The effect of plausibility on eye movements in reading: Testing E-Z Reader’s null predictions

• E-Z Reader 10 supports staged lexical and post-lexical processing.
• We manipulated word frequency and plausibility with a large sample (N = 112).
• We computed Bayes factors to test null main effects and interactions in ANOVAs.
• The results support a staged processing architecture.

The E-Z Reader 10 model of eye movements in reading (Reichle, Warren, & McConnell, 2009) posits that the process of word identification strictly precedes the process of integration of a word into its syntactic and semantic context. The present study reports a single large-scale (N = 112) eyetracking experiment in which the frequency and plausibility of a target word in each sentence were factorially manipulated. The results were consistent with E-Z Reader’s central predictions: frequency but not plausibility influenced the probability that the word was skipped over by the eyes rather than directly fixated, and the two variables had additive, not interactive, effects on all reading time measures. Evidence in favor of null effects and null interactions was obtained by computing Bayes factors, using the default priors and sampling methods for ANOVA models implemented by Rouder, Morey, Speckman, and Province (2012). The results suggest that though a word’s plausibility may have a measurable influence as early as the first fixation duration on the target word, in fact plausibility may be influencing only a post-lexical processing stage, rather than lexical identification itself.