Luminance-Induced Shift in the Apparent Direction of Gaze

Perception ◽  
10.1068/p3332 ◽  
2002 ◽  
Vol 31 (6) ◽  
pp. 657-674 ◽  
Author(s):  
Shinki Ando
Keyword(s):  
Flux Ratio ◽  
Apparent Size ◽  
Gaze Direction ◽  
Irradiation Effects ◽  
Alternative Source ◽  
Gaze Shift ◽  
The Gaze ◽  
Apparent Direction ◽  
Apparent Shift ◽  
Level Analysis

Changing the luminance of one side of the sclera induces an apparent shift of the perceived direction of gaze toward the darker side of the sclera. This luminance-induced gaze shift was measured in photographic and schematic images of eyes. The effect was substantial: a moderate darkening of one side of the sclera induced an apparent shift of 8 to 10 deg of gaze; the maximum darkening induced a shift of 15 deg of gaze or more. The effect of scleral darkening was also compared to the gaze shift induced by an actual shift of the iris. The effects of the two cues were measured independently and in combination. When pitted against each other, their effects could be nulled, demonstrating that they act on a common level. Predictions of the relative strengths of the luminance and iris shift cues were developed for two simple luminance-based mechanisms: flux ratio and luminance centroid. The data showed the luminance cue was less effective than the models predicted in determining gaze direction. As an alternative source for the gaze shift, irradiation effects on apparent size could create a perceived shift in the iris position but a direct measure of the irradiation shift showed that this was far too small. The results suggest that at least one important mechanism for gaze judgment is based on low-level analysis of the luminance configuration within the eye.

scholarly journals Enhanced use of gaze cue in a face-following task after brief trial experience in individuals with autism spectrum disorder

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takao Fukui ◽  
Mrinmoy Chakrabarty ◽  
Misako Sano ◽  
Ari Tanaka ◽  
Mayuko Suzuki ◽  
...  
Keyword(s):  
Autism Spectrum ◽  
Face Image ◽  
Fixation Time ◽  
Gaze Shift ◽  
The Gaze ◽  
Face Images ◽  
Trial Experience ◽  
Short Period ◽  
The Face ◽  
Gaze Cues

AbstractEye movements toward sequentially presented face images with or without gaze cues were recorded to investigate whether those with ASD, in comparison to their typically developing (TD) peers, could prospectively perform the task according to gaze cues. Line-drawn face images were sequentially presented for one second each on a laptop PC display, and the face images shifted from side-to-side and up-and-down. In the gaze cue condition, the gaze of the face image was directed to the position where the next face would be presented. Although the participants with ASD looked less at the eye area of the face image than their TD peers, they could perform comparable smooth gaze shift to the gaze cue of the face image in the gaze cue condition. This appropriate gaze shift in the ASD group was more evident in the second half of trials in than in the first half, as revealed by the mean proportion of fixation time in the eye area to valid gaze data in the early phase (during face image presentation) and the time to first fixation on the eye area. These results suggest that individuals with ASD may benefit from the short-period trial experiment by enhancing the usage of gaze cue.

Perisaccadic Mislocalization of Visual Targets by Head-Free Gaze Shifts: Visual or Motor?

2008 ◽  
Vol 100 (4) ◽  
pp. 1848-1867 ◽  
Author(s):  
Sigrid M. C. I. van Wetter ◽  
A. John van Opstal
Keyword(s):  
Target Location ◽  
Saccadic Eye Movements ◽  
Open Loop ◽  
Spatial Updating ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
The Gaze ◽  
Visual Probe ◽  
Saccade Onset ◽  
Saccade Direction

Such perisaccadic mislocalization is maximal in the direction of the saccade and varies systematically with the target-saccade onset delay. We have recently shown that under head-fixed conditions perisaccadic errors do not follow the quantitative predictions of current visuomotor models that explain these mislocalizations in terms of spatial updating. These models all assume sluggish eye-movement feedback and therefore predict that errors should vary systematically with the amplitude and kinematics of the intervening saccade. Instead, we reported that errors depend only weakly on the saccade amplitude. An alternative explanation for the data is that around the saccade the perceived target location undergoes a uniform transient shift in the saccade direction, but that the oculomotor feedback is, on average, accurate. This “ visual shift” hypothesis predicts that errors will also remain insensitive to kinematic variability within much larger head-free gaze shifts. Here we test this prediction by presenting a brief visual probe near the onset of gaze saccades between 40 and 70° amplitude. According to models with inaccurate gaze-motor feedback, the expected perisaccadic errors for such gaze shifts should be as large as 30° and depend heavily on the kinematics of the gaze shift. In contrast, we found that the actual peak errors were similar to those reported for much smaller saccadic eye movements, i.e., on average about 10°, and that neither gaze-shift amplitude nor kinematics plays a systematic role. Our data further corroborate the visual origin of perisaccadic mislocalization under open-loop conditions and strengthen the idea that efferent feedback signals in the gaze-control system are fast and accurate.

