A schematic model of the human information processing system is presented, and, within this framework, differences between adults and children in information processing limits are discussed. It is tentatively concluded that some irreducible maturational differences in processing rate are present, along with differences due to nonprocessing factors of incentive, motivation, attentiveness, and practice. The following areas of investigation of rapid information processing are discussed as they relate to reported or potential developmental research: tachistoscopic recognition, visual search, stimulus familiarity, stimulus sequential effects, choice reaction time, and central channel limitations. Tentative conclusions are drawn concerning possible loci in the processing model of age differences in processing rate capacity.