The ability to remember a briefly presented scene depends on a number of factors, such as its saliency, novelty, degree of threat, or behavioral relevance to a task. Generally, attention is thought to be key, in that people can only remember part of a visual scene when paying attention to it at any given moment.

University of Washington researchers, however, say that memory for visual scenes may not depend on attention level or what a scene contains, but when the scene is presented. Their study, they say, shows how visual scenes are encoded into memory at behaviorally relevant points in time.

The results are published in PLoS Biology.

Study participants performed an attention-demanding "target detection task at fixation," while also viewing a rapid sequence of full-field photographs of urban and natural scenes. Participants were then tested on whether they recognized a specific scene from the sequence they had been shown or not.

"Usually, the addition of a secondary task decreases performance on the first task. However, in this particular case, adding a second task (letter identification) actually enhanced performance in the first task (scene memory) when targets were accurately detected in the second letter identification task," says Jeffrey Lin, the lead author of the study.

The study may enhance scientists' understanding of how selective attention can influence the ability to remember specific features of our environment. The results point to a brain mechanism that automatically encodes certain visual features into memory at behaviorally relevant points in time, regardless of the spatial focus of attention.

Citation: Lin et al., 'Enhanced Memory for Scenes Presented at Behaviorally Relevant Points in Time', March 2010, PLoS Biol 8(3), e1000337; doi:10.1371/journal.pbio.1000337