Abstracting time in memory

Planning the future relies on the ability to remember how long events last, yet, how durations are stored in memory is unknown. Here, we developed a novel n-item delayed duration reproduction task to assess whether elapsed time is stored as a continuous feature or as a discrete item in memory. In three experiments (N = 58), participants were presented with non-isochronous sequences composed of empty time intervals delimited by brief tones. Time intervals varied in number (n-items) and in duration. Participants had to reproduce as precisely as possible the duration of all time intervals in the sequence following a delay period. We manipulated the number of time intervals (n-item) and the sequence duration to separate their effects on recall precision. In all three experiments, the precision of recall decreased with the number of items in the sequence, showing that durations can be stored as discrete items in working memory. Our analyses emphasize the distinction between reproduction biases that are captured by relative reproduction, and decreased precision which indexes working memory load. Future research is needed to spell out the conditions under which durations are fully abstracted in working memory.