Band-limited interactions between mask and target in continuous flash suppression

Abstract

Continuous Flash Suppression (CFS) has become a widely-used technique in the study of visual perception without conscious awareness, even though key aspects of the underlying neural mechanisms are not well known. Here we analyze the effect of overlapping and non-overlapping spatial frequencies between systematically aligned masks and targets, showing strong interactions exist in both cases. These interactions may significantly prolong CFS response times (up to several hundred milliseconds, or more than twice the suppression duration compared to baseline) but are attenuated in case of absence of overlap, even completely absent in certain cases. Our results provide insights for the design of bias-free masks in CFS experiments and will be useful to avoid mask-induced biases in CFS studies, which might otherwise be misinterpreted as differences in unconscious processing of visual stimuli.