bluuebunny/crossref_metadata_2025 huggingface dataset:
Hearing in a world of light: why, where, and how visual and auditory information are connected by the brain
Authors: Groh Jennifer M.
Published: February 2021

Keynote by Jenny Groh (Duke University) at the 20th European Conference on Eye Movement Research (ECEM) in Alicante, 19.8.2019
Video stream: https://vimeo.com/356576513
Abstract:
Information about eye movements with respect to the head is required for reconciling visual and auditory space. This keynote presentation describes recent findings concerning how eye movements affect early auditory processing via motor processes in the ear (eye movement-related eardrum oscillations, or EMREOs). Computational efforts to understand how eye movements are factored in to auditory processing to produce a reference frame aligned with visual space uncovered a second critical issue: sound location is not mapped but is instead rate (meter) coded in the primate brain, unlike visual space. Meter coding would appear to limit the representation of multiple simultaneous sounds. The second part of this presentation concerns how such a meter code could use fluctuating activity patterns to circumvent this limitation
The fate and function of vision during saccades
Authors: Rolfs Martin
Published: February 2021

Keynote at the 20th European Conference on Eye Movement Research (ECEM) in Alicante, 20.8.2019,
(Video stream not punlished on internet)
Unraveling Concussion Impact by Impact
Authors: Rucker Janet C.
Published: February 2021

Keynote at the 20th European Conference on Eye Movement Research (ECEM) in Alicante, 20.8.2019.
Video stream: https://vimeo.com/357889739
MAD saccade: statistically robust saccade threshold estimation via the median absolute deviation
Authors: Voloh Benjamin , Watson Marcus R , Konig Seth , Womelsdorf Thilo
Published: February 2021

Saccade detection is a critical step in the analysis of gaze data. A common method for saccade detection is to use a simple threshold for velocity or acceleration values, which can be estimated from the data using the mean and standard deviation. However, this method has the downside of being influenced by the very signal it is trying to detect, the outlying velocities or accelerations that occur during saccades. We propose instead to use the median absolute deviation (MAD), a robust estimator of dispersion that is not influenced by outliers. We modify an algorithm proposed by Nyström and colleagues, and quantify saccade detection performance in both simulated and human data. Our modified algorithm shows a significant and marked improvement in saccade detection - showing both more true positives and less false negatives – especially under higher noise levels. We conclude that robust estimators can be widely adopted in other common, automatic gaze classification algorithms due to their ease of implementation.
Effect of a visual tracking intervention on attention and behavior of attention deficit hyper activity children
Authors: Janmohammadi Shiva , Haghgoo Hojjat Allah , Farahbod Mojgan , Overton Paul G. , Pishyareh Ebrahim
Published: February 2021

Attention deficit hyperactivity disorder is characterized by several cognitive and behavioral problems such as inattention and impulsivity, abnormal control of eye movements and relocation, visual fixation and visuospatial perception. There is a link between core motor functions such as oculomotor function and cognition to the extent that the oculomotor system acts as a mediator between the motor and cognitive functions. Therefore, the effects of eye-tracking intervention were investigated on attention in these children. Thirty - nine boys with ADHD, 6 to 10 years of age were recruited and randomized to receive current occupational therapy (control group), or occupational therapy accompanied with eye-tracking exercises (experimental group). They were evaluated using the Conner's Parent Rating Scale, the Continuous Performance Task-2, and the Test of Visual-Motor Skills-Revised before and after the intervention. Significant improvements in the mean scores of cognitive problems (F=9/22), coping behavior (F=6.03) and hyperactivity (F=9.77) were detected in the posttest between the two groups (p<0.05). Furthermore, in the Continuous Performance Test scores, detectability (F=5.68), omission errors (F=17.89), commission errors (F=19.45), reaction time (F=8.95), variability (F=7.07), and preservation (F=6.33) showed significant differences between control and experimental groups (p<0.01). It appears that eye-tracking interventions designed based on the isolation of neck and eye movement might have an important role in improving cognitive function and coping behaviors in these children. It seems that these exercises could increase eye movement control; improve cognitive function and response inhibition.
Calibration-free gaze interfaces based on linear smooth pursuit
Authors: Zeng Zhe , Siebert Felix Wilhelm , Venjakob Antje Christine , Roetting Matthias
Published: February 2021

