Eye Movements Of Observers Research Articles

Overview of the Use of Eye-Tracking Technology for Monitoring Consumer Views

Abstract Eye-tracking technology has become increasingly popular in studying consumer behavior and decision-making as a part of the marketing research area. The paper highlights the importance of eye tracking in the study of consumer behavior including the use of eye tracking in virtual reality environments, the integration of eye tracking with other physiological measures, and the development of more sophisticated analytical techniques. By observing eye movements and fixations researchers can gain insight into the visual and cognitive processes underlying consumer choices. For this reason, a literature review of relevant studies provides a detailed synthesis of the development of eye-tracking experiments. This paper contributes to the latest findings on consumer behavior in the field of eye-tracking technology.

Диагностика дислексии с использованием методов искусственного интеллекта по данным движений глаз: обзор

<p style="text-align: justify;">The review considers methods of dyslexia diagnostics based on eye movement data and implemented on the basis of artificial intelligence. A number of studies have shown that eye movements in people with dyslexia may differ from those of people with normal reading abilities. Since 2015, studies have begun to appear in which the eye movements of observers with and without dyslexia were analyzed using various artificial intelligence methods. To date, there are a number of papers using both simple and more complex models (with neural networks and deep learning). This review discusses what accuracy of diagnosis has been achieved by researchers, for which groups of subjects and for which languages the current results have been shown, what types of algorithms have been used, and other practical aspects of conducting such diagnosis. According to the data analyzed, dyslexia diagnostics by eye movements and artificial intelligence methods is very promising and may have a significant impact on early diagnosing of reading problems.</p>

Attention Trajectories Capture Utility Accumulation and Predict Brand Choice

Trajectories of attention capture the accumulation of brand utility during complex decision-making tasks. Thus, attention trajectories, as reflected in eye movements, predict the final brand choice of 85% of consumers before they implement it. Even when observing eye movements in only the first quarter of the decision process, attention already predicts brand choice much better (45%) than chance levels (20%). This superior prediction performance is due to a “double attention lift” for the chosen brand: The chosen brand receives progressively more attention toward the moment of choice, and more of this attention is devoted to integrating information about the brand rather than to comparing it with other options. In contrast, the currently owned brand grabs attention early in the task, and its attention gain persists for brand-loyal consumers and shifts for brand-switching consumers. A new attention and choice model used in tandem with the Bayesian K-fold cross-validation methodology on eye-tracking data from 325 representative consumers uncovered these attention trajectory effects. The findings contribute to closing important knowledge gaps in the attention and choice literature and have implications for marketing research and managerial practice.

A review on the effectiveness of driver drowsiness detection system using computerised devices

Driver drowsiness is a critical factor contributing to road accidents worldwide, with potentially devastating consequences. To mitigate this problem, numerous driver drowsiness detection systems have been developed, employing various computerized devices and technologies. The development of technologies for detecting drowsiness is a major challenge in the field of accident-avoidance systems. Since the dangers of drowsiness exist on the road, techniques need to be advanced to prevent its consequences. The most crucial aspect of this work is to develop a drowsiness detection system by tracking the driver's eyes. It is believed that signs of driver exhaustion can be detected early enough to prevent a car accident. This technology aims to enhance road safety by alerting drivers or triggering safety measures when drowsiness is detected, ultimately saving lives and preventing accidents. Detecting fatigue involves observing eye movements and blink patterns. This review aims to provide an in-depth analysis of the effectiveness of these systems in identifying and alerting drowsy drivers, ultimately enhancing road safety. The analysis of facial images is a popular research area with applications such as face recognition and human identification security systems. Furthermore, this review delves into the various methodologies and algorithms used in driver drowsiness detection, including machine learning, image analysis, and signal processing techniques. It also highlights the need for further research to address the challenges and limitations faced by these systems and suggests potential avenues for improvement.

The unique rectus extraocular muscles of cetaceans: Homologies and possible functions.

