Visual search has memory

By monitoring subjects' eye movements during a visual search task, we exami ned the possibility that the mechanism responsible for guiding attention du ring visual search has no memory for which locations have already been exam ined. Subjects did reexamine some items during their search, but the patter n of revisitations did not fit the predictions of the memoryless search mod el. In addition, a large proportion of the refixations were directed at the target, suggesting that the revisitations were due to subjects' rememberin g which items had not been adequately identified. We also examined the patt erns of fixations and compared them with the predictions of a memoryless se arch model. Subjects' fixation patterns showed an increasing hazard functio n, whereas the memoryless model predicts a flat function. Lastly, we found no evidence suggesting that fixations were guided by amnesic covert scans t hat scouted the environment for new items during fixations. Results do not support the claims of the memoryless search model, and instead suggest that visual search does have memory.