Global and high-level effects in crowding cannot be predicted by either high-dimensional pooling or target cueing

Area of Science:

• Visual perception
• Cognitive psychology
• Computational neuroscience

Background:

• Visual crowding occurs when target perception degrades with nearby flankers.
• Traditionally, crowding was viewed as local, low-level feature interactions.
• Recent studies reveal high-level effects (e.g., grouping, face-holistic crowding), suggesting a more global phenomenon.

Purpose of the Study:

• To test if the Texture Tiling model (TTM) can explain high-level crowding effects.
• To determine if grouping effects in crowding are mediated by post-perceptual factors.

Main Methods:

• The TTM's predictions were rigorously evaluated against data from six studies exhibiting high-level crowding.
• Grouping effects were analyzed to assess the role of post-perceptual target cueing.

Main Results:

• The TTM failed to account for any of the observed high-level crowding effects.
• The TTM's performance was comparable to simple pooling models.
• Grouping effects in crowding were not explained by post-perceptual factors like target cueing.

Conclusions:

• Complex target-flanker interactions, not sophisticated pooling, drive high-level crowding.
• Crowding is a multilevel phenomenon occurring across various stages of visual processing.
• Post-perceptual factors do not account for grouping effects in visual crowding.