The temporary storage of information in working memory is at the heart of theoretical models of consciousness and plays a fundamental role in all sub-fields of psychology and neuroscience, including synchronisation and memory. The encoding and temporary storage of durations in working memory are essential for predicting and planning the future, yet the processes involved in storing temporal information are currently unknown.
In this study, the researchers looked at the processing of durations by working memory, a short-term storage system with a limited capacity. Participants had to memorise the duration of several successive time intervals, presented in the form of non-isochronous sequences delimited by short sounds. After a certain delay, they had to reproduce the duration of each interval as accurately as possible. The question was whether the time sequence would be discretised so that each time interval was represented distinctly in memory (like a bit of information), or whether the entire sequence would be held in memory. In this sense, adding new items to the temporary storage would reduce the number of bits that could be used to specify each item, and therefore the accuracy with which it could be retrieved. The results of three behavioural experiments (N=58) showed that the greater the number of time intervals to be memorised, the less accurate the participants were in retrieving durations. This reduction in accuracy seemed to be directly linked to the workload imposed on their memory. On the other hand, the length of the sequence itself did not affect accuracy.
These results, showing that the greater the number of time intervals to be memorised the less accurate the participants were in reproducing the times, suggest a direct link with the workload imposed on their memory. On the other hand, the length of the intervals did not seem to affect accuracy, leading the authors to propose that duration is memorised as abstract information that our brain processes as distinct information within our working memory, in a way comparable to the processing of other objects in memory, such as an image or a sound.
Contacts : Sophie Herbst (sophie.herbst@cea.fr) ; Virginie van Wassenhove (virginie.van-wassenhove@cea.fr)
Short-term or working memory, also known as 'buffer memory', is the memory we use all the time to retain and store information temporarily (a few seconds) (keeping a telephone number in our heads long enough to write it down...).