Gaze Position Research Articles

Effect of juggling expertise on pointing performance in peripheral vision.

Juggling is a very complex activity requiring motor, visual and coordination skills. Expert jugglers experience a "third eye" monitoring leftward and rightward ball zenith positions alternately, in the upper visual fields, while maintaining their gaze straight-ahead. This "third eye" reduces their motor noise (improved body stability and decrease in hand movement variability) as it avoids the numerous head and eye movements that add noise into the system and make trajectories more uncertain. Neuroimaging studies have shown that learning to juggle induces white and grey matter hypertrophy at the posterior intraparietal sulcus. Damage to this brain region leads to optic ataxia, a clinical condition characterised by peripheral pointing bias toward gaze position. We predicted that expert jugglers would, conversely, present better accuracy in a peripheral pointing task. The mean pointing accuracy of expert jugglers was better for peripheral pointing within the upper visual field, compatible with their subjective experience of the "third eye". Further analyses showed that experts exhibited much less between-subject variability than beginners, reinforcing the interpretation of a vertically asymmetrical calibration of peripheral space, characteristic of juggling and homogenous in the expert group. On the contrary, individual pointing variability did not differ between groups neither globally nor in any sector of space, showing that the reduced motor noise of experts in juggling did not transfer to pointing. It is concluded that the plasticity of the posterior intraparietal sulcus related to juggling expertise does not consist of globally improved visual-to-motor ability. It rather consists of peripheral space calibration by practicing horizontal covert shifts of the attentional spotlight within the upper visual field, between left and right ball zenith positions.

Appearance-based Gaze Estimation with Deep Learning: A Review and Benchmark.

Human gaze provides valuable information on human focus and intentions, making it a crucial area of research. Recently, deep learning has revolutionized appearance-based gaze estimation. However, due to the unique features of gaze estimation research, such as the unfair comparison between 2D gaze positions and 3D gaze vectors and the different pre-processing and post-processing methods, there is a lack of a definitive guideline for developing deep learning-based gaze estimation algorithms. In this paper, we present a systematic review of the appearance-based gaze estimation methods using deep learning. Firstly, we survey the existing gaze estimation algorithms along the typical gaze estimation pipeline: deep feature extraction, deep learning model design, personal calibration and platforms. Secondly, to fairly compare the performance of different approaches, we summarize the data pre-processing and post-processing methods, including face/eye detection, data rectification, 2D/3D gaze conversion and gaze origin conversion. Finally, we set up a comprehensive benchmark for deep learning-based gaze estimation. We characterize all the public datasets and provide the source code of typical gaze estimation algorithms. This paper serves not only as a reference to develop deep learning-based gaze estimation methods, but also a guideline for future gaze estimation research. The project web page can be found at https://phi-ai.buaa.edu.cn/Gazehub/.

Leyenes: A gaze-based text entry method using linear smooth pursuit and target speed

Gaze-based writing is one of the most widespread eye tracking applications for human–computer interaction. While eye tracking communication has traditionally been employed as an assistive technology, declining prices of eye trackers now make it a feasible alternative to keyboards or touchscreens in many contexts (for example, the interaction with public info points). In this paper we propose Leyenes, a text entry method based on smooth pursuit, a natural eye movement that occurs when the gaze follows a moving target. Our approach requires no explicit calibration by the user, allowing for more spontaneous interaction and enabling eye input even when calibration is difficult to achieve or maintain. To the best of our knowledge, Leyenes is the first text entry technique based on smooth pursuit that considers both (approximate) gaze speed and position and employs a linear interface instead of the more common circular layouts. The results of the user study we conducted show that the proposed solution is slow but robust, with a very low error rate, which makes it particularly suitable for extemporaneous writing of short text.

The Influence of Phosphene Synchrony in Driving Object Binding in a Simulation of Artificial Vision.

Electrical microstimulation techniques used in visual prostheses are designed to restore visual function following acquired blindness. Patterns of induced focal percepts, known as phosphenes, are achieved by applying localized electrical pulses to the visual pathway to bypass the impaired site in order to convey images from the external world. Here, we use a simulation of artificial vision to manipulate relationships between individual phosphenes to observe the effects on object binding and perception. We hypothesize that synchronous phosphene presentation will facilitate object perception as compared to asynchronous presentation. A model system that tracks gaze position of normal, sighted participants to present patterns of phosphenes on a computer screen was used to simulate prosthetic vision. Participants performed a reading task at varying font sizes (1.1-1.4 logMAR) and under varying levels of phosphene temporal noise while reading accuracy and speed were measured. Reading performance was significantly affected by temporal noise in phosphene presentation, with increasing desynchronization leading to lower reading scores. A drop in performance was also observed when the total latency between the gaze position and phosphene update was increased without adding temporal noise. Object perception (here, text perception) is enhanced with synchronously presented phosphenes as compared to asynchronously presented ones. These results are fundamental for developing an efficient temporal pattern of stimulation and for the creation of high-fidelity prosthetic vision.