Since smooth pursuit eye movements can be used without calibration in spontaneous gaze interaction, the intuitiveness of the gaze interface design has been a topic of great interest in the human-computer interaction field. However, since most related research focuses on curved smooth-pursuit trajectories, the design issues of linear trajectories are poorly understood. Hence, this study evaluated the user performance of gaze interfaces based on linear smooth pursuit eye movements. We conducted an experiment to investigate how the number of objects (6, 8, 10, 12, or 15) and object moving speed (7.73 ˚/s vs. 12.89 ˚/s) affect the user performance in a gaze-based interface.
Results show that the number and speed of the displayed objects influence users’ performance with the interface. The number of objects significantly affected the correct and false detection rates when selecting objects in the display. Participants’ performance was highest on interfaces containing 6 and 8 objects and decreased for interfaces with 10, 12, and 15 objects. Detection rates and orientation error were significantly influenced by the moving speed of displayed objects.
Faster moving speed (12.89 ˚/s) resulted in higher detection rates and smaller orientation error compared to slower moving speeds (7.73 ˚/s).
Our findings can help to enable a calibration-free accessible interaction with gaze interfaces.
A two-step approach for interest estimation from gaze behavior in digital catalog browsing
Authors: Shimonishi Kei , Kawashima Hiroaki
Published: February 2021

While eye gaze data contain promising clues for inferring the interests of viewers of digital catalog content, viewers often dynamically switch their focus of attention. As a result, a direct application of conventional behavior analysis techniques, such as topic models, tends to be affected by items or attributes of little or no interest to the viewer. To overcome this limitation, we need to identify “when” the user compares items and to detect “which attribute types/values” reflect the user’s interest. This paper proposes a novel two-step approach to addressing these needs. Specifically, we introduce a likelihood-based short-term analysis method as the first step of the approach to simultaneously determine comparison phases of browsing and detect the attributes on which the viewer focuses, even when the attributes cannot be directly obtained from gaze points. Using probabilistic latent semantic analysis, we show that this short-term analysis step greatly improves the results of the subsequent step. The effectiveness of the framework is demonstrated in terms of the capability to extract combinations of attributes relevant to the viewer’s interest, which we call aspects, and also to estimate the interest described by these aspects.
The closer, the better? Processing relations between picture elements in historical paintings
Authors: Glaser Manuela , Knoos Manuel , Schwan Stephan
Published: February 2021

The present eye-tracking study investigated how audio explanations influence perception and the cognitive processing of historical paintings. Spatially close and distant pairs of picture elements and their semantic relations were named in an audio text either immediately after each other or with descriptions of other elements in between. It was assumed that the number of backward fixation counts on the first of the two mentioned related picture elements should be higher if they are spatially close rather than spatially distant. There should also be more backward fixation counts if the elements are named temporally close rather than temporally distant. Similar predictions were made for the retention of these picture elements and their relations. A 2x2x2 within-subject design (n=36) with spatial distance (close vs. distant), temporal distance (close vs. distant) and painting (Leutze vs. West) revealed more background fixation counts for spatially close compared to spatially distant elements but just for the Leutze painting. Accordingly, the relations between the spatially close pairs were retained better than between the spatially distant pairs in the Leutze painting but vice versa for the West painting. The results are discussed with regard to the spatial contiguity principle of multimedia learning and research on text coherence.
You read best what you read most: An eye tracking study
Authors: Nedeljković Uroš , Jovančić Kata , Pušnik Nace
Published: February 2021

At the threshold of the digital era, Zuzana Licko was of the opinion that familiar letterforms owe legibility to centuries-long exposure and that all new, prototypically unmatching forms would be equally legible if used as frequently. This paper examined the legibility in the context of familiarity – is it affected by the time of exposure to a particular typeface or a typeface’s universal structure. We ran repeated measures tests with exposure period in-between. The experiment was conducted using for this purpose designed typefaces as stimuli, and the eye-tracking on-screen reading technology. The results confirmed that one’s familiarity with a typeface influences one’s reading speed. The universal letter structure, recognised by Frutiger as the prototype skeleton, is the constant that a priori provides legibility. On the other hand, the period of exposure to uncommon letterforms also has a positive impact on legibility. Therefore, considering that the period of familiarity with the humanist letterforms has been continuous since their establishment, the maxim from the dawn of the digital era can be regarded as valid.
To look or not to look: Subliminal abrupt-onset cues influence constrained free-choice saccades
Authors: Prasad Seema Gorur , Mishra Ramesh Kumar
Published: February 2021

Subliminal cues have been shown to capture attention and modulate manual response behaviour but their impact on eye movement behaviour is not well-studied. In two experiments, we examined if subliminal cues influence constrained free-choice saccades and if this influence is under strategic control as a function of task-relevancy of the cues. On each trial, a display containing four filled circles at the centre of each quadrant was shown. A central coloured circle indicated the relevant visual field on each trial (Up or Down in Experiment 1; Left or Right in Experiment 2). Next, abrupt-onset cues were presented for 16 ms at one of the four locations. Participants were then asked to freely choose and make a saccade to one of the two target circles in the relevant visual field. The analysis of the frequency of saccades, saccade endpoint deviation and saccade latency revealed a significant influence of the relevant subliminal cues on saccadic decisions. Latency data showed reduced capture by spatially-irrelevant cues under some conditions. These results indicate that spatial attentional control settings as defined in our study could modulate the influence of subliminal abrupt-onset cues on eye movement behaviour. We situate the findings of this study in the attention-capture debate and discuss the implications for the subliminal cueing literature.
An eye-tracking study of reading long and short novel and lexicalized compound words
Authors: Hyönä Jukka , Pollatsek Alexander , Koski Minna , Olkoniemi Henri
Published: February 2021

