Children’s Eye Movements during Reading (стр. 1 )

Children’s Eye Movements during Reading.

Hazel I. Blythea and Holly S. S.L. Josephb*

a School of Psychology

Shackleton Building

University of Southampton

Highfield

Southampton

SO17 1BJ

Email: *****@***ac. uk

b Department of Experimental Psychology

University of Oxford

South Parks Road

Oxford

OX1 3UD.

Email: holly. *****@***ox. ac. uk

*The order of authors is alphabetical, and entirely arbitrary

Word count = 10,010

Keywords: CHILDREN; EYE MOVEMENTS; READING; DEVELOPMENT

Abstract

Children’s eye movements during reading. In this chapter, we evaluate the literature on children’s eye movements during reading to date. We describe the basic, developmental changes that occur in eye movement behaviour during reading, discuss age-related changes in the extent and time course of information extraction during fixations in reading, and compare the effects of visual and linguistic manipulations in the text on children’s eye movement behaviour in relation to skilled adult readers. We argue that future research will benefit from examining how eye movement behaviour during reading develops in relation to language and literacy skills, and use of computational modelling with children’s eye movement data may improve our understanding of the mechanisms that underlie the progression from beginning to skilled reader.

1. Introduction

There has been a great deal of research that has used eye movement recordings to examine the psychological processes underlying skilled adult reading (see Rayner, 1998, 2009 for a review). This line of research has grown to the point where there are several well-developed computational models that can account for many of the phenomena associated with eye movement behaviour during reading (e. g., the , Engbert, Longtin, & Kliegl, 2002; Engbert, Nuthmann, Richter, & Kliegl, 2005; the E-Z Reader model, Pollatsek, Reichle, & Rayner, 2006; Reichle, Pollatsek, Fisher, & Rayner, 1998; Reichle, Pollatsek, & Rayner, 2006; Reichle, Rayner, & Pollatsek, 1999, 2003; see also the chapters by Reichle, and by Engbert & Kliegl in the present volume). These models are, however, currently limited to explaining the end point of development: the skilled adult reader. This is largely a consequence of there having been very few studies that have examined children’s eye movements during reading in proportion to the vast body of research that has studied adults.

It is unsurprising that there has been little research in this area with children. Taking accurate eye movement recordings is a process that requires the participant to sit very still and follow instructions from the researcher, often for prolonged periods of time, requiring a lot of patience. This is difficult with adults and, understandably, even more so with children as participants. Finding young children who are willing and able to cooperate for the duration of an experiment can be extremely challenging and this has been a constraining factor in the sample size of some studies (depending on the particular equipment used and, consequently, the spatial and temporal accuracy of the data). As eye tracking technology improves, however, it is increasingly possible to take accurate eye movement recordings from larger samples of children across a broader range of ages.

In order to fully understand the cognitive processes underlying reading it is necessary to study the trajectory of reading development through on-line research methods such as eye movement recordings. In this chapter, we review the small, existing literature on children’s eye movements during reading both to assess the current state of knowledge in this field, and also in an effort to highlight areas where future eye movement research might be effective in improving understanding of the cognitive changes underlying children’s reading development. We do not discuss in detail the body of literature that exists on the eye movements during reading of children with dyslexia, as it is beyond the scope of this chapter. In experiments investigating the relationship between dyslexia and eye movements, typically developing children are frequently used for both reading age and chronological age control groups; however, the data analyses are strongly focused upon comparisons of the different groups and the experiments are not designed to examine the characteristics of typically developing children’s oculomotor control during reading. For a review of the literature on eye movements and dyslexia, see Kirkby, Webster, Blythe and Liversedge (2008).

In this chapter, we first comment on some theoretical and methodological issues which are particularly relevant to conducting eye movement research with children. Second, we discuss several studies which were largely exploratory and which examined the basic characteristics of children’s eye movements during reading at different ages. The third section considers developmental changes in the encoding of visual information during fixations in reading. The latter half of the chapter then focuses on the influences of specific manipulations within text upon children’s cognitive processing, as indexed by their eye movement behaviour. We give a review of studies which have manipulated lexical characteristics in text and then, following on from this, the influence of higher-level processing manipulations are considered. The chapter concludes with a discussion of how future research into children’s eye movements during reading may inform our understanding of the cognitive developmental changes underlying the progression from beginning to skilled reader.

