Crowding in peripheral vision: why bigger is better.
We enjoy the illusion that visual resolution is high across the entire field of vision. However, this illusion can be easily dispelled by trying to identify objects in a cluttered environment out of the corner of your eye. This reflects, in part, the well-known decline in visual resolution in peripheral vision; however, the main bottleneck for reading or object recognition in peripheral vision is crowding. Objects that can be easily identified in isolation seem indistinct and jumbled in clutter. Crowding is thought to reflect inappropriate integration of the target and flankers in peripheral vision [1, 2]. Here, we uncover and explain a paradox in peripheral crowding: under certain conditions, increasing the size or number of flanking rings results in a paradoxical decrease in the magnitude of crowding-i.e., the bigger or more numerous the flanks, the smaller the crowding. These surprising results are predicted by a model in which crowding is determined by the centroids of approximately 4-8 independent features within approximately 0.5x the target eccentricity. These features are then integrated into a texture beyond the stage of feature analysis. We speculate that this process may contribute to the illusion of high resolution across the field of vision.
Levi
Dennis M
DM
School of Optometry and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720-2020, USA. dlevi@berkeley.edu
Carney
Thom
T
D000328:Adult; D004192:Discrimination, Psychological; D005364:Field Dependence-Independence; D006801:Humans; D010364:Pattern Recognition, Visual; D010470:Perceptual Masking; D011601:Psychophysics; D014796:Visual Perception / Q000502:physiology*