Abstract
We often consecutively search for the same target category; airport security screeners search for weapons in multiple bags and when driving in traffic we constantly monitor for brake lights and pedestrians. Identical target repetition results in faster search, less target information stored in visual working memory (VWM) as indicated by contralateral-delay-activity (CDA), and an increased reliance on long-term-memory (LTM) as indicated by the frontal P170 (Woodman, Carlisle, Reinhart, 2013). Moreover, when a difficult search is expected, more target details are maintained in VWM as indicated by increased CDA; importantly, participants who maintain additional target details were least affected by the increased search difficulty (Schmidt & Zelinsky, 2017). This suggests that target representations affect search performance and change over-time. We asked if consecutive target category repetition would result in a reduced reliance on VWM (as indicated by reduced CDA) and an increased reliance on LTM (as indicated by a decrease in the frontal P170), in addition to a search benefit. Participants searched for a fish, flower, butterfly, car, or teddy bear target for five consecutive trials before the target category changed; eye movements and EEG were recorded throughout. Participants were cued to attend to one of the bilaterally presented stimuli which designated the search target (200ms). This was followed by a 1000ms ISI in which CDA was recorded. In the search display, participants localized search targets, which were 100% present and appeared along with five distractors from non-target categories. Despite target category repetition producing no observable change in behavioral and eye movement measures of search accuracy, search guidance, or target verification time, and a lack of an observable frontal P170; CDA significantly decreased (p< .001) with target category repetition. This suggests that target category repeats results in less reliance on VWM, consistent with the use of a more categorical target representation.
Meeting abstract presented at VSS 2018