Rapid horizontal gaze movement in the monkey

1995 ◽  
Vol 73 (4) ◽  
pp. 1632-1652 ◽  
Author(s):  
J. O. Phillips ◽  
L. Ling ◽  
A. F. Fuchs ◽  
C. Siebold ◽  
J. J. Plorde
Keyword(s):  
Eye Movement ◽  
Head Movement ◽  
Vertical Axis ◽  
Head Position ◽  
Head Movements ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
The Gaze ◽  
Small Correction ◽  
Horizontal Gaze

1. We studied horizontal eye and head movements in three monkeys that were trained to direct their gaze (eye position in space) toward jumping targets while their heads were both fixed and free to rotate about a vertical axis. We considered all gaze movements that traveled > or = 80% of the distance to the new visual target. 2. The relative contributions and metrics of eye and head movements to the gaze shift varied considerably from animal to animal and even within animals. Head movements could be initiated early or late and could be large or small. The eye movements of some monkeys showed a consistent decrease in velocity as the head accelerated, whereas others did not. Although all gaze shifts were hypometric, they were more hypometric in some monkeys than in others. Nevertheless, certain features of the gaze shift were identifiable in all monkeys. To identify those we analyzed gaze, eye in head position, and head position, and their velocities at three points in time during the gaze shift: 1) when the eye had completed its initial rotation toward the target, 2) when the initial gaze shift had landed, and 3) when the head movement was finished. 3. For small gaze shifts (< 20 degrees) the initial gaze movement consisted entirely of an eye movement because the head did not move. As gaze shifts became larger, the eye movement contribution saturated at approximately 30 degrees and the head movement contributed increasingly to the initial gaze movement. For the largest gaze shifts, the eye usually began counterrolling or remained stable in the orbit before gaze landed. During the interval between eye and gaze end, the head alone carried gaze to completion. Finally, when the head movement landed, it was almost aimed at the target and the eye had returned to within 10 +/- 7 degrees, mean +/- SD, of straight ahead. Between the end of the gaze shift and the end of the head movement, gaze remained stable in space or a small correction saccade occurred. 4. Gaze movements < 20 degrees landed accurately on target whether the head was fixed or free. For larger target movements, both head-free and head-fixed gaze shifts became increasingly hypometric. Head-free gaze shifts were more accurate, on average, but also more variable. This suggests that gaze is controlled in a different way with the head free. For target amplitudes < 60 degrees, head position was hypometric but the error was rather constant at approximately 10 degrees.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Saccades and smooth pursuit eye movements trigger equivalent gaze-cued orienting effects

2018 ◽  
Vol 71 (9) ◽  
pp. 1860-1872 ◽  
Author(s):  
Stephen RH Langton ◽  
Alex H McIntyre ◽  
Peter JB Hancock ◽  
Helmut Leder
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Target Location ◽  
Eye Gaze ◽  
Saccadic Eye Movements ◽  
Gaze Shift ◽  
The Gaze ◽  
Orienting Effect ◽  
Motion Speed ◽  
Uncued Target

Research has established that a perceived eye gaze produces a concomitant shift in a viewer’s spatial attention in the direction of that gaze. The two experiments reported here investigate the extent to which the nature of the eye movement made by the gazer contributes to this orienting effect. On each trial in these experiments, participants were asked to make a speeded response to a target that could appear in a location toward which a centrally presented face had just gazed (a cued target) or in a location that was not the recipient of a gaze (an uncued target). The gaze cues consisted of either fast saccadic eye movements or slower smooth pursuit movements. Cued targets were responded to faster than uncued targets, and this gaze-cued orienting effect was found to be equivalent for each type of gaze shift both when the gazes were un-predictive of target location (Experiment 1) and counterpredictive of target location (Experiment 2). The results offer no support for the hypothesis that motion speed modulates gaze-cued orienting. However, they do suggest that motion of the eyes per se, regardless of the type of movement, may be sufficient to trigger an orienting effect.

scholarly journals Fear-specific leftward bias in gaze direction judgment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yue Zhang ◽  
Qiqi Hu ◽  
Xinwei Lai ◽  
Zhonghua Hu ◽  
Shan Gao
Keyword(s):  
Judgment Task ◽  
Gaze Direction ◽  
Emotional Information ◽  
Cerebral Lateralization ◽  
Low Level ◽  
The Gaze ◽  
Fearful Faces ◽  
Perception Bias ◽  
Behavioural Experiments ◽  
Direction Judgment

