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The Anderson-Winawer illusion: it's not occlusion
1Université de Montréal, Montréal, Québec, Canada. frederic.poirier@umontreal.ca
Attention, Perception & Psychophysics
|July 28, 2009
Summary
A lightness illusion causes identical textures to appear black or white. Occlusion-based theories fail to explain this, as demonstrated by new modeling and psychophysical data.
Area of Science:
- Visual perception
- Computational neuroscience
- Psychophysics
Background:
- Anderson and Winawer (2005) demonstrated a striking lightness illusion where identical textures are perceived as black or white.
- Albert (2007) proposed an occlusion-based theory to explain this illusion by inferring surface depth and visibility.
Purpose of the Study:
- To test the validity of Albert's (2007) occlusion-based theory for the Anderson and Winawer (2005) lightness illusion.
- To propose an alternative explanation for the observed lightness effects.
Main Methods:
- Utilized computational modeling to simulate visual scene interpretation.
- Employed psychophysical experiments to gather human perception data.
- Manipulated figure contrast levels within the range tested by Anderson and Winawer (2005).
Main Results:
- Modifications based on Albert's (2007) theory reversed the illusion, contrary to the original findings.
- This reversal occurred within the lower figure-contrast range investigated.
- Occlusion-based theories were found insufficient to account for the Anderson and Winawer (2005) data.
Conclusions:
- Albert's (2007) occlusion-based theory cannot explain the Anderson and Winawer (2005) lightness illusion.
- A novel scene-interpretation strategy is proposed to account for the illusion's effects, particularly at lower contrasts.
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