Attention, Perception, & Psychophysics

, Volume 80, Issue 8, pp 1974–1987 | Cite as

Continuous flash suppression and monocular pattern masking impact subjective awareness similarly

  • J. D. KnottsEmail author
  • Hakwan Lau
  • Megan A. K. Peters


Peters and Lau (eLife, 4, e09651, 2015) found that when criterion bias is controlled for, there is no evidence for unconscious visual perception in normal observers, in the sense that they cannot directly discriminate a target above chance without knowing it. One criticism of that study is that the visual suppression method used, forward and backward masking (FBM), may be too blunt in the way it interferes with visual processing to allow for unconscious forced-choice discrimination. To investigate this question, we compared FBM directly to continuous flash suppression (CFS) in a two-interval forced-choice task. Although CFS is popular, and may be thought of as a more powerful visual suppression technique, we found no difference in the degree of perceptual impairment between the two suppression types. To the extent that CFS impairs perception, both objective discrimination and subjective awareness are impaired to similar degrees under FBM. This pattern was consistently observed across three experiments in which various experimental parameters were varied. These findings provide evidence for an ongoing debate about unconscious perception: normal observers cannot perform forced-choice discrimination tasks unconsciously.


Visual awareness Binocular vision: Rivalry/ Bistable Perception visual perception 



This work was supported by a grant from the National Institutes of Health (U.S.) to H.L. (Grant No. R01NS088628), and a National Science Foundation Graduate Research Fellowship to J.D.K.


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Copyright information

© The Psychonomic Society, Inc. 2018

Authors and Affiliations

  • J. D. Knotts
    • 1
    Email author
  • Hakwan Lau
    • 1
    • 2
    • 3
  • Megan A. K. Peters
    • 1
    • 4
    • 5
  1. 1.Department of PsychologyUniversity of California Los AngelesLos AngelesUSA
  2. 2.Brain Research InstituteUniversity of California Los AngelesLos AngelesUSA
  3. 3.Department of PsychologyUniversity of Hong KongPokfulamHong Kong
  4. 4.Department of BioengineeringUniversity of California RiversideRiversideUSA
  5. 5.Interdepartmental Graduate Program in NeuroscienceUniversity of California RiversideRiversideUSA

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