A Minimal Quantitative Model of Perceptual Suppression and Breakthrough in Visual Rivalry

TL;DR

This paper introduces a simple, mathematically tractable model of visual rivalry that explains the hysteresis observed in perceptual suppression and breakthrough, and it makes testable predictions validated by human data.

Contribution

It provides the first analytical model of visual rivalry that captures hysteresis and predicts perceptual durations, validated with psychophysical experiments.

Findings

Model explains hysteretic transitions in visual rivalry.

Distributions of dominance and suppression durations are approximately equal.

Model's predictions are empirically validated with human data.

Abstract

When conflicting images are presented to either eye, binocular fusion is disrupted. Rather than experiencing a blend of both percepts, often only one eye's image is experienced, whilst the other is suppressed from awareness. Importantly, suppression is transient - the two rival images compete for dominance, with stochastic switches between mutually exclusive percepts occurring every few seconds with law-like regularity. From the perspective of dynamical systems theory, visual rivalry offers an experimentally tractable window into the dynamical mechanisms governing perceptual awareness. In a recently developed visual rivalry paradigm - tracking continuous flash suppression (tCFS) - it was shown that the transition between awareness and suppression is hysteretic, with a higher contrast threshold required for a stimulus to breakthrough suppression into awareness than to be suppressed from awareness. Here, we present an analytically-tractable model of visual rivalry that quantitatively explains the hysteretic transition between periods of awareness and suppression in tCFS. Grounded in the theory of neural dynamics, we derive closed-form expressions for the duration of perceptual dominance and suppression, and for the degree of hysteresis (i.e. the depth of perceptual suppression), as a function of model parameters. Finally, our model yields a series of novel behavioural predictions, the first of which - distributions of dominance and suppression durations during tCFS should be approximately equal - we empirically validate in human psychophysical data.