Limited Influence of Sleep on Drawings Made From Memory

It is well known that memory fades over time, but it is unclear how actions taken between encoding and recall affect this fading, especially for visual recall. To assess the effect of sleep on visual recall, we conducted two experiments. In the first experiment, participants drew scene images from memory after a 10-hour delay of either wake or sleep. Through crowdsourced scoring of these drawings, we found that participants recalled significantly fewer images, and fewer objects within those images, after the delay compared to images drawn from memory immediately after encoding. However, we surprisingly found no significant difference in memory quality depicted in the drawings between the sleep and wake conditions. In the second experiment, we increased interference between images by having participants memorize and draw multiple images from the same scene category, and an equal number of images from different scene categories. Participants recalled significantly more images from the same scene category, but significantly more objects from the different scene categories. However, despite successfully increasing interference between images, we found no significant difference between sleep and wake for either metric. These results challenge the commonly held belief that sleep benefits all types of memory and suggest that sleep has a limited influence on visual recall performance.