bluuebunny/crossref_metadata_2025 huggingface dataset:
Error Correction in Vergence Eye Movements: Evidence Supporting Hering’s Law
Authors: Semmlow John L. , Alvarez Tara L. , Granger-Donetti Bérangère
Published: February 2021

In pure symmetrical vergence eye movements, a fusion initiating component quickly brings the eyes close to the desired position. A small error usually remains after this response which must be corrected to attain the small final vergence error (i.e., fixation disparity). Error correction will usually involve both version and version movements so possible mechanisms include: small saccades, smooth pursuit, symmetrical vergence, or some combination. Alternatively, an asymmetrical vergence or uniocular slow eye movement could be used to achieve the highly precise final position. Saccade-free late fusion sustaining components during the steady state to a symmetrical vergence step stimulus are analyzed using independent component analysis. Results suggest that fine correction is most likely the product of closely coordinated version and vergence components.
LCD vs. E-ink: An Analysis of the Reading Behavior
Authors: Siegenthaler Eva , Schmid Laura , Wyss Michael , Wurtz Pascal
Published: February 2021

Electronic books (e-book) are an interesting option compared to classic paper books. Most e-reading devices of the first generation were based on e-ink technology. With the appearance of the Apple iPad on the market, TFT-LCDs became important in the field of e-reading. Both technologies have advantages and disadvantages but the question remains whether one or the other technology is better for reading. In the present study we analyzed and compared reading behavior when reading on e-inkreader (e-ink displays) and on tablets (TFT-LCDs) as measured by eye-tracking. The results suggest that the reading behavior on tablets is indeed very similar to the reading behavior on e-ink-reader. Participants showed no difference in fixation duration. Significant differences in reading speed and in the proportion of regressive saccades suggest that tablets, under special artificial light conditions, may even provide better legibility.
Influence of soundtrack on eye movements during video exploration
Authors: Coutrot Antoine , Guyader Nathalie , Ionescu Gelu , Caplier Alice
Published: February 2021

Models of visual attention rely on visual features such as orientation, intensity or motion to predict which regions of complex scenes attract the gaze of observers. So far, sound has never been considered as a possible feature that might influence eye movements. Here, we evaluate the impact of non-spatial sound on the eye movements of observers watching videos. We recorded eye movements of 40 participants watching assorted videos with and without their related soundtracks. We found that sound impacts on eye position, fixation duration and saccade amplitude. The effect of sound is not constant across time but becomes significant around one second after the beginning of video shots.
Comparing scanpaths during scene encoding and recognition: A multi-dimensional approach
Authors: Foulsham Tom , Dewhurst Richard , Nyström Marcus , Jarodzka Halszka , Johansson Roger , Underwood Geoffrey , Holmqvist Kenneth
Published: February 2021

Complex stimuli and tasks elicit particular eye movement sequences. Previous research has focused on comparing between these scanpaths, particularly in memory and imagery research where it has been proposed that observers reproduce their eye movements when recognizing or imagining a stimulus. However, it is not clear whether scanpath similarity is related to memory performance and which particular aspects of the eye movements recur. We therefore compared eye movements in a picture memory task, using a recently proposed comparison method, MultiMatch, which quantifies scanpath similarity across multiple dimensions including shape and fixation duration. Scanpaths were more similar when the same participant’s eye movements were compared from two viewings of the same image than between different images or different participants viewing the same image. In addition, fixation durations were similar within a participant and this similarity was associated with memory performance.
On the Structure of Measurement Noise in Eye-Tracking
Authors: Coey Charles A. , Wallot Sebastian , Richardson Michael J. , Orden Guy Van
Published: February 2021

Past research has discovered fractal structure in eye movement variability and interpreted this result as having theoretical ramifications. No research has, however, investigated how properties of the eye-tracking instrument might affect the structure of measurement varia-bility. The current experiment employed fractal and multifractal methods to investigate whether an eye-tracker produced intrinsic random variation and how features of the data recording procedure affected the structure measurement variability. The results of this experiment revealed that the structure of variation from a fake eye was indeed random and uncorrelated in contrast to the fractal structure from a fixated, real human eye. Moreover, the results demonstrated that data-averaging generally changes the structure of variation, introducing spurious structure into eye movement variability.
Do you look where I look? Attention shifts and response preparation following dynamic social cues
Authors: Hermens Frouke , Walker Robin
Published: February 2021

