scholarly journals Attention and distraction in the modular visual system of a jumping spider

2021 ◽  
pp. jeb.231035
Author(s):  
Margaret Bruce ◽  
Daniel Daye ◽  
Skye M. Long ◽  
Alex M. Winsor ◽  
Gil Menda ◽  
...  
Keyword(s):  
Visual System ◽  
Field Of View ◽  
Gaze Direction ◽  
Distractor Stimulus ◽  
Jumping Spider ◽  
Order Processing ◽  
Primary Stimulus ◽  
Jumping Spiders ◽  
The Gaze ◽  
High Acuity

Animals must selectively attend to relevant stimuli and avoid being distracted by unimportant stimuli. Jumping spiders (Salticidae) do this by coordinating eyes with different capabilities. Objects are examined by a pair of high-acuity principal eyes, whose narrow field of view is compensated for by retinal movements. The principal eyes overlap in field of view with motion-sensitive anterior-lateral eyes, which direct their gaze to new stimuli. Using a salticid-specific eyetracker, we monitored the gaze direction of the principal eyes as they examined a primary stimulus. We then presented a distractor stimulus visible only to the ALEs and observed whether the principal eyes reflexively shifted their gaze to it or whether this response was flexible. Whether spiders redirected their gaze to the distractor depended on properties of both the primary and distractor stimuli. This flexibility suggests that higher-order processing occurs in the management of the attention of the principal eyes.

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 Assessment of Stereoscopic Multi-resolution Images for a Virtual Reality System

2010 ◽  
Vol 9 (2) ◽  
pp. 31-37 ◽  
Author(s):  
Masahiko Ogawa ◽  
Kazunori Shidoji ◽  
Yuji Matsuki
Keyword(s):  
High Resolution ◽  
Field Of View ◽  
Monitor System ◽  
Wide Angle ◽  
Camera System ◽  
Technical Limitation ◽  
Resolution Image ◽  
The Gaze ◽  
High Resolution Image ◽  
Perceptual Characteristics

A camera and monitor system that projects actual real-world images has yet to be developed due to the technical limitation that the existing cameras cannot simultaneously acquire high-resolution and wide-angle images. In this research, we try to resolve this issue by superimposing images; a method which is effective because the entire wide-angle image does not necessarily need to be of high resolution because of perceptual characteristics of the human visual system. First, we examined the minimum resolution required for the field of view, which indicated that a triple-resolution image where positions more than 20 and 40 deg from the center of the visual field were decreased to 25% and approximately 11% of the resolution of the gaze point, respectively, was perceived as similar to a completely high-resolution image. Next, we investigated whether the participants could distinguish between the original completely high-resolution image and processed images, which included triple-resolution, dual-resolution, and low-resolution images. Our results suggested that the participants could not differentiate between the triple-resolution image and the original image. Finally, we developed a stereoscopic camera system based on our results

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 Descriptions of three new species of jumping-spiders, genus Arnoliseus (Araneae, Salticidae), from Rio de Janeiro state, Brazil, with comments on their genital morphology and a key to species

2020 ◽  
Vol 96 (1) ◽  
pp. 73-90
Author(s):  
Renner Luiz Cerqueira Baptista ◽  
Pedro de Souza Castanheira ◽  
Gabriel Assunção Oliveira ◽  
André Wanderley do Prado
Keyword(s):  
New Species ◽  
Atlantic Forest ◽  
Rio De Janeiro ◽  
Genital Morphology ◽  
Key To Species ◽  
Jumping Spider ◽  
Jumping Spiders ◽  
Three New Species ◽  
The City ◽  
Janeiro State

New data on the jumping-spider genus Arnoliseus are presented. Three new species from the Atlantic Forest in Rio de Janeiro state are described, based on both sexes: Arnoliseus cariocasp. nov. from the city of Rio de Janeiro, and Arnoliseus hastatussp. nov. and Arnoliseus falcatussp. nov. from the municipality of Cachoeiras de Macacu. The genus’ genital morphology is discussed in detail and new English terminology for their structures is created. An identification key for all Arnoliseus species is given.

TRIAL-AND-ERROR SOLVING OF A CONFINEMENT PROBLEM BY A JUMPING SPIDER, PORTIA FIMBRIATA

Behaviour ◽  
2001 ◽  
Vol 138 (10) ◽  
pp. 1215-1234 ◽  
Author(s):  
Robert Jackson ◽  
Chris Carter ◽  
Michael Tarsitano
Keyword(s):  
The Other ◽  
Trial And Error ◽  
Jumping Spider ◽  
Aggressive Mimicry ◽  
Jumping Spiders ◽  
Test Algorithm

Abstract Portia is a genus of web-invading araneophagic jumping spiders known from earlier studies to derive aggressive-mimicry signals by using a generate-and-test algorithm (trial-and-error tactic). Here P. fimbriata's use of trial-and-error to solve a confinement problem (how to escape from an island surrounded by water) is investigated. Spiders choose between two potential escape tactics (leap or swim), one of which will fail (bring spider no closer to edge of tray) and the other of which will partially succeed (bring spider closer to edge of tray). The particular choice that will partially succeed is unknown to the spider. Using trial-anderror, P.fimbriata solves the confinement problem both when correct choices are rewarded (i.e. when the spider is moved closer to edge of tray) and when incorrect choices are punished (i.e. when the spider gets no closer to edge of tray).

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