Breaking Continuous Flash Suppression Research Articles

Visual input signaling threat gains preferential access to awareness in a breaking continuous flash suppression paradigm

Visual input that signals threat is inherently relevant for survival. Accordingly, it has been demonstrated that threatening visual input elicits faster behavioral responses than non-threatening visual input. Considering that awareness is a prerequisite for performing demanding tasks and guiding novel behavior, we hypothesized that threatening visual input would gain faster access to awareness than non-threatening visual input. In the present study, we associated one of two basic visual stimuli, that were devoid of intrinsic relevance (colored annuli), with aversive stimulation (i.e., electric shocks) following a classical fear conditioning procedure. In the subsequent test phase no more electric shocks were delivered, and a breaking continuous flash suppression task was used to measure how fast these stimuli would access awareness. The results reveal that stimuli that were previously paired with an electric shock break through suppression faster than comparable stimuli that were not paired with an electric shock.

Are visual threats prioritized without awareness? A critical review and meta-analysis involving 3 behavioral paradigms and 2696 observers.

Given capacity limits, only a subset of stimuli give rise to a conscious percept. Neurocognitive models suggest that humans have evolved mechanisms that operate without awareness and prioritize threatening stimuli over neutral stimuli in subsequent perception. In this meta-analysis, we review evidence for this 'standard hypothesis' emanating from 3 widely used, but rather different experimental paradigms that have been used to manipulate awareness. We found a small pooled threat-bias effect in the masked visual probe paradigm, a medium effect in the binocular rivalry paradigm and highly inconsistent effects in the breaking continuous flash suppression paradigm. Substantial heterogeneity was explained by the stimulus type: the only threat stimuli that were robustly prioritized across all 3 paradigms were fearful faces. Meta regression revealed that anxiety may modulate threat-biases, but only under specific presentation conditions. We also found that insufficiently rigorous awareness measures, inadequate control of response biases and low level confounds may undermine claims of genuine unconscious threat processing. Considering the data together, we suggest that uncritical acceptance of the standard hypothesis is premature: current behavioral evidence for threat-sensitive visual processing that operates without awareness is weak. (PsycINFO Database Record

Fear conditioned visual information is prioritized for visual awareness

The present study addresses the question whether visual information that signals threat is prioritized for access to awareness. We combined a fear conditioning procedure with a breaking continuous flash suppression (b-CFS) task. In this task, participants were presented with high contrast dynamic masks to one eye, and a target grating presented to the other eye (suppression condition) or to the same eye (monocular condition). Participants were asked to report the orientation of the target as soon as it became visible. Throughout the entire experiment, target gratings were surrounded by a blue or red annulus. During the acquisition phase (phase 1), participants passively viewed both monocular and suppression trials, in which one annulus color was repeatedly paired with an electrical shock (from now on the CS+) while the other color was not (CS-). Subsequently, participants completed four blocks of b-CFS trials (phase 2), in which monocular and suppression conditions were intermixed, with CS+ and CS- annuli surrounding the targets. The results revealed that target orientation was reported faster on trials with CS+ annuli than with CS- annuli in the suppression condition. This difference in reaction times reflected shorter suppression durations for CS+ annuli rather than a response bias, as no difference in reaction times emerged between targets surrounded by CS+ or CS- annuli in the monocular condition. This pattern of findings is particularly striking, as (1) participants knew that no shocks would be administered during the b-CFS task, (2) the CS+ and CS- annuli were irrelevant for participants' behavioral task and (3) participants reported to be unaware of phenomenal differences between monocular and suppression conditions. Taken together, these results demonstrate that visual information that was previously paired with aversive stimulation, and thus signaled threat, is prioritized by the perceptual system such that it more readily breaches the threshold of awareness. Meeting abstract presented at VSS 2015. Language: en

Serial correlations in Continuous Flash Suppression.

Research on visual rivalry has demonstrated that consecutive dominance durations are serially dependent, implying that the underlying competition mechanism is not driven by some random process but includes a memory component. Here we asked whether serial dependence is also observed in continuous flash suppression (CFS). We addressed this question by analyzing a large dataset of time series of suppression durations obtained in a series of so-called “breaking CFS” experiments in which the duration of the period is measured until a suppressed target breaks through the CFS mask. Across experimental manipulations, stimuli, and observers, we found that (i) the distribution of breakthrough rates was fit less well by a gamma distribution than in conventional visual rivalry paradigms, (ii) the suppression duration on a previous trial influenced the suppression duration on a later trial up to as long as a lag of eight trials, and (iii) the mechanism underlying these serial correlations was predominantly monocular. We conclude that the underlying competition mechanism of CFS also includes a memory component that is primarily, but not necessarily exclusively, monocular in nature. We suggest that the temporal dependency structure of suppression durations in CFS is akin to those observed in binocular rivalry, which might imply that both phenomena tap into similar rather than distinct mechanisms.

Visual directional anisotropy does not mirror the directional anisotropy apparent in postural sway.

