To evaluate whether performance differences between good and poor readers relate to reading-specific cognitive factors that result from engaging in reading activities and other experiential factors, the authors gave students in Grades 4 and 6 a perceptual identification test of words not only drawn from their personal lexicon but also varying in familiarity. During the experimental phase, on a video monitor for a duration of 60 ms, age-matched and reading-matched groups were each shown a set of pretested words varying in personal familiarity. After a 5-s delay, a "test" word was displayed, at which point participants were asked to decide whether the second word was the same as or different from the first. Measures of accuracy and reaction times for correct responses indicated that differences between reader groups still existed, despite attempts to minimize the contribution of experiential factors. Remedial interventions are discussed. (Contains 4 tables and 2 figures.)