Pupil adjustments to illusory perceptions of the light intensity of object surfaces
Using infrared eye tracking, we show that when gaze is maintained at the center of one of two equiluminant surfaces of a Cornsweet stimulus, designed by Lotto and Purves, that illusorily appear to be lighter or darker than the other, the eye pupils constrict or dilate, respectively. That is, pupil s...
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Frontiers Media S.A.
2025-08-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnhum.2025.1604114/full |
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| author | Bruno Laeng Bruno Laeng Hüseyin Berke Canoluk Hüseyin Berke Canoluk Shoaib Nabil Shoaib Nabil |
| author_facet | Bruno Laeng Bruno Laeng Hüseyin Berke Canoluk Hüseyin Berke Canoluk Shoaib Nabil Shoaib Nabil |
| author_sort | Bruno Laeng |
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| description | Using infrared eye tracking, we show that when gaze is maintained at the center of one of two equiluminant surfaces of a Cornsweet stimulus, designed by Lotto and Purves, that illusorily appear to be lighter or darker than the other, the eye pupils constrict or dilate, respectively. That is, pupil sizes mirror the subjective experience of differential brightness. Previous studies of pupil responses to illusions of light had focused on illusions of unveridical light sources (e.g., patterns resembling the sun), whereas in the present study, we show pupil adjustments to the illusory brightness of object surfaces within images of realistic scenes. In two control experiments, we also showed that when the edge gradients of the Cornsweet stimulus, which do differ in luminance, were either occluded or presented alone in a black field, there were no differences in pupil diameters. We also conclude that adjustments to the perception of surface reflectance are unlikely to represent anticipatory responses to probable risks of temporary visual impairment (i.e., dazzle to sunlight) and, instead, indicate that a gradual process of disambiguation of the visual scene is sufficient to elicit adjustments to the apparent light intensity of an object’s surface. |
| format | Article |
| id | doaj-art-a35b3df1be464d35a9c8960a5cb1f33a |
| institution | Kabale University |
| issn | 1662-5161 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj-art-a35b3df1be464d35a9c8960a5cb1f33a2025-08-26T11:05:48ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612025-08-011910.3389/fnhum.2025.16041141604114Pupil adjustments to illusory perceptions of the light intensity of object surfacesBruno Laeng0Bruno Laeng1Hüseyin Berke Canoluk2Hüseyin Berke Canoluk3Shoaib Nabil4Shoaib Nabil5Department of Psychology, University of Oslo, Oslo, NorwayRITMO Centre for Interdisciplinary Studies in Rhythm, Time and Motion, University of Oslo, Oslo, NorwayDepartment of Psychology, University of Oslo, Oslo, NorwayFaculty of Medicine, İzmir Bakircay University, İzmir, TürkiyeDepartment of Psychology, University of Oslo, Oslo, NorwaySchool of Psychology, University of Sussex, Brighton, United KingdomUsing infrared eye tracking, we show that when gaze is maintained at the center of one of two equiluminant surfaces of a Cornsweet stimulus, designed by Lotto and Purves, that illusorily appear to be lighter or darker than the other, the eye pupils constrict or dilate, respectively. That is, pupil sizes mirror the subjective experience of differential brightness. Previous studies of pupil responses to illusions of light had focused on illusions of unveridical light sources (e.g., patterns resembling the sun), whereas in the present study, we show pupil adjustments to the illusory brightness of object surfaces within images of realistic scenes. In two control experiments, we also showed that when the edge gradients of the Cornsweet stimulus, which do differ in luminance, were either occluded or presented alone in a black field, there were no differences in pupil diameters. We also conclude that adjustments to the perception of surface reflectance are unlikely to represent anticipatory responses to probable risks of temporary visual impairment (i.e., dazzle to sunlight) and, instead, indicate that a gradual process of disambiguation of the visual scene is sufficient to elicit adjustments to the apparent light intensity of an object’s surface.https://www.frontiersin.org/articles/10.3389/fnhum.2025.1604114/fullCornsweet effectillusionbrightnesslightnessluminancesurfaces |
| spellingShingle | Bruno Laeng Bruno Laeng Hüseyin Berke Canoluk Hüseyin Berke Canoluk Shoaib Nabil Shoaib Nabil Pupil adjustments to illusory perceptions of the light intensity of object surfaces Frontiers in Human Neuroscience Cornsweet effect illusion brightness lightness luminance surfaces |
| title | Pupil adjustments to illusory perceptions of the light intensity of object surfaces |
| title_full | Pupil adjustments to illusory perceptions of the light intensity of object surfaces |
| title_fullStr | Pupil adjustments to illusory perceptions of the light intensity of object surfaces |
| title_full_unstemmed | Pupil adjustments to illusory perceptions of the light intensity of object surfaces |
| title_short | Pupil adjustments to illusory perceptions of the light intensity of object surfaces |
| title_sort | pupil adjustments to illusory perceptions of the light intensity of object surfaces |
| topic | Cornsweet effect illusion brightness lightness luminance surfaces |
| url | https://www.frontiersin.org/articles/10.3389/fnhum.2025.1604114/full |
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