Studies investigating the effects of observing a gaze shift in another person often apply static images of a person with an averted gaze, while measuring response times to a peripheral target. Static images, however, are unlike how we normally perceive gaze shifts of others. Moreover, response times might only reveal the effects of a cue on covert attention and might fail to uncover cueing effects on overt attention or response preparation. We therefore extended the standard paradigm and measured cueing effects formore realistic, dynamic cues (video clips),while comparing response times, saccade direction errors and saccade trajectories. Three cues were compared: A social cue, consisting of a eye-gaze shift, and two socially less relevant cues, consisting of a head tilting movement and a person walking past. Similar results were found for the two centrally presented cues (eye-gaze shift and head tilting) on all three response measures, suggesting that cueing is unaffected by the social status of the cue. Interestingly, the cue showing a person walking past showed a dissociation in the direction of the effects on response times on the one hand, and saccade direction errors and latencies on the other hand, suggesting the involvement of two types of (endogenous and exogenous) attention or a distinction between attention and sacadic response preparation. Our results suggest that by using dynamic cues and multiple response measures, properties of cueing can be revealed that would not be found otherwise.
Parsing eye movement analysis of scanpaths of naïve viewers of art: How do we differentiate art from non-art pictures?
Authors: Zangemeister Wolfgang H. , Privitera Claudio
Published: February 2021

Relating to G. Buswell’s early work we posed the questions: How do art-naïve people look at pairs of artful pictures and similarly looking snapshots? Does the analysis of their eye movement recordings reveal a difference in their perception? Parsing eye scanpaths using string editing, similarity coefficients can be sorted out and represented for the two measures ‘Sp’ (Similarities of position) and ‘Ss’ (Similarities of sequences). 25 picture pairs were shown 5 times to 7 subjects with no specific task, who were ‘art-naïve’ to avoid confounding of the results through specific art knowledge of the subjects. A significant difference between scanpaths of artful pictures compared to snapshots was not found in our subjects´ repeated viewing sessions. Auto-similarity (same subject viewing the same picture) and cross-similarity (different subjects viewing the same picture) significantly demonstrated this result, for sequences of eye fixations (Ss) as well as their positions (Sp): In case of global (different subjects and different pairs) sequential similarity Ss we found that about 84 percent of the picture pairs where viewed with very low similarity, in quasi random mode within the range of random values. Only in 4 out of 25 artful-picture snapshot pairs was a high similarity found. A specific restricted set of representative regions in the internal cognitive model of the picture is essential for the brain to perceive and eventually recognize the picture: This representative set is quite similar for different subjects and different picture pairs independently of their art–non art features that where in most cases not recognized by our subjects. Furthermore our study shows that the distinction of art versus non-art has vanished, causing confusion about the ratio of signal and noise in the communication between artists and viewers of art.
Tracking Visual Scanning Techniques in Training Simulation for Helicopter Landing
Authors: Robinski Maxi , Stein Michael
Published: February 2021

Research has shown no consistent findings about how scanning techniques differ between experienced and inexperienced helicopter pilots depending on mission demands. To explore this question, 33 military pilots performed two different landing maneuvers in a flight simulator. The data included scanning data (eye tracking) as well as performance, workload, and a self-assessment of scanning techniques (interviews). Fifty-four percent of scanning-related differences between pilots resulted from the factor combination of expertise and mission demands. A comparison of eye tracking and interview data revealed that pilots were not always clearly aware of their actual scanning techniques. Eye tracking as a feedback tool for pilots offers a new opportunity to substantiate their training as well as research interests within the German Armed Forces.
Dynamic programming for re-mapping noisy fixations in translation tasks
Authors: Carl Michael
Published: February 2021

Eyetrackers which allow for free head movements are in many cases imprecise to the extent that reading patterns become heavily distorted. The poor usability and interpretability of these gaze patterns is corroborated by a "naïve" fixation-to-symbol mapping, which often wrongly maps the possibly drifted center of the observed fixation onto the symbol directly below it. In this paper I extend this naïve fixation-to-symbol mapping by introducing background knowledge about the translation task. In a first step, the sequence of fixation-to-symbol mappings is extended into a lattice of several possible fixated symbols, including those on the line above and below the naïve fixation mapping. In a second step a dynamic programming algorithm applies a number of heuristics to find the best path through the lattice, based on the probable distance in characters, in words and in pixels between successive fixations and the symbol locations, so as to smooth the gazing path according to the background gazing model. A qualitative and quantitative evaluation shows that the algorithm increases the accuracy of the re-mapped symbol sequence.
Different types of sounds influence gaze differently in videos
Authors: Song Guanghan , Pellerin Denis , Granjon Lionel
Published: February 2021

