Continuous flash suppression: Known and unknowns

Abstract

Studies utilizing continuous flash suppression (CFS) provide valuable information regarding conscious and nonconscious perception. There are, however, crucial unanswered questions regarding the mechanisms of suppression and the level of visual processing in the absence of consciousness with CFS. Research suggests that the answers to these questions depend on the experimental configuration and how we assess consciousness in these studies. The aim of this review is to evaluate the impact of different experimental configurations and the assessment of consciousness on the results of the previous CFS studies. We review studies that evaluated the influence of different experimental configuration on the depth of suppression with CFS and discuss how different assessments of consciousness may impact the results of CFS studies. Finally, we review behavioral and brain recording studies of CFS. In conclusion, previous studies provide evidence for survival of low-level visual information and complete impairment of high-level visual information under the influence of CFS. That is, studies suggest that nonconscious perception of lower-level visual information happens with CFS but there is no evidence for nonconscious highlevel recognition with CFS.

Degree and Complexity of Non-conscious Emotional Information Processing – A Review of Masked Priming Studies

“…Awareness of the prime is prevented through constant changes in the masking stimulus or stimuli (i.e., every 100 ms) so that attention and awareness remain on this constantly changing information; thereby the name continuous flash suppression. As any technique, CFS comes with its own peculiarities, and the extent of non-conscious processing with this technique is still debated ( Pournaghdali and Schwartz, 2020 ). For example, Hedger et al (2016) applied CFS to investigate whether threat stimuli gain privileged access to awareness due to their evolutionary importance.…”

Slower access to visual awareness but otherwise intact implicit perception of emotional faces in schizophrenia-spectrum disorders

“…Similarly, Caruana et al (2019) reported a preserved perceptual prioritization of upright faces, compared to inverted faces, in schizophrenia-spectrum disorders. These mixed findings in the literature may be related to the use of distinct stimuli and methodology, namely suppressors, opacity manipulation, stimulus location, and low-level features (Pournaghdali & Schwartz, 2020). For instance, in the three studies showing similar suppression times (Caruana & Seymour, 2021;Caruana et al, 2019;Seymour et al, 2016), stimuli were viewed through a mirror stereoscope, while anaglyph glasses were used in our and Zhou et al (2020) study.…”

Generality and content-specificity in the study of the neural correlates of perceptual consciousness

“…In particular, while there is a general agreement that lower level visual features such as stimulus orientation can be perceived unconsciously under Continuous Flash Suppression, unconscious perception of higher-level features, such as face identity or facial expression, was not demonstrated beyond reasonable doubt. For the most comprehensive recent review of Continuous Flash Suppression studies, and the controversies surrounding the results, seePournaghdali & Schwartz (2020).4 The signals in sensory areas during unconscious processing are weaker then during conscious processing. This does not contradict our hypothesis.…”