Each rectus extraocular muscle in cetaceans divides into two portions: a massive palpebral belly that inserts into the deep surface of the eyelids and a smaller scleral belly that inserts onto the eyeball. While the cetacean palpebral insertions have long been recognized, their homologies and functions remain unclear. To compare cetacean rectus EOM insertions with the global and orbital rectus EOM insertions of other mammals we dissected orbital contents of 20 odontocete species, 2 mysticete species and 18 non-cetacean species, both aquatic and terrestrial. Four cetacean species were also examined with magnetic resonance imaging (MRI). All four rectus muscles in cetaceans had well-developed palpebral bellies and insertions. Adjacent palpebral bellies showed varying degrees of fusion, from near independence to near complete fusion. Fusion was most complete towards palpebral insertions and less towards origins. A medial moiety of the superior rectus palpebral belly is likely the levator palpebrae superioris. Smaller but still robust scleral insertions were present on all recti, with the medial rectus (MR) being significantly more muscular than the others. All non-cetacean species examined had recti with distinct global and orbital insertions, the latter generally onto Tenon's capsule. Orbital insertions in pygmy hippopotamus and Florida manatee extended into the deep surfaces of the eyelids, hence qualifying as palpebral insertions. Our results suggest that rectus EOMs of mammals generally have both global and orbital insertions, and that palpebral bellies of cetaceans and other species are modified homologs of the orbital insertions. The presence of palpebral insertions in pygmy hippopotamus and absence in other cetartiodactyls suggests an intermediate condition between terrestrial cetartiodactyls and cetaceans. Palpebral insertions in Florida manatee and reports of their presence in some pinnipeds suggest parallel evolution in multiple aquatic lineages. Various functions of cetacean palpebral recti have been proposed, including eyelid dilators, protection during diving and thermogenesis for warming eye and brain. For further insight into their possible functions, we observed eye movements of captive bottlenose dolphins (Tursiops truncatus) at the U.S. National Aquarium. Our observations showed that in addition to rotation of the eyeball the entire surrounding palpebral region also moves during gaze changes. For example during upward gaze the globe not only rotates in supraduction but translates dorsally as well. It appears the rectus palpebral bellies are responsible for flexing the palpebral structures and thus also translating the globe, while the scleral insertions act directly for ocular rotation. Along with frequent non-conjugate eye movements, the oculomotor mechanics and repertoire of cetaceans are thus quite distinctive. Summarily, axial displacement within the orbit is a major 'eye movement' in cetaceans, with protrusion and retraction mediated by well-developed circular muscles and retractor bulbi respectively. Torsional eye movements driven by elaborate oblique EOMs are likewise significant. The roles of rectus EOMs for ocular rotation via their scleral insertions, especially the highly muscular MR, are for typical supra/infraductions and nasal/temporal ductions. The palpebral bellies accentuate these ductions by translating the globe and surrounding structures in the same direction.

Rapid saccadic categorization of other-race faces.

The human visual system is very fast and efficient at extracting socially relevant information from faces. Visual studies employing foveated faces have consistently reported faster categorization by race response times for other-race compared with same-race faces. However, in everyday life we typically encounter faces outside the foveated visual field. In study 1, we explored whether and how race is categorized extrafoveally in same- and other-race faces normalized for low-level properties by tracking eye movements of Western Caucasian and East Asian observers in a saccadic response task. The results show that not only are people sensitive to race in faces presented outside of central vision, but the speed advantage in categorizing other-race faces occurs astonishingly quickly in as little as 200 ms. Critically, this visual categorization process was approximately 300 ms faster than the typical button press responses on centrally presented foveated faces. Study 2 investigated the genesis of the extrafoveal saccadic response speed advantage by comparing the influences of the response modality (button presses and saccadic responses), as well as the potential contribution of the impoverished low-spatial frequency spectrum characterizing extrafoveal visual information processing. Button press race categorization was not significantly faster with reconstructed retinal-filtered low spatial frequency faces, regardless of the visual field presentation. The speed of race categorization was significantly boosted only by extrafoveal saccades and not centrally foveated faces. Race is a potent, rapid, and effective visual signal transmitted by faces used for the categorization of ingroup/outgroup members. This fast universal visual categorization can occur outside central vision, igniting a cascade of social processes.