This paper presents an analysis of the effect of different types of sounds on visual gaze when a person is looking freely at videos, which would be helpful to predict eye position. In order to test the effect of sound, an audio-visual experiment was designed with two groups of participants, with audio-visual (AV) and visual (V) conditions. By using statistical tools, we analyzed the difference between eye position of participants with AV and V conditions. We observed that the effect of sound is different depending on the kind of sound, and that the classes with human voice (i.e. speech, singer, human noise and singers) have the greatest effect. Furthermore, the results of the distance between sound source and eye position of the group with AV condition, suggested that only particular types of sound attract human eye position to the sound source. Finally, an analysis of the fixation duration between AV and V conditions showed that participants with AV condition move eyes more frequently than those with V condition.
Examining the visual screening patterns of emotional facial expressions with gender, age and lateralization
Authors: Cangöz Banu , Altun Arif , Aşkar Petek , Baran Zeynel , Mazman Sacide Güzin
Published: February 2021

The main objective of the study is to investigate the effects of age of model, gender of observer, and lateralization on visual screening patterns while looking at the emotional facial expressions. Data were collected through eye tracking methodology. The areas of interests were set to include eyes, nose and mouth. The selected eye metrics were first fixation duration, fixation duration and fixation count. Those eye tracking metrics were recorded for different emotional expressions (sad, happy, neutral), and conditions (the age of model, part of face and lateralization). The results revealed that participants looked at the older faces shorter in time and fixated their gaze less compared to the younger faces. This study also showed that when participants were asked to passively look at the face expressions, eyes were important areas in determining sadness and happiness, whereas eyes and noise were important in determining neutral expression. The longest fixated face area was on eyes for both young and old models. Lastly, hemispheric lateralization hypothesis regarding emotional face process was supported.
Eye movements in surgery : A literature review
Authors: Hermens Frouke , Flin Rhona , Ahmed Irfan
Published: February 2021

h recent advances in eye tracking technology, it is now possible to track surgeons’ eye movements while engaged in a surgical task or when surgical residents practice their surgical skills. Several studies have compared eye movements of surgical experts and novices, developed techniques to assess surgical skill on the basis of eye movements, and examined the role of eye movements in surgical training. We here provide an overview of these studies with a focus on the methodological aspects. We conclude that the different studies of eye movements in surgery suggest that the recording of eye movements may be beneficial both for skill assessment.
Combining EEG and Eye Tracking: Using Fixation-Locked Potentials in Visual Search
Authors: Winslow Brent , Carpenter Angela , Flint Jesse , Wang Xuezhong , Tomasetti David , Johnston Matthew , Hale Kelly
Published: February 2021

Visual search is a complex task that involves many neural pathways to identify relevant areas of interest within a scene. Humans remain a critical component in visual search tasks, as they can effectively perceive anomalies within complex scenes. However, this task can be challenging, particularly under time pressure. In order to improve visual search training and performance, an objective, process-based measure is needed. Eye tracking technology can be used to drive real-time parsing of EEG recordings, providing an indication of the analysis process. In the current study, eye fixations were used to generate ERPs during a visual search task. Clear differences were observed following performance, suggesting that neurophysiological signatures could be developed to prevent errors in visual search tasks.
Mapping the Pupil-Glint Vector to Gaze Coordinates in a Simple Video-Based Eye Tracker
Authors: Blignaut Pieter
Published: February 2021

In a video-based eye tracker, the normalized pupil-glint vector changes as the eyes move. Using an appropriate model, the pupil-glint vector can be mapped to gaze coordinates. Using a simple hardware configuration with one camera and one infrared source, several mapping functions – some from literature and some derived here – were compared with one another with respect to the accuracy that could be achieved. The study served to confirm the results of a previous study with another data set and to expand on the possibilities that are considered from the previous study. The data of various participants was examined for trends which led to derivation of a mapping model that proved to be more accurate than all but one model from literature. It was also shown that the best calibration configuration for this hardware setup is one that contains fourteen targets while taking about 20 seconds for the procedure to be completed.
Introduction to the PETMEI special issue
Authors: Bulling Andreas , Bednarik Roman
Published: February 2021

Latest developments in remote and head-mounted eye tracking and automated eye movement analysis point the way toward unobtrusive eye-based human-computer interfaces that will become pervasively usable in everyday life. We call this new paradigm pervasive eye tracking – continuous eye monitoring and analysis 24/7. Pervasive Eye Tracking and Mobile Eye-Based Interaction (PETMEI) is a workshop series that revolves around the theme of pervasive eye-tracking as a trailblazer for pervasive eye-based human-computer interaction and eye-based context-awareness. This special issue is composed from extended versions of the top-scoring papers from the 3rd workshop in the PETMEI series held in 2013.
A cheap portable eye-tracker solution for common setups
Authors: Ferhat Onur , Vilarino Fernando , Sanchez Francisco Javier
Published: February 2021