The Relationship Between Environmental Statistics and Predictive Gaze Behaviour During a Manual Interception Task: Eye Movements as Active Inference

AbstractHuman observers are known to frequently act like Bayes-optimal decision-makers. Growing evidence indicates that the deployment of the visual system may similarly be driven by probabilistic mental models of the environment. We tested whether eye movements during a dynamic interception task were indeed optimised according to Bayesian inference principles. Forty-one participants intercepted oncoming balls in a virtual reality racquetball task across five counterbalanced conditions in which the relative probability of the ball’s onset location was manipulated. Analysis of pre-onset gaze positions indicated that eye position tracked the true distribution of onset location, suggesting that the gaze system spontaneously adhered to environmental statistics. Eye movements did not, however, seek to minimise the distance between the target and foveal vision according to an optimal probabilistic model of the world and instead often reflected a ‘best guess’ about onset location. Trial-to-trial changes in gaze position were, however, found to be better explained by Bayesian learning models (hierarchical Gaussian filter) than associative learning models. Additionally, parameters relating to the precision of beliefs and prediction errors extracted from the participant-wise models were related to both task-evoked pupil dilations and variability in gaze positions, providing further evidence that probabilistic context was reflected in spontaneous gaze dynamics.

Acute acquired concomitant esotropia: May COVID-19 lockdowns have changed its presentation?

To evaluate the effects of COVID-19 lockdown in Italy on the features of Acute Acquired Concomitant Esotropia (AACE). Patients of the Polyclinic Hospital of Bari diagnosed with AACE between January 2018 and December 2021, subdivided in pre-lockdown group - diagnosed before March 2020 - and post-lockdown group. Medical records were reviewed, and statistical analysis performed. Deviation size was assessed in the 9 cardinal positions of gaze with refractive correction. Wilcoxon test for unpaired samples was used to compare data of age, near maximum deviation and best corrected visual acuity (BCVA) for each eye; Student's t test was used to compare far maximum deviation, difference far/near maximum deviation and spherical equivalent data. Fisher exact test was used to compare subtype cases (Bielschowsky vs Non-Bielschowsky) in the two groups. A p-value lower than 0.05 was considered statistically significant.The primary outcome measure was the difference in AACE subtypes between the two groups. Nineteen patients were included, of which 12 males (63.2%); 7 belong to the pre-lockdown group and 12 to the post-lockdown group. The difference in types between the two groups proved to be statistically significant (p = 0.01977).The differences in the mean of age, right BCVA, right spherical equivalent and mean spherical equivalent between the two groups proved to be statistically significant (p < 0.05). After the COVID-19 pandemic, the profile of the typical patient with AACE has probably changed, and now it is more probably myopic and elderly than before. Thus, we observed an increase in the Bielschowsky subtype.

Clinical Insights into Internuclear Ophthalmoplegia: A Case Report

Background: Internuclear ophthalmoplegia (INO) is a rare neuro-ophthalmological disorder characterized by impaired horizontal eye movement coordination due to lesion in the medial longitudinal fasciculus. INO commonly results from demyelinating diseases, vascular lesions, or structural brain abnormalities.&#x0D; Case presentation: A 60-year-old male patient presented with diplopia for the past 4 days. He had history of hypertension and diabetes mellitus and “mild” stroke for past years. Clinical examination revealed normal primary gaze, limited medial movement of the left eye, and diplopia in all gaze positions. Hess screen examination demonstrated underaction of the left medial rectus muscle and overaction of the right lateral rectus muscle. The laboratory results an elevated blood sugar level. Brain CT scan revealed multiple infarcts in the right parietal and cerebellar lobes and left parieto-occipital lobe, with evidence of brain atrophy. The patient was diagnosed with INO. Management involved addressing the underlying systemic diseases, namely diabetes and hypertension, in collaboration with internist and neurologist. The patient also received citicoline therapy and underwent regular follow-up. In the third-month follow-up, the patient demonstrated significant improvement, with reduction in diplopia and enhancement in left eye medial movement.&#x0D; Conclusion: This case report highlights the importance of considering INO in patients presenting with diplopia and a history of vascular risk factors. Timely diagnosis and comprehensive management with regular follow-up is crucial to monitor the progress and enhance the patient's quality of life.

