Using interrupted visual displays to explore the capacity, time course, and format of fixation plans during visual search

Abstract

We assessed fixation planning in visual search in two experiments by tracking participants’ eye movements while they each searched for a simple target (a T shape) among a set of distractors (L shapes). On some trials, the search display was briefly interrupted with a blank screen and, following a randomly determined period of elapsed time, the search display was reinstated. In Experiment 1, we found that search continued during the interruption but fixation durations were increased and the accuracy of saccadic targeting was impaired. A MLM demonstrated that acuity played a role in determining whether fixated missing objects were processed during the interruption and that fixation planning was uninfluenced by the length of time available prior to the interruption. In Experiment 2, to check that fixations in the interruption periods were not random, half the distractors were blue (the target was blue as well) and half were yellow. All of the findings from Experiment 1 were replicated and the majority of fixations in the interruption period landed upon blue distractors. Results are discussed in relation to the capacity, time course, and format of fixation plans in visual search. (PsycINFO Database Record (c) 2016 APA, all rights reserved)