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Public Statement:

New paper: Dynamics of retrospective timing: A big data approach

We tested over 24000 participants (one of the largest samples tested in experimental psychology) in a retrospective timing task. Participants simply filled out a set of questionnaires, after which we asked them to judge how long it took them to complete them.  We found that participants were most accurate at estimating 15 minutes; they overestimated durations shorter than 15 minutes and underestimated durations longer than 15 minutes. We also found a very robust manifestation of whole number bias; participants tended to report their estimates at multiples of 5 minutes. These results tell us a lot about our timing ability in daily life and how we communicate durations to others. We tend to say let's meet at 10 minutes rather than 7 minutes or 11 minutes. This study was a collaboration of researchers from Turkey, Canada, France, and Germany. The raw data are available as part of the Timing Database (pick Retrospective Timing Task from the dropdown menu).

Abstract: Most interval timing research has focused on prospective timing tasks, in which participants are explicitly asked to pay attention to time as they are tested over multiple trials. Our current understanding of interval timing primarily relies on prospective timing. However, most real-life temporal judgments are made without knowing beforehand that the durations of events will need to be estimated (i.e., retrospective timing). The current study investigated the retrospective timing performance of ~24,500 participants with a wide range of intervals (5–90 min). Participants were asked to judge how long it took them to complete a set of questionnaires that were filled out at the participants’ own pace. Participants overestimated and underestimated durations shorter and longer than 15 min, respectively. They were most accurate at estimating 15-min long events. The between-subject variability in duration estimates decreased exponentially as a function of time, reaching the lower asymptote after 30 min. Finally, a considerable proportion of participants exhibited whole number bias by rounding their duration estimates to the multiples of 5 min. Our results provide evidence for systematic biases in retrospective temporal judgments, and show that variability in retrospective timing is relatively higher for shorter durations (e.g., < 30 min). The primary findings gathered from our dataset were replicated based on the secondary analyses of another dataset (Blursday). The current study constitutes the most comprehensive study of retrospective timing regarding the range of durations and sample size tested.

Public Statement:

New Paper: Mice are near-optimal timers 

Your child just told you that she had a tear in her snow pants and she would like you to mend it. Assume that you do not have time to climb down the stairs to inspect the tear before preparing your thread and needle. In such a scenario, you will probably cut a very long thread so that you will not have to redo the mending job; you do not have time for that as you are running behind the morning schedule. Here overestimating the size of the tear will pay off, given the fairly low cost of thread. But if your child shows you the tear before you prepare for mending, you will probably cut a thread that better matches the size of the job. In these two hypothetical scenarios (real for many of us), what determines how long of a thread you will cut is your differential uncertainty regarding the size of the tear. The more uncertain you are, the longer the thread; this is an optimal strategy for the mending task at hand. Similarly, if you are more uncertain about the arrival time of a bus, you will go to the bus stop earlier. But if you know the bus schedule, you will lose less time waiting for the bus at the bus stop as you have more important things to do. In this paper, we show that mice can adopt such optimal strategies when they are producing time intervals (by depressing a lever for a minimum amount of time) to receive a reward. We find that those mice that have higher timing uncertainty tend to be more cautious and depress the lever much longer than required compared to those mice that are more certain regarding the passage of time. This work is the most recent example of a series of studies we have published over the years that show that humans and non-human animals can take near normative account of their timing uncertainty while making decisions about time intervals. We use clocks to reduce this very uncertainty that we would face if we were just relying on the time keeping capacity of our brain.