and KR is taken as evidence against this hypothesis. Experiments 2 and 3 further studied the effects of KR in a reproduction and a production task, respectively. The effects of KR were small in the reproduction and substantial in the production task. The results are interpreted in terms of a clock-based tithing model and the findings taken together converge on the interpretation that KR affects the reference memory (RM), rather than the other components of the model. (C) 2002 Elsevier Science B.V. All rights reserved.