Eye movements and on-line comprehension processes

Reading is a rather complex process in which comprehension at a number of levels is essential. In this chapter, we will provide an overview of how different kinds of variable influence eye movements. We want to stress at the outset that eye movement data are highly informative with respect to understanding reading. They provide a moment-to-moment indicator of the ease (or the difficulty) with which readers are able to comprehend the text that they read. Because eye movements are a natural part of the reading process, secondary tasks are not needed to make inferences about reading comprehension. Rather, information about where readers fixate in the text and how long they look at different part of the text provides remarkably reliable data about comprehension at a number of levels. We will begin with a brief overview of the characteristics of eye movements during reading, which will include a discussion of the different eye movement measures that are typically employed in reading research (these issues are discussed in greater detail in Rayner, 1998, and in Rayner and Pollatsek, forthcoming). We will then discuss in turn: (1) effects of lexical processing on eye movements, (2) effects of syntactic processing on eye movements, and (3) effects of discourse processing on eye movements. Thus, these sections focus on comprehension at the word level, at the level of syntax, and at the level of higher-level discourse. Shillcock (Chapter 6 this volume) also discusses eye movements and word recognition. 19.2 Basic characteristics of eye movements during reading