An eye-tracking experiment examined the recognition of novel and lexicalized compound words during sentence reading. The frequency of the head noun in modifier-head compound words was manipulated to tap into the degree of compositional processing. This was done separately for long (12–16 letter) and short (7-9 letters) compound words. Based on the dual-route race model (Pollatsek et al., 2000) and the visual acuity principle (Bertram & Hyönä, 2003), long lexicalized and novel compound words were predicted to be processed via the decomposition route and short lexicalized compound words via the holistic route. Gaze duration and selective regression-path duration demonstrated a constituent frequency effect of similar size for long lexicalized and novel compound words. For short compound words the constituent frequency effect was negligible for lexicalized words but robust for novel words. The results are consistent with the visual acuity principle that assumes long novel compound words to be recognized via the decomposition route and short lexicalized compound words via the holistic route.
The information gathering framework - a cognitive model of regressive eye movements during reading
Authors: Weiss Anna Fiona
Published: February 2021

In this article we present a new eye movement control framework that describes the interaction between fixation durations and regressive saccades during reading: The Information Gathering Framework (IGF).
Based on the FC model proposed by Bicknell and Levy (2010), the basic idea of the IGF is that a confidence level for each word is computed while being monitored by three independent thresholds. These thresholds shape eye movement behavior by increasing fixation duration, triggering a regression, or guiding regression target selection. In this way, the IGF does not only account for regressive eye movements but also provides a framework able to model eye movement control during reading across different scenarios. Importantly, within the IGF it is assumed that two different types of regressive eye movements exist which differ with regard to their releases (integrations difficulties vs. missing evidence) but also with regard to their time course.
We tested the predictions of the IGF by re-analyzing an experiment of Weiss et al. (2018) and found, inter alia, clear evidence for shorter fixation durations before regressive saccades relative to progressive saccades, with the exception of the last region. This clearly supports the assumptions of the IGF. In addition, we found evidence that there exists a window of about 15–20 characters to the left of the current fixation that plays an important role in target selection, probably indicating the perceptual span during a regressive saccade.
Two hours in Hollywood: A manually annotated ground truth data set of eye movements during movie clip watching
Authors: Agtzidis Ioannis , Startsev Mikhail , Dorr Michael
Published: February 2021

In this short article we present our manual annotation of the eye movement events in a subset of the large-scale eye tracking data set Hollywood2. Our labels include fixations, saccades, and smooth pursuits, as well as a noise event type (the latter representing either blinks, loss of tracking, or physically implausible signals). In order to achieve more consistent annotations, the gaze samples were labelled by a novice rater based on rudimentary algorithmic suggestions, and subsequently corrected by an expert rater. Overall, we annotated eye movement events in the recordings corresponding to 50 randomly selected test set clips and 6 training set clips from Hollywood2, which were viewed by 16 observers and amount to a total of approximately 130 minutes of gaze data. In these labels, 62.4% of the samples were attributed to fixations, 9.1% – to saccades, and, notably, 24.2% – to pursuit (the remainder marked as noise). After evaluation of 15 published eye movement classification algorithms on our newly collected annotated data set, we found that the most recent algorithms perform very well on average, and even reach human-level labelling quality for fixations and saccades, but all have a much larger room for improvement when it comes to smooth pursuit classification. The data set is made available at https://gin.g- node.org/ioannis.agtzidis/hollywood2_em.
Microsaccadic rate signatures correlate under monocular and binocular stimulation conditions
Authors: Essig Peter , Leube Alexander , Rifai Katharina , Wahl Siegfried
Published: February 2021

Microsaccades are involuntary eye movements occurring naturally during fixation. In this study, microsaccades were investigated under monocularly and binocularly stimulated conditions with respect to their directional distribution and rate signature, that refers to a curve reporting the frequency modulation of microsaccades over time. For monocular stimulation the left eye was covered by an infrared filter. In both stimulation conditions, participants fixated a Gabor patch presented randomly in orientation of 45° or 135° over a wide range of spatial frequencies appearing in the center of a monitor. Considering the microsaccadic directions, this study showed microsaccades to be preferably horizontally oriented in their mean direction, regardless of the spatial characteristics of the grating. Furthermore, this outcome was found to be consistent between both stimulation conditions. Moreover, this study found that the microsaccadic rate signature curve correlates between both stimulation conditions, while the curve given for binocular stimulation was already proposed as a tool for estimation of visual performance in the past.
Therefore, this study extends the applicability of microsaccades to clinical use, since parameters as contrast sensitivity, has been measured monocularly in the clinical attitude.
Objective measurement of nine gaze-directions using an eye-tracking device
Authors: Iwata Yo , Handa Tomoya , Ishikawa Hitoshi
Published: February 2021

