Continuous flash suppression operates in local spatial zones: Effects of mask size and contrast

Abstract

Continuous flash suppression (CFS) is a technique in which presenting one eye with a dynamic Mondrian sequence prevents a low-contrast target in the other eye from being perceived for many seconds. Frequently used to study unconscious visual processing, CFS bears many similarities with binocular rivalry (BR), another popular dichoptic stimulation technique. It is therefore puzzling that the effect of mask size and contrast seem to differ between CFS and BR. To resolve this discrepancy, we conducted a systematic investigation on the effects of mask size and contrast in CFS. Also, building on findings from BR, we asked if the collinearity of the contours in the Mondrian masker play a role in CFS suppression. Our results showed a robust effect of mask contrast on suppression durations, and an effect of mask size that depended on collinearity.Specifically, higher mask contrasts produced longer suppression regardless of collinearity and mask size. Mask size, on the other hand, had little effect on suppression when collinearity was low and it weakened suppression when collinearity is high. These observations parallel prior findings in BR, further substantiating the close link between the two paradigms and demonstrating the usefulness of a shared explanatory framework describing both phenomena.Note. Sizes are measured in degrees of visual angle.

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

“…For example, presumed unaware processing has been identi ed for faces and facial expressions (Webb & Hibbard, 2020;Yang et al, 2007), simple geometric features, such as closure (Meng et al, 2012; and animacy (Sun et al, 2022;Zhu, Drewes, Peat eld, et al, 2016). While it has been shown that the properties of the masks in uence suppression effectiveness in multiple ways (Drewes et al, 2018(Drewes et al, , 2020Han et al, 2016Han et al, , 2019, in many cases, the masks used in the relevant studies were treated as independent of the targets, or at least were not designed with speci c targets in mind (Drewes et al, 2023;Pournaghdali & Schwartz, 2020). Only few studies directly investigated mask design with respect to the target stimuli (Drewes et al, 2023;Han et al, 2021).…”

Feature-based interaction between masks and target in continuous flash suppression

“…Further investigation of different kinds of random noise for CFS masking found that spatial pink noise (1/F noise) achieved the longest suppression duration compared to other random noises 29 . Other features and specially constructed masks have also received some recent attention [30][31][32] . Contrary to this, the direct relationships between masks and targets have received very little if any attention, even though in binocular rivalry 33,34 interactions in suppression (or dominance) duration between rivaling stimuli are well documented [35][36][37][38] .…”

Brief localised monocular deprivation in adults alters binocular rivalry predominance retinotopically and reduces spatial inhibition

“…In vision, cooperative and inhibitory interactions among neighbouring spatial zones have been observed in both binocular 29 , 30 and dichoptic viewing conditions 31 – 36 . This raises two questions: (1) whether or not the DE is a retinotopic effect that only affects stimuli presented to deprived retinal locations, and (2) if local DEs interact with neighbouring spatial zones.…”