Theories Of Eye Movement Control Research Articles

Beyond cloze probability: Parafoveal processing of semantic and syntactic information during reading

Abstract Theories of eye movement control in reading assume that early oculomotor decisions are determined by a word’s frequency and cloze probability. This assumption is challenged by evidence that readers are sensitive to the contextual plausibility of an upcoming word: First-pass fixation probability and duration are reduced when the parafoveal preview is a plausible, but unpredictable, word relative to an implausible word. The present study sought to establish whether the source of this effect is sensitivity to violations of syntactic acceptability. In two experiments, the gaze-contingent boundary paradigm was used to compare contextually plausible previews to semantically acceptable and anomalous previews that either matched or violated syntactic rules. Results showed that readers benefited from the convergence of semantic and syntactic acceptability early enough in the timecourse of reading to affect skipping. In addition, both semantic and syntactic plausibility yielded preview effects on target fixation duration measures, providing direct evidence of parafoveal syntactic processing in reading. These results highlight the limitations of relying solely on cloze probability to index contextual influences on early lexical processing. The implications of the data for models of eye movement control and language comprehension are discussed.

Word Skipping in Reading English as a Foreign Language: Evidence from Eye Tracking

Word Skipping in Reading English as a Foreign Language: Evidence from Eye Tracking

Reversed preview benefit effects: Forced fixations emphasize the importance of parafoveal vision for efficient reading.

Current theories of eye movement control in reading posit that processing of an upcoming parafoveal preview word is used to facilitate processing of that word once it is fixated (i.e., as a foveal target word). This preview benefit is demonstrated by shorter fixation durations in the case of valid (i.e., identical or linguistically similar) compared with invalid (i.e., dissimilar) preview conditions. However, we suggest that processing of the preview can directly influence fixation behavior on the target, independent of similarity between them. In Experiment 1, unrelated high and low frequency words were used as orthogonally crossed previews and targets and we observed a reversed preview benefit for low frequency targets-shorter fixation durations with an invalid, higher frequency preview compared with a valid, low frequency preview. In Experiment 2, the target words were replaced with orthographically legal and illegal nonwords and we found a similar effect of preview frequency on fixation durations on the targets, as well as a bimodal distribution in the illegal nonword target conditions with a denser early peak for high than low frequency previews. In Experiment 3, nonwords were used as previews for high and low frequency targets, replicating standard findings that "denied" preview increases fixation durations and the influence of target properties. These effects can be explained by forced fixations, cases in which fixations on the target were shortened as a consequence of the timing of word recognition of the preview relative to the time course of saccade programming to that word from the prior one. That is, the preview word was (at least partially) recognized so that it should have been skipped, but the word could not be skipped because the saccade to that word was in a nonlabile stage. In these cases, the system preinitiates the subsequent saccade off the upcoming word to the following word and the intervening fixation is short. (PsycINFO Database Record

Neural correlates of active vision: An fMRI comparison of natural reading and scene viewing

Theories of eye movement control during active vision tasks such as reading and scene viewing have primarily been developed and tested using data from eye tracking and computational modeling, and little is currently known about the neurocognition of active vision. The current fMRI study was conducted to examine the nature of the cortical networks that are associated with active vision. Subjects were asked to read passages for meaning and view photographs of scenes for a later memory test. The eye movement control network comprising frontal eye field (FEF), supplementary eye fields (SEF), and intraparietal sulcus (IPS), commonly activated during single-saccade eye movement tasks, were also involved in reading and scene viewing, suggesting that a common control network is engaged when eye movements are executed. However, the activated locus of the FEF varied across the two tasks, with medial FEF more activated in scene viewing relative to passage reading and lateral FEF more activated in reading than scene viewing. The results suggest that eye movements during active vision are associated with both domain-general and domain-specific components of the eye movement control network.

Stable individual differences in saccadic eye movements during reading, pseudoreading, scene viewing, and scene search.