Purpose: To investigate the usefulness and efficacy of a novel eye-tracking device that can objectively measure nine gaze-directions.
Methods: We measured each of the nine gaze-directions subjectively, using a conventional Hess screen test, and objectively, using the nine gaze-direction measuring device, and de-termined the correlation, addition error, and proportional error. We obtained two consecu-tive measurements of the nine gaze-directions using the newly developed device in healthy young people with exophoria and investigated the reproducibility of the measurements. We further measured the nine gaze-directions using a Hess screen test and the newly developed device in three subjects with cover test-based strabismus and compared the results.
Results: We observed that the objective measurements obtained with the newly developed gaze-direction measuring device had significant correlation and addition error compared to the conventional subjective method, and we found no proportional error. These measure-ments had good reproducibility.
Conclusion: The novel device can be used to observe delayed eye movement associated with limited eye movement in the affected eye, as well as the associated excessive movement of the healthy eye in patients with strabismus, similar to the Hess screen test. This is a useful device that can provide objective measurements of nine gaze-directions.
Parafoveal-on-foveal effects are not an artifact of mislocated saccades
Authors: Kennedy Allan
Published: February 2021

Oculomotor error leads to a proportion of saccades during reading missing the intended target. In this paper two kinds of mislocation are identified: either a word is erroneously refixated, or a word that was about to skipped is erroneously fixated. In both cases recorded fixation duration could be influenced by the fact that the overt fixation reflects neither the reader’s intentions, not the current locus of attention. It has been argued that mislocations of this kind account for apparent “parafoveal-on-foveal” interactions and that, consequently, the challenge posed by such effects for serial processing models of eye movement control is more apparent than real. It is argued here that this analysis is flawed: mislocated fixations cannot plausibly act within the architecture of a serial model to produce effects mimicking parafoveal-on-foveal cross-talk. The claim that parafoveal-on-foveal effects are restricted to measurements made when the eyes are very close to the relevant parafoveal target is not supported in an analysis of the effects of cumulative lexical frequency on foveal processing time.
Conditional co-occurrence probability acts like frequency in predicting fixation durations
Authors: Ong James K. Y. , Kliegl Reinhold
Published: February 2021

The predictability of an upcoming word has been found to be a useful predictor in eye movement research, but is expensive to collect and subjective in nature. It would be desirable to have other predictors that are easier to collect and objective in nature if these predictors were capable of capturing the information stored in predictability. This paper contributes to this discussion by testing a possible predictor: conditional co-occurrence probability. This measure is a simple statistical representation of the relatedness of the current word to its context, based only on word co-occurrence patterns in data taken from the Internet. In the regression analyses, conditional co-occurrence probability acts like lexical frequency in predicting fixation durations, and its addition does not greatly improve the model fits. We conclude that readers do not seem to use the information contained within conditional co-occurrence probability during reading for meaning, and that similar simple measures of semantic relatedness are unlikely to be able to replace predictability as a predictor for fixation durations. Keywords: Co-occurrence probability, Cloze predictability, frequency, eye movement, fixation duration.
Fixation sequences in imagery and in recognition during the processing of pictures of real-world scenes
Authors: Humphrey Katherine , Underwood Geoffrey
Published: February 2021

Thirty photographs of real-world scenes were presented for encoding, and half the participants then performed a recognition test, deciding whether each of 60 images were old (from the original set) or new. The other participants performed an imagery task immediately after encoding each of the 30 images. After completing this task, the recognition group then performed the imagery task in response to prompts that were unique verbal descriptors, and the imagery group performed the recognition task. All participants returned 2 days later, and repeated the imagery test. Eye movements were recorded during all phases. Differences in average fixation duration, average number of fixations and average saccadic amplitude were found between task groups and between experimental phases. Scan patterns were compared with a string-editing algorithm. Close similarities were observed between experimental phases that involved more similar tasks (e.g., initial encoding vs. recognition, and immediate imagery vs. delayed imagery). Scan patterns were equally similar when the task was presented immediately or after 2 days. We propose that the more similar the encoding and retrieval processes are, the more similar eye movements will be at each of these experimental stages.
Editorial
Authors: Pannasch Sebastian , Helmert Jens R. , Velichkovsky Boris M.
Published: February 2021

Editorial to the Special Issue on Eye tracking and Usability Research
Gaze Tracking in Semi-Autonomous Grasping
Authors: Castellini Claudio
Published: February 2021

