Using eye tracking to investigate failure to notice word transpositions in reading

Previous research (Mirault, Snell, & Grainger, 2018) has demonstrated that subjects sometimes incorrectly judge an ungrammatical sentence as grammatical when it is created by the transposition of two words in a grammatical sentence (e.g., The white was cat big). Here we present two eye-tracking experiments designed to assess the prevalence of this phenomenon in a more natural reading task, and to explore theoretical explanations. Readers failed to notice transpositions at about the same rate as in Mirault et al. (2018). Failure to notice the transposition was more common when both words were short, and when readers' eyes skipped, rather than directly fixated, one of the two words. The status of the transposed words as open- or closed-class did not have a reliable effect. The transposed words caused disruption in the eye movement record only on trials when participants ultimately judged the sentence to be ungrammatical, not when they judged the sentence to be grammatical. We argue that the results are not entirely consistent with the account offered by Mirault et al. (2018), which attributes failure to notice transpositions to parallel processing of adjacent words, or with a late, post-perceptual rational inference account (Gibson, Bergen, & Piantadosi, 2013). We propose that word recognition is serial, but post-lexical integration of each word into its context may not be perfectly incremental.