One visual search, many memory searches: An eye-tracking investigation of hybrid search

Journal of vision

Jeremy M. Wolfe¹  Sage E. P. Boettcher²  Trafton Drew³ 

[1] Brigham and Women's Hospital, Boston, MA, USA;University of Oxford, Oxford, UK;University of Utah, Salt Lake City, UT, USA,

关键词: memory;    eye tracking;    visual search;   

DOI  :  10.1167/17.11.5

学科分类：眼科学

来源: Association for Research in Vision and Ophthalmology

【 摘 要 】

Suppose 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.

【 授权许可】

CC BY