In critical human/robotic interactions such as, e.g., teleoperation by a disabled master or with insufficient bandwidth, it is highly desirable to have semi-autonomous robotic artifacts interact with a human being. Semi-autonomous grasping, for instance, consists of having a smart slave able to guess the master’s intentions and initiating a grasping sequence whenever the master wants to grasp an object in the slave’s workspace. In this paper we investigate the possibility of building such an intelligent robotic artifact by training a machine learning system on data gathered from several human subjects while trying to grasp objects in a teleoperation setup. In particular, we investigate the usefulness of gaze tracking in such a scenario. The resulting system must be light enough to be usable on-line and flexible enough to adapt to different masters, e.g., elderly and/or slow. The outcome of the experiment is that such a system, based upon Support Vector Machines, meets all the requirements, being (a) highly accurate, (b) compact and fast, and (c) largely unaffected by the subjects’ diversity. It is also clearly shown that gaze tracking significantly improves both the accuracy and compactness of the obtained models, if compared with the use of the hand position alone. The system can be trained with something like 3.5 minutes of human data in the worst case.task is neutral.
On object selection in gaze controlled environments
Authors: Huckauf Anke , Urbina Mario H.
Published: February 2021

In the past twenty years, gaze control has become a reliable alternative input method not only for handicapped users. The selection of objects, however, which is of highest importance and of highest frequency in computer control, requires explicit control not inherent in eye movements. Objects have been therefore usually selected via prolonged fixations (dwell times). Dwell times seemed to be for many years the unique reliable method for selection. In this paper, we review pros and cons of classical selection methods and novel metaphors, which are based on pies and gestures. The focus is on the effectiveness and efficiency of selections. In order to estimate the potential of current suggestions for selection, a basic empirical comparison is recommended.
Gaze Path Stimulation in Retrospective Think-Aloud
Authors: Hyrskykari Aulikki , Ovaska Saila , Majaranta Pävi , Räihä Kari-Jouko , Lehtinen Merja
Published: February 2021

For a long time, eye tracking has been thought of as a promising method for usability testing. During the last couple of years, eye tracking has finally started to live up to these expectations, at least in terms of its use in usability laboratories. We know that the user’s gaze path can reveal usability issues that would otherwise go unnoticed, but a common understanding of how best to make use of eye movement data has not been reached. Many usability practitioners seem to have intuitively started to use gaze path replays to stimulate recall for retrospective walk through of the usability test. We review the research on thinkaloud protocols in usability testing and the use of eye tracking in the context of usability evaluation. We also report our own experiment in which we compared the standard, concurrent think-aloud method with the gaze path stimulated retrospective think-aloud method. Our results suggest that the gaze path stimulated retrospective think-aloud method produces more verbal data, and that the data are more informative and of better quality as the drawbacks of concurrent think-aloud have been avoided.
Eye Movements in Reading: Models and Data
Authors: Rayner Keith
Published: February 2021

Models of eye movement control in reading and their impact on the field are discussed. Differences between the E-Z Reader model and the SWIFT model are reviewed, as are benchmark data that need to be accounted for by any model of eye movement control. Predictions made by the models and how models can sometimes account for counterintuitive findings are also discussed. Finally, the role of models and data in further understanding the reading process is considered.
Eye fixations to figures in a four-choice situation with luminance balanced areas: Evaluating practice effects
Authors: Pessôa Candido V. B. B. , Huziwara Edson M. , Perez William F. , Endemann Peter , Tomanari Gerson Y.
Published: February 2021

Contingency analyses of eye movements may reveal variables that are relevant to the stimulus control of observing behavior. The present research tracked the eye movements of four adults exposed to a simultaneous discrimination among four stimuli, two two-dimensional (square and circle) and two three-dimensional (cube and cylinder) mono-chromatic figures with approximately equal luminance. On each discrimination trial, the stimuli were displayed in the four corners of a video monitor and participants chose among them by pressing corresponding keys. For two participants, choosing either cube or square (S+) was followed by the word “correct” and a 3-second inter-trial interval. Alternatively, choosing either cylinder or circle (S-) was followed by "incorrect" and a 30-second inter-trial interval. For the other two participants, contingencies were reversed. The position of the stimuli on the screen varied randomly across trials. The procedure continued for 80 trials. During these trials, discriminated choices were established. Despite the presence of both a two- and a three-dimensional S+ on each trial, responses to the three-dimensional S+ tended to prevail. Although general eye fixations tended to decrease as discrimination was established, subjects tended to observe S+ for longer durations than S-. Characteristics of the stimuli may interact with the contingencies of reinforcement in the stimulus control of observing behavior.
Quick Models for Saccade Amplitude Prediction
Authors: Komogortsev Oleg V. , Ryu Young Sam , Koh Do H.
Published: February 2021