Biometric Recognition Based on Recurrence Plot and InceptionV3 Model Using Eye Movements.

The ability to use eye movement signals as a feature in biometric recognition is a novel characteristic of biometric recognition technology. However, present technologies have not fully exploited the correlation features between eye movement signals. To address this, we propose an eye movement biometric recognition model that is based on recurrence plot encoding and the InceptionV3 model. We first encode the original eye movement signal using the recurrence plot to obtain a two-dimensional image that is then used as input for the InceptionV3 model to perform biometric recognition. Our experimental results using the GazeBaseV2.0 eye movement dataset demonstrate that our proposed model achieved a high biometric recognition accuracy of 96.58% ± 0.66% using the recurrence plot transformation of the horizontal gaze position signals and the InceptionV3 model, surpassing the accuracy achieved by other models. The use of horizontal gaze position eye movement signals for biometric recognition outperforms the use of vertical gaze position signals when using our proposed methods. Furthermore, the biometric recognition that is achieved through recurrent plot encoding is superior to that achieved using Markov transition fields and Gramian angular field transformations.

Astronauts eye-head coordination dysfunction over the course of twenty space shuttle flights.

Coordination of motor activity is adapted to Earth's gravity (1 g). However, during space flight the gravity level changes from Earth gravity to hypergravity during launch, and to microgravity (0 g) in orbit. This transition between gravity levels may alter the coordination between eye and head movements in gaze performance. We explored how weightlessness during space flight altered the astronauts' eye-head coordination (EHC) with respect to flight day and target eccentricity. Thirty-four astronauts of 20 Space Shuttle missions had to acquire visual targets with angular offsets of 20°, 30°, and 49°. Measurements of eye, head, and gaze positions collected before and during flight days 1 to 15 indicated changes during target acquisition that varied as a function of flight days and target eccentricity. The in-flight alterations in EHC were presumably the result of a combination of several factors, including a transfer from allocentric to egocentric reference for spatial orientation in absence of a gravitational reference, the generation of slower head movements to attenuate motion sickness, and a decrease in smooth pursuit and vestibulo-ocular reflex performance. These results confirm that humans have several strategies for gaze behavior, between which they switch depending on the environmental conditions.

Autism symptoms, functional impairments, and gaze fixation measured using an eye-tracker in 6-year-old children.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder clinically characterized by abnormalities in eye contact during social exchanges. We aimed to clarify whether the amount of gaze fixation, measured at the age of 6 years using Gazefinder, which is an established eye-tracking device, is associated with ASD symptoms and functioning. The current study included 742 participants from the Hamamatsu Birth Cohort Study. Autistic symptoms were evaluated according to the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2), and the functioning of the participating children in real life was assessed using the Japanese version of the Vineland Adaptive Behavior Scales, Second Edition (VABS-II). The Gazefinder system was used for gaze fixation rates; two areas of interest (eyes and mouth) were defined in a talking movie clip, and eye gaze positions were calculated through corneal reflection techniques. The participants had an average age of 6.06 ± 0.14 years (males: 384; 52%). According to ADOS, 617 (83%) children were assessed as having none/mild ASD and 51 (7%) as severe. The average VABS-II scores were approximately 100 (standard deviation = 12). A higher gaze fixation rate on the eyes was associated with a significantly lower likelihood of the child being assigned to the severe ADOS group after controlling for covariates (odds ratio [OR], 0.02; 95% confidence interval [CI], 0.002-0.38). The gaze fixation rate on the mouth was not associated with ASD symptoms. A higher gaze fixation rate on the mouth was associated with a significantly lower likelihood of the child being assigned to the low score group in VABS-II socialization after controlling for covariates (OR, 0.18; 95% CI, 0.04-0.85). The gaze fixation rate on the eyes was not associated with functioning. We found that children with low gaze fixation rates on the eyes were likely to have more ASD symptoms, and children with low gaze fixation rates on the mouth were likely to demonstrate poorer functioning in socialization. Hence, preschool children could be independently assessed in the general population for clinically relevant endophenotypes predictive of ASD symptoms and functional impairments.

The long-term outcomes of the Anderson-Kestenbaum procedure.

