The hypothesis that eyeblinks could modulate a perceptual switch between the eyes is of critical importance for studies in which the occurrence and/or time of this switch constitutes the dependent variable. Whereas this is clearly the case in binocular rivalry and for ambiguous figures, it is also true in an increasingly popular paradigm to study visual consciousness, namely breaking continuous flash suppression (b-CFS; Jiang, Costello, & He,
2007). This b-CFS is a variant of binocular rivalry in which a dynamic noise pattern is presented to one eye, while the other eye is presented with a static target stimulus. The dynamic presentation to one eye suppresses the conscious visibility of the static target stimulus. The b-CFS enables the presentation of a visual stimulus below the threshold for conscious perception for a long duration without suppressing the unconscious processing of the identity of the target stimulus (Tsuchiya & Koch,
2005). In b-CFS, participants need to respond as fast as possible when the suppressed stimulus breaks through suppression. Their response time is then typically used to make inferences about unconscious processing (e.g., De Loof, Poppe, Cleeremans, Gevers, & Van Opstal,
2015; Mudrik & Koch,
2013; but also see Stein, Kaiser, & Peelen,
2015). While the limits of b-CFS have been abundantly discussed recently (e.g., Gayet, Van der Stigchel, & Paffen,
2014; Stein, Hebart, & Sterzer,
2011), the potential effect of eyeblinks on b-CFS has not yet been considered. This is all the more surprising given that if eyeblinks can elicit a perceptual switch from one eye to the other, they could also modulate the timing of the break through suppression and hence constitute a potential confound in any b-CFS paradigm. It is well known, for instance, that EBR changes depending on cognitive load (Fukuda,
1994,
2001; Ohira,
1996) or on the availability of information processing resources (Ichikawa & Ohira,
2004). Therefore, studies comparing b-CFS between conditions with unequal load (e.g., when studying the relation between working memory and visual consciousness; De Loof et al.,
2015; experiments 1 and 5 of Gayet, Paffen, & Van der Stigchel,
2013), or with differences in processing resources (e.g., when comparing cued versus noncued conditions; Lupyan & Ward,
2013; Stein, Thoma, & Sterzer,
2015), could be potentially confounded by differences in blinking behavior between conditions. It is not always clear, however, whether participants are explicitly instructed to refrain from blinking during a b-CFS trial.