This paper presents a new saccade amplitude prediction model. The model is based on a Kalman filter and regression analysis. The aim of the model is to predict a saccade’s am-plitude extremely quickly, i.e., within two eye position samples at the onset of a saccade. Specifically, the paper explores saccade amplitude prediction considering one or two sam-ples at the onset of a saccade. The models’ prediction performance was tested with 35 subjects. The amplitude accuracy results yielded approximately 5.26° prediction error, while the error for direction prediction was 5.3% for the first sample model and 1.5% for the two samples model. The practical use of the proposed model lays in the area of real-time gaze-contingent compression and extreme eye-gaze aware interaction applications. The paper provides theoretical evaluation of the benefits of saccade amplitude prediction to the gaze-contingent multimedia compression, estimating a 21% improvement in com-pression for short network delays.
Microsaccades under monocular viewing conditions
Authors: Kloke Wilhelm Bernhard , Jaschinski Wolfgang , Jainta Stephanie
Published: February 2021

Among the eye movements during fixation, the function of small saccades occuring quite commonly at fixation is still unclear. It has been reported that a substantial number of these microsaccades seem to occur in only one of the eyes. The aim of the present study is to investigate microsaccades in monocular stimulation conditions. Although this is an artificial test condition which does not occur in natural vision, this monocular presentation paradigm allows for a critical test of a presumptive monocular mechanism of saccade generation. Results in these conditions can be compared with the normal binocular stimulation mode. We checked the statistical properties of microsaccades under monocular stimulation conditions and found no indication for specific interactions for monocularly detected small saccades, which might be present if they were based on a monocular physiological activation mechanism.
Eye movements and attention in visual feature search with graded target-distractor-similarity
Authors: Wienrich Carolin , Heße Uta , Müller-Plath Gisela
Published: February 2021

We conducted a visual feature search experiment in which we varied the target-distractor-similarity in four steps, the number of items (4, 6, and 8), and the presence of the target. In addition to classical search parameters like error rate and reaction time (RT), we analyzed saccade amplitudes, fixation durations, and the portion of reinspections (recurred fixation on an item with at least one different item fixated in between) and refixations (recurred fixation on an item without a different item fixated in between) per trial. When target-distractor-similarity was increased, more errors and longer RTs were observed, accompa-nied by shorter saccade amplitudes, longer fixation durations, and more reinspec-tions/refixations. An increasing set size resulted in longer saccade amplitudes and shorter fixation durations. Finally, in target absent trials we observed more reinspections than refixations, whereas in target present trials refixations were more frequent than reinspec-tions. The results on saccade amplitude and fixation duration support saliency-based search theo-ries that assume an attentional focus variable in size according to task demands and a vari-able attentional dwell time. Reinspections and refixations seem to be rather a sign of in-complete perceptual processing of items than being due to memory failure.
A statistical mixture method to reveal bottom-up and top-down factors guiding the eye-movements
Authors: Couronné Thomas , Guérin-Dugué Anne , Dubois Michel , Faye Pauline , Marendaz Christian
Published: February 2021

When people gaze at real scenes, their visual attention is driven both by a set of bottom-up processes coming from the signal properties of the scene and also from top-down effects such as the task, the affective state, prior knowledge, or the semantic context. The context of this study is an assessment of manufactured objects (here car cab interior). From this dedicated context, this work describes a set of methods to analyze the eye-movements during the visual scene evaluation. But these methods can be adapted to more general contexts. We define a statistical model to explain the eye fixations measured experimentally by eye-tracking even when the ratio signal/noise is bad or lacking of raw data. One of the novelties of the approach is to use complementary experimental data obtained with the “Bubbles” paradigm. The proposed model is an additive mixture of several a priori spatial density distributions of factors guiding visual attention. The “Bubbles” paradigm is adapted here to reveal the semantic density distribution which represents here the cumulative effects of the top-down factors. Then, the contribution of each factor is compared depending on the product and on the task, in order to highlight the properties of the visual attention and the cognitive activity in each situation.
“Trait” and “state” aspects of fixation disparity during reading
Authors: Jainta Stephanie , Jaschinski Wolfgang
Published: February 2021

In our study, 14 subjects read 60 sentences from the Potsdam Sentence Corpus twice (viewing distance: 60 cm), while eye movements were measured with the EyeLink II. We analyzed fixation disparities for complete sentence replications (N=388). After subtracting the average fixation disparity of each sentence from each observation (which gave the “state” fixation disparity), 99% of all remaining fixation disparities were aligned, i.e. smaller than one character width (20 min arc) – depending mostly on incoming saccade amplitude and fixation position. Additionally, we measured the heterophoria for each subject during calibration and found a qualitative relationship between average, individual measures of fixation disparity (“trait” fixation disparity) and heterophoria, after dividing the sample in 3 groups of esophore, exophore and orthophore subjects. We showed that the magnitude of “trait” fixation disparity was biased by the direction of heterophoria: the more eso the heterophoria, the more eso the average sentence fixation disparity. In sum, despite a large “trait” fixation disparity (in the range of -6.6 to +33.6 min arc), “state” fixation disparities within a sentence were on average -0.9 (± 8.7) min arc and, thus, as precise as needed, i.e. within the expected extent of Panum’s area.
What determines the direction of microsaccades?
Authors: Hermens Frouke , Walker Robin
Published: February 2021

