Suppressed visual looming stimuli are not integrated with auditory looming signals: Evidence from continuous flash suppression.

Pieter Moors,Hanne Huygelier,Raymond Van Ee,Lee De-Wit,Johan Wagemans

doi:10.1068/i0678

Pieter Moors, Hanne Huygelier + Show 3 more

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https://doi.org/10.1068/i0678

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Abstract

Previous studies using binocular rivalry have shown that signals in a modality other than the visual can bias dominance durations depending on their congruency with the rivaling stimuli. More recently, studies using continuous flash suppression (CFS) have reported that multisensory integration influences how long visual stimuli remain suppressed. In this study, using CFS, we examined whether the contrast thresholds for detecting visual looming stimuli are influenced by a congruent auditory stimulus. In Experiment 1, we show that a looming visual stimulus can result in lower detection thresholds compared to a static concentric grating, but that auditory tone pips congruent with the looming stimulus did not lower suppression thresholds any further. In Experiments 2, 3, and 4, we again observed no advantage for congruent multisensory stimuli. These results add to our understanding of the conditions under which multisensory integration is possible, and suggest that certain forms of multisensory integration are not evident when the visual stimulus is suppressed from awareness using CFS.

Highlights

When both eyes are presented with incompatible images, the phenomenological consequence usually is one of binocular rivalry in which the percept alternates between the two images instead of mixing them into one coherent interpretation (Blake & Logothetis, 2002; Tong, Meng, & Blake, 2006)
All analyses were done in a Bayesian framework, relying on Bayes Factors (BF) and 95% credible intervals (CI) on effect sizes
Critical for our study, BFs can be used to quantify the evidence for a null model compared to a model containing an effect of condition, which is impossible in standard null hypothesis significance testing

Summary

Introduction

When both eyes are presented with incompatible images, the phenomenological consequence usually is one of binocular rivalry in which the percept alternates between the two images instead of mixing them into one coherent interpretation (Blake & Logothetis, 2002; Tong, Meng, & Blake, 2006). It has become clear that non-visual stimuli can influence the rivalry between visual stimuli, from audition (Alais, van Boxtel, Parker, & van Ee, 2010; Chen, Yeh, & Spence, 2011; Conrad et al, 2013; Conrad, Bartels, Kleiner, & Noppeney, 2010; Guzman-Martinez, Ortega, Grabowecky, Mossbridge, & Suzuki, 2012; Kang & Blake, 2005; van Ee, van Boxtel, Parker, & Alais, 2009), to touch (Lunghi & Alais, 2013; Lunghi, Binda, & Morrone, 2010; Lunghi, Morrone, & Alais, 2014; Lunghi & Morrone, 2013), and even olfaction (Zhou, Zhang, Chen, Wang, & Chen, 2012; Zhou, Jiang, He, & Chen, 2010) Most of these studies have demonstrated that the influence of multisensory stimulation from the auditory modality increases the duration of the already dominant (conscious) stimulus, rather than causing visual perception to switch to a non-dominant (unconscious) stimulus (Chen et al, 2011; Conrad et al, 2010; Kang & Blake, 2005). This provides the opportunity to assess whether the suppressed stimulus is integrated with the stimulus presented in the non-visual modality

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