Willpower and conscious percept: volitional switching in binocular rivalry

Area of Science:

• Neuroscience
• Cognitive Psychology
• Visual Perception

Background:

• Binocular rivalry occurs when dissimilar images are presented to each eye, leading to spontaneous switches in awareness.
• Historically, it was believed that perceptual switching during binocular rivalry is involuntary, despite attentional influences.

Purpose of the Study:

• To investigate whether volitional control over perceptual switching in binocular rivalry is possible.
• To explore the role of top-down attention and neural pathways (dorsal and ventral streams) in conscious perceptual control.

Main Methods:

• Examined volitional control over rivalry using apparent motion (AM), drifting (DM), and stationary (ST) grating pairs.
• Measured perceptual switches and objectively verified them using optokinetic nystagmus (OKN).
• Assessed the role of saccadic eye movements by comparing their frequency in volitional versus non-volitional conditions.

Main Results:

• Observers could intentionally switch perception for AM and DM stimuli but not for ST stimuli.
• OKN pursuit direction switches confirmed the intentional perceptual switches.
• Saccadic eye movement frequency decreased significantly during volitional switching, ruling them out as the primary trigger.

Conclusions:

• Volitional control over perceptual switching in binocular rivalry is achievable under specific conditions.
• The findings suggest a synergy between dorsal and ventral visual streams is crucial for conscious control over rivalrous percepts.
• Challenges the long-standing assumption of inherent lack of control over perceptual switching.