Local motion governs visibility and suppression of biological motion in continuous flash suppression

TL;DR

This study shows that local motion, rather than high-level meaning, determines how visual stimuli are suppressed when shown to each eye.

Contribution

The study demonstrates that suppression depth depends on low-level motion features, not semantic content of biological motion.

Findings

Suppression depth varies based on low-level motion features rather than the suppressor's strength alone.

Disrupting semantic information in biological motion does not change suppression depth.

Results support the low-level local-precedence hypothesis in interocular suppression.

Abstract

Presenting unique visual stimuli to each eye induces a dynamic perceptual state where only one image is perceived at a time, and the other is suppressed from awareness. This phenomenon, known as interocular suppression, has allowed researchers to probe the dynamics of visual awareness and unconscious processing in the visual system. A key result is that different categories of visual stimuli may not be suppressed equally, but there is still a wide debate as to whether low- or high-level visual features modulate interocular suppression. Here we quantify and compare the strength of suppression for various motion stimuli in comparison to biological motion stimuli that are rich in high-level semantic information. We employ the tracking continuous flash suppression method, which recently demonstrated uniform suppression depth for a variety of static images that varied in semantic content. The accumulative findings of our three experiments outline that suppression depth is varied not by the strength of the suppressor alone but with different low-level visual motion features, in contrast to the uniform suppression depth previously shown for static images. Notably, disrupting high-level semantic information via the inversion or rotation of biological motion did not alter suppression depth. Ultimately, our data support the dependency of suppression depth on local motion information, further supporting the low-level local-precedence hypothesis of interocular suppression.

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