During visual fixation, our eyes are not entirely still. Instead, small eye movements, such as microsaccades, can be observed. We here investigate what determines the direction and frequency of these microsaccades, as this information might help to clarify what purpose they serve. The relative contribution of three possible factors was examined: (1) the orienting of covert attention, (2) the spatial distribution of possible target locations, and (3) whether monocular or binocular microsaccades are considered. The orienting of covert attention and the distribution of possible target locations had a relatively weak effect on microsaccade rates and directions. In contrast, the classification of micro-saccades as binocular (occurring in both eyes simultaneously) or monocular (observed in one eye only) strongly affected both the rate and the direction of microsaccades. The results are discussed in the context of existing findings.
This is it ! : Indicating and looking in collaborative work at distance
Authors: Cherubini Mauro , Nüssli Marc-Antoine , Dillenbourg Pierre
Published: February 2021

Little is known of the interplay between deixis and eye movements in remote collaboration. This paper presents quantitative results from an experiment where participant pairs had to collaborate at a distance using chat tools that differed in the way messages could be enriched with spatial information from the map in the shared workspace. We studied how the availability of what we defined as an Explicit Referencing mechanism (ER) affected the coordination of the eye movements of the participants. The manipulation of the availability of ER did not produce any significant difference on the gaze coupling. However, we found a primary relation between the pairs recurrence of eye movements and their task performance. Implications for design are discussed.
The contribution of interference control for young children`s working memory performance: Insights from eye-tracking
Authors: Roebers Claudia M. , Schmid Corinne , Roderer Thomas
Published: February 2021

In the present study, the role of visual attentional processes for working memory performance in a sample of 6-year-olds was investigated. This was done by combining an individual differences approach with an experimental manipulation: For the individual differences approach, participants were grouped based on their performance in a classical interference control task, and their working memory skills were systematically compared. For the experimental manipulation, the need to control interference while performing a working memory task was increased in one condition through presentation of distracting stimuli. In a between-subject design performance in this condition was contrasted with a control condition without distractors. Additionally, fixation time during stimuli presentation were quantified by tracking participants` gazes. Results revealed that children with higher interference control skills showed superior working memory performance. Increasing the need to inhibit attention towards task-irrelevant information through presentation of distractors decreased working memory performance. The present study offers supporting evidence for a close relationship between young children`s working memory and attention.
The Effects of Age-of-Acquisition on Ambiguity Resolution: Evidence from Eye Movements
Authors: Juhasz Barbara J. , Gullick Margaret M. , Shesler Leah W.
Published: February 2021

Words that are rated as acquired earlier in life receive shorter fixation durations than later acquired words, even when word frequency is adequately controlled (Juhasz & Rayner, 2003; 2006). Some theories posit that age-of-acquisition (AoA) affects the semantic representation of words (e.g., Steyvers & Tenenbaum, 2005), while others suggest that AoA should have an influence at multiple levels in the mental lexicon (e.g. Ellis & Lambon Ralph, 2000). In past studies, early and late AoA words have differed from each other in orthography, phonology, and meaning, making it difficult to localize the influence of AoA. Two experiments are reported which examined the locus of AoA effects in reading. Both experiments used balanced ambiguous words which have two equally-frequent meanings acquired at different times (e.g. pot, tick). In Experiment 1, sentence context supporting either the early- or late-acquired meaning was presented prior to the ambiguous word; in Experiment 2, disambiguating context was presented after the ambiguous word. When prior context disambiguated the ambiguous word, meaning AoA influenced the processing of the target word. However, when disambiguating sentence context followed the ambiguous word, meaning frequency was the more important variable and no effect of meaning AoA was observed. These results, when combined with the past results of Juhasz and Rayner (2003; 2006) suggest that AoA influences access to multiple levels of representation in the mental lexicon. The results also have implications for theories of lexical ambiguity resolution, as they suggest that variables other than meaning frequency and context can influence resolution of noun-noun ambiguities.
Microsaccades and Exploratory Saccades in a Naturalistic Environment
Authors: Benedetto Simone , Pedrotti Marco , Bridgeman Bruce
Published: February 2021