We analyze the feasibility of a cheap eye-tracker where the hardware consists of a single webcam and a Raspberry Pi device. Our aim is to discover the limits of such a system and to see whether it provides an acceptable performance. We base our work on the open source Opengazer (Zielinski, 2013) and we propose several improvements to create a robust, real-time system which can work on a computer with 30Hz sampling rate. After assessing the accuracy of our eye-tracker in elaborated experiments involving 12 subjects under 4 different system setups, we install it on a Raspberry Pi to create a portable stand-alone eye-tracker which achieves 1.42° horizontal accuracy with 3Hz refresh rate for a building cost of 70 Euros.
Evaluation of accurate eye corner detection methods for gaze estimation
Authors: Bengoechea Jose Javier , Cerrolaza Juan J. , Villanueva Arantxa , Cabeza Rafael
Published: February 2021

Accurate detection of iris center and eye corners appears to be a promising approach for low cost gaze estimation. In this paper we propose novel eye inner corner detection methods. Appearance and feature based segmentation approaches are suggested. All these methods are exhaustively tested on a realistic dataset containing images of subjects gazing at different points on a screen. We have demonstrated that a method based on a neural network presents the best performance even in light changing scenarios. In addition to this method, algorithms based on AAM and Harris corner detector present better accuracies than recent high performance face points tracking methods such as Intraface.
The inter-trial spatial biases of stimuli and goals in saccadic programming
Authors: Rastgardani Tara , Abegg Mathias , Barton Jason J S
Published: February 2021

Prior studies have shown an ‘alternate antisaccade-goal bias’, in that the saccadic landing points of antisaccades were displaced towards the location of antisaccade goals used in other trials in the same experimental block. Thus the motor response in one trial induced a spatial bias of a motor response in another trial. In this study we investigated whether sensory information, i.e. the location of a visual stimulus, might have a spatial effect on a motor response too. Such an effect might be attractive as for the alternate antisaccade-goal bias or repulsive. For this purpose we used block of trials with either antisaccades, prosaccades or mixed trials in order to study the alternate-trial biases generated by antisaccade goals, antisaccade stimuli, and prosaccade goals. in contrast to the effects of alternate antisaccade goals described in prior studies, alternate antisaccade stimuli generated a significant repulsive bias of about 1.8°: furthermore, if stimulus and motor goal coincide, as with an alternate prosaccade, the repulsive effect of a stimulus prevails, causing a bias of about 0.9°. Taken together with prior results, these findings may reflect averaging of current and alternate trial activity in a salience map, with excitatory activity from the motor response and inhibitory activity from the sensory input..
SMOOVS: Towards calibration-free text entry by gaze using smooth pursuit movements
Authors: Lutz Otto Hans-Martin , Venjakob Antje Christine , Ruff Stefan
Published: February 2021

Gaze-based text spellers have proved useful for people with severe motor diseases, but lack acceptance in general human-computer interaction. In order to use gaze spellers for public displays, they need to be robust and provide an intuitive interaction concept. However, traditional dwell- and blink-based systems need accurate calibration which contradicts fast and intuitive interaction. We developed the first gaze speller explicitly utilizing smooth pursuit eye movements and their particular characteristics. The speller achieves sufficient accuracy with a one-point calibration and does not require extensive training. Its interface consists of character elements which move apart from each other in two stages. As each element has a unique track, gaze following this track can be detected by an algorithm that does not rely on the exact gaze coordinates and compensates latency-based artefacts. In a user study, 24 participants tested four speed-levels of moving elements to determine an optimal interaction speed. At 300 px/s users showed highest overall performance of 3.34 WPM (without training). Subjective ratings support the finding that this pace is superior.
Accuracy and precision of fixation locations recorded with the low-cost Eye Tribe tracker in different experimental set-ups
Authors: Ooms Kristien , Dupont Lien , Lapon Lieselot , Popelka Stanislav
Published: February 2021

This article compares the accuracy and precision of the low-cost Eye Tribe tracker and a well-established comparable eye tracker: SMI RED 250. Participants were instructed to fixate on predefined point locations on a screen. The accuracy is measured by the distance between the recorded fixation locations and the actual location. Precision is represented by the standard deviation of these measurements. Furthermore, the temporal precision of both eye tracking devices (sampling rate) is evaluated as well. The obtained results illustrate that a correct set-up and selection of software to record and process the data are of utmost importance to obtain acceptable results with the low-cost device. Nevertheless, with careful selections in each of these steps, the quality (accuracy and precision) of the recorded data can be considered comparable.
Integration and prediction difficulty in Hindi sentence comprehension: Evidence from an eye-tracking corpus
Authors: Husain Samar , Vasishth Shravan , Srinivasan Narayanan
Published: February 2021

