Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects

The brighter portions of a shaded complex object are in principle more informative about its lightness and are preferentially fixated during lightness judgments. In this study, we investigate whether preventing this strategy also has measurable detrimental effects on performance. Observers were pres...

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Main Authors: Matteo Toscani, Matteo Valsecchi
Format: Article
Language:English
Published: SAGE Publishing 2019-11-01
Series:i-Perception
Online Access:https://doi.org/10.1177/2041669519884335
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author Matteo Toscani
Matteo Valsecchi
author_facet Matteo Toscani
Matteo Valsecchi
author_sort Matteo Toscani
collection DOAJ
description The brighter portions of a shaded complex object are in principle more informative about its lightness and are preferentially fixated during lightness judgments. In this study, we investigate whether preventing this strategy also has measurable detrimental effects on performance. Observers were presented with a reference and a comparison three-dimensional rendered object and had to choose which one was “painted with a lighter gray.” The comparison was rendered with different diffuse reflectance values. We compared precision between three different conditions: full image, 20% of the lightest pixels removed, or 20% of the darkest pixels removed. Removing the bright pixels maximally impaired performance. The results confirm that the strategy of relying on the brightest areas of a complex object in order to estimate lightness is functionally optimal, yielding more precise representations.
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spelling doaj.art-3016324a026a4cc0ba8cf11fd4a6392d2022-12-21T17:59:21ZengSAGE Publishingi-Perception2041-66952019-11-011010.1177/2041669519884335Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional ObjectsMatteo ToscaniMatteo ValsecchiThe brighter portions of a shaded complex object are in principle more informative about its lightness and are preferentially fixated during lightness judgments. In this study, we investigate whether preventing this strategy also has measurable detrimental effects on performance. Observers were presented with a reference and a comparison three-dimensional rendered object and had to choose which one was “painted with a lighter gray.” The comparison was rendered with different diffuse reflectance values. We compared precision between three different conditions: full image, 20% of the lightest pixels removed, or 20% of the darkest pixels removed. Removing the bright pixels maximally impaired performance. The results confirm that the strategy of relying on the brightest areas of a complex object in order to estimate lightness is functionally optimal, yielding more precise representations.https://doi.org/10.1177/2041669519884335
spellingShingle Matteo Toscani
Matteo Valsecchi
Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects
i-Perception
title Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects
title_full Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects
title_fullStr Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects
title_full_unstemmed Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects
title_short Lightness Discrimination Depends More on Bright Rather Than Shaded Regions of Three-Dimensional Objects
title_sort lightness discrimination depends more on bright rather than shaded regions of three dimensional objects
url https://doi.org/10.1177/2041669519884335
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AT matteovalsecchi lightnessdiscriminationdependsmoreonbrightratherthanshadedregionsofthreedimensionalobjects