Word predictability affects saccade length in Chinese reading: An evaluation of the dynamic-adjustment model

Towards a model of eye-movement control in Chinese reading

The Chinese writing system has several features that make it markedly different from the alphabetic systems that have most often been examined in reading research, including the fact that individual words consist of various uniformly sized, box-shaped characters whose boundaries are not clearly demarcated (e.g., by blank spaces). These features raise the question: How do readers of Chinese "know" where to move their eyes for the purpose of efficiently segmenting and/or identifying words? To answer this question, we used the E-Z Reader model of eye-movement control in reading to run an 'experiment' involving a series of simulations in which two saccade-targeting assumptions (i.e., directing the eyes towards default targets vs. adjusting saccade length as a function of parafoveal processing difficulty) were factorially manipulated with three word-segmentation heuristics (i.e., ideal-observer knowledge of word boundaries vs. probabilistic guessing vs. familiarity-based segmentation) to examine which combination of assumptions provide the best quantitative account of eye-movement control during the reading of Chinese. Based on these simulations, we conclude the best account is one in which readers use relative differences in the familiarity of groups of parafoveal characters to dynamically adjust the lengths of saccades in a manner that affords efficient word identification. We discuss the broader theoretical implications of these conclusions for models of Chinese reading and for models of reading more generally.

Cross-linguistic comparison in reading sentences of uniform length: Visual-perceptual demands override readers' experience

Accurate saccadic targeting is critical for efficient reading and is driven by the sensory input under the eye-gaze. Yet whether a reader's experience with the distributional properties of their written language also influences saccadic targeting is an open debate. This study of Russian sentence reading follows Cutter et al.'s (2017) study in English and presents readers with sentences consisting of words of the same length. We hypothesised that if the readers' experience matters as per discrete control account, Russian readers would produce longer saccades and farther landing positions than the ones produced by English readers. On the contrary, if the saccadic targeting is primarily driven by the immediate perceptual demands that override readers' experience as per the dynamic adjustment account, the saccades of Russian and English readers would be of the same length, resulting in similar landing positions. The results in both Cutter et al. and the present study provided evidence for the latter account: Russian readers showed rapid and accurate adjustment of saccade lengths and landing positions to the highly constrained input. Crucially, the saccade lengths and landing positions did not differ between English and Russian readers even in the cross-linguistically length-matched stimuli.

The graded predictive pre-activation in Chinese sentence reading: evidence from eye movements

Previous research has revealed that graded pre-activation rather than specific lexical prediction is more likely to be the mechanism for the word predictability effect in English. However, whether graded pre-activation underlies the predictability effect in Chinese reading is unknown. Accordingly, the present study tested the generality of the graded pre-activation account in Chinese reading. We manipulated the contextual constraint of sentences and the predictability of target words as independent variables. Readers' eye movement behaviors were recorded via an eye tracker. We examined whether processing an unpredictable word in a solid constraining context incurs a prediction error cost when this unpredictable word has a predictable alternative. The results showed no cues of prediction error cost on the early eye movement measures, supported by the Bayes Factor analyses. The current research indicates that graded predictive pre-activation underlies the predictability effect in Chinese reading.

Word complexity modulates the divided-word effect during Chinese reading

The present study examined the influence of word complexity on the divided-word effect. By manipulating presentation conditions (line-final presentation vs. divided-word presentation vs. line-initial presentation) and visual complexity (high vs. low), we found a significant divided-word effect that the reading times such as gaze duration and total reading time were significantly longer in the divided-word presentation condition than in both the line-final and line-initial presentation conditions. On the measure of total reading time, the marginally significant interaction between the divided-word versus line-final presentation comparison and complexity showed that the divided-word effect was larger for low complexity words than that for high complexity words. These results suggest that dividing a word across two lines interferes with reading, and word complexity modulates this effect.

Word's Contextual Predictability and Its Character Frequency Effects in Chinese Reading: Evidence From Eye Movements

The present study sought to establish how a word's contextual predictability impacts the early stages of word processing when reading Chinese. Two eye-movement experiments were conducted in which the predictability of the target two-character word was manipulated; the frequency of the target's initial character was manipulated in Experiment 1, as was the target's end character frequency in Experiment 2. No reliable interaction effect of predictability with initial character frequency was observed in Experiment 1. Reliable interactions of word predictability with end character frequency were observed in Experiment 2. The end character frequency effects, in which the words with high-frequency end characters were fixated for a shorter time and re-fixated less often, were only observed when reading unpredictable words. Reliable interactions were also observed with incoming saccade length, as high-frequency end character words elicited longer saccades to themselves than low-frequency end character words when reading predictable words. The effects of pervasive predictability on measures of fixation time, probability, and saccade length were noted in both experiments. Our findings suggest that a word's contextual predictability facilitates the processing of its constituent characters.