This is the first attempt at characterizing reading difficulty in Hindi using naturally occurring sentences. We created the Potsdam-Allahabad Hindi Eyetracking Corpus by recording eye-movement data from 30 participants at the University of Allahabad, India. The target stimuli were 153 sentences selected from the beta version of the Hindi-Urdu treebank. We find that word- or low-level predictors (syllable length, unigram and bigram frequency) affect first-pass reading times, regression path duration, total reading time, and outgoing saccade length. An increase in syllable length results in longer fixations, and an increase in word unigram and bigram frequency leads to shorter fixations. Longer syllable length and higher frequency lead to longer outgoing saccades. We also find that two predictors of sentence comprehension difficulty, integration and storage cost, have an effect on reading difficulty. Integration cost (Gibson, 2000) was approximated by calculating the distance (in words) between a dependent and head; and storage cost (Gibson, 2000), which measures difficulty of maintaining predictions, was estimated by counting the number of predicted heads at each point in the sentence. We find that integration cost mainly affects outgoing saccade length, and storage cost affects total reading times and outgoing saccade length. Thus, word-level predictors have an effect in both early and late measures of reading time, while predictors of sentence comprehension difficulty tend to affect later measures. This is, to our knowledge, the first demonstration using eye-tracking that both integration and storage cost influence reading difficulty.
Comparing graphs and text: Effects of complexity and task
Authors: Kim Sunjung , Lombardino Linda J.
Published: February 2021

Graphs are commonly believed to facilitate users’ compre-hension. We explored the effect of graphs on comprehension compared to text, manipulating content complexity (single bar vs. double bar graphs) and question type (point-locating vs. comparison questions). A total 78 college students viewed graph and text stimuli and answered comprehension questions while their eye movements were recorded. The results indicate that students do not always process graphs more efficiently than text conveying the same information. Students processed graphs significantly faster than text only when the more complex questions were shown. When the more complex graphic patterns were presented, the advantage of graphs over text became less apparent. The students also spent the majority of their time looking at specific information on the axes and label regions of the graphs with the increasing complexity of graphs and tasks. These findings are discussed related to theories of learning including cognitive load theory and perceptual salience theory.
How form and structure of Chinese characters affect eye movement control
Authors: Ma Min-Yuan , Chuang Hsien-Chih
Published: February 2021

This study investigated the correlations between the form features and legibility of Chinese characters by employing the eye tracking method in two experiments: Experiment 1 examined factors affecting Chinese character legibility with character modules and identified the correlations between character form and legibility of crossing strokes; and Experiment 2 examined the effect of crossing strokes on subjective complicacy perception in both Chinese characters and English letters. This study determined that enclosed Chinese characters affect subjective complicacy perception and reduce saccadic amplitude. In addition, greater number of stroke crossings produced higher subjective complicacy perceived for both Chinese characters and English letters. The results of this study serve as a reference for predicting Chinese character legibility and assessing type design superiority.
Simple Configuration Effects on Eye Movements in Horizontal Scanning Tasks
Authors: Laicane Ilze , Skilters Jurgis , Lacis Ivars
Published: February 2021

When reading text, observers alternate periods of stable gaze (fixations) and shifts of gaze (saccades). An important debate in the literature concerns the processes that drive the control of these eye movements. Past studies using strings of letters rather than meaningful text ('z-reading') suggest that eye movement control during reading is, to a large extent, controlled by low-level image properties. These studies, however, have failed to take into account perceptual grouping processes that could drive these low-level effects. We here study the role of various grouping factors in horizontal scanning eye movements, and compare these to reading meaningful text. The results show that sequential horizontal scanning of meaningless and visually distinctive stimuli is slower than for meaningful stimuli (e.g. letters instead of dots). Moreover, we found strong evidence for anticipatory processes in saccadic processing during horizontal scanning tasks. These results suggest a strong role of perceptual grouping in oculomotor control in reading.
An easy iris center detection method for eye gaze tracking system
Authors: Yu Mingxin , Lin Yingzi , Tang Xiaoying , Xu Jing , Schmidt David , Wang Xiangzhou , Guo Yikang
Published: February 2021

Iris center detection accuracy has great impact on eye gaze tracking system performance. This paper proposes an easy and efficient iris center detection method based on modeling the geometric relationship between the detected rough iris center and the two corners of the eye. The method fully considers four states of iris within the eye region, i.e. center, left, right, and upper. The proposed active edge detection algorithm is utilized to extract iris edge points for ellipse fitting. In addition, this paper also presents a predicted edge point algorithm to solve the decrease in ellipse fitting accuracy, when part of the iris becomes hidden from rolling into a nasal or temporal eye corner. The evaluated result of the method on our eye database shows the global average accuracy of 94.3%. Compared with existing methods, our method achieves the highest iris center detection accuracy. Additionally, in order to test the performance of the proposed method in gaze tracking, this paper presents the results of gaze estimation achieved by our eye gaze tracking system.
Abstracts of the 18th European Conference on Eye Movements 2015
Authors: Ansorge Ulrich , Ditye Thomas , Florack Arnd , Leder Helmut
Published: February 2021