AbstractPrevious studies have shown that humans have a left spatial attention bias in cognition and behaviour. However, whether there exists a leftward perception bias of gaze direction has not been investigated. To address this gap, we conducted three behavioural experiments using a forced-choice gaze direction judgment task. The point of subjective equality (PSE) was employed to measure whether there was a leftward perception bias of gaze direction, and if there was, whether this bias was modulated by face emotion. The results of experiment 1 showed that the PSE of fearful faces was significantly positive as compared to zero and this effect was not found in angry, happy, and neutral faces, indicating that participants were more likely to judge the gaze direction of fearful faces as directed to their left-side space, namely a leftward perception bias. With the response keys counterbalanced between participants, experiment 2a replicated the findings in experiment 1. To further investigate whether the gaze direction perception variation was contributed by emotional or low-level features of faces, experiment 2b and 3 used inverted faces and inverted eyes, respectively. The results revealed similar leftward perception biases of gaze direction in all types of faces, indicating that gaze direction perception was biased by emotional information in faces rather than low-level facial features. Overall, our study demonstrates that there a fear-specific leftward perception bias in processing gaze direction. These findings shed new light on the cerebral lateralization in humans.

scholarly journals What is unique about the human eye? Comparative image analysis on the external eye morphology of human and nonhuman great apes

2021 ◽  
Author(s):  
Fumihiro Kano ◽  
Takeshi Furuichi ◽  
Chie Hashimoto ◽  
Christopher Krupenye ◽  
Jesse G Leinwand ◽  
...  
Keyword(s):  
Image Analysis ◽  
Eye Gaze ◽  
Great Apes ◽  
Gaze Direction ◽  
Human Eye ◽  
The Gaze ◽  
Eye Morphology ◽  
New Findings ◽  
Heated Debate ◽  
Signaling Hypothesis

The gaze-signaling hypothesis and the related cooperative-eye hypothesis posit that humans have evolved special external eye morphology, including exposed white sclera (the white of the eye), to enhance the visibility of eye-gaze direction and thereby facilitate conspecific communication through joint-attentional interaction and ostensive communication. However, recent quantitative studies questioned these hypotheses based on new findings that humans are not necessarily unique in certain eye features compared to other great ape species. Therefore, there is currently a heated debate on whether external eye features of humans are distinguished from those of other apes and how such distinguished features contribute to the visibility of eye-gaze direction. This study leveraged updated image analysis techniques to test the uniqueness of human eye features in facial images of great apes. Although many eye features were similar between humans and other species, a key difference was that humans have uniformly white sclera which creates clear visibility of both eye outline and iris; the two essential features contributing to the visibility of eye-gaze direction. We then tested the robustness of the visibility of these features against visual noises such as darkening and distancing and found that both eye features remain detectable in the human eye, while eye outline becomes barely detectable in other species under these visually challenging conditions. Overall, we identified that humans have distinguished external eye morphology among other great apes, which ensures robustness of eye-gaze signal against various visual conditions. Our results support and also critically update the central premises of the gaze-signaling hypothesis.

Irrelevant Robot Signals in a Categorization Task Induce Cognitive Conflict in Performance, Eye Trajectories, the N2 ERP-EEG Component, and Frontal Theta Oscillations

2021 ◽  
pp. 1-19
Author(s):  
Jairo Perez-Osorio ◽  
Abdulaziz Abubshait ◽  
Agnieszka Wykowska
Keyword(s):  
Eye Tracking ◽  
Cognitive Conflict ◽  
Mental States ◽  
Error Rates ◽  
Gaze Shift ◽  
Categorization Task ◽  
The Gaze ◽  
Spectral Perturbation ◽  
Trial Participants ◽  
Lateral Head

Abstract Understanding others' nonverbal behavior is essential for social interaction, as it allows, among others, to infer mental states. Although gaze communication, a well-established nonverbal social behavior, has shown its importance in inferring others' mental states, not much is known about the effects of irrelevant gaze signals on cognitive conflict markers during collaborative settings. Here, participants completed a categorization task where they categorized objects based on their color while observing images of a robot. On each trial, participants observed the robot iCub grasping an object from a table and offering it to them to simulate a handover. Once the robot “moved” the object forward, participants were asked to categorize the object according to its color. Before participants were allowed to respond, the robot made a lateral head/gaze shift. The gaze shifts were either congruent or incongruent with the object's color. We expected that incongruent head cues would induce more errors (Study 1), would be associated with more curvature in eye-tracking trajectories (Study 2), and induce larger amplitude in electrophysiological markers of cognitive conflict (Study 3). Results of the three studies show more oculomotor interference as measured in error rates (Study 1), larger curvatures eye-tracking trajectories (Study 2), and higher amplitudes of the N2 ERP of the EEG signals as well as higher event-related spectral perturbation amplitudes (Study 3) for incongruent trials compared with congruent trials. Our findings reveal that behavioral, ocular, and electrophysiological markers can index the influence of irrelevant signals during goal-oriented tasks.

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