The Time-course of Lexical Influences on Fixation Durations during Reading: Evidence from Distributional Analyses

• Main Author: Sheridan, Heather
• Other Authors: Reingold, Eyal M.
• Language: en_ca
• Published: 2013
• Subjects: reading; eye movements; distributional analysis; lexical processing; 0633; 0623; 0621
• Online Access: http://hdl.handle.net/1807/35996

Competing models of eye movement control during reading disagree over the extent to which eye movements reflect ongoing linguistic and lexical processing, as opposed to visual/oculomotor factors (for reviews, see Rayner, 1998, 2009a). To address this controversy, participants’ eye movements were monitored in four experiments that manipulated a wide range of lexical variables. Specifically, Experiment 1 manipulated contextual predictability by presenting target words (e.g., teeth) in a high-predictability prior context (e.g. “The dentist told me to brush my teeth to prevent cavities.”) versus a low-predictability prior context (e.g., “I'm planning to take better care of my teeth to prevent cavities.”), Experiment 2 manipulated lexical ambiguity by presenting biased homographs (e.g., bank, crown, dough) in a subordinate-instantiating versus a dominant-instantiating prior context, and Experiments 3A and 3B manipulated word frequency by contrasting high frequency target words (e.g., table) and low frequency target words (e.g., banjo). In all four experiments, I used distributional analyses to examine the time-course of lexical influences on fixation times. Ex-Gaussian fitting (Staub, White, Drieghe, Hollway, & Rayner, 2010) revealed that all three lexical variables (i.e., predictability, lexical ambiguity, word frequency) were fast-acting enough to shift the entire distribution of fixation times, and a survival analysis technique (Reingold, Reichle, Glaholt, & Sheridan, 2012) revealed rapid lexical effects that emerged as early as 112 ms from the start of the fixation. Building on these findings, Experiments 3A and 3B provided evidence that lexical processing is delayed in an unsegmented text condition that contained numbers instead of spaces (e.g., “John4decided8to5sell9the7table2in3the9garage6sale”), relative to a normal text condition (e.g., “John decided to sell the table in the garage sale”). These findings have implications for ongoing theoretical debates concerning eye movement control, lexical ambiguity resolution, and the role of interword spaces during reading. In particular, the present findings provide strong support for models of eye movement control that assume that lexical influences can have a rapid influence on the majority of fixation durations, and are inconsistent with models that assume that fixation times are primarily determined by visual/oculomotor constraints.