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Eye movements were monitored as subjects read sentences containing high- or low-predictable target words. The extent to which target words were predictable from prior context was varied: Half of the target words were predictable, and the other half were unpredictable. In addition, the length of the target word varied: The target words were short (4?6 letters), medium (7?9 letters), or long (10?12 letters). Length and predictability both yielded strong effects on the probability of skipping the target words and on the amount of time readers fixated the target words (when they were not skipped). However, there was no interaction in any of the measures examined for either skipping or fixation time. The results demonstrate that word predictability (due to contextual constraint) and word length have strong and independent influences on word skipping and fixation durations. Furthermore, because the long words extended beyond the word identification span, the data indicate that skipping can occur on the basis of partial information in relation to word identity.

Much recent research using word recognition paradigms such as lexical decision and speeded pronunciation has investigated how a range of variables affect the location and shape of response time distributions, using both parametric and non-parametric techniques. In the present article, we explore the distributional effects of a word frequency manipulation on fixation durations in normal reading, making use of data from two recent eye movement experiments (Drieghe, Rayner, & Pollatsek, 2008; White, 2008). The ex-Gaussian distribution provided a good fit to the shape of individual subjects’ distributions in both experiments. The frequency manipulation was found to affect both the shift and skew of the distributions, in both experiments, and this conclusion was supported by the non-parametric vincentizing technique. Finally, a new experiment demonstrated that White’s (2008) frequency manipulation also affects both shift and skew in RT distributions in the lexical decision task. These results argue against models of eye movement control in reading that propose that word frequency influences only a subset of fixations, and are taken to support models in which there is a tight connection between eye movement control and the progress of lexical processing.