Perceived Size and Spatial Coding

Arnold, Derek H.; Birt, Annette; Wallis, Thomas S. A.

doi:10.1523/jneurosci.0578-08.2008

Cited by 17 publications

(16 citation statements)

References 32 publications

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“…Similar mechanisms might hold beyond the retina as well. For example, perceived size appears to be represented in early visual cortex (Arnold, Birt, & Wallis, 2008; Murray, Boyaci, & Kersten, 2006), and population coding of object size could also give rise to ensemble coding of average size. Along these lines, Im and Chong (2009) reported that the mean sizes of sets of target circles embedded in rings of smaller or larger surrounding circles were perceived as a function of the Ebbinghaus illusion induced by the surrounding circles, and not based on the physical sizes of the target circles.…”

Section: Discussionmentioning

confidence: 99%

An aftereffect of adaptation to mean size

et al. 2012

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The visual system rapidly represents the mean size of sets of objects. Here, we investigated whether mean size is explicitly encoded by the visual system, along a single dimension like texture, numerosity, and other visual dimensions susceptible to adaptation. Observers adapted to two sets of dots with different mean sizes, presented simultaneously in opposite visual fields. After adaptation, two test patches replaced the adapting dot sets, and participants judged which test appeared to have the larger average dot diameter. They generally perceived the test that replaced the smaller mean size adapting set as being larger than the test that replaced the larger adapting set. This differential aftereffect held for single test dots (Experiment 2) and high-pass filtered displays (Experiment 3), and changed systematically as a function of the variance of the adapting dot sets (Experiment 4), providing additional support that mean size is adaptable, and therefore explicitly encoded dimension of visual scenes.

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Section: Discussionmentioning

confidence: 99%

An aftereffect of adaptation to mean size

et al. 2012

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“…Specifically, Arnold et al (2008) found that perceived size could influence the spatial profile of the TAE. Similarly, our results suggest that the spatial location of the TAE is influenced by the perceived location of the adaptor when it is shifted by a motion-based illusion.…”

Section: Discussionmentioning

confidence: 99%

“…This selectivity of the TAE appears to be largely dependent on the match between the retinotopic locations of the adaptor and test stimuli (Boi,Öğmen, & Herzog, 2011; Knapen, Rolfs, Wexler, & Cavanagh, 2010), though there were earlier reports of spatiotopic transfer of the TAE across saccades (Melcher, 2005). Intriguingly, Arnold, Birt, and Wallis (2008) demonstrated that the TAE can be influenced by an illusion of perceived size. In their experiment, they manipulated distance cues to influence the perceived size of an adapting stimulus and showed that the perceptual overlap between the adapting and test grating could bias the direction of the TAE.…”

Section: Introductionmentioning

confidence: 99%

The motion-induced shift in the perceived location of a grating also shifts its aftereffect

et al. 2012

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Motion can bias the perceived location of a stationary stimulus, but whether this occurs at a high level of representation or at early, retinotopic stages of visual processing remains an open question. As coding of orientation emerges early in visual processing, we tested whether motion could influence the spatial location at which orientation adaptation is seen. Specifically, we examined whether the tilt aftereffect (TAE) depends on the perceived or the retinal location of the adapting stimulus, or both. We used the flash-drag effect (FDE) to produce a shift in the perceived position of the adaptor away from its retinal location. Subjects viewed a patterned disk that oscillated clockwise and counterclockwise while adapting to a small disk containing a tilted linear grating that was flashed briefly at the moment of the rotation reversals. The FDE biased the perceived location of the grating in the direction of the disk's motion immediately following the flash, allowing dissociation between the retinal and perceived location of the adaptor. Brief test gratings were subsequently presented at one of three locations—the retinal location of the adaptor, its perceived location, or an equidistant control location (antiperceived location). Measurements of the TAE at each location demonstrated that the TAE was strongest at the retinal location, and was larger at the perceived compared to the antiperceived location. This indicates a skew in the spatial tuning of the TAE consistent with the FDE. Together, our findings suggest that motion can bias the location of low-level adaptation.

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“…In this illusion, the size of the moon appears bigger when it is viewed near the horizon and smaller when it is at the top of the sky. Previous explorations were based on the retinal images and spatial code interactions and led the authors suppose that spatial coding mechanisms modulate the retina output [4] and in the absence of contextual references the retinal circuity had less *Address correspondence to this author to the Departamento de Psicologia Experimental, Instituto de Psicologia USP, Av. Prof. Mello Moraes, 1721, 05338-030, Butantã, São Paulo, SP, Brasil; Tel: +55 11 3091 1918; E-mail: costamf@usp.br information to compare spatially and the output to the visual cortex were biased.…”

Section: Introductionmentioning

confidence: 99%

Depth Cues Changes Circle Size Judgment Measured by Psychophysical Scaling

Costa

Nagy²,

Magalhães³

2014

TOPSYJ

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Abstract:The aim of our study was to investigate whether different circle sizes, in conditions of pure size judgment and in a simple contextual judgment with an interfering depth suggesting background, produce different size perceptions. We used the magnitude estimation to obtain the apparent size of circles under two different experimental conditions: with a neutral black background and with a convergent gradient to generate an artificial horizon to evoke depth cues. Twentytwo subjects with normal or corrected-to-normal visual acuity (mean age = 21.3 yrs; SD = 1.6) were tested. The procedure consisted of two gray circles at luminance of 40 cd/m2, separated 10 degrees of visual angle apart from each other. On the left side was always present the reference circle (visual angle of 1.1 degree) in which was assigned an arbitrary value of 50 was assigned. The subjects' task was to judge the size of the circles appearing in the right side of the monitor screen assigning a number proportional to the perceived altered size, relative to the reference circle. Seven different sizes (0.6, 0.8, 1.0, 1.1, 1.3, 1.4, 1.5 degrees) were presented in each condition. Our results have shown a high correlation for circle size and depth conditions (R = 0.987 and R = 0.997) between the logs of the stimuli and the subjective magnitude estimated values. The exponents obtained by the Power Law were 0.79 and 1.09, respectively to each condition. Additionally, a gender effect was observed in which males had showed an expansive perception of size with no dependence on the background. We concluded that in the induced depth condition, the perception of the circle sizes were judged subjectively closer to their respective physical size than in the condition of free visual cues. Our data reinforces the integrative manner of perceptual system when working with the sensory information.

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Perceived Size and Spatial Coding

Cited by 17 publications

References 32 publications

An aftereffect of adaptation to mean size

An aftereffect of adaptation to mean size

The motion-induced shift in the perceived location of a grating also shifts its aftereffect

Depth Cues Changes Circle Size Judgment Measured by Psychophysical Scaling

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