The study by researchers at the University of Washington shows how visual scenes are encoded into memory at behaviourally relevant points in time.
The ability to remember a briefly presented scene depends on a number of factors, such as its saliency, novelty, degree of threat, or behavioural relevance to a task.
It is believed that attention is the key, i.e., people can only remember part of a visual scene when paying attention to it at any given moment.
In the 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," said Jeffrey Lin, the lead author of the study.
The study adds to the understanding of how selective attention can influence the ability to remember specific features of our environment.
The results indicate a brain mechanism that automatically encodes certain visual features into memory at behaviorally relevant points in time, regardless of the spatial focus of attention.
Timing may not be everything, but it's more important than we realize.
The study has been published in this week in the open access journal PLoS Biology.