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Multi-stability in visual perception and eye movements: does action control perception or vice-versa?

Abstract : Multi-stable perception refers to the perceptual dynamics that emerge when the human's sensory system is confronted with a stationary, ambiguous visual stimulus. Though the stimulus is stationary, humans observe alternations in perception. Since its first observations by Necker (1832), multi-stable perception has been a tool to investigate the inference processes of the visual system when reconstructing a rich perceptual world from incomplete, and sometimes poor, sensory information. In this thesis, the relationships and dependencies between the oculomotor action and perceptual systems are approached in the context of multi-stable perception. The main questions driving the investigation can be formulated as follows: can we infer percepts from oculomotor behaviour and thus, what are the (hierarchical) relations between the perceptual and oculomotor systems? At first, we have studied ocular micro-movements in fixations that have been detected during exploration of a bi-stable visual stimulus with motion. We propose to classify them as micro-pursuit; a class of fixational eye movements, correlating with smooth, predictable, small-scale stimulus' target trajectories. We replicated these findings in an explicit pursuit task with a luminance change detection task, but only when the moving object was a target, and not when it was a distractor. Inter-experiment analysis suggests that the manipulation of task, stimulus target motion, and the level of ambiguity of the stimulus affect the generation of micro-pursuits: a result that may hint that bi-stable perception may play a role in the oculomotor decision to attend either the fixation cross, or the moving object. We have modelled this behaviour with a predictive model based on an energy potential field in which gaze is represented by the dynamics of a unitary mass. We further extend this model to capture multi-stable perception. An exploration of the model's capacity to reproduce fixational eye movement -- covering micro-saccades, micro-pursuits and stable fixations -- is presented. To further study perceptual multi-stability and oculomotor control, we used the moving plaid: a tri-stable stimulus, composed of two transparent gratings moving in different directions and visualised through an aperture, making perceived motion direction ambiguous. We investigate how the plaid's ambiguity can be manipulated at the individual subject level, using a probabilistic model and an experimental protocol to estimate its parameters. As such, points of maximal ambiguity can be identified for an observer based on the manipulation of the gratings' transparencies. We further looked at oculomotor manipulation in the context of the moving plaid stimulus and provide a brief outlook at a no-report paradigm that aims to exploit eye movements to infer the perception dynamics of an observer. This exploration aims to provide a road map for further investigation of perceptual and oculomotor coupling in multi-stable perception, and opens up to methods using neuro-imaging techniques to investigate multi-stability. The work presented here raises questions on the link between stability regimes and how bottom-up and top-down processes may play a role in modulating the brain into mono-, multi- or meta-stable dynamics.
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https://hal.archives-ouvertes.fr/tel-03109729
Contributor : Kevin Parisot <>
Submitted on : Wednesday, January 13, 2021 - 10:56:29 PM
Last modification on : Friday, January 15, 2021 - 3:31:29 AM

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  • HAL Id : tel-03109729, version 1

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Kevin Parisot. Multi-stability in visual perception and eye movements: does action control perception or vice-versa?. Cognitive science. Université Grenoble Alpes, 2020. English. ⟨tel-03109729⟩

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