Perception of 3D shape in context: contrast and assimilation

Area of Science:

• Visual Perception
• Computational Neuroscience
• Psychophysics

Background:

• The integration of shape and its surrounding context is traditionally understood to rely on cue-dependent representations.
• Existing models suggest that visual information processing is primarily driven by specific sensory cues.

Purpose of the Study:

• To investigate the roles of both cue-invariant and cue-dependent representations in shape-surround integration.
• To determine how different visual cues (binocular disparity and motion) influence this integration process.

Main Methods:

• Experiments utilized a central hinged plane and flanking planes defined by either binocular disparity or motion.
• A 'within-cue' condition used identical cues for shape and surround, while a 'cross-cue' condition used different cues.
• Observers performed a task comparing the dihedral angle of the central shape against a reference.

Main Results:

• When the central shape was defined by disparity, a contrast bias occurred in the within-cue condition, but shape assimilation in the cross-cue condition.
• When the central shape was defined by motion, no significant results were found overall, though a contrast bias in the within-cue condition suggested cue-dependent integration.

Conclusions:

• Shape-surround integration involves both cue-invariant and cue-dependent representations, challenging previous assumptions.
• The specific visual cues employed significantly modulate the integration process and perceptual outcomes.
• Cue-dependent representations play a role in integration, particularly when consistent cues are used.