Presenting a large optic flow pattern to observers is likely to cause postural sway. However, directional anisotropies have been reported, in that contracting optic flow induces more postural sway than expanding optic flow. Recently, we showed that the biomechanics of the lower leg cannot account for this anisotropy (Holten, Donker, Verstraten, & van der Smagt, 2013, Experimental Brain Research, 228, 117-129). The question we address in the current study is whether differences in visual processing of optic flow directions, in particular the perceptual strength of these directions, mirrors the anisotropy apparent in postural sway. That is, can contracting optic flow be considered to be a perceptually stronger visual stimulus than expanding optic flow? In the current study we use a breaking continuous flash suppression paradigm where we assume that perceptually stronger visual stimuli will break the flash suppression earlier, making the suppressed optic flow stimulus visible sooner. Surprisingly, our results show the opposite, in that expanding optic flow is detected earlier than contracting optic flow.

Unconscious semantic processing? No evidence for extracting the semantics of words during interocular suppression.

Continuous Flash Suppression (CFS) has been used as a method to probe unconscious processing of visually suppressed stimuli. One line of research pertains to the extent to which semantic information of words is processed in the absence of awareness. Since CFS was introduced, it has been reported that neutral words break suppression faster than negative words (Yang and Yeh, 2011) (and vice versa (Sklar et al. , 2013)) and that congruent prime-target relations influence suppression time (Costello et al., 2009), but do not influence electrophysiological correlates of semantic congruency (Kang et al., 2011). In this study, we used the breaking CFS paradigm to probe whether words break suppression faster than pseudo words and whether suppression time of words is influenced by its word frequency. In all experiments, participants were instructed to indicate the location of the initially suppressed words as fast as possible upon breakthrough. In Experiment 1, we found neither evidence for word type (real vs. pseudo words) nor word frequency influencing suppression time. In Experiment 2, we scrambled pseudo words to eliminate readability of pseudo words, included an inverted condition (to control for familiarity) and used a test-retest design (to examine the consistency of suppression times). Again, no effect of word type nor word frequency was found. Moreover, no effect of inversion was found and test-retest reliability was low. A control experiment was conducted to verify that reliable data could be obtained with this CFS paradigm. The target was a white disc of which the radius was manipulated. Bigger discs broke suppression faster than smaller discs indicating a basic stimulus manipulation can indeed yield reliable results in the predicted direction. In conclusion, our results provide no evidence for the extraction of semantic information in the absence of awareness induced by interocular suppression. Meeting abstract presented at VSS 2014

Frequent words do not break continuous flash suppression differently from infrequent or nonexistent words: implications for semantic processing of words in the absence of awareness.

Continuous flash suppression (CFS) has been used as a paradigm to probe the extent to which word stimuli are processed in the absence of awareness. In the two experiments reported here, no evidence is obtained that word stimuli are processed up to the semantic level when suppressed through CFS. In Experiment 1, word stimuli did not break suppression faster than their pseudo-word variants nor was suppression time modulated by word frequency. Experiment 2 replicated these findings, but more critically showed that differential effects can be obtained with this paradigm using a simpler stimulus. In addition, pixel density of the stimuli did prove to be related to suppression time in both experiments, indicating that the paradigm is sensitive to differences in detectability. A third and final experiment replicated the well-known face inversion effect using the same set-up as Experiments 1 and 2, thereby demonstrating that the employed methodology can capture more high-level effects as well. These results are discussed in the context of previous evidence on unconscious semantic processing and two potential explanations are advanced. Specifically, it is argued that CFS might act at a level too low in the visual system for high-level effects to be observed or that the widely used breaking CFS paradigm is merely ill-suited to capture effects in the context of words.

Breaking Continuous Flash Suppression: A New Measure of Unconscious Processing during Interocular Suppression?

Until recently, it has been thought that under interocular suppression high-level visual processing is strongly inhibited if not abolished. With the development of continuous flash suppression (CFS), a variant of binocular rivalry, this notion has now been challenged by a number of reports showing that even high-level aspects of visual stimuli, such as familiarity, affect the time stimuli need to overcome CFS and emerge into awareness. In this “breaking continuous flash suppression” (b-CFS) paradigm, differential unconscious processing during suppression is inferred when (a) speeded detection responses to initially invisible stimuli differ, and (b) no comparable differences are found in non-rivalrous control conditions supposed to measure non-specific threshold differences between stimuli. The aim of the present study was to critically evaluate these assumptions. In six experiments we compared the detection of upright and inverted faces. We found that not only under CFS, but also in control conditions upright faces were detected faster and more accurately than inverted faces, although the effect was larger during CFS. However, reaction time (RT) distributions indicated critical differences between the CFS and the control condition. When RT distributions were matched, similar effect sizes were obtained in both conditions. Moreover, subjective ratings revealed that CFS and control conditions are not perceptually comparable. These findings cast doubt on the usefulness of non-rivalrous control conditions to rule out non-specific threshold differences as a cause of shorter detection latencies during CFS. Thus, at least in its present form, the b-CFS paradigm cannot provide unequivocal evidence for unconscious processing under interocular suppression. Nevertheless, our findings also demonstrate that the b-CFS paradigm can be fruitfully applied as a highly sensitive device to probe differences between stimuli in their potency to gain access to awareness.