Interaction effects of aging, word frequency, and predictability on saccade length in Chinese reading

BACKGROUND

It was well known that age has an impact on word processing (word frequency or predictability) in terms of fixating time during reading. However, little is known about whether or not age modulates these impacts on saccade behaviors in Chinese reading (i.e., length of incoming/outgoing saccades for a target word).

METHODS

Age groups, predictability, and frequency of target words were manipulated in the present study. A larger frequency effect on lexical accessing (i.e., gaze duration) and on context integration (i.e., go-past time, total reading time), as well as larger predictability effects on data of raw total reading time, were observed in older readers when compared with their young counterparts.

RESULTS

Effect of predictability and frequency on word skipping and re-fixating rate did not differ across the two age groups. Notably, reliable interaction effects of age, along with word predictability and/or frequency, on the length of the first incoming/outgoing saccade for a target word were also observed.

DISCUSSION

Our findings suggest that the word processing function of older Chinese readers in terms of saccade targeting declines with age.

Linguistic processes do not beat visuo-motor constraints, but they modulate where the eyes move regardless of word boundaries: Evidence against top-down word-based eye-movement control during reading

Where readers move their eyes, while proceeding forward along lines of text, has long been assumed to be determined in a top-down word-based manner. According to this classical view, readers of alphabetic languages would invariably program their saccades towards the center of peripheral target words, as selected based on the (expected) needs of ongoing (word-identification) processing, and the variability in within-word landing positions would exclusively result from systematic and random errors. Here we put this predominant hypothesis to a strong test by estimating the respective influences of language-related variables (word frequency and word predictability) and lower-level visuo-motor factors (word length and saccadic launch-site distance to the beginning of words) on both word-skipping likelihood and within-word landing positions. Our eye-movement data were collected while forty participants read 316 pairs of sentences, that differed only by one word, the prime; this was either semantically related or unrelated to a following test word of variable frequency and length. We found that low-level visuo-motor variables largely predominated in determining which word would be fixated next, and where in a word the eye would land. In comparison, language-related variables only had tiny influences. Yet, linguistic variables affected both the likelihood of word skipping and within-word initial landing positions, all depending on the words’ length and how far on average the eye landed from the word boundaries, but pending the word could benefit from peripheral preview. These findings provide a strong case against the predominant word-based account of eye-movement guidance during reading, by showing that saccades are primarily driven by low-level visuo-motor processes, regardless of word boundaries, while being overall subject to subtle, one-off, language-based modulations. Our results also suggest that overall distributions of saccades’ landing positions, instead of truncated within-word landing-site distributions, should be used for a better understanding of eye-movement guidance during reading.

The effects of parafoveal word frequency and segmentation on saccade targeting during Chinese reading

Two eye-movement experiments are reported in which a boundary paradigm was used to manipulate the presence versus absence of boundaries for high-frequency and low-frequency target words in the parafovea. In Experiment 1, this was done by introducing a blank space after the target words, whereas in Experiment 2 this was done by rendering the target words in red. In both experiments, higher frequency targets engendered longer saccades, whereas the presence of parafoveal word boundaries engendered shorter saccades. This pattern suggests the operation of two countermanding saccade-targeting mechanisms: one that uses parafoveal processing difficulty to adjust saccade lengths and a second that uses word boundaries to direct the eyes toward specific saccade targets. The implications of these findings for models of eye-movement control during reading are discussed, as are suggestions for integrating dynamic-adjustment and default-targeting accounts.

The dynamic adjustment of saccades during Chinese reading: Evidence from eye movements and simulations

This article reports an eye-movement experiment in which participants scanned continuous sequences of Landolt-Cs for target circles to examine the visual and oculomotor constraints that might jointly determine where the eyes move in a task that engages many of the perceptual and motor processes involved in Chinese reading but without lexical or linguistic processing. The lengths of the saccades entering the Landolt-C clusters were modulated by the processing difficulty (i.e., gap sizes) of those clusters. Simulations using implemented versions of default-targeting (Yan, Kliegl, Richter, Nuthmann, & Shu, 2010) versus dynamic-adjustment (Liu, Reichle, & Li, 2016) models of saccadic targeting indicated that the latter provided a better account of our participants' eye movements, further supporting the hypothesis that Chinese readers "decide" where to move their eyes by adjusting saccade length in response to processing difficulty rather than by selecting default saccade targets. We discuss this hypothesis in relation to both what is known about saccadic targeting during the reading of English versus Chinese and current models of eye-movement control in reading. (PsycINFO Database Record (c) 2019 APA, all rights reserved).