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Microsaccades as an overt measure of covert attention shifts
1Center for Intelligent Machines, McGill University, 3480 University Street, Montreal, H3A 2A7, Que, Canada. zhafed@im.mcgill.ca
Abstract:
Microsaccades, or tiny eye movements that take place during periods of fixation, have long been thought to be random artifacts of the oculomotor system. Here we demonstrate a possible link between microsaccades and covert attention shifts. We designed two psychophysical tasks involving spatial cues that had identical sensory stimuli but differing patterns of attentional benefits and costs. We found that microsaccades, rather than being randomly distributed, had directions that were directly correlated with the directions of covert attention shifts in the two tasks. Our results suggest that microsaccades occur because of subliminal activation of the oculomotor system by covert attention.
Insights
Tiny eye movements called microsaccades are not random. New research shows their direction correlates with covert attention shifts, suggesting a link between eye movements and attention.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Oculomotor Research
Background:
- Microsaccades, small, rapid eye movements during fixation, were traditionally considered random artifacts.
- The precise function and underlying mechanisms of microsaccades remain an active area of research.
Purpose of the Study:
- To investigate a potential relationship between microsaccades and covert attention shifts.
- To determine if microsaccade direction is influenced by attentional allocation.
Main Methods:
- Developed two psychophysical tasks using spatial cues with identical sensory stimuli.
- Manipulated attentional benefits and costