Word Identification and Eye Movement Control in Reading as Rational Decision Making

Duan, Yunyan

doi:https://doi.org/10.21985/n2-63t6-6324

Work

Word Identification and Eye Movement Control in Reading as Rational Decision Making

Public

Download PDF

Download All Files (.zip)

This dissertation provides evidence that reading is best explained as rational gathering of visual information to identify words efficiently. Although empirical evidence from human reading research suggests a close link between eye movements and cognitive process, it is not clear how readers decide when and where to move their eyes as a function of their cognitive states, and why they make certain eye movement decisions the way they do. The standard model of word identification assumes that a word requires a fixed amount of time to identify, which is a function of its word frequency, predictability, and the distance between the fixation location and the word center. Due to visual acuity constraints, reading time is minimized at the word center. Since word identification is considered the main driver of eye movements, dominant models of eye movements in reading assume that readers always target their eyes toward the word center to obtain best-quality visual information of the whole word and thus minimize the time needed to identify the word. In contrast, the rational model of eye movements in reading considers a word to be identified from a combination of visual and linguistic information, sensitive to the interaction of these two sources of information and therefore sensitive to that word's particular visual neighborhood structure. As a result, readers move their eyes to the position that best distinguishes a word from its neighbors to identify the word quickly and accurately. Previous modeling studies have shown that a rational model of eye movements in reading provides natural explanations for several eye movement phenomena, which can also be explained in dominant models but in less parsimonious ways. In this dissertation, we present qualitative evidence that the rational model explains eye movement phenomena that cannot be explained by dominant models, and quantitative evidence that the rational model better predicts eye movement phenomena. Specifically, in Chapter 2 we demonstrate that human readers seek visual information of the uncertain part of the word instead of always targeting the word center when they decide where to refixate, which cannot be explained by dominant models with a standard account of word identification. In Chapter 3 we demonstrate that the letter position that maximizes word identification efficiency varies as a function of the structure of the particular word, which is only predicted by a rational model. In Chapter 4, we provide quantitative evidence that the rational model predicts humans' decision to skip a word better than a model based on the standard account of word identification. In Chapter 5, we provide quantitative evidence that predicting readers' comprehension from eye movements through a rational model is more robust than through using the features from a dominant model. Altogether, this dissertation provides evidence that the rational model of eye movements in reading, which captures the complicated interaction between visual and linguistic information and optimizes eye movement decisions accordingly, is able to better explain and predict human eye movements than dominant models of eye movements that take a standard account of word identification. Therefore, the eye-mind link between eye movements and online language processing is naturally understood as rational eye movement decision making based on the knowledge from a probabilistic word identification process.

Creator