Ensemble size judgments account for size constancy.

Area of Science:

• Visual perception
• Cognitive psychology
• Ensemble coding

Background:

• The visual system compresses redundant environmental information into ensemble representations.
• Ensemble perception flexibly integrates information across various visual domains.

Purpose of the Study:

• To investigate if ensemble size representations are based on physical object size or perceptual size influenced by size constancy.
• To determine the role of linear perspective cues in modulating ensemble size perception.

Main Methods:

• Presenting sets of triangles with and without linear perspective cues to induce perceptual size changes.
• Observers judged if a test triangle matched the average size of the preceding set.
• Comparing the influence of linear perspective with other depth cues like occlusion and height-in-field.

Main Results:

• Ensemble size representations incorporated size constancy, reflecting perceived rather than absolute physical size.
• The bias in ensemble perception was predictable from individual item biases.
• Linear perspective cues significantly influenced ensemble size perception, unlike occlusion or height-in-field alone.

Conclusions:

• Average size perception is modulated by size constancy, reflecting perceived object size.
• Ensemble coding mechanisms are sensitive to perceptual transformations, not just raw physical input.
• Linear perspective is a potent cue for size constancy within ensemble perception.