Eye Movements and Fixation-Related Potentials in Reading: A Review

The present review is addressed to researchers in the field of reading and psycholinguistics who are both familiar with and new to co-registration research of eye movements (EMs) and fixation related-potentials (FRPs) in reading. At the outset, we consider a conundrum relating to timing discrepancies between EM and event related potential (ERP) effects. We then consider the extent to which the co-registration approach might allow us to overcome this and thereby discriminate between formal theoretical and computational accounts of reading. We then describe three phases of co-registration research before evaluating the existing body of such research in reading. The current, ongoing phase of co-registration research is presented in comprehensive tables which provide a detailed summary of the existing findings. The thorough appraisal of the published studies allows us to engage with issues such as the reliability of FRP components as correlates of cognitive processing in reading and the advantages of analysing both data streams (i.e., EMs and FRPs) simultaneously relative to each alone, as well as the current, and limited, understanding of the relationship between EM and FRP measures. Finally, we consider future directions and in particular the potential of analytical methods involving deconvolution and the potential of measurement of brain oscillatory activity

The impact of cognitive load on processing efficiency and performance effectiveness in anxiety: evidence from event-related potentials and pupillary responses

Anxiety has been associated with poor attentional control, as reflected in lowered performance on experimental measures of executive attention and inhibitory control. Recent conceptualisations of anxiety propose that individuals who report elevated anxiety symptoms worry about performance and will exert greater cognitive effort to complete tasks well, particularly when cognitive demands are high. Across two experiments, we examined the effect of anxiety on task performance and across two load conditions using (1) measures of inhibitory control (behavioural reaction times and eye-movement responses) and (2) task effort with pupillary and electrocortical markers of effort (CNV) and inhibitory control (N2). Experiment 1 used an oculomotor-delayed-response task that manipulated load by increasing delay duration to create a high load, relative to a low load, condition. Experiment 2 used a Go/No-Go task and load was manipulated by decreasing the No-Go probabilities (i.e., 20% No-Go in the high load condition and 50% No-Go in the low load condition). Experiment 1 showed individuals with high (vs. low) anxiety made more antisaccade errors across load conditions, and made more effort during the high load condition, as evidenced by greater frontal CNV and increased pupillary responses. In Experiment 2, individuals with high anxiety showed increased effort (irrespective of cognitive load), as characterised by larger pupillary responses. In addition, N2 amplitudes were sensitive to load only in individuals with low anxiety. Evidence of reduced performance effectiveness and efficiency across electrophysiological, pupillary, and oculomotor systems in anxiety provides some support for neurocognitive models of frontocortical attentional dysfunction in anxiety

Parafoveal Previews and Lexical Frequency in Natural Reading: Evidence from Eye Movements and Fixation-Related Potentials

Participants’ eye movements and EEG signal were recorded as they read sentences displayed according to the gaze-contingent boundary paradigm. Two target words in each sentence were manipulated for lexical frequency (high vs. low frequency) and parafoveal preview of each target word (identical vs. string of random letters vs. string of Xs). Eye movement data revealed visual parafoveal-on-foveal effects (POF), as well as foveal visual and orthographic preview effects and word frequency effects. Fixation-related potentials (FRPs) showed visual and orthographic PoF effects as well as foveal visual and orthographic preview effects. Our results replicated the early preview positivity effect (Dimigen et al., 2012) in the X-string preview condition, and revealed different neural correlates associated with a preview comprised of a string of random letters relative to a string of Xs. The former effects seem likely to reflect difficulty associated with the integration of parafoveal and foveal information, as well as feature overlap, while the latter reflect inhibition, and potentially disruption, to processing underlying reading. Interestingly, and consistent with Kretzschmar, Schlesewsky and Staub (2015), no frequency effect was reflected in the FRP measures. The findings provide insight into the neural correlates of parafoveal processing and written word recognition in reading and demonstrate the value of utilising ecologically valid paradigms to study well established phenomena that occur as text is read naturally