Microsaccades, small saccadic eye movements made during fixation, might accompany shifts of visual attention, serve to refresh the retinal image, or have some other function. We tested the relative importance of these functions by recording exploratory saccades and microsaccades with a free head during a lane-change task in a simulated driving environment, accompanied by a simultaneous visual search task in which drivers searched for a target among similar distractors on a panel to the driver's right where an electronic display would normally be located. After training, observers performed a baseline run with the lane-change task only, followed by four dual-task runs and a final control run. In the dual-task condition, where more visual attention shifts occur, we found a significantly increased frequency of microsaccades along with an even larger increase in frequency of large exploratory saccades. However the proportion of microsaccades significantly decreased in the dual task, consistent with the idea of a common neurological origin for microsaccades and exploratory saccades.
A simple way to estimate similarity between pairs of eye movement sequences
Authors: Mathôt Sebastiaan , Cristino Filipe , Gilchrist Iain D. , Theeuwes Jan
Published: February 2021

We propose a novel algorithm to estimate the similarity between a pair of eye movement sequences. The proposed algorithm relies on a straight-forward geometric representation of eye movement data. The algorithm is considerably simpler to implement and apply than existing similarity measures, and is particularly suited for exploratory analyses. To validate the algorithm, we conducted a benchmark experiment using realistic artificial eye movement data. Based on similarity ratings obtained from the proposed algorithm, we defined two clusters in an unlabelled set of eye movement sequences. As a measure of the algorithm's sensitivity, we quantified the extent to which these data-driven clusters matched two pre-defined groups (i.e., the 'real' clusters). The same analysis was performed using two other, commonly used similarity measures. The results show that the proposed algorithm is a viable similarity measure.
Individual Differences in Eye-Movements During Reading: Working Memory and Speed-of-Processing Effects
Authors: Traxler Matthew J. , Johns Clinton L. , Long Debra L. , Zirnstein Megan , Tooley Kristen M. , Jonathan Eunike
Published: February 2021

Mathematical models of eye-movement control do not yet incorporate individual differences as a source of variation in reading. These models nonetheless provide an excellent foundation for describing and explaining how and why patterns of eye-movements differ across readers (e.g., Rayner et al., 2006). We focus in this article on two aspects of individual variation: global processing speed (e.g., Salthouse, 1996) and working-memory capacity (e.g., Just & Carpenter, 1992). Using Hierarchical Linear Modeling (HLM) (Raudenbush & Bryk, 2001), we tested the extent to which overall reading speed and working-memory capacity moderate the degree to which syntactic and semantic information affect fixation times. We found that working-memory capacity interacted with sentence-characteristic variables only when processing speed was not included in the model.
Vergence tracking: a tool to assess oculomotor performance in stereoscopic displays
Authors: Neveu Pascaline , Philippe Matthieu , Priot Anne-Emmanuelle , Fuchs Philippe , Roumes Corinne
Published: February 2021

Oculomotor conflict induced between the accommodative and vergence components in stereoscopic displays represents an unnatural viewing condition. There is now some evidence that stereoscopic viewing may induce discomfort and changes in oculomotor parameters. The present study sought to measure oculomotor performance during stereoscopic viewing. Using a 3D stereo setup and an eye-tracker, vergence responses were measured during 20-min exposure to a virtual visual target oscillating in depth, which participants had to track. The results showed a significant decline in the amplitude of the in-depth oscillatory vergence response over time. We propose that eye-tracking provides a useful tool to objectively assess the timevarying alterations of the vergence system when using stereoscopic displays.
Assessment of Dual-Mode and Switched-Channel Models with Experimental Vergence Responses
Authors: Lee You Yun , Semmlow John L. , Alvarez Tara L.
Published: February 2021

Controversy exists in the literature regarding the basic neural control structure that mediates convergence responses. This study constructed and simulated two models, the switched-channel feedback model and the dual-mode model consisting of preprogrammed with feedback control. Models were constructed and compared to experimental data. The stimuli consisted of 2 deg and 4 deg vergence steps. Both closed- and open-loop settings were utilized. After parameter adjustment, both models could accurately simulate step responses from subjects having a range of response dynamics. The model with a preprogrammed element required less parameter modification when stimulus amplitude changed. Both models could accurately simulate some attributes of vergence; however, neither model could represent the modifications commonly observed within the transient portion of the vergence response.
It's all about the transient: Intra-saccadic onset stimuli do not capture attention
Authors: Mathôt Sebastiaan , Theeuwes Jan
Published: February 2021

An abrupt onset stimulus was presented while the participants' eyes were in motion. Because of saccadic suppression, participants did not perceive the visual transient that normally accompanies the sudden appearance of a stimulus. In contrast to the typical finding that the presentation of an abrupt onset captures attention and interferes with the participants' responses, we found that an intra-saccadic abrupt onset does not capture attention: It has no effect beyond that of increasing the set-size of the search array by one item. This finding favours the local transient account of attentional capture over the novel object hypothesis.