Mean fixation duration and mean saccade amplitude during active viewing tasks differ from person to person. Previous studies have shown that these individual differences tend to be stable across at least some tasks, suggesting that they may reflect underlying traits associated with individuals. However, whether these individual differences are also stable over time has not been established. The present study established stable individual differences in mean fixation duration and mean saccade amplitude across 4 viewing tasks, showed that the observed individual differences are stable over several days, and extended these results to standard deviations of fixation duration and saccade amplitude. The results have implications for theories of eye movement control and for using eye movement characteristics as individual difference measures.

Eye Movements During Mindless Reading

Mindless reading occurs when the eyes continue moving across the page even though the mind is thinking about something unrelated to the text. Despite how commonly it occurs, very little is known about mindless reading. The present experiment examined eye movements during mindless reading. Comparisons of fixation-duration measures collected during intervals of normal reading and intervals of mindless reading indicate that fixations during the latter were longer and less affected by lexical and linguistic variables than fixations during the former. Also, eye movements immediately preceding self-caught mind wandering were especially erratic. These results suggest that the cognitive processes that guide eye movements during normal reading are not engaged during mindless reading. We discuss the implications of these findings for theories of eye movement control in reading, for the distinction between experiential awareness and meta-awareness, and for reading comprehension.

Saccade generation during reading: Are words necessary?

Most current theories of eye movement control during reading are word based in multiple ways: They assume that saccade onset times result from word‐based processes, and that words are involved in selecting a saccade target. In the current study the role of words was examined by occasionally replacing the text with one of five alternate stimulus patterns for a single fixation during reading, and observing the effects on the time, direction, and length of the saccade that ends that fixation. The onset times of many saccades are unaffected by replacing spaces with random letters, thus removing visible word‐units; also, the effects of this removal on saccade length is not different than that of having space‐delimited nonwords. It does not appear that words play a critical role in generating saccades. The results are compatible with the Competition/Interaction theory of eye movement control during reading (Yang & McConkie, 2001).

Fixation location effects on fixation durations during reading: an inverted optimal viewing position effect

Previous research has found that words are identified most quickly when the eyes are near their center (the Optimal Viewing Position effect). A study was conducted to determine whether this same phenomenon is observed during reading, as revealed by a relationship between fixation position in a word and the duration of the fixation. An analysis of three large existing corpora of eye movement data, two from adults and one from children, showed a surprising inverted Optimal Viewing Position curve: mean fixation duration is greatest, rather than lowest, when the eyes were at the centers of words. From this phenomenon, we suggest an alternative explanation to the fixation duration trade-off effect in word refixations [O'Regan & Lévy-Schoen, Attention and performance XII: the psychology of reading (1987)]; the phenomenon also contradicts expectations of both oculomotor and cognitive theories of eye movement control. Attempts to test alternative explanations led to the discovery of another phenomenon, the Saccade Distance effect: mean fixation durations vary with the distance of the prior fixation from the currently-fixated word, being longer with greater distances. The durations of fixations in reading are complexly determined, with influences both from language and perceptual/oculomotor levels.

Eye movement control during reading: foveal load and parafoveal processing.

We tested theories of eye movement control in reading by looking at parafoveal processing. According to attention-processing theories, attention shifts towards word n + 1 only when processing of the fixated word n is finished, so that attended parafoveal processing does not start until the programming of the saccade programming to word n + 1 is initiated (Henderson & Ferreira, 1990; Morrison, 1984), or even later when the processing of word n takes too long (Henderson & Ferreira, 1990). Parafoveal preview benefit should be constant whatever the foveal processing load (Morrison, 1984), or should decrease when processing word n outlasts an eye movement programming deadline (Henderson & Ferreira, 1990). By manipulating the frequency and length of the foveal word n and the visibility of the parafoveal word n + 1, we replicated the finding that the parafoveal preview benefit is smaller with a low-frequency word in foveal vision. Detailed analyses, however, showed that the eye movement programming deadline hypothesis could not account for this finding which was due not to cases where the low-frequency words n had received a long fixation, but to cases of a short fixations less than 240 msec. In addition, there was a spill-over effect of word n to word n + 1, and there was an element of parallel processing of both words. The results are more in line with parallel processing limited by the extent to which the parafoveal word processing on fixation n can be combined with the foveal word processing on fixation n + 1.