Three Criteria for Evaluating High-Level Processing in Continuous Flash Suppression

A deeply challenging and popular question concerns what information is preserved during processing of invisible stimuli. Can an invisible stimulus reach processing stages commonly attributed to high-level semantic or cognitive processing? Continuous flash suppression (CFS) is a perceptual suppression technique that provides a means to test this question because it allows for keeping stimuli invisible for considerably more time than traditional suppression methods. Over the past 15 years, a substantive literature has accumulated and parts of this literature suggest that high-level processing of unseen stimuli as integrated, semantic entities can indeed occur. This notion of integrated high-level processing was recently challenged by highlighting that interocular suppression, the putative mechanism underlying CFS, likely relies on representations of fractionated stimuli early in visual cortex [ 1 Moors P. et al. Continuous flash suppression: stimulus fractionation rather than integration. Trends Cogn. Sci. 2017; 21: 719-721 Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar , 2 Zadbood A. et al. Stimulus fractionation by interocular suppression. Front. Hum. Neurosci. 2011; 5: 135 Crossref PubMed Google Scholar ]. That is, interocular competition acts on the low-level features that are the consequence of stimulus fractionation in early visual processing.