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Annual Review of Vision Science Sep 2023As we navigate and behave in the world, we are constantly deciding, a few times per second, where to look next. The outcomes of these decisions in response to visual... (Review)
Review
As we navigate and behave in the world, we are constantly deciding, a few times per second, where to look next. The outcomes of these decisions in response to visual input are comparatively easy to measure as trajectories of eye movements, offering insight into many unconscious and conscious visual and cognitive processes. In this article, we review recent advances in predicting where we look. We focus on evaluating and comparing models: How can we consistently measure how well models predict eye movements, and how can we judge the contribution of different mechanisms? Probabilistic models facilitate a unified approach to fixation prediction that allows us to use explainable information explained to compare different models across different settings, such as static and video saliency, as well as scanpath prediction. We review how the large variety of saliency maps and scanpath models can be translated into this unifying framework, how much different factors contribute, and how we can select the most informative examples for model comparison. We conclude that the universal scale of information gain offers a powerful tool for the inspection of candidate mechanisms and experimental design that helps us understand the continual decision-making process that determines where we look.
Topics: Fixation, Ocular; Eye Movements
PubMed: 37419107
DOI: 10.1146/annurev-vision-120822-072528 -
Journal of Vision Jul 2022Neurotypical observers show large and reliable individual differences in gaze behavior along several semantic object dimensions. Individual gaze behavior toward faces...
Neurotypical observers show large and reliable individual differences in gaze behavior along several semantic object dimensions. Individual gaze behavior toward faces has been linked to face identity processing, including that of neurotypical observers. Here, we investigated potential gaze biases in Super-Recognizers (SRs), individuals with exceptional face identity processing skills. Ten SRs, identified with a novel conservative diagnostic framework, and 43 controls freely viewed 700 complex scenes depicting more than 5000 objects. First, we tested whether SRs and controls differ in fixation biases along four semantic dimensions: faces, text, objects being touched, and bodies. Second, we tested potential group differences in fixation biases toward eyes and mouths. Finally, we tested whether SRs fixate closer to the theoretical optimal fixation point for face identification. SRs showed a stronger gaze bias toward faces and away from text and touched objects, starting from the first fixation onward. Further, SRs spent a significantly smaller proportion of first fixations and dwell time toward faces on mouths but did not differ in dwell time or first fixations devoted to eyes. Face fixation of SRs also fell significantly closer to the theoretical optimal fixation point for identification, just below the eyes. Our findings suggest that reliable superiority for face identity processing is accompanied by early fixation biases toward faces and preferred saccadic landing positions close to the theoretical optimum for face identification. We discuss future directions to investigate the functional basis of individual fixation behavior and face identity processing ability.
Topics: Bias; Face; Facial Recognition; Fixation, Ocular; Humans; Saccades; Semantics
PubMed: 35900724
DOI: 10.1167/jov.22.8.17 -
The Journal of Neuroscience : the... Feb 2022Omnipause neurons (OPNs) in the nucleus raphe interpositus have tonic activity while the eyes are stationary ("fixation") but stop firing immediately before and during...
Omnipause neurons (OPNs) in the nucleus raphe interpositus have tonic activity while the eyes are stationary ("fixation") but stop firing immediately before and during saccades. To locate the source of suppression, we analyzed synaptic inputs from the rostral and caudal superior colliculi (SCs) to OPNs by using intracellular recording and staining, and investigated pathways transmitting the inputs in anesthetized cats of both sexes. Electrophysiologically or morphologically identified OPNs received monosynaptic excitation from the rostral SCs with contralateral dominance, and received disynaptic inhibition from the caudal SCs with ipsilateral dominance. Cutting the tectoreticular tract transversely between the contralateral OPN and inhibitory burst neuron (IBN) regions eliminated inhibition from the caudal SCs, but not excitation from the rostral SCs in OPNs. In contrast, a midline section between IBN regions eliminated disynaptic inhibition in OPNs from the caudal SCs but did not affect the monosynaptic excitation from the rostral SCs. Stimulation of the contralateral IBN region evoked monosynaptic inhibition in OPNs, which was facilitated by preconditioning SC stimulation. Three-dimensional reconstruction of HRP-stained cells revealed that individual OPNs have axons that terminate in the opposite IBN area, while individual IBNs have axon collaterals to the opposite OPN area. These results show that there are differences in the neural circuit from the rostral and caudal SCs to the brainstem premotor circuitry and that IBNs suppress OPNs immediately before and during saccades. Thus, the IBNs, which are activated by caudal SC saccade neurons, shut down OPN firing and help to trigger saccades and suppress ("latch") OPN activity during saccades. Saccades are the fastest eye movements to redirect gaze to an object of interest and bring its image on the fovea for fixation. Burst neurons (BNs) and omnipause neurons (OPNs) which behave reciprocally in the brainstem, are important for saccade generation and fixation. This study investigated unsolved important questions about where these neurons receive command signals and how they interact for initiating saccades from visual fixation. The results show that the rostral superior colliculi (SCs) excite OPNs monosynaptically for fixation, whereas the caudal SCs monosynaptically excite inhibitory BNs, which then directly inhibit OPNs for the initiation of saccades. This inhibition from the caudal SCs may account for the omnipause behavior of OPNs for initiation and maintenance of saccades in all directions.
Topics: Animals; Brain Stem; Cats; Female; Fixation, Ocular; Inhibitory Postsynaptic Potentials; Male; Microelectrodes; Nerve Net; Saccades; Superior Colliculi; Synaptic Potentials
PubMed: 34880121
DOI: 10.1523/JNEUROSCI.1731-21.2021 -
Psychological Research Sep 2022Recent research on return-sweep saccades has improved our understanding of eye movements when reading paragraphs. However, these saccades, which take our gaze from the...
Recent research on return-sweep saccades has improved our understanding of eye movements when reading paragraphs. However, these saccades, which take our gaze from the end of one line to the start of the next line, have been studied only within the context of silent reading. Articulatory demands and the coordination of the eye-voice span (EVS) at line boundaries suggest that the execution of this saccade may be different in oral reading. We compared launch and landing positions of return-sweeps, corrective saccade probability and fixations adjacent to return-sweeps in skilled adult readers while reading paragraphs aloud and silently. Compared to silent reading, return-sweeps were launched from closer to the end of the line and landed closer to the start of the next line when reading aloud. The probability of making a corrective saccade was higher for oral reading than silent reading. These indicate that oral reading may compel readers to rely more on foveal processing at the expense of parafoveal processing. We found an interaction between reading modality and fixation type on fixation durations. The reading modality effect (i.e., increased fixation durations in oral compared to silent reading) was greater for accurate line-initial fixations and marginally greater for line-final fixations compared to intra-line fixations. This suggests that readers may use the fixations adjacent to return-sweeps as natural pause locations to modulate the EVS.
Topics: Adult; Eye Movements; Fixation, Ocular; Fovea Centralis; Humans; Reading; Saccades
PubMed: 34694488
DOI: 10.1007/s00426-021-01610-6 -
Journal of Vision Aug 2023During natural vision, the human visual system has to process upcoming eye movements in parallel to currently fixated stimuli. Saccades targeting isolated faces are...
During natural vision, the human visual system has to process upcoming eye movements in parallel to currently fixated stimuli. Saccades targeting isolated faces are known to have lower latency and higher velocity, but it is unclear how this generalizes to the natural cycle of saccades and fixations during free-viewing of complex scenes. To which degree can the visual system process high-level features of extrafoveal stimuli when they are embedded in visual clutter and compete with concurrent foveal input? Here, we investigated how free-viewing dynamics vary as a function of an upcoming fixation target while controlling for various low-level factors. We found strong evidence that face- versus inanimate object-directed saccades are preceded by shorter fixations and have higher peak velocity. Interestingly, the boundary conditions for these two effects are dissociated. The effect on fixation duration was limited to face saccades, which were small and followed the trajectory of the preceding one, early in a trial. This is reminiscent of a recently proposed model of perisaccadic retinotopic shifts of attention. The effect on saccadic velocity, however, extended to very large saccades and increased with trial duration. These findings suggest that multiple, independent mechanisms interact to process high-level features of extrafoveal targets and modulate the dynamics of natural vision.
Topics: Humans; Saccades; Fixation, Ocular; Eye Movements; Attention; Memory
PubMed: 37552021
DOI: 10.1167/jov.23.8.11 -
Journal of Physiological Anthropology Sep 2020Saccadic eye movements can allude to emotional states and visual attention. Recent studies have shown that microsaccadic responses (i.e., small fixational eye movements)... (Review)
Review
Saccadic eye movements can allude to emotional states and visual attention. Recent studies have shown that microsaccadic responses (i.e., small fixational eye movements) reflect advanced brain activity during attentional and cognitive tasks. Moreover, the microsaccadic activity related to emotional attention provides new insights into this field. For example, emotional pictures attenuate the microsaccadic rate, and microsaccadic responses to covert attention occur in the direction opposite to a negative emotional target. However, the effects of various emotional events on microsaccadic activity remain debatable. This review introduces visual attention and eye movement studies that support findings on the modulation of microsaccadic responses to emotional events, comparing them with typical microsaccadic responses. This review also discusses the brain neuronal mechanisms governing microsaccadic responses to the attentional shifts triggered by emotion-related stimuli. It is hard to reveal the direct brain pathway of the microsaccadic modulation, especially in advanced (e.g., sustained anger, envy, distrust, guilt, frustration, delight, attraction, trust, and love), but also in basic human emotions (i.e., anger, disgust, fear, happiness, sadness, and surprise). However, non-human primates and human studies can uncover the possible brain pathways of emotional attention and microsaccades, thus providing future research directions. In particular, the facilitated (or reduced) attention is common evidence that microsaccadic activities change under a variety of social modalities (e.g., cognition, music, mental illness, and working memory) that elicit emotions and feelings.
Topics: Attention; Brain; Emotions; Fear; Fixation, Ocular; Humans; Mental Disorders; Saccades
PubMed: 32887665
DOI: 10.1186/s40101-020-00238-6 -
Brazilian Journal of Otorhinolaryngology 2022To investigate ocular movements measures of vectoelectro-nystagmography and video-nystagmography in dyslexic children and compare with measures of typical children. (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To investigate ocular movements measures of vectoelectro-nystagmography and video-nystagmography in dyslexic children and compare with measures of typical children.
METHODS
A systematic review of observational studies comparing the ocular movements differences between dyslexic and typical children with no publication date or language restriction. The literature survey included the bibliographic databases MEDLINE, ScienceDirect, Scopus, Web of Science, SciELO, Lilacs and CENTRAL. Gray literature databases were also searched, including: OpenGrey.eu, DissOnline.de, The New York Academy of Medicine and WorldCat. The meta-analysis was performed using software RevMan 5.3 (Cochran Collaboration).
RESULTS
A total of 2375 articles were found of which 113 fell within the inclusion criteria. Among these, 52 were duplicates (found in more than one research source), and 45 articles were selected for reading in full. Thirteen (13) articles were included for analysis and discussion. Meta-analysis showed statistical differences between the two groups for the total number of saccades and duration of fixation.
CONCLUSION
The study revealed that children with dyslexia have longer duration of fixation and fewer saccades during ocular movements on vectoelectro-nystagmography and video-nystagmography when compared to children without dyslexia.
Topics: Child; Humans; Fixation, Ocular; Dyslexia; Saccades; Reading; Eye Movements
PubMed: 35094959
DOI: 10.1016/j.bjorl.2021.10.006 -
Journal of Vision Feb 2023Humans differ in the amount of time they direct their gaze toward different types of stimuli. Individuals' preferences are known to be reliable and can predict various...
Humans differ in the amount of time they direct their gaze toward different types of stimuli. Individuals' preferences are known to be reliable and can predict various cognitive and affective processes. However, it remains unclear whether humans are aware of their visual gaze preferences and are able to report it. In this study, across three different tasks and without prior warning, participants were asked to estimate the amount of time they had looked at a certain visual content (e.g., faces or texts) at the end of each experiment. The findings show that people can report accurately their visual gaze preferences. The implications are discussed in the context of visual perception, metacognition, and the development of applied diagnostic tools based on eye tracking.
Topics: Humans; Fixation, Ocular; Visual Perception; Awareness
PubMed: 36799868
DOI: 10.1167/jov.23.2.9 -
Psychonomic Bulletin & Review Aug 2022In an eye-tracking experiment during reading, we examined the repetition effect, whereby words that are repeated in the same paragraph receive shorter fixation...
In an eye-tracking experiment during reading, we examined the repetition effect, whereby words that are repeated in the same paragraph receive shorter fixation durations. Target words that were either high-frequency or low-frequency words and of which the parafoveal preview was either correct or with all letters replaced were embedded three times in the same paragraph. Shorter fixation times and higher skipping rates were observed for high-frequency compared to low-frequency words, words for which the parafoveal preview was correct versus incorrect, and as the word was being repeated more often. An interaction between frequency and repetition indicated that the reduction in fixation times due to repetition was more pronounced for low-frequency words. We also observed influences of word repetition on parafoveal processing, as repeated words were skipped more often. An interaction between parafoveal preview and repetition indicated an absent repetition effect when the preview was incorrect, but this effect was short lived, as it was restricted to the first fixation duration on the target word.
Topics: Fixation, Ocular; Fovea Centralis; Humans; Reading; Time Factors
PubMed: 35217984
DOI: 10.3758/s13423-021-02054-0 -
Attention, Perception & Psychophysics May 2024Competing theories attempt to explain what guides eye movements when exploring natural scenes: bottom-up image salience and top-down semantic salience. In one study, we...
Competing theories attempt to explain what guides eye movements when exploring natural scenes: bottom-up image salience and top-down semantic salience. In one study, we apply language-based analyses to quantify the well-known observation that task influences gaze in natural scenes. Subjects viewed ten scenes as if they were performing one of two tasks. We found that the semantic similarity between the task and the labels of objects in the scenes captured the task-dependence of gaze (t(39) = 13.083; p < 0.001). In another study, we examined whether image salience or semantic salience better predicts gaze during a search task, and if viewing strategies are affected by searching for targets of high or low semantic relevance to the scene. Subjects searched 100 scenes for a high- or low-relevance object. We found that image salience becomes a worse predictor of gaze across successive fixations, while semantic salience remains a consistent predictor (X(1, N=40) = 75.148, p < .001). Furthermore, we found that semantic salience decreased as object relevance decreased (t(39) = 2.304; p = .027). These results suggest that semantic salience is a useful predictor of gaze during task-related scene viewing, and that even in target-absent trials, gaze is modulated by the relevance of a search target to the scene in which it might be located.
Topics: Humans; Semantics; Fixation, Ocular; Attention; Male; Female; Young Adult; Adult; Pattern Recognition, Visual; Eye Movements
PubMed: 38594445
DOI: 10.3758/s13414-024-02883-w