Eye movement strategies in face ethnicity categorization vs. face identification tasks

A quick look at a face allows us to identify the person, their gender, and emotion. Humans direct their first eye movement towards points on the face that vary moderately across these common tasks and maximize performance. However, not known is the extent to which humans alter their oculomotor strategies to maximize accuracy in more specialized face categorization tasks. We studied the eye movements of Indian observers during a North vs. South Indian face categorization task and compared them to those in a person-identification task. We found that observers did not alter their first eye movement strategy for the ethnic categorization task, i.e., they directed their first fixations to a similar preferred point as in the person-identification task. To assess whether using a similar preferred point of fixation for both tasks resulted in a performance cost for the categorization task, we measured performance as a function of fixation position along the face. Fixating away from the preferred point of fixation reduced observer performance in the person identification task, but not in the ethnicity categorization task. We used computational modeling to assess whether the results could be explained by an interaction between the distribution of task information across the face and the foveated properties of the visual system. A foveated ideal observer analysis revealed a spatially more distributed task information and lower dependence of performance on the point of fixation for the ethnicity categorization task relative to the person identification. We conclude that, unlike the person identification task, humans can access the information for the ethnicity categorization task from various points of fixation. Thus, the observer strategy to utilize the typical person identification first eye movement for the ethnicity categorization task is a simple solution that incurs little or no performance cost.

Eye, head, and gaze contributions to smooth pursuit in macular degeneration.

Macular degeneration (MD) often leads to the loss of the fovea and surrounding central visual field. This type of visual loss is very common and can present particular challenges for oculomotor tasks that may rely on the fovea. For certain tasks, individuals develop a new, eccentric fixational locus. Our previous work has shown that smooth pursuit is impaired in MD. However, extent of retinal lesion size and eccentricity of fixation do not directly contribute to changes in smooth pursuit gain. Oculomotor limitations due to eccentric eye position in the orbit may be another culprit. Here we test the hypothesis that deficits in smooth pursuit in MD would be reduced under head-unrestrained conditions. To that end, we examined eye, head, and gaze movements in eight individuals with MD and seven age-matched controls in response to a step-ramp pursuit stimulus. We found that despite variability across participants, both groups had similar smooth pursuit head movements (P = 0.76), while both had significantly higher pursuit gains in the head-restrained condition (P < 0.0001), suggesting that in older populations, head movements may lead to a decrease in pursuit gain. Furthermore, we did not find a correlation between eccentricity of fixation and amount of head displacement during the trial (P = 0.25), suggesting that eccentric eye position does not lead to higher reliance on head movements in smooth pursuit. Our finding that individuals with MD have lower pursuit gains, despite similar head movements as controls, suggests a difference in how MD affects mechanisms underlying eye versus head movements in smooth pursuit.NEW & NOTEWORTHY This article is the first to look at eye and head movements in observers with macular degeneration. It is the first to show that in older individuals, regardless of central field defect, freedom of head movement may reduce pursuit gain. Despite oculomotor limitations due to eccentric fixation, individuals with macular degeneration do not rely on head movements more than age-matched controls, with both groups having a similarly heterogenous eye and head movement strategy for pursuit.

Tracking the Mind’s Eye: Primate Gaze Behavior during Virtual Visuomotor Navigation Reflects Belief Dynamics

To take the best actions, we often need to maintain and update beliefs about variables that cannot be directly observed. To understand the principles underlying such belief updates, we need tools to uncover subjects' belief dynamics from natural behavior. We tested whether eye movements could be used to infer subjects' beliefs about latent variables using a naturalistic navigation task. Humans and monkeys navigated to a remembered goal location in a virtual environment that provided optic flow but lacked explicit position cues. We observed eye movements that appeared to continuously track the goal location even when no visible target was present there. Accurate goal tracking was associated with improved task performance, and inhibiting eye movements in humans impaired navigation precision. These results suggest that gaze dynamics play a key role in action selection during challenging visuomotor behaviors and may possibly serve as a window into the subject's dynamically evolving internal beliefs.