Nystagmus is an involuntary, conjugated, rhythmic movement of the eye that can be idiopathic or secondary to ocular or neurologic pathologies. Patients with nystagmus often have a position of gaze in which their symptoms are dampened or absent, referred to as the "null zone." The Anderson-Kestenbaum procedure is a bilateral recess-resect procedure of the four horizontal rectus muscles which aims to bring the null position into the primary gaze. This study aims to further elucidate long-term outcomes and factors associated with optimal postoperative outcomes. Patients with a diagnosis of nystagmus and a surgical code for strabismus between June 1990 and August 2017 were considered for inclusion in the study. Patients were included if they had undergone the Anderson-Kestenbaum procedure and had follow-up lasting at least 24 months post-operatively. Data collected included demographic information, characteristics of the nystagmus, underlying etiology of nystagmus, and pre-and post-operative measurements. 25 patients were included. At their last recorded follow-up, 44% of patients achieved an optimal surgical outcome -an abnormal head position of 10 degrees or less. 88% of patients showed an overall improvement in their head posture at the last follow-up. The absence of an abnormal head position at the visit closest to 24 months post-operatively was found to be significantly associated with the lack of a significant head position at the last follow-up visit. Optimal surgical outcomes were not significantly associated with the underlying diagnosis, the direction of the abnormal head position, or the type of nystagmus. The relatively long follow-up of this cohort allows this study to further elucidate the long-term outcomes of the Anderson-Kestenbaum procedure. Overall, our results suggest that although improvement in head position post-operatively is likely, it is still expected that many patients will have a residual abnormal head position after the procedure. The results of this study are helpful in counseling patients, especially knowing that if they do not have a significant head position at 24 months follow-up, they are unlikely to develop one. However, due to the small sample size, larger cohorts and more standardized follow-up may provide further insight into the procedure's outcomes.

Exploratory Development of Algorithms for Determining Driver Attention Status.

Varying driver distraction algorithms were developed using vehicle kinematics and driver gaze data obtained from a camera-based driver monitoring system (DMS). Distracted driving characteristics can be difficult to accurately detect due to wide variation in driver behavior across driving environments. The growing availability of information about drivers and their involvement in the driving task increases the opportunity for accurately recognizing attention state. A baseline for driver distraction levels was developed using a video feed of 24 separate drivers in varying naturalistic driving conditions. This initial assessment was used to develop four buffer-based algorithms that aimed to determine a driver's real-time attentiveness, via a variety of metrics and combinations thereof. Of those tested, the optimal algorithm included ungrouped glance locations and speed. Notably, as an algorithm's performance of detecting very distracted drivers improved, its accuracy for correctly identifying attentive drivers decreased. At a minimum, drivers' gaze position and vehicle speed should be included when designing driver distraction algorithms to delineate between glance patterns observed at high and low speeds. Distraction algorithms should be designed with an understanding of their limitations, including instances in which they may fail to detect distracted drivers, or falsely notify attentive drivers. This research adds to the body of knowledge related to driver distraction and contributes to available methods to potentially address and reduce occurrences. Machine learning algorithms can build on the data elements discussed to increase distraction detection accuracy using robust artificial intelligence.

Objective Diplopia Outcomes for Patients Treated With Teprotumumab for Thyroid Eye Disease.

Thyroid eye disease (TED) is a condition caused by inflammatory damage to the periocular tissue that often leads to double vision. Teprotumumab is an insulin-like growth factor 1 receptor antibody that was FDA approved for the management of TED in 2020, although much is yet to be elucidated regarding its effects on diplopia outcomes among patients with TED. Diplopia is a significant and life-altering effect of TED. Previous studies have reported the effect of teprotumumab on double vision subjectively using the Gorman diplopia score. However, there is a gap in the literature addressing the effect of teprotumumab treatment on objective ocular alignment measures. The purpose of our study was to address this gap. We performed a retrospective review of patients who were diagnosed with TED, presented with diplopia, and treated with teprotumumab in a single-center academic ophthalmology practice. The primary outcome was change in ocular alignment in primary gaze position at 6 months (completion of teprotumumab treatment). Secondary outcomes included change in ocular alignment in other gaze positions, proptosis, eyelid position, and clinical activity score (CAS) at 6 months compared with baseline. To determine what factors may predict ocular alignment response to teprotumumab, we analyzed baseline characteristics among 3 groups, divided based on whether ocular alignment was worsened, stable, or improved at 6 months. Seventeen patients met inclusion criteria, 3 (18%) worsened, 10 (59%) were stable, and 4 (24%) improved. CAS ( P = 0.02) was significantly different among the groups and was higher in those who worsened and those who improved compared with those who remained stable. Right gaze horizontal prism deviation ( P = 0.01) and left gaze horizontal prism deviation ( P = 0.03) were significantly different among the groups, with a greater degree of left gaze horizontal prism deviation in the worse group than the stable group ( P = 0.04). Our study demonstrated that most patients remained stable after teprotumumab treatment regarding ocular alignment in primary gaze and the number of patients who improved was slightly higher than the number of patients who worsened after teprotumumab treatment. There are some baseline measures, such as CAS and right and left gaze horizontal prism deviation that can help better predict how a patient will respond to teprotumumab treatment. Our results can better inform physicians of how to counsel patients with TED when considering teprotumumab therapy.