This document contains all abstracts of the 18th European Conference on Eye Movements, August 16-21 2015 in Vienna, Austria
Program of the 18th European Conference on Eye Movements 2015
Authors: Ansorge Ulrich , Ditye Thomas , Florack Arnd , Leder Helmut
Published: February 2021

This document contains the Program of the 18th European Conference on Eye Movements, August 16-21 2015 in Vienna, Austria
Robust Head Mounted Wearable Eye Tracking System for Dynamical Calibration
Authors: Lanata Antonio , Valenza Gaetano , Greco Alberto , Scilingo Enzo Pasquale
Published: February 2021

In this work, a new head mounted eye tracking system is presented. Based on computer vision techniques, the system integrates eye images and head movement, in real time, performing a robust gaze point tracking. Nystagmus movements due to vestibulo-ocular reflex are monitored and integrated. The system proposed here is a strongly improved version of a previous platform called HATCAM, which was robust against changes of illumination conditions. The new version, called HAT-Move, is equipped with accurate inertial motion unit to detect the head movement enabling eye gaze even in dynamical conditions. HAT-Move performance is investigated in a group of healthy subjects in both static and dynamic conditions, i.e. when head is kept still or free to move. Evaluation was performed in terms of amplitude of the angular error between the real coordinates of the fixed points and those computed by the system in two experimental setups, specifically, in laboratory settings and in a 3D virtual reality (VR) scenario. The achieved results showed that HAT-Move is able to achieve eye gaze angular error of about 1 degree along both horizontal and vertical directions
Gaze transitions when learning with multimedia
Authors: Krejtz Krzysztof , Duchowski Andrew T. , Krejtz Izabela , Kopacz Agata , Chrząstowski-Wachtel Piotr
Published: February 2021

Eye tracking methodology is used to examine the influence of interactive multimedia on the allocation of visual attention and its dynamics during learning. We hypothesized that an interactive simulation promotes more organized switching of attention between different elements of multimedia learning material, e.g., textual description and pictorial visualization. Participants studied a description of an algorithm accompanied either by an interactive simulation, self-paced animation, or static illustration. Using a novel framework for entropy-based comparison of gaze transition matrices, results showed that the interactive simulation elicited more careful visual investigation of the learning material as well as reading of the problem description through to its completion.
Idiosyncratic Feature-Based Gaze Mapping
Authors: Blignaut Pieter
Published: February 2021

It is argued that polynomial expressions that are normally used for remote, video-based, low cost eye tracking systems, are not always ideal to accommodate individual differences in eye cleft, position of the eye in the socket, corneal bulge, astigmatism, etc. A procedure to identify a set of polynomial expressions that will provide the best possible accuracy for a specific individual is proposed.  It is also proposed that regression coefficients are recalculated in real-time, based on a subset of calibration points in the region of the current gaze and that a real-time correction is applied, based on the offsets from calibration targets that are close to the estimated point of regard.It was found that if no correction is applied, the choice of polynomial is critically important to get an accuracy that is just acceptable.  Previously identified polynomial sets were confirmed to provide good results in the absence of any correction procedure.  By applying real-time correction, the accuracy of any given polynomial improves while the choice of polynomial becomes less critical.  Identification of the best polynomial set per participant and correction technique in combination with the aforementioned correction techniques, lead to an average error of 0.32° (sd = 0.10°) over 134 participant recordings.The proposed improvements could lead to low-cost systems that are accurate and fast enough to do reading research or other studies where high accuracy is expected at framerates in excess of 200 Hz.
Examining the validity of the total dwell time of eye fixations to identify landmarks in a building
Authors: Viaene Pepijn , Vansteenkiste Pieter , Lenoir Matthieu , De Wulf Alain , De Maeyer Philippe
Published: February 2021

It is uncertain to what extent the duration of eye fixations reflects the use of landmarks during navigation. Therefore, a study was conducted in which eye tracking data and route descriptions were collected of 23 participants who were highly familiar with the indoor test environment. Based on the total fixation time on different landmark categories, two measures were calculated, namely the calculated landmark category use and the probable landmark category use. Based on the ratio between these measures an object was considered to be a landmark or not. The results were then compared with the objects referenced to in written route instructions. It can be concluded that promising results were provided by this method to identify landmarks. This landmark identification criterion strongly reflected the landmarks that came forward in the written route instructions. However, issues related to the identification of structural landmarks remain a problem.
Recurrence Metrics for Assessing Eye Movements in Perceptual Experiments
Authors: Farnand Susan , Vaidyanathan Preethi , Pelz Jeff B.
Published: February 2021