On Gaze Deployment to Audio-Visual Cues of Social Interactions

Attention supports our urge to forage on social cues. Under certain circumstances, we spend the majority of time scrutinising people, markedly their eyes and faces, and spotting persons that are talking. To account for such behaviour, this article develops a computational model for the deployment of gaze within a multimodal landscape, namely a conversational scene. Gaze dynamics is derived in a principled way by reformulating attention deployment as a stochastic foraging problem. Model simulation experiments on a publicly available dataset of eye-tracked subjects are presented. Results show that the simulated scan paths exhibit similar trends of eye movements of human observers watching and listening to conversational clips in a free-viewing condition.

Evaluating driver cognitive distraction by eye tracking: From simulator to driving

Driver cognitive distraction, a critical factor for road safety, is challenging for researchers to evaluate, especially under real conditions. This paper introduces a novel method for simulating involuntary eye movement by combining the vestibulo-ocular reflex model and the optokinetic response. The difference between the predicted and observed eye movements is then assumed to be a measure of the level of cognitive distraction. When this hypothesis was validated under two sets of conditions, in a driving simulator and in a naturalistic situation, our algorithm was able to capture the cognitive distraction event in the naturalistic case. In addition, we also review and discuss the eye-movement sensor, which has a marked effect on the results of the evaluation, and the potential of using eye-movement sensors to evaluate cognitive distraction in drivers.

The mean point of vergence is biased under projection.

The point of interest in three-dimensional space in eye tracking is often computed based on intersecting the lines of sight with geometry, or finding the point closest to the two lines of sight. We first start by theoretical analysis with synthetic simulations. We show that the mean point of vergence is generally biased for centrally symmetric errors and that the bias depends on the horizontal vs. vertical noise distribution of the tracked eye positions. Our analysis continues with an evaluation on real experimental data. The estimated mean vergence points seem to contain different errors among individuals but they generally show the same bias towards the observer. And it tends to be larger with an increased viewing distance. We also provided a recipe to minimize the bias, which applies to general computations of gaze estimation under projection. These findings not only have implications for choosing the calibration method in eye tracking experiments and interpreting the observed eye movements data; but also suggest to us that we shall consider the mathematical models of calibration as part of the experiment.

Neural Representations of Faces Are Tuned to Eye Movements.

Eye movements provide a functional signature of how human vision is achieved. Many recent studies have consistently reported robust idiosyncratic visual sampling strategies during face recognition. Whether these interindividual differences are mirrored by idiosyncratic neural responses remains unknown. To this aim, we first tracked eye movements of male and female observers during face recognition. Additionally, for every observer we obtained an objective index of neural face discrimination through EEG that was recorded while they fixated different facial information. We found that foveation of facial features fixated longer during face recognition elicited stronger neural face discrimination responses across all observers. This relationship occurred independently of interindividual differences in preferential facial information sampling (e.g., eye vs mouth lookers), and started as early as the first fixation. Our data show that eye movements play a functional role during face processing by providing the neural system with the information that is diagnostic to a specific observer. The effective processing of identity involves idiosyncratic, rather than universal face representations.SIGNIFICANCE STATEMENT When engaging in face recognition, observers deploy idiosyncratic fixation patterns to sample facial information. Whether these individual differences concur with idiosyncratic face-sensitive neural responses remains unclear. To address this issue, we recorded observers' fixation patterns, as well as their neural face discrimination responses elicited during fixation of 10 different locations on the face, corresponding to different types of facial information. Our data reveal a clear interplay between individuals' face-sensitive neural responses and their idiosyncratic eye-movement patterns during identity processing, which emerges as early as the first fixation. Collectively, our findings favor the existence of idiosyncratic, rather than universal face representations.

