Unconscious processing under interocular suppression: getting the right measure.

Timo Stein,Philipp Sterzer

doi:10.3389/fpsyg.2014.00387

Abstract

In order to demonstrate unconscious visual processing, researchers need to select a technique for rendering stimuli invisible and a measure reflecting the processing of these stimuli. The most popular techniques are backward masking, in which the visibility of a very brief stimulus is degraded by the presentation of a succeeding visual pattern (Breitmeyer and Ogmen, 2006), and interocular suppression, where a stimulus shown to one eye degrades the visibility of a stimulus presented to the other eye (Lin and He, 2009). Recently, much work has been carried out using continuous flash suppression (CFS; Tsuchiya and Koch, 2005), a particularly potent interocular suppression technique. In CFS, a train of high-contrast patterns flashed into one eye can suppress the visibility of a stationary stimulus shown to the other eye for up to several seconds (Figure (Figure1).1). Because CFS allows for extended periods of reliable invisibility of complex stimuli, this technique has sparked a surge of interest in unconscious visual processing. Figure 1 Competing models of the processes mediating detection performance in the b-CFS paradigm. (A) The single-process model posits that both the CFS and the control condition measure differences between stimuli in accessing awareness that exist independent ... Ideally, research aimed at delineating the scope and limits of visual processing without awareness should adopt the technique that is most sensitive to unconscious processing. This is because a failure to find evidence for a certain unconscious effect could always be due to constraints imposed by the specific technique rather than to the genuine absence of unconscious processing (Faivre et al., 2012). However, since the extent to which a technique allows for unconscious processing is difficult to determine, and due to a lack of general consensus on valid measures of unconscious processing, no definite criteria exist for choosing the most sensitive technique.

Highlights

In order to demonstrate unconscious visual processing, researchers need to select a technique for rendering stimuli invisible and a measure reflecting the processing of these stimuli
CLASSIC DISSOCIATION APPROACHES TO UNCONSCIOUS PROCESSING Most commonly, unconscious processing is studied using some variant of the classic dissociation paradigm, in which a direct measure of stimulus awareness is contrasted with an indirect measure of stimulus processing
BREAKING CONTINUOUS FLASH SUPPRESSION (b-CFS) This notion has recently been challenged by findings obtained with the novel breaking continuous flash suppression (b-CFS)

Summary

Introduction

In order to demonstrate unconscious visual processing, researchers need to select a technique for rendering stimuli invisible and a measure reflecting the processing of these stimuli. Stein and Sterzer paradigm in which differential unconscious processing during CFS is inferred from the time different stimuli need to overcome CFS and break into awareness, as reflected in speeded localization (or detection) responses (Jiang et al, 2007).

Results

Conclusion