August 2012
Volume 12, Issue 9
Free
Vision Sciences Society Annual Meeting Abstract  |   August 2012
When luminance increment thresholds depend on apparent lightness
Author Affiliations
  • Marianne Maertens
    Technische Univeristät Berlin and Bernstein Center for Computational Neuroscience Berlin
  • Felix Wichmann
    Bernstein Center for Computational Neuroscience Tübingen and Wilhelm Schickhard Institute for Computer Sciences Eberhard Karls University Tübingen
Journal of Vision August 2012, Vol.12, 1213. doi:10.1167/12.9.1213
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      Marianne Maertens, Felix Wichmann; When luminance increment thresholds depend on apparent lightness. Journal of Vision 2012;12(9):1213. doi: 10.1167/12.9.1213.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

p { margin-bottom: 0.08in; } The just noticeable difference (JND) between two stimulus intensities increases proportional to the background intensity (Weber's law). It is less clear, however, whether the JND is a function of the proximal or perceptual stimulus intensity. In the domain of achromatic surface colors the question would translate to whether the JND depends on local luminance or surface lightness. In the laboratory using simple stimuli such as uniform patches, proximal (luminance) and perceived intensity (lightness) often coincide. Reports that tried to disentangle the two factors yielded inconsistent results (e.g. Heinemann, 1961 JEP 61 389-399; Cornsweet and Teller, 1965 JOSA 55(10) 1303-1308; Zaidi and Krauskopf, 1985 Vision Res 26 759-62; McCourt and Kingdom, 1996 Vision Res 36 2563-73; Henning, Millar and Hill, 2000 JOSA 17(7) 1147-1159; Hillis and Brainard, 2007 CurrBiol 17 1714-1719).

Following a previous experiment (Maertens and Wichmann, 2010 JVis 10 424) we measured discrimination thresholds in the Adelson checkerboard pattern for two equiluminant checks which differed in lightness (black vs. white). Discrimination performance was measured in two conditions: in the 'blob' condition, the increment was a two-dimensional gaussian centered on the check, in the 'check' condition, the increment was a constant that was added to the entire check. Performance was assessed in a 2-interval forced-choice and a yes-no task. In the 'blob' condition thresholds were indistinguishable between equiluminant checks and did not differ between the tasks. In the 'check' condition thresholds differed between equiluminant checks and were elevated for the lighter one. This was true for the yes-no task and to a lesser extent in the 2-IFC task. We think that these results require discussion beyond the question for the appropriate type of increment. We believe that the visual system might respond fundamentally different to light emanating from meaningful surfaces and to isolated spots of light.

Meeting abstract presented at VSS 2012

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