Waldo reveals cultural differences in return fixations

ABSTRACTHumans routinely perform visual search towards targets to adapt to the environment. These sequences of ballistic eye movements are shaped by a combination of top–down and bottom–up factors. Recent research documented that human observers display cultural-specific fixation patterns in a range of visual processing tasks. In particular, eye movement strategies extracting information from faces clearly differs between Western Caucasian (WC) and East Asian (EA) observers. However, whether such cultural differences are also present for visual scene processing remains debated. To this aim, we recorded the eye movements of WC and EA observers while they were solving visual search problems parametrically varying in difficulty: Where’s Waldo. Both groups had a comparable familiarity with the Waldo books reaching a comparable level of accuracy in target detection. Both cultural groups also showed a comparable temporal effect on inhibition of return, with longer fixation durations when saccades were performed to a return location compared to other locations. Westerners, however, located Waldo faster than Easterners. Interestingly, this modulation of speed was likely related to differences occurring on the low-level mechanisms of spatial inhibition of return, with EA observers returning more often to previously visited locations than the WC observers. This suboptimal eye movement strategy in the Easterners might be engendered by their cultural perceptual bias consisting in⁠ a greater use of extra-foveal information. Overall, our data point towards the existence of a subtle, but significant difference in the processing of visual scenes across observers from different cultures during active visual search.

Selective eye fixations on diagnostic face regions of dynamic emotional expressions: KDEF-dyn database

Prior research using static facial stimuli (photographs) has identified diagnostic face regions (i.e., functional for recognition) of emotional expressions. In the current study, we aimed to determine attentional orienting, engagement, and time course of fixation on diagnostic regions. To this end, we assessed the eye movements of observers inspecting dynamic expressions that changed from a neutral to an emotional face. A new stimulus set (KDEF-dyn) was developed, which comprises 240 video-clips of 40 human models portraying six basic emotions (happy, sad, angry, fearful, disgusted, and surprised). For validation purposes, 72 observers categorized the expressions while gaze behavior was measured (probability of first fixation, entry time, gaze duration, and number of fixations). Specific visual scanpath profiles characterized each emotional expression: The eye region was looked at earlier and longer for angry and sad faces; the mouth region, for happy faces; and the nose/cheek region, for disgusted faces; the eye and the mouth regions attracted attention in a more balanced manner for surprise and fear. These profiles reflected enhanced selective attention to expression-specific diagnostic face regions. The KDEF-dyn stimuli and the validation data will be available to the scientific community as a useful tool for research on emotional facial expression processing.

The Impact of Beliefs Concerning Deception on Perceptions of Nonverbal Behavior: Implications for Neuro-Linguistic Programming-Based Lie Detection

Regularly employed in a forensic context, the Neuro-Linguistic Programming (NLP) model purports that the behavioral distinction between somebody who is remembering information and somebody who is constructing information lies in the direction of their eye movements. This strategy reflects numerous current approaches to lie detection, which presume that nonverbal behavior influences perceptions and judgments about deception. The present study emphasized a reverse order by investigating whether beliefs that an individual is deceptive influence perceptions of the respective individual’s nonverbal behavior as indicated by observed eye movement patterns. Sixty participants were randomly assigned to either a group informed that right eye movements indicate constructed and thus deceptive information or a group informed that left eye movements indicate constructed and thus deceptive information. Each participant viewed six investigative interviews depicting the eye movement patterns of mock suspects labeled as deceptive or truthful. The interviews were structured according to different right/left eye movement ratios. Results revealed that participants reportedly observed the deceptive suspects displaying significantly more eye movements in the direction allegedly indicative of deception than did the truthful suspects. This result occurred despite the fact that the actual eye movement ratios in both deceptive/truthful sets of interviews were identical and the eye movements were predominantly in the opposite direction of that allegedly indicative of deception. The results are discussed in the context of encoding-based cognitive-processing theories. Limitations on the generality of the results are emphasized and the applicability (or lack thereof) of NLP-based lie detection in forensic contexts is discussed.

