Touch Accelerates Visual Awareness

Abstract

To efficiently interact with the external environment, our nervous system combines information arising from different sensory modalities. Recent evidence suggests that cross-modal interactions can be automatic and even unconscious, reflecting the ecological relevance of cross-modal processing. Here, we use continuous flash suppression (CFS) to directly investigate whether haptic signals can interact with visual signals outside of visual awareness. We measured suppression durations of visual gratings rendered invisible by CFS either during visual stimulation alone or during visuo-haptic stimulation. We found that active exploration of a haptic grating congruent in orientation with the suppressed visual grating reduced suppression durations both compared with visual-only stimulation and to incongruent visuo-haptic stimulation. We also found that the facilitatory effect of touch on visual suppression disappeared when the visual and haptic gratings were mismatched in either spatial frequency or orientation. Together, these results demonstrate that congruent touch can accelerate the rise to consciousness of a suppressed visual stimulus and that this unconscious cross-modal interaction depends on visuo-haptic congruency. Furthermore, since CFS suppression is thought to occur early in visual cortical processing, our data reinforce the evidence suggesting that visuo-haptic interactions can occur at the earliest stages of cortical processing.

Invisible Flashes Alter Perceived Sound Location

“…Indeed, in line with the first prediction, a vast body of research has demonstrated that aware signals from one sensory modality thrust unaware signals in another sensory modality into perceptual awareness according to the classical multisensory principles of temporal coincidence, spatial concordance and semantic and phonological congruency 6 – 17 . With respect to the spatial ventriloquist illusion, we have recently demonstrated that a sound that we are aware of can boost a flash under dynamic flash suppression into perceptual awareness depending on audiovisual spatial congruency 18 .…”

Visual and somatosensory information contribute to distortions of the body model

“…As a matter of fact, we showed that the tactile acuity significantly predicts the misestimation of the proximo-distal dimension of body parts whereas it does not have an effect on the medio-lateral estimation. Multisensory representations of the body are formed in parietal cortex 35 and/or through interactions between unisensory processing centers: for example, it has been shown that visual information modulates somatosensory processing 36 and conversely, that somatosensory information affects visual processing 37 .…”

Effects of Multimodal Association on Ambiguous Perception in Binocular Rivalry

“…There have been several speculations on how multisensory integration occurs and subsequently resolves the given perceptual ambiguity to achieve unequivocal interpretation (Deroy, Spence, & Noppeney, 2016; Faivre, Filevich, Solovey, Kühn, & Blanke, 2018; Hsiao, Chen, Spence, & Yeh, 2012; Hu & Knill, 2010; Lunghi, Lo Verde, & Alais, 2017; Salomon et al., 2016; Salomon, Kaliuzhna, Herbelin, & Blanke, 2015; Salomon, Lim, Herbelin, Hesselmann, & Blanke, 2013; Shams & Beierholm, 2010; Smith, Grabowecky, & Suzuki, 2007). One of the highly plausible explanations is that some intrinsic commonality in one stimulus can bias the perception of the other stimulus.…”