Polarity-dependent orientation illusions: Review, model, and simulations.

Area of Science:

• Visual Perception
• Computational Neuroscience
• Psychophysics

Background:

• Polarity-dependent orientation illusions, like the Münsterberg/Café Wall illusion, demonstrate that luminance contrast influences perceived orientation.
• These illusions highlight the complex interplay between geometric and luminance information in visual processing.

Purpose of the Study:

• To present novel variants of polarity-dependent orientation illusions.
• To introduce and test a computational model explaining the neural basis of these illusions.
• To investigate the neural correlates of illusory and veridical tilt perception.

Main Methods:

• Presentation of numerous examples of polarity-dependent orientation illusions, including novel variants.
• Development of a two-level convolutional neural network model simulating visual processing.
• Simulation analysis to identify spatial patterns of neural activation in response to illusory and non-illusory figures.

Main Results:

• A common spatial pattern of neural activation, termed 'oblique clusters,' was identified in figures inducing illusory tilt.
• These 'oblique clusters' were absent in related non-illusory figures.
• Similar 'oblique cluster' patterns were observed in simulations of figures inducing veridical tilt perception.

Conclusions:

• The perception of tilt, both illusory and veridical, may be based on specific spatial patterns of neural activity rather than narrowly tuned neurons.
• 'Oblique clusters' represent a potential neural signature for tilt perception.
• The findings offer insights into the neural mechanisms underlying orientation perception and visual illusions.