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Mechanisms underlying simultaneous brightness contrast: Early and innate

Sinha, Pawan and Crucilla, Sarah and Gandhi, Tapan and Rose, Dylan and Singh, Amy and Ganesh, Suma and Mathur, Umang and Bex, Peter (2020) Mechanisms underlying simultaneous brightness contrast: Early and innate. Vision Research, 173 . pp. 41-49. ISSN 0042-6989.

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In the phenomenon of simultaneous brightness contrast, two patches, one on a dark background and the other on a light one, appear to have different brightness despite being physically equi-luminant. Elucidating the phenomenon’s underlying mechanisms is relevant for the larger question of how the visual system makes photometric judgments in images. Accounts over the past century have spanned low-, mid- and high-level visual processes, but a definitive resolution has not emerged. We present three studies that collectively demonstrate that the computations underlying this phenomenon are low-level, instantiated prior to binocular fusion, and available innately, without need for inferential learning via an individual’s visual experience. In our first two studies, we find that strong brightness induction is obtained even when observers are unaware of any luminance differences in the neighborhoods of the probe patches. Results with dichoptic displays reveal that eye of origin, although not evident consciously, has a marked influence on the eventual brightness percept of the probe patches, thereby localizing brightness estimation to a site preceding binocular fusion. The third study uses conventional simultaneous brightness contrast displays, but an unusual group of participants: Congenitally blind children whom we were able to treat surgically. The results demonstrate an immediate susceptibility to the simultaneous brightness illusion after sight onset. Together, these data strongly constrain the search for mechanisms underlying a fundamental brightness phenomenon.

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Additional Information:© 2020 Elsevier Ltd. Received 29 October 2019, Revised 25 April 2020, Accepted 26 April 2020, Available online 25 May 2020.
Funding AgencyGrant Number
NIHR01 EY020517
Subject Keywords:Brightness perception; Late sight onset; Dichoptic displays; Nature versus nurture; Simultaneous contrast illusion
Record Number:CaltechAUTHORS:20200526-125656932
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Official Citation:Pawan Sinha, Sarah Crucilla, Tapan Gandhi, Dylan Rose, Amy Singh, Suma Ganesh, Umang Mathur, Peter Bex, Mechanisms underlying simultaneous brightness contrast: Early and innate, Vision Research, Volume 173, 2020, Pages 41-49, ISSN 0042-6989, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:103454
Deposited By: Tony Diaz
Deposited On:26 May 2020 20:10
Last Modified:26 May 2020 20:10

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