Jane Ashby

The effects of frequency and predictability on eye fixations in reading: Implications for the E-Z Reader model

Readers read sentences containing target words varying in frequency and predictability. The observed pattern of data for fixation durations only mildly departed from additivity, with predictability effects that were slightly larger for low-frequency than for high-frequency words. The pattern of data for skipping was different as predictability affected only the probability of skipping for high-frequency target words. Simulations of these data using the E-Z Reader model indicated that a single-process model was unlikely to provide a good fit for both measures. A version of the model that assumes that (a) word-encoding time is additively affected by frequency and predictability and (b) difficulty with postlexical processing of the target word causes a double take accounted for the data while indicating that the relationship between the duration of hypothesized word-encoding stages and observed fixation durations is not likely to be transparent.

Eye Movements as Reflections of Comprehension Processes in Reading.

In this article, we discuss the use of eye movement data to assess moment-to-moment comprehension processes. We first review some basic characteristics of eye movements during reading and then present two studies in which eye movements are monitored to confirm that eye movements are sensitive to (a) global text passage difficulty and (b) inconsistencies in text. We demonstrate that processing times increased (and especially that the number of fixations increased) when text is difficult. When there is an inconsistency, readers fixated longer on the region where the inconsistency occurred. In both studies, the probability of making a regressive eye movement increased as well. Finally, we discuss the use of eye movement recording as a research tool to further study moment-to-moment comprehension processes and the possibility of using this tool in more applied school settings.

Eye movements of highly skilled and average readers: Differential effects of frequency and predictability

This study offers a glimpse of the moment-by-moment processes used by highly skilled and average readers during silent reading. The eye movements of adult readers were monitored while they silently read sentences. Fixation durations and the spatial–temporal patterns of eye movements were examined to see whether the two groups of readers exhibited differential effects of frequency and/or predictability. In Experiment 1, high- and low-frequency target words were embedded in nonconstraining sentence contexts. In Experiment 2, the same participants read high- and low-frequency target words that were either predictable or unpredictable, embedded in highly constraining sentence contexts. Results indicated that when target words appeared in highly constraining sentence contexts, the average readers showed different effects of frequency and predictability from those shown in the highly skilled readers. It appears that reading skill can interact with predictability to affect the word recognition processes used during silent reading.

The prosodic property of lexical stress affects eye movements during silent reading

The present study examined lexical stress in the context of silent reading by measuring eye movements. We asked whether lexical stress registers in the eye movement record and, if so, why. The study also tested the implicit prosody hypothesis, or the idea that readers construct a prosodic contour during silent reading. Participants read high and low frequency target words with one or two stressed syllables embedded in sentences. Lexical stress affected eye movements, such that words with two stressed syllables took longer to read and received more fixations than words with one stressed syllable. Findings offer empirical support for the implicit prosody hypothesis and suggest that stress assignment may be the completing phase of lexical access, at least in terms of eye movement control.

Representing syllable information during silent reading: Evidence from eye movements

Two eye movement experiments investigated the nature of the phonological representations used in reading English. Each tested whether sublexical, syllable information is part of that representation. Target words with CV-initial syllables (DE.MAND) or CVC-initial syllables (LAN.TERN) were preceded by primes that exactly matched or mismatched their initial syllable. In Experiment 1, the primes were presented foveally using a fast-priming technique. Target words of both types were read faster when preceded by a three-letter than a two-letter prime, and no effect of matching syllable information was observed. In Experiment 2, primes were presented parafoveally using a preview technique. First fixation durations were shorter on words which were preceded by a matching syllable preview than a mismatching preview. These results indicate that proficient readers do process sublexical, syllable information while reading, which provides evidence for a multi-layered phonological representation. The results of Experiments 1 and 2 suggest that syllable information is encoded as part of the memory processes that preserve information across saccades.

