Visual awareness is essential for grouping based on mirror symmetry

Dina Devyatko, Ruth Kimchi

Research output: Contribution to journalArticlepeer-review


We examined whether symmetry‐based grouping can take place in the absence of visual awareness. To this end, we used a priming paradigm, sandwich masking as an invisibility‐inducing method, and primes and targets composed of two vertical symmetric or asymmetric lines. The target could be congruent or incongruent with the prime in symmetry. In Experiment 1, participants were presented with masked primes and clearly visible targets. In each trial, the participants performed a two‐alternative discrimination task on the target, and then rated the visibility of the prime on a subjective visibility four‐point scale (used to assess prime awareness). Subjectively invisible primes failed to produce response priming, suggesting that symmetry processing might depend on visual awareness. However, participants barely saw the prime, and the results for the visible primes were inconclusive, even when we used a conservative criterion for awareness. To rule out the possibility that our prime stimuli could not produce priming per se, we conducted a control visibility experiment (Experiment 2), in which participants were presented with unmasked, clearly visible primes and performed a target task. The results showed that our primes could elicit significant response priming when visible. Taken together, our findings indicate that symmetry‐based grouping requires visual awareness.

Original languageEnglish
Article number1872
Pages (from-to)1-12
Number of pages12
Issue number11
StatePublished - Nov 2020

Bibliographical note

Funding Information:
Funding: This research was supported by a grant (grant number 1473/15) from the Israel Science Foundation (ISF) to Ruth Kimchi.

Publisher Copyright:
© 2020, MDPI AG. All rights reserved.


  • Masking
  • Perceptual grouping
  • Perceptual organization
  • Response priming
  • Symmetry
  • Symmetry‐based grouping
  • Visual awareness

ASJC Scopus subject areas

  • Computer Science (miscellaneous)
  • Chemistry (miscellaneous)
  • Mathematics (all)
  • Physics and Astronomy (miscellaneous)


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