Three experiments are reported, examining the effects of a typographical error in parafoveal vision on aspects of foveal inspection time and saccade targeting. All the experiments involved reading for comprehension. A contingent presentation procedure ensured that typographical errors were restored to their correct form before they were viewed in foveal vision: They were never available for foveal processing. In Experiment 1, the error was formed by replacing the first letter of the target word with a second occurrence of its second letter, producing an illegal nonword. This manipulation had no significant effect on foveal inspection time, but lowered the probability that a short word (“de” or “du”) prior to the target would be skipped. In Experiment 2 the familiarity of the target's initial letters was maintained constant across conditions. This manipulation removed the target 1 skipping effect, suggesting that the outcome of Experiment 1 was due to orthographic rather than lexical illegality, but revealed shorter foveal inspection times as a function of the presence of the error. Experiment 3 manipulated lexical and sublexical properties of the parafoveal typing error. Properties of the parafoveal error again influenced prior foveal inspection times. The pattern of results suggested that the determining properties were sublexical rather than lexical. The results as a whole are incompatible with a view of information processing in reading in which foveal processing remains immune from concurrent parafoveal influences.

An experiment is reported in which participants read sequences of five words, looking for items describing articles of clothing. The third and fourth words in critical sequences were defined as “foveal” and “parafoveal” words, respectively. The length and frequency of foveal words and the length, frequency, and initial-letter constraint of parafoveal words were manipulated. Gaze and refixation rate on the foveal word were measured as a function of properties of the parafoveal word. The results show that measured gaze on a given foveal word is systematically modulated by properties of an unfixated parafoveal word. It is suggested that apparent inconsistencies in previous studies of parafoveal-on-foveal effects relate to a failure to control for foveal word length and hence the visibility of parafoveal words. A serial-sequential attention-switching model of eye movement control cannot account for the pattern of obtained effects. The data are also incompatible with various forms of parallel-processing model. They are best accounted for by postulating a process-monitoring mechanism, sensitive to the simultaneous rate of acquisition of information from foveal and parafoveal sources.