The standard model is that word identification in reading isa holistic process, most efficient when words are centered inthe visual field. In contrast, rational models of reading predictword identification to be a constructive process, where readersefficiently gather visual information about a word, and maycombine visual information about different parts of the wordobtained across multiple fixations to identify it. We tease apartthese accounts by arguing that rational models should predictthat the most efficient place in a word to make a second fixa-tion (refixation) depends on the visual information the readerhas already obtained. We present evidence supporting this pre-diction from an eye movement corpus. Computational modelsimulations confirm that a rational model predicts this find-ing, but a model implementing holistic identification does not.These results suggest that refixations can be well understoodas rationally gathering visual information, and that word iden-tification works constructively.