Mixture model investigation of the inner–outer asymmetry in visual crowding reveals a heavier weight towards the visual periphery

Adi Shechter, Amit Yashar

Research output: Contribution to journalArticlepeer-review


Crowding, the failure to identify a peripheral item in clutter, is an essential bottleneck in visual information processing. A hallmark characteristic of crowding is the inner–outer asymmetry in which the outer flanker (more eccentric) produces stronger interference than the inner one (closer to the fovea). We tested the contribution of the inner-outer asymmetry to the pattern of crowding errors in a typical radial crowding display in which both flankers are presented simultaneously on the horizontal meridian. In two experiments, observers were asked to estimate the orientation of a Gabor target. Instead of the target, observers reported the outer flanker much more frequently than the inner one. When the target was the outer Gabor, crowding was reduced. Furthermore, when there were four flankers, two on each side of the target, observers misreported the outer flanker adjacent to the target, not the outermost flanker. Model comparisons suggested that orientation crowding reflects sampling over a weighted sum of the represented features, in which the outer flanker is more heavily weighted compared to the inner one. Our findings reveal a counterintuitive phenomenon: in a radial arrangement of orientation crowding, within a region of selection, the outer item dominates appearance more than the inner one.

Original languageEnglish
Article number2116
Pages (from-to)2116
JournalScientific Reports
Issue number1
StatePublished - 22 Jan 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s).


  • Adult
  • Algorithms
  • Analysis of Variance
  • Female
  • Humans
  • Male
  • Models, Theoretical
  • Orientation/physiology
  • Pattern Recognition, Visual/physiology
  • Photic Stimulation/methods
  • Psychomotor Performance/physiology
  • Space Perception/physiology
  • Visual Fields/physiology
  • Young Adult

ASJC Scopus subject areas

  • General


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