Eye movement control in reading: word predictability has little influence on initial landing positions in words

We examined the initial landing position of the eyes in target words that were either predictable or unpredictable from the preceding sentence context. Although readers skipped over predictable words more than unpredictable words and spent less time on predictable words when they did fixate on them, there was no difference in the launch site of the saccade to the target word. Moreover, there was only a very small difference in the initial landing position on the target word as a function of predictability when the target words were fixated which is most parsimoniously explained by positing that a few programmed skips of the target word fell short of their intended target. These results suggest that low-level processing is primarily responsible for landing position effects in reading.

Prosodic phonological representations early in visual word recognition

Two experiments examined the nature of the phonological representations used during visual word recognition. We tested whether a minimality constraint (R. Frost, 1998) limits the complexity of early representations to a simple string of phonemes. Alternatively, readers might activate elaborated representations that include prosodic syllable information before lexical access. In a modified lexical decision task (Experiment 1), words were preceded by parafoveal previews that were congruent with a targets initial syllable as well as previews that contained 1 letter more or less than the initial syllable. Lexical decision times were faster in the syllable congruent conditions than in the incongruent conditions. In Experiment 2, we recorded brain electrical potentials (electroencephalograms) during single word reading in a masked priming paradigm. The event-related potential waveform elicited in the syllable congruent condition was more positive 250-350 ms posttarget compared with the waveform elicited in the syllable incongruent condition. In combination, these experiments demonstrate that readers process prosodic syllable information early in visual word recognition in English. They offer further evidence that skilled readers routinely activate elaborated, speechlike phonological representations during silent reading.

Vowel Processing During Silent Reading: Evidence from Eye Movements.

Two eye movement experiments examined whether skilled readers include vowels in the early phonological representations used in word recognition during silent reading. Target words were presented in sentences preceded by parafoveal previews in which the vowel phoneme was concordant or discordant with the vowel phoneme in the target word. In Experiment 1, the orthographic vowel differed from the target in both the concordant and discordant preview conditions. In Experiment 2, the vowel letters in the preview were identical to those in the target word. The phonological vowel was ambiguous, however, and the final consonants of the previews biased the vowel phoneme either toward or away from the targets vowel phoneme. In both experiments, shorter reading times were observed for targets preceded by concordant previews than by discordant previews. Implications for models of word recognition are discussed.

Skilled Readers Begin Processing Sub-phonemic Features by 80 ms during Visual Word Recognition: Evidence from ERPs

Two masked priming experiments investigated the time-course of the activation of sub-phonemic information during visual word recognition. EEG was recorded as participants read targets with voiced and unvoiced final consonants (e.g., fad and fat), preceded by nonword primes that were incongruent or congruent in voicing and vowel duration (e.g., fap or faz). Experiment 1 used a long duration mask (100 ms) between prime and target, whereas Experiment 2 used a short mask (22 ms). Phonological feature congruency began modulating the amplitude of brain potentials by 80 ms; the feature incongruent condition evoked greater negativity than the feature congruent condition in both experiments. The early onset of the congruency effect indicates that skilled readers initially activate sub-phonemic feature information during word identification. Congruency effects also appeared in the middle and late periods of word recognition, suggesting that readers use phonological representations in multiple aspects of visual word recognition.

Dyslexia and fluency: parafoveal and foveal influences on rapid automatized naming.

The ability to coordinate serial processing of multiple items is crucial for fluent reading but is known to be impaired in dyslexia. To investigate this impairment, we manipulated the orthographic and phonological similarity of adjacent letters online as dyslexic and nondyslexic readers named letters in a serial naming (RAN) task. Eye movements and voice onsets were recorded. Letter arrays contained target item pairs in which the second letter was orthographically or phonologically similar to the first letter when viewed either parafoveally (Experiment 1a) or foveally (Experiment 1b). Relative to normal readers, dyslexic readers were more affected by orthographic confusability in Experiment 1a and phonological confusability in Experiment 1b. Normal readers were slower to process orthographically similar letters in Experiment 1b. Findings indicate that the phonological and orthographic processing problems of dyslexic readers manifest differently during parafoveal and foveal processing, with each contributing to slower RAN performance and impaired reading fluency.