Attraction versus repulsion: Are central tendency effects and duration adaptation effects based on an altered perception of time?

Subjective judgments of the duration of temporal intervals can deviate from their objective physical duration. A prominent example is that duration judgments are influenced by the temporal context. Central tendency effects indicate an attraction of duration judgments toward the mean of previously experienced durations, whereas adaptation effects indicate a repulsion of duration judgments from this mean. These two effects stand in apparent contrast and the question arises which (if either) of them can be attributed to an altered perception of time, and which is based on a response bias. In the present study, participants judged a target duration (2.4 s) in a short-duration versus a long-duration context, while both the target duration and the context durations were independently judged using either reproduction or estimation (the latter involving a click on a line representing 0 to 8 s). Although for both reproduction and estimation tasks central tendency effects were observed within short-duration and long-duration blocks, a between-block analysis shows that the attraction of the target duration toward the temporal context vanishes when the temporal context is induced by estimation (rather than reproduction), and even reverses to a repulsion from the temporal context when the target duration is judged by estimation (rather than reproduction). We conclude that central tendency effects in time reproduction tasks are largely based on the repetition of motor actions rather than on a genuine change in the perception of time. Our findings shed light on the important question of whether temporal context effects emerge at the level of perception or at the response level.