2. Conducting eye movement research to investigate children’s reading

2.1. Theoretical issues.

First, it is vital to consider the possible contributions of chronological age and reading skill in relation to each other, and how they might impact on eye movement behaviour. As age increases, reading ability also improves as the child progresses from a beginning to a skilled reader. Thus, any changes in eye movement behaviour that are observed between different age groups may be attributable to the difference in chronological age, or they may be attributable to a difference in reading skill. When a skilled adult reads a line of text, their eyes make a sequence of extremely quick saccades that accurately position the eyes such that new information falls on the fovea. As with many different motor skills, it is possible that control of these eye movements improves with age in terms of speed and accuracy. Indeed, previous research using non-reading tasks has demonstrated developmental decreases in saccadic latency (e. g., Cohen & Ross, 1978; Groll & Ross, 1982; Huestegge, Radach, Corbic, & Huestegge, 2009) although saccadic accuracy, peak saccadic velocity, and saccadic overshoot have all been observed to be the same in children as in adults (e. g., Cohen & Ross, 1978; Fukushima, Hatta, & Fukushima, 2000; Salman et al., 2006). Thus, one possibility is that on a task such as reading, where optimal performance depends on the execution of small but fast and accurate eye movements, improvements in motor control associated with increasing chronological age may be one factor underlying the observed developmental changes in eye movement behaviour.

On the other hand, and perhaps more obviously, developmental changes in eye movement control are also a behavioural consequence of increasing reading skill. As reading skill increases, changes in eye movements will reflect the decrease in cognitive processing difficulty associated with text comprehension. In this case, we might expect to see differences between children of the same chronological age who vary significantly in reading skill. While several of the studies reviewed in this chapter have been careful to exclude children who were not within the normal range of reading ability for their age, to our knowledge no study has explicitly addressed this potential dichotomy. The possibility that differences in eye movement behaviour during reading between children and adults may be a combination of both age-related changes in motor skill and differences in reading proficiency should also be considered. The relative contributions of these two factors are not yet well understood in the eye movement literature; however, future research may allow separate examination of the causes underlying age-related change by including multiple child participant groups and matching both for chronological age and reading age, as well as making systematic manipulations of text difficulty in relation to reading skill (see discussion in Section 2.2 below).

Second, a critical issue with respect to age-related changes in eye movement behaviour during reading is that of cause and effect. Does increased processing difficulty cause readers to make more, longer fixations, etc., or is it the case that poor control of eye movements leads to difficulty in reading? The results of two eye movement studies with children have indicated that processing difficulty during reading causes changes in eye movement behaviour. Rayner (1986) found that, within a group of 9- to 10-year old children, reading rates were slower, more fixations were made, fixation durations were longer, and the perceptual span was smaller when they read more difficult sentences compared to when they read relatively easy sentences. Thus, for an individual reader, the difficulty of the reading material impacts upon eye movement behaviour. Häikiö, Bertram, Hyönä and Niemi (2009) found that less able readers (aged 8-, 10-, and 12-years as well as adults) have slower reading speeds and a smaller perceptual span than more able readers (see Section 5.1 for an explanation of the perceptual span). Thus, processing difficulty is reflected in the reader’s eye movement behaviour. It is less clear whether poor eye movement control can cause reading pared to their typically developing peers, children with dyslexia have been reported to have unstable fixation, increased numbers of express saccades, poor visual attention span, and limited perceptual span (see Kirkby et al., 2008 for a review). Most researchers agree, however, that differences in eye movement behaviour are either correlates or consequences of the reading difficulties experienced by children with dyslexia (e. g., Rayner, 1985). There are no published data, to date, which provide compelling evidence for a causal role of poor eye movement control in dyslexia.