EYE-MOVEMENTS REVEAL THE SPATIOTEMPORAL DYNAMICS OF VISUAL-SEARCH

Given that attention precedes an eye movement to a target, it becomes possible to use fixation sequences to probe the spatiotemporal dynamic s of search. Applying this method to a realistic search task, we found eye movements directed to the geometric centers of progressively smal ler groups of objects rather than accurate fixations to individual obj ects in a display. Such a binary search strategy is consistent with zo om-lens models positing an initially broad distribution of search, fol lowed by a narrowing of this search region until only the target is se lected. We also interpret this oculomotor averaging behavior as eviden ce for an initially parallel search analysis that becomes increasingly serial as the search process converges on the target.