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.