scholarly journals How wide is the cone of direct gaze?

2018 ◽  
Vol 5 (8) ◽  
pp. 180249 ◽  
Author(s):  
Tarryn Balsdon ◽  
Colin W. G. Clifford
Keyword(s):  
Gaze Direction ◽  
Considerable Evidence ◽  
Direct Gaze ◽  
The Gaze ◽  
Insight Into ◽  
Clinical Populations

The cone of direct gaze refers to the range of gaze deviations an observer accepts as looking directly at them. Previous experiments have calculated the width of the cone of direct gaze using the gaze deviations actually presented to the observer, however, there is considerable evidence that observers actually perceive gaze to be systematically more deviated than actually presented. Here, we examine the width of the cone of direct gaze in units of perceived gaze deviation. In doing so, we are able to disambiguate differences in width both within and between observers that are due to differences in their perception of gaze and due to differences in what observers consider to be looking at them. We suggest that this line of inquiry can offer further insight into the perception of gaze direction, and how this perception may differ in clinical populations.

Examining Gaze Cone Shape and Size

Perception ◽  
2021 ◽  
pp. 030100662110599
Author(s):  
Gernot Horstmann ◽  
Linda Linke
Keyword(s):  
Present Experiment ◽  
Cone Angle ◽  
Important Task ◽  
Gaze Direction ◽  
Direct Gaze ◽  
The Gaze ◽  
Extended Range ◽  
The Mean ◽  
Fixation Points ◽  
Shape And Size

Another person's looking behavior is used by observers to judge gaze direction and fixation points. An important task in this context is the judgement of direct gaze, that is, the perception of being looked at. The cone of gaze can be defined as the range of fixation points that support direct gaze. The cone concept implies that this range lawfully increases with distance, but that the cone angle is constant. The present experiment tested the concept with a larger number and a more extended range of distances than previously done, and took care of possible directional errors. The gaze cone was found to be roughly linear, and stable between 1.6 m and 7.9 m – an almost perfect cone. The mean cone size subtended 5.2° in diameter when averaged over ascending and descending series. Measures differed, however, in ascending and descending series, consistent with a conservative bias. Also, the variability of judgements increased slightly with distance. Results are discussed considering whether cone size is actually smaller than often reported in the literature.

Relational property between head and eye regions is the primary determinant of the efficiency in search for a deviant gaze

2009 ◽  
Vol 62 (9) ◽  
pp. 1723-1737 ◽  
Author(s):  
Hirokazu Doi ◽  
Kazuhiro Ueda ◽  
Kazuyuki Shinohara
Keyword(s):  
Visual System ◽  
Human Visual System ◽  
Gaze Direction ◽  
Relational Property ◽  
Direct Gaze ◽  
The Gaze ◽  
Primary Determinant ◽  
Feature Information ◽  
Types Of Information ◽  
Eye Region

The human visual system is extremely sensitive to the directions of the gazes of others. However, the mechanism underlying gaze direction perception has yet to be clarified. The primary aim of the present study is to investigate whether the relational property between the local eye region and other facial regions serves as the primary visual system cue in detecting a direct gaze. Our results showed that search efficiency was determined primarily by the gaze direction indicated by the relational property regardless of the direction indicated by the local feature information of the eye region; this was true even when the gaze directions indicated by these two types of information were conflicting. These results bolster the hypothesis that the human visual system primarily accesses socially meaningful information in searching for a deviant gaze.

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.

scholarly journals MEASUREMENT OF SUN INDUCED CHLOROPHYLL FLUORESCENCE USING HYPERSPECTRAL SATELLITE IMAGERY

2016 ◽  
Vol XLI-B8 ◽  
pp. 911-913
Author(s):  
S. M. Irteza ◽  
J. E. Nichol
Keyword(s):  
Chlorophyll Fluorescence ◽  
Steady State ◽  
Satellite Images ◽  
Plant Stress ◽  
Fluorescence Signal ◽  
Absorption Bands ◽  
Considerable Evidence ◽  
Different Seasons ◽  
Insight Into ◽  
Accurate Indicator

Solar Induced Chlorophyll Fluorescence (SIF), can be used as an indicator of stress in vegetation. Several scientific approaches have been made and there is considerable evidence that steady state Chlorophyll fluorescence is an accurate indicator of plant stress hence a reliable tool to monitor vegetation health status. Retrieval of Chlorophyll fluorescence provides an insight into photochemical and carbon sequestration processes within vegetation. Detection of Chlorophyll fluorescence has been well understood in the laboratory and field measurement. Fluorescence retrieval methods were applied in and around the atmospheric absorption bands 02B (Red wavelength) approximately 690 nm and 02A (Far red wavelengths) 740 nm. Hyperion satellite images were acquired for the years 2012 to 2015 in different seasons. Atmospheric corrections were applied using the 6S Model. The Fraunhofer Line Discrimanator (FLD) method was applied for retrieval of SIF from the Hyperion images by measuring the signal around the absorption bands in both vegetated and non vegetated land cover types. Absorption values were extracted in all the selected bands and the fluorescence signal was detected. The relationships between NDVI and Fluorescence derived from the satellite images are investigated to understand vegetation response within the absorption bands.

Eye-Tracking Technology

2017 ◽  
pp. 283-302
Author(s):  
Chandni Parikh
Keyword(s):  
Eye Movements ◽  
Eye Tracking ◽  
Eye Gaze ◽  
Autism Spectrum ◽  
Gaze Direction ◽  
Red Flags ◽  
High Risk Infants ◽  
Behavioral Markers ◽  
Tracking Technology ◽  
Insight Into

Eye movements and gaze direction have been utilized to make inferences about perception and cognition since the 1800s. The driving factor behind recording overt eye movements stem from the fundamental idea that one's gaze provides tremendous insight into the information processing that takes place early on during development. One of the key deficits seen in individuals diagnosed with Autism Spectrum Disorders (ASD) involves eye gaze and social attention processing. The current chapter focuses on the use of eye-tracking technology with high-risk infants who are siblings of children diagnosed with ASD in order to highlight potential bio-behavioral markers that can inform the ascertainment of red flags and atypical behaviors associated with ASD within the first few years of development.

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