The Dynamics of Prosthetically Elicited Vestibulo-Ocular Reflex Function Across Frequency and Context in the Rhesus Monkey.

Electrical vestibular neurostimulation may be a viable tool for modulating vestibular afferent input to restore vestibular function following injury or disease. To do this, such stimulators must provide afferent input that can be readily interpreted by the central nervous system to accurately represent head motion to drive reflexive behavior. Since vestibular afferents have different galvanic sensitivity, and different natural sensitivities to head rotational velocity and acceleration, and electrical stimulation produces aphysiological synchronous activation of multiple afferents, it is difficult to assign a priori an appropriate transformation between head velocity and acceleration and the properties of the electrical stimulus used to drive vestibular reflex function, i.e., biphasic pulse rate or pulse current amplitude. In order to empirically explore the nature of the transformation between vestibular prosthetic stimulation and vestibular reflex behavior, in Rhesus macaque monkeys we parametrically varied the pulse rate and current amplitude of constant rate and current amplitude pulse trains, and the modulation frequency of sinusoidally modulated pulse trains that were pulse frequency modulated (FM) or current amplitude modulated (AM). In addition, we examined the effects of differential eye position and head position on the observed eye movement responses. We conclude that there is a strong and idiosyncratic, from canal to canal, effect of modulation frequency on the observed eye velocities that are elicited by stimulation. In addition, there is a strong effect of initial eye position and initial head position on the observed responses. These are superimposed on the relationships between pulse frequency or current amplitude and eye velocity that have been shown previously.

Towards online detection of driver distraction: Eye-movement simulation based on a combination of vestibulo–ocular reflex and optokinetic reflex models

With the aim of developing a method for evaluating driver distraction based on the difference between simulated and observed eye movements, we integrated a vestibulo–ocular reflex (VOR) model and an optokinetic reflex (OKR) model. On the basis of 2 × 2 factorial design analysis (VOR model only and VOR+OKR model; with and without visual stimulus), we confirmed that the VOR+OKR model showed a better performance than the VOR model, with a smaller mean-square error. We also conducted an experiment that used an n-back task to simulate mental workload while driving. The mean-square error between the simulated and observed eye movement became larger in the presence of mental workload. This result suggests that the VOR+OKR model could be applied in the evaluation of driver distraction.

Evaluating Driver Mental Workload in a Realistic Condition using Eye Movement Sensor

Driver’s mental workload is not only a critical factor for road safety but also a challenging for the researcher to evaluate. This research introduces a novel of measuring the level of driver mental workload by using the difference between the predicted and observed eye movements. In this paper, the involuntary eye movement predicted based on the combination of the vestibule-ocular reflex model and the optokinetic response. By using n-back task to impose the mental workload for the driver, this hypothesis was validated and confirmed in a driving simulator as well as in a naturalistic situation.

Observing eye movements and the influence of cognition during a symbol search task: a comparison across three age groups

This study examined eye movements during a visual search task as well as cognitive abilities within three age groups. The aim was to explore scanning patterns across symbol grids and to better understand the impact of symbol location in AAC displays on speed and accuracy of symbol selection. For the study, 60 students were asked to locate a series of symbols on 16 cell grids. The EyeLink 1000 was used to measure eye movements, accuracy, and response time. Accuracy was high across all cells. Participants had faster response times, longer fixations, and more frequent fixations on symbols located in the middle of the grid. Group comparisons revealed significant differences for accuracy and reaction times. The Leiter-R was used to evaluate cognitive abilities. Sustained attention and cognitive flexibility scores predicted the participants’ reaction time and accuracy in symbol selection. Findings suggest that symbol location within AAC devices and individuals’ cognitive abilities influence the speed and accuracy of retrieving symbols.