Tracking gaze position from EEG: Exploring the possibility of an EEG-based virtual eye-tracker.

Ocular artifact has long been viewed as an impediment to the interpretation of electroencephalogram (EEG) signals in basic and applied research. Today, the use of blind source separation (BSS) methods, including independent component analysis (ICA) and second-order blind identification (SOBI), is considered an essential step in improving the quality of neural signals. Recently, we introduced a method consisting of SOBI and a discriminant and similarity (DANS)-based identification method, capable of identifying and extracting eye movement-related components. These recovered components can be localized within ocular structures with a high goodness of fit (>95%). This raised the possibility that such EEG-derived SOBI components may be used to build predictive models for tracking gaze position. As proof of this new concept, we designed an EEG-based virtual eye-tracker (EEG-VET) for tracking eye movement from EEG alone. The EEG-VET is composed of a SOBI algorithm for separating EEG signals into different components, a DANS algorithm for automatically identifying ocular components, and a linear model to transfer ocular components into gaze positions. The prototype of EEG-VET achieved an accuracy of 0.920° and precision of 1.510° of a visual angle in the best participant, whereas an average accuracy of 1.008°±0.357° and a precision of 2.348°±0.580° of a visual angle across all participants (N=18). This work offers a novel approach that readily co-registers eye movement and neural signals from a single-EEG recording, thus increasing the ease of studying neural mechanisms underlying natural cognition in the context of free eye movement.

Reliability of gaze-contingent perimetry.

Standard automated perimetry, a psychophysical task performed routinely in eyecare clinics, requires observers to maintain fixation for several minutes at a time in order to measure visual field sensitivity. Detection of visual field damage is confounded by eye movements, making the technique unreliable in poorly attentive individuals and those with pathologically unstable fixation, such as nystagmus. Microperimetry, which utilizes 'partial gaze-contingency' (PGC), aims to counteract eye movements but only corrects for gaze position errors prior to each stimulus onset. Here, we present a novel method of visual field examination in which stimulus position is updated during presentation, which we refer to as 'continuous gaze-contingency' (CGC). In the first part of this study, we present three case examples that demonstrate the ability of CGC to measure the edges of the physiological blind spot in infantile nystagmus with greater accuracy than PGC and standard 'no gaze-contingency' (NoGC), as initial proof-of-concept for the utility of the paradigm in measurements of absolute scotomas in these individuals. The second part of this study focused on healthy observers, in which we demonstrate that CGC has the lowest stimulus positional error (gaze-contingent precision: CGC = ± 0.29°, PGC = ± 0.54°, NoGC = ± 0.81°). CGC test-retest variability was shown to be at least as good as both PGC and NoGC. Overall, CGC is supported as a reliable method of visual field examination in healthy observers. Preliminary findings demonstrate the spatially accurate estimation of visual field thresholds related to retinal structure using CGC in individuals with infantile nystagmus.

Pseudoneglect during object search in naturalistic scenes

Pseudoneglect, that is the tendency to pay more attention to the left side of space, is typically assessed with paper-and-pencil tasks, particularly line bisection. In the present study, we used an everyday task with more complex stimuli. Subjects’ task was to look for pre-specified objects in images of real-world scenes. In half of the scenes, the search object was located on the left side of the image (L-target); in the other half of the scenes, the target was on the right side (R-target). To control for left–right differences in the composition of the scenes, half of the scenes were mirrored horizontally. Eye-movement recordings were used to track the course of pseudoneglect on a millisecond timescale. Subjects’ initial eye movements were biased to the left of the scene, but less so for R-targets than for L-targets, indicating that pseudoneglect was modulated by task demands and scene guidance. We further analyzed how horizontal gaze positions changed over time. When the data for L- and R-targets were pooled, the leftward bias lasted, on average, until the first second of the search process came to an end. Even for right-side targets, the gaze data showed an early left-bias, which was compensated by adjustments in the direction and amplitude of later saccades. Importantly, we found that pseudoneglect affected search efficiency by leading to less efficient scan paths and consequently longer search times for R-targets compared with L-targets. It may therefore be prudent to take spatial asymmetries into account when studying visual search in scenes.