In a recent study evaluating the impact of image content on the consistency of eye movements in perceptual experiments (Farnand, 2013) image complexity was inversely related to scanpath consistency. This work involved a qualitative analysis of eye movements along with analysis of the number and duration of fixations. No quantitative analysis of scan path consistency was performed. Recently, Anderson et al. developed a quantitative tool - Recurrence Quantification Analysis - for analyzing eye movement patterns (Anderson et al., 2013). In the present study, the RQA method was applied to the fixation data of Farnand (2013). The results suggest that RQA analysis provides relevant quantitative information regarding the attentional focus of observers viewing pictorial images and, as such, a potentially powerfully tool for eye-tracking studies.
Pupil size affects measures of eye position in video eye tracking: implications for recording vergence accuracy
Authors: Jaschinski Wolfgang
Published: February 2021

Video eye trackers rely on the position of the pupil centre. However, the pupil centre can shift when the pupil size changes. This pupillary artifact is investigated for binocular vergence accuracy (i.e. fixation disparity) in near vision where the pupil is smaller in the binocular test phase than in the monocular calibration. A regression between recordings of pupil size and fixation disparity allows correcting the pupillary artefact. This corrected fixation disparity appeared to be favourable with respect to reliability and validity, i. e. the correlation of fixation disparity versus heterophoria. The findings provide a quantitative estimation of the pupillary artefact on measured eye position as function of viewing distance and luminance, both for measures of monocular and binocular eye position.
Do Graph Readers Prefer the Graph Type Most Suited to a Given Task? Insights from Eye Tracking
Authors: Strobel Benjamin , Saß Steffani , Lindner Marlit Annalena , Köller Olaf
Published: February 2021

Research on graph comprehension suggests that point differences are easier to read in bar graphs, while trends are easier to read in line graphs. But are graph readers able to detect and use the most suited graph type for a given task? In this study, we applied a dual repre-sentation paradigm and eye tracking methodology to determine graph readers’ preferential processing of bar and line graphs while solving both point difference and trend tasks. Data were analyzed using linear mixed-effects models. Results show that participants shifted their graph preference depending on the task type and refined their preference over the course of the graph task. Implications for future research are discussed.
A Focus on Selection for Fixation
Authors: Tsotsos John , Kotseruba Iuliia , Wloka Calden
Published: February 2021

A computational explanation of how visual attention, interpretation of visual stimuli, and eye movements combine to produce visual behavior, seems elusive. Here, we focus on one component: how selection is accomplished for the next fixation. The popularity of saliency map models drives the inference that this is solved, but we argue otherwise. We provide arguments that a cluster of complementary, conspicuity representations drive selection, modulated by task goals and history, leading to a hybrid process that encompasses early and late attentional selection. This design is also constrained by the architectural characteristics of the visual processing pathways. These elements combine into a new strategy for computing fixation targets and a first simulation of its performance is presented. A sample video of this performance can be found by clicking on the "Supplementary Files" link under the "Article Tools" heading.
Eye movements as a window to cognitive processes
Authors: König Peter , Wilming Niklas , Kietzmann Tim C. , Ossandón Jose P. , Onat Selim , Ehinger Benedikt V. , Gameiro Ricardo R. , Kaspar Kai
Published: February 2021

Eye movement research is a highly active and productive research field. Here we focus on how the embodied nature of eye movements can act as a window to the brain and the mind. In particular, we discuss how conscious perception depends on the trajectory of fixated locations and consequently address how fixation locations are selected. Specifically, we argue that the selection of fixation points during visual exploration can be understood to a large degree based on retinotopically structured models. Yet, these models largely ignore spatiotemporal structure in eye-movement sequences. Explaining spatiotemporal structure in eye-movement trajectories requires an understanding of spatiotemporal properties of the visual sampling process. With this in mind, we discuss the availability of external information to internal inference about causes in the world. We demonstrate that visual foraging is a dynamic process that can be systematically modulated either towards exploration or exploitation. For an analysis at high temporal resolution, we suggest a new method: The renewal density allows the investigation of precise temporal relation of eye movements and other actions like a button press. We conclude with an outlook and propose that eye movement research has reached an appropriate stage and can easily be combined with other research methods to utilize this window to the brain and mind to its fullest.
Learning to search. The importance of eye movements in the decrease of response times during a visual choice reaction time task
Authors: Kroll Aleksandra , Mak Monika , Samochowiec Jerzy
Published: February 2021

Reaction times are often used as an indicator of the efficiency of the processes in thecentral nervous system. While extensive research has been conducted on the possibleresponse time correlates, the role of eye movements in visual tasks is yet unclear. Here wereport data to support the role of eye movements during visual choice reaction time training.Participant performance, reaction times, and total session duration improved. Eyemovementsshowed expected changes in saccade amplitude and resulted in improvementin visual target searching.
Covert Attention Tracking: Towards Two-Dimensional Real-Time Recordings
Authors: Gregori Grgic Regina , De'Sperati Claudio
Published: February 2021

Achieving attention tracking as easily as recording eye movements is still beyond reach. However, by exploiting Steady-State Visual Evoked Potentials (SSVEPs) we could recently record in a satisfactory way the horizontal trajectory of covert visuospatial attention in single trials, both when attending target motion and during mental motion extrapolation. Here we show that, despite the different cortical functional architecture for horizontal and vertical motion processing, the same result is obtained for vertical attention tracking. Thus, it seems that trustworthy real-time two-dimensional attention tracking, with both physical and imagined target motion, is not a too far goal.
The Central Bias in Day-to-Day Viewing
Authors: Ioannidou Flora , Hermens Frouke , Hodgson Timothy L
Published: February 2021

Eye tracking studies have suggested that, when viewing images centrally presented on a computer screen, observers tend to fixate the middle of the image. This so-called `central bias' was later also observed in mobile eye tracking during outdoors navigation, where observers were found to fixate the middle of the head-centered video image. It is unclear, however, whether the extension of the central bias to mobile eye tracking in outdoors navigation may have been due to the relatively long viewing distances towards objects in this task and the constant turning of the body in the direction of motion, both of which may have reduced the need for large amplitude eye movements. To examine whether the central bias in day-to-day viewing is related to the viewing distances involved, we here compare eye movements in three tasks (indoors navigation, tea making, and card sorting), each associated with interactions with objects at different viewing distances. Analysis of gaze positions showed a central bias for all three tasks that was independent of the task performed. These results confirm earlier observations of the central bias in mobile eye tracking data, and suggest that differences in the typical viewing distance during different tasks have little effect on the bias. The results could have interesting technological applications, in which the bias is used to estimate the direction of gaze from head-centered video images, such as those obtained from wearable technology.
Effects of conversation content on viewing dyadic conversations
Authors: Hautala Jarkko , Loberg Otto , Hietanen Jari K , Nummenmaa Lauri , Astikainen Piia
Published: February 2021

People typically follow conversations closely with their gaze. We asked whether this viewing is influenced by what is actually said in the conversation and by the viewer’s psychological condition. We recorded the eye movements of healthy (N = 16) and depressed (N = 25) participants while they were viewing video clips. Each video showed two people, each speaking one line of dialogue about socio-emotionally important (i.e., personal) or unimportant topics (matter-of-fact). Between the spoken lines, the viewers made more saccadic shifts between the discussants, and looked more at the second speaker, in personal vs. matter-of-fact conversations. Higher depression scores were correlated with less looking at the currently speaking discussant. We conclude that subtle social attention dynamics can be detected from eye movements and that these dynamics are sensitive to the observer’s psychological condition, such as depression.
The effect of age on gaze behavior in drivers and pedestrians – a review
Authors: Ziv Gal , Lidor Ronnie
Published: February 2021

Gaze behavior can play an important role in the safety of both older drivers and older pedestrians, and therefore evidence-based knowledge related to gaze behavior in the older population should be communicated to those professionals who regularly work with this group. A review of 25 studies examining the effect of age on gaze behavior in drivers and pedestrians was conducted. A number of differences in gaze behavior in older and younger drivers and pedestrians are observed, among them (a) when changing lanes, older drivers do not glance as frequently as younger drivers at three important areas – the rear view mirror, the left side mirror, and the left blind spot, and (b) older drivers have a smaller horizontal gaze amplitude compared to younger drivers. Several methodological concerns were observed, among them: a scarcity of data on gaze behavior and elderly pedestrians and a lack of intervention studies. Additional studies should examine the use of a vision-in-action paradigm and designated gaze-training interventions in both the elderly driver and elderly pedestrian populations, in order to reduce the number of motor vehicle accidents and pedestrian injuries among the older population
Health and Well-Being Measures of Collegiate Athlete and Non-Athlete Graduates
Authors: DeFreese J.D. , Weight Erianne , Kerr Zachary , Kroshus Emily
Published: February 2021

American collegiate sport participation has been linked with psychosocial and career-related benefits as well as with mental and physical health risks, with extant research on this topic revealing mixed results. The study purpose was, informed by the Health through Sport Conceptual Model, to describe and compare associations among health related quality of life and psychosocial measures of former U.S. collegiate athletes and non-athletes from four university graduation cohorts. Results suggest on aggregate former collegiate athletes report more positive measures than their non-athlete peers. Study findings were, in some instances, mitigated/reversed when participants endorsed concussion, career ending injury or revenue sport participation histories or were female. Though limited by a cross-sectional design and a potential health worker effect, results provide some support for protective associations of collegiate athletics participation. This study also provides a theoretical bridge from intercollegiate athletics participation to broader sport promotion literatures.