Parafoveal-on-foveal effects on eye movements during reading

Parafoveal-on-foveal effects refer to the possibility that processing of the parafoveal word can influence the fixation durations on the foveal word during reading. In this Chapter, I will review the literature of studies examining this issue. Effects observed in reading-like tasks have been questioned on methodological grounds with regards to the generalisibility to normal reading. The clearest evidence for the existence of parafoveal-on-foveal effects comes from experiments allowing tight control over the stimuli but restricting the observations to fixation locations very close to the parafoveal word, and from corpus studies showing reliable but numerically small effects. I will make the claim that with regards to taking reported parafoveal-on-foveal effects as evidence for parallel lexical processing, the jury is still out. The argument is that as long as parafoveal-on-foveal effects are numerically small and difficult to replicate in a controlled experiment, they can be explained on the basis of mislocated fixations, machine error and binocular disparity. These latter three influences can create apparent parafoveal-on-foveal effects without being linked to parallel lexical processing