Real-time continuous EOG-based gaze angle estimation with baseline drift compensation under stationary head conditions

Objective:This work aims to propose a novel method to estimate the gaze from electrooculography (EOG) signals while compensating for the baseline drift, and which intrinsically detects fixations, saccades and blinks. In contrast to existing baseline drift mitigation techniques, the proposed framework is real-time-implementable, and does not require the average point of gaze to lie at the primary gaze position, nor does it disrupt the overall ocular pose-induced EOG signal DC characteristics. The EOG data used to validate the proposed method is also being made publicly available. Methods:The proposed method is based on the dual Kalman filter, which estimates the gaze angles (GAs) and the baseline concurrently, taking into consideration the EOG signal’s non-stationary and temporally-multimodal characteristics. In fact, it is a multiple-model technique based on a battery model of the eye wherein fixations, saccades and blinks are modelled separately. Results:When applied to short EOG data segments, a horizontal and vertical GA estimation error of 1.64 ± 0.82°and 1.97 ± 0.34°, respectively, was obtained, which compared well with the corresponding results obtained using the state-of-the-art linear regression models. Conversely, for longer data segments, the proposed framework yielded superior GA estimation performance when compared to the state-of-the-art techniques. Eye movement detection and labelling F-scores exceeding 90% were achieved. Conclusion:The proposed method yields reliable gaze estimation performance, and accurately detects fixations, saccades and blinks. Significance:This work proposes an integrated method to simultaneously estimate the GAs and address the baseline drift issue without the limitations of existing baseline drift mitigation techniques.

The Distribution of Gaze Positions of Human Infants in Natural Behavior

The Distribution of Gaze Positions of Human Infants in Natural Behavior

Importance of head movements in gaze tracking during table tennis forehand stroke

The purpose of this study was to clarify the properties of gaze and head movements during forehand stroke in table tennis. Collegiate table tennis players (n = 12) conducted forehand strokes toward a ball launched by a skilled experimenter. A total of ten trials were conducted for the experimental task. Horizontal and vertical movements of the ball, gaze, head and eye were analyzed from the image recorded by an eye tracking device. The results showed that participants did not always keep their gaze and head position on the ball throughout the entire ball path. Our results indicate that table tennis players tend to gaze at the ball in the initial ball-tracking phase. Furthermore, there was a significant negative correlation between eye and head position especially in the vertical direction. This result suggests that horizontal VOR is suppressed more than vertical VOR in ball-tracking during table tennis forehand stroke. Finally, multiple regression analysis showed that the effect of head position to gaze position was significantly higher than that of eye position. This result indicates that gaze position during forehand stroke could be associated with head position rather than eye position. Taken together, head movements may play an important role in maintaining the ball in a constant egocentric direction in table tennis forehand stroke.

A perceptual field test in object experts using gaze-contingent eye tracking

A hallmark of expert object recognition is rapid and accurate subordinate-category recognition of visually homogenous objects. However, the perceptual strategies by which expert recognition is achieved is less known. The current study investigated whether visual expertise changes observers’ perceptual field (e.g., their ability to use information away from fixation for recognition) for objects in their domain of expertise, using a gaze-contingent eye-tracking paradigm. In the current study, bird experts and novices were presented with two bird images sequentially, and their task was to determine whether the two images were of the same species (e.g., two different song sparrows) or different species (e.g., song sparrow and chipping sparrow). The first study bird image was presented in full view. The second test bird image was presented fully visible (full-view), restricted to a circular window centered on gaze position (central-view), or restricted to image regions beyond a circular mask centered on gaze position (peripheral-view). While experts and novices did not differ in their eye-movement behavior, experts’ performance on the discrimination task for the fastest responses was less impaired than novices in the peripheral-view condition. Thus, the experts used peripheral information to a greater extent than novices, indicating that the experts have a wider perceptual field to support their speeded subordinate recognition.