Warning – Taboo Words Ahead! Avoiding Attentional Capture by Spoken Taboo Distractors

We examine whether the disruption of serial short-term memory (STM) by spoken taboo distractors is due to attentional diversion and unrelated to the underlying disruptive effect of sound on serial STM more generally, which we have argued is due to order cues arising from the automatic pre-categorical processing of acoustic changes in the sound conflicting with serial–order processing within the memory task (interferenceby-process). We test whether the taboo-distractor effect is, unlike effects attributable to interference-by-process, amenable to top-down control. Experiment 1 replicated the taboo-distractor effect and showed that it is not merely a valence effect. However, promoting cognitive control by increasing focal task-load did not attenuate the effect. However, foreknowledge of the distractors did eliminate the taboo-distractor effect while having no effect on disruption by neutral words (Experiment 2). We conclude that the taboo-distractor effect results from a controllable attentional-diversion mechanism distinct from the effect of any acoustically-changing sound

Examining Semantic Parafoveal-on-Foveal Effects Using a Stroop Boundary Paradigm

The issue of whether lexical processing occurs serially or in parallel has been a central and contentious issue in respect of models of eye movement control in reading for well over a decade. A critical question in this regard concerns whether lexical parafoveal-on-foveal effects exist in reading. Because Chinese is an unspaced and densely packed language, readers may process parafoveal words to a greater extent than they do in spaced alphabetic languages. In two experiments using a novel Stroop boundary paradigm (Rayner, 1975), participants read sentences containing a single-character color-word whose preview was manipulated (identity or pseudocharacter, printed in black [no-color], or in a color congruent or incongruent with the character meaning). Two boundaries were used, one positioned two characters before the target and one immediately to the left of the target. The previews changed from black to color and then back to black as the eyes crossed the first and then the second boundary respectively. In Experiment 1 four color-words (red, green, yellow and blue) were used and in Experiment 2 only red and green color-words were used as targets. Both experiments showed very similar patterns such that reading times were increased for colored compared to no-color previews indicating a parafoveal visual interference effect. Most importantly, however, there were no robust interactive effects. Preview effects were comparable for congruent and incongruent color previews at the pretarget region when the data were combined from both experiments. These results favour serial processing accounts and indicate that even under very favourable experimental conditions, lexical semantic parafoveal-on-foveal effects are minimal

The Susceptibility of Compound Remote Associate Problems to Disruption by Irrelevant Sound: A Window onto the Component Processes Underpinning Creative Cognition?

Controversy exists regarding the processes involved in creative thinking with the Remote Associates Test (RAT) and the Compound Remote Associates Test (CRAT). We report three experiments that aimed to shed light on the component processes underpinning CRAT performance by using the mere presence of task-irrelevant sound as a key theoretical tool. Experiments 1 and 2 revealed that CRAT performance was impaired relative to a quiet condition by the presence of sequences of changing letters and tones, respectively. In both experiments a non-changing sound (a repeated letter or a repeated tone) produced no disruption relative to quiet. Experiment 3 established that additional disruption was engendered by having to ignore meaningful speech as compared to meaningless speech. These experiments demonstrate that both semantic activation and subvocalisation are important determinants of successful creative thinking with CRAT problems. We suggest that semantic activation underpins solution-generation processes whereas subvocalisation underpins solution-evaluation processes

Auditory Distraction During Reading: Investigating the Effects of Background Sounds on Parafoveal Processing

Previous research suggests that unexpected (deviant) sounds negatively affect reading performance by inhibiting saccadic planning, which models of reading agree takes place simultaneous to parafoveal processing. The present study examined the effect of deviant sounds on foveal and parafoveal processing. Participants read single sentences in quiet, standard (repeated sounds), or deviant sound conditions (a new sound within a repeated sound sequence). Sounds were presented with a variable delay coincident with the onset of fixations on target words during a period when saccadic programming and parafoveal processing occurred. We used the moving window paradigm (McConkie & Rayner, 1975) to manipulate the amount of information readers could extract from the parafovea (the entire sentence or a 13-character window of text). Global, sentence-level analyses showed typical disruption to reading by the window, and under quiet conditions similar effects were observed at the target and post-target word in the local analyses. Standard and deviant sounds also produced clear distraction effects of differing magnitudes at the target and post-target words, though at both regions, these effects were qualified by interactions. Effects at the target word suggested that with sounds, readers engaged in less effective parafoveal processing than under quiet. Similar patterns of effects due to standard and deviant sounds, each with a different time course, occurred at the post-target word. We conclude that distraction via auditory deviation causes disruption to parafoveal processing during reading, with such effects being modulated by the degree to which a sound’s characteristics are more or less unique

Peripheral preview abolishes N170 face-sensitivity at fixation: Using fixation-related potentials to investigate dynamic face processing

The N170 ERP peak has been found to be consistently larger in response to the presentation of faces than to other objects, yet it is not clear whether this face-sensitive N170 is also elicited during fixations made subsequent to the initial presentation. To investigate this question, the current study utilised Event and Fixation-Related Potentials in two experiments, time-locking brain potentials to the presentation of faces and objects (watches) images in participants’ peripheral vision, and to their first fixations on the images. Experiment 1 found that a face-sensitive N170 was elicited by the onset of images but not by a subsequent fixation on the images, and that face inversion did not modulate N170 beyond presentation. Experiment 2 found that disrupting the structure of the peripheral preview (phase-scrambling) led to a face-sensitive N170 at fixation onsets on the intact-images. Interestingly, N170 amplitudes for both faces and objects were significantly enhanced after the peripheral preview was phase-scrambled, suggesting that the N170 in part reflects a category-detection process that is elicited once when an image structure is viewed. These results indicate that neural processing during fixations will be significantly modulated when they are immediately preceded by peripheral previews, and is not specific to faces

A co-registration investigation of inter-word spacing and parafoveal preview: Eye movements and fixation-related potentials

Participants’ eye movements (EMs) and EEG signal were simultaneously recorded to examine foveal and parafoveal processing during sentence reading. All the words in the sentence were manipulated for inter-word spacing (intact spaces vs. spaces replaced by a random letter) and parafoveal preview (identical preview vs. random letter string preview). We observed disruption for unspaced text and invalid preview conditions in both EMs and fixation-related potentials (FRPs). Unspaced and invalid preview conditions received longer reading times than spaced and valid preview conditions. In addition, the FRP data showed that unspaced previews disrupted reading in earlier time windows of analysis, compared to string preview conditions. Moreover, the effect of parafoveal preview was greater for spaced relative to unspaced conditions, in both EMs and FRPs. These findings replicate well-established preview effects, provide novel insight into the neural correlates of reading with and without inter-word spacing and suggest that spatial selection precedes lexical processing

Co-registration of eye movements and brain potentials to investigate processes underlying reading

The present thesis reports three experiments conducted simultaneously recording eye movements (EMs) and fixation-related potentials (FRPs) to examine parafoveal and foveal processing during silent reading of sentences. Experiment 1 examined the influence of preview quality and target word frequency on reading. Experiment 2 investigated the influence that different types of parafoveal previews as well as target word frequency exert on processing. Experiment 3 explored the effects of parafoveal inter-word spacing and parafoveal preview when a word is currently fixated. Overall, all three experiments indicated that visual and orthographic properties of an upcoming word are pre-processed in the parafovea, and that this pre-processing influences processing during fixations on pretarget and target words. No evidence of lexical processing of a word in parafovea was obtained neither in Experiment 1 nor in Experiment 2. Experiment 2 and Experiment 3 also demonstrated the added value of the FRP data in showing qualitative differences in relation to effects that appear as quantitatively similar in EM measures. In addition, all three experiments indicated that neural correlates associated with processing during natural reading might be different to those associated with less natural reading conditions. The thesis also considers a number of methodological implementations and implications of coregistration methodology for future experiments aiming to investigate reading