Heather Sheridan

The time course of predictability effects in reading: Evidence from a survival analysis of fixation durations

To investigate the time course of predictability effects in reading, the present study examined distributions of first-fixation durations on target words in a low predictability versus a high predictability prior context. In a replication of Staub (2011), ex-Gaussian fitting demonstrated that the low predictability distribution was significantly shifted to the right of the high predictability distribution in the absence of any contextual differences in the degree of skew. Extending this finding, the present study used a survival analysis technique to demonstrate a significant influence of predictability on fixation duration as early as 140 ms from the start of fixation, which is similar to prior results obtained with the word frequency variable. These results provide convergent evidence that lexical variables have a fast acting influence on fixation durations during reading. Implications for models of eye-movement control are discussed.

Using puns to study contextual influences on lexical ambiguity resolution: Evidence from eye movements

Participants’ eye movements were monitored while they read sentences containing biased homographs in either a single-meaning context condition that instantiated the subordinate meaning of the homograph without ruling out the dominant meaning (e.g., “The man with a toothache had a crown made by the best dentist in town”) or a dual-meaning pun context condition that supported both the subordinate and dominant meanings (e.g., “The king with a toothache had a crown made by the best dentist in town”). In both of these conditions, the homographs were followed by disambiguating material that supported the subordinate meaning and ruled out the dominant meaning. Fixation times on the homograph were longer in the single-meaning condition than in the dual-meaning condition, whereas the reverse pattern was demonstrated for fixation times on the disambiguating region; these effects were observed as early as first-fixation duration. The findings strongly support the reordered access model of lexical ambiguity resolution.

Unsegmented text delays word identification: Evidence from a survival analysis of fixation durations

The present study employed distributional analyses of fixation times to examine the impact of removing spaces between words during reading. Specifically, we presented high and low frequency target words in a normal text condition that contained spaces (e.g., “John decided to sell the table in the garage sale”) and in an unsegmented text condition that contained random numbers instead of spaces (e.g., “John4decided8to5sell9the7table2in3the9garage6sale”). The unsegmented text condition produced larger word frequency effects relative to the normal text condition for the gaze duration and total time measures (for similar findings, see Rayner, Fischer, & Pollatsek, 1998), which indicates that removing spaces can impact the word identification stage of reading. To further examine the effect of spacing on word identification, we used distributional analyses of first-fixation durations to contrast the time course of word frequency effects in the normal versus the unsegmented text conditions. In replication of prior findings (Reingold, Reichle, Glaholt, & Sheridan, 2012; Staub, White, Drieghe, Hollway, & Rayner, 2010), ex-Gaussian fitting revealed that the word frequency variable impacted both the shift and the skew of the distributions, and this pattern of results occurred for both the normal and unsegmented text conditions. In addition, a survival analysis technique revealed a later time course of word frequency effects in the unsegmented relative to the normal condition, such that the earliest discernible influence of word frequency was 112 ms from the start of fixation in the normal text condition, and 152 ms in the unsegmented text condition. This delay in the temporal onset of word frequency effects in the unsegmented text condition strongly suggests that removing spaces delays the word identification stage of reading. Possible underlying mechanisms are discussed, including lateral masking and word segmentation.

Expert vs. novice differences in the detection of relevant information during a chess game: evidence from eye movements.

The present study explored the ability of expert and novice chess players to rapidly distinguish between regions of a chessboard that were relevant to the best move on the board, and regions of the board that were irrelevant. Accordingly, we monitored the eye movements of expert and novice chess players, while they selected whites best move for a variety of chess problems. To manipulate relevancy, we constructed two different versions of each chess problem in the experiment, and we counterbalanced these versions across participants. These two versions of each problem were identical except that a single piece was changed from a bishop to a knight. This subtle change reversed the relevancy map of the board, such that regions that were relevant in one version of the board were now irrelevant (and vice versa). Using this paradigm, we demonstrated that both the experts and novices spent more time fixating the relevant relative to the irrelevant regions of the board. However, the experts were faster at detecting relevant information than the novices, as shown by the finding that experts (but not novices) were able to distinguish between relevant and irrelevant information during the early part of the trial. These findings further demonstrate the domain-related perceptual processing advantage of chess experts, using an experimental paradigm that allowed us to manipulate relevancy under tightly controlled conditions.

Estimating the divergence point: a novel distributional analysis procedure for determining the onset of the influence of experimental variables

The divergence point analysis procedure is aimed at obtaining an estimate of the onset of the influence of an experimental variable on response latencies (e.g., fixation duration, reaction time). The procedure involves generating survival curves for two conditions, and using a bootstrapping technique to estimate the timing of the earliest discernible divergence between curves. In the present paper, several key extensions for this procedure were proposed and evaluated by conducting simulations and by reanalyzing data from previous studies. Our findings indicate that the modified versions of the procedure performed substantially better than the original procedure under conditions of low experimental power. Furthermore, unlike the original procedure, the modified procedures provided divergence point estimates for individual participants and permitted testing the significance of the difference between estimates across conditions. The advantages of the modified procedures are illustrated, the theoretical and methodological implications are discussed, and promising future directions are outlined.

A further examination of the lexical-processing stages hypothesized by the E-Z Reader model

Participants’ eye movements were monitored while they read sentences in which high- and low-frequency target words were presented normally (i.e., the normal condition) or with either reduced stimulus quality (i.e., the faint condition) or alternating lower- and uppercase letters (i.e., the case-alternated condition). Both the stimulus quality and case alternation manipulations interacted with word frequency for the gaze duration measure, such that the magnitude of word frequency effects was increased relative to the normal condition. However, stimulus quality (but not case alternation) interacted with word frequency for the early fixation time measures (i.e., first fixation, single fixation), whereas case alternation (but not stimulus quality) interacted with word frequency for the later fixation time measures (i.e., total time, go-past time). We interpret this pattern of results as evidence that stimulus quality influences an earlier stage of lexical processing than does case alternation, and we discuss the implications of our results for models of eye movement control during reading.

The locus of Katakana-English masked phonological priming effects

Japanese–English bilinguals completed a masked phonological priming study with Japanese Katakana primes and English targets. Event related potential (ERP) data were collected in addition to lexical decision responses. A cross-script phonological priming effect was observed in both measures, and the effect did not interact with frequency. In the ERP data, the phonological priming effect was evident before the frequency effect. These data, along with analyses of response latency distributions, provide evidence that the cross-script phonological priming effects were the consequence of the activation of sublexical phonological representations in a store shared by both Japanese and English. This activation fed back to sublexical and lexical orthographic representations, influencing lexical decision latencies. The implications for the Bilingual Interactive Activation (BIA+) model of word recognition are discussed.

The Mechanisms and Boundary Conditions of the Einstellung Effect in Chess: Evidence from Eye Movements

In a wide range of problem-solving settings, the presence of a familiar solution can block the discovery of better solutions (i.e., the Einstellung effect). To investigate this effect, we monitored the eye movements of expert and novice chess players while they solved chess problems that contained a familiar move (i.e., the Einstellung move), as well as an optimal move that was located in a different region of the board. When the Einstellung move was an advantageous (but suboptimal) move, both the expert and novice chess players who chose the Einstellung move continued to look at this move throughout the trial, whereas the subset of expert players who chose the optimal move were able to gradually disengage their attention from the Einstellung move. However, when the Einstellung move was a blunder, all of the experts and the majority of the novices were able to avoid selecting the Einstellung move, and both the experts and novices gradually disengaged their attention from the Einstellung move. These findings shed light on the boundary conditions of the Einstellung effect, and provide convergent evidence for Bilalić, McLeod, & Gobet (2008)’s conclusion that the Einstellung effect operates by biasing attention towards problem features that are associated with the familiar solution rather than the optimal solution.

Perceptually specific and perceptually non-specific influences on rereading benefits for spatially transformed text: Evidence from eye movements

The present study used eye tracking methodology to examine rereading benefits for spatially transformed text. Eye movements were monitored while participants read the same target word twice, in two different low-constraint sentence frames. The congruency of perceptual processing was manipulated by either applying the same type of transformation to the word during the first and second presentations (i.e., the congruent condition), or employing two different types of transformations across the two presentations of the word (i.e., the incongruent condition). Perceptual specificity effects were demonstrated such that fixation times for the second presentation of the target word were shorter for the congruent condition compared to the incongruent condition. Moreover, we demonstrated an additional perceptually non-specific effect such that second reading fixation times were shorter for the incongruent condition relative to a baseline condition that employed a normal typography (i.e., non-transformed) during the first presentation and a transformation during the second presentation. Both of these effects (i.e., perceptually specific and perceptually non-specific) were similar in magnitude for high and low frequency words, and both effects persisted across a 1 week lag between the first and second readings. We discuss the present findings in the context of the distinction between conscious and unconscious memory, and the distinction between perceptually versus conceptually driven processing.

Character-complexity effects in Chinese reading and visual search: A comparison and theoretical implications

Three eye-movement experiments were conducted to examine how the complexity of characters in Chinese words (i.e., number of strokes per character) influences their processing and eye-movement behaviour. In Experiment 1, English speakers with no significant knowledge of Chinese searched for specific low-, medium-, and high-complexity target characters in a multi-page narrative containing characters of varying complexity (3–16 strokes). Fixation durations and skipping rates were influenced by the visual complexity of both the target characters and the characters being searched even though participants had no knowledge of Chinese. In Experiment 2, native Chinese speakers performed the same character-search task, and a similar pattern of results was observed. Finally, in Experiment 3, a second sample of native Chinese speakers read the same text used in Experiments 1 and 2, with text characters again exhibiting complexity effects. These results collectively suggest that character-complexity effects on eye movements may not be due to lexical processing per se but may instead reflect whatever visual processing is required to know whether or not a character corresponds to an episodically represented target. The theoretical implications of this for our understanding of normal reading are discussed.