Drew, TraftonBoettcher, Sage E. P.Wolfe, Jeremy2017-12-052017Drew, Trafton, Sage E. P. Boettcher, and Jeremy M. Wolfe. 2017. “One visual search, many memory searches: An eye-tracking investigation of hybrid search.” Journal of Vision 17 (11): 5. doi:10.1167/17.11.5. http://dx.doi.org/10.1167/17.11.5.http://nrs.harvard.edu/urn-3:HUL.InstRepos:34491828Suppose you go to the supermarket with a shopping list of 10 items held in memory. Your shopping expedition can be seen as a combination of visual search and memory search. This is known as “hybrid search.” There is a growing interest in understanding how hybrid search tasks are accomplished. We used eye tracking to examine how manipulating the number of possible targets (the memory set size [MSS]) changes how observers (Os) search. We found that dwell time on each distractor increased with MSS, suggesting a memory search was being executed each time a new distractor was fixated. Meanwhile, although the rate of refixation increased with MSS, it was not nearly enough to suggest a strategy that involves repeatedly searching visual space for subgroups of the target set. These data provide a clear demonstration that hybrid search tasks are carried out via a “one visual search, many memory searches” heuristic in which Os examine items in the visual array once with a very low rate of refixations. For each item selected, Os activate a memory search that produces logarithmic response time increases with increased MSS. Furthermore, the percentage of distractors fixated was strongly modulated by the MSS: More items in the MSS led to a higher percentage of fixated distractors. Searching for more potential targets appears to significantly alter how Os approach the task, ultimately resulting in more eye movements and longer response times.en-USJournal Article2017-12-0510.1167/17.11.5