Abstract
Prior work investigating the role of fixation dwell time on incidental objects in visual search has primarily used static search arrays presented on computer screens. Previously, we found that time spent fixating an irrelevant item did not correlate with later recognition for having seen that item. However, in a search task where the target changed on every trial, dwell time on distractors correlated with later recognition (Hout et al., 2012). In the current study, we used mobile eye-tracking to investigate whether fixation behavior may act differently in a real-world dynamic search task involving navigation along novel paths. Participants were asked to memorize six target objects. We placed pictures of both the target and irrelevant distractor items in a series of hallways. We monitored eye-movements as they walked down the hallways looking for these items. Participants indicated when they recognized a target item, but they were not instructed to remember the locations of the items. At the end of the path, they were tested on their memory for the presence and location of all the items they encountered. Consistent with Hout et al.'s work, cumulative dwell time was lower for distractors that participants failed to recall seeing than those that were correctly recalled. Fixation dwell time appears to help encode the presence of the distractor items during navigation, but it did not have an effect on memory for where the items were located. While this suggests that location information is not incidentally encoded under these tasks constraints, in future work we hope to investigate the effects of fixation dwell time when the participants are explicitly asked to remember the location of the items. This work highlights differences observed when engaged in real-world search tasks as compared to the typical laboratory design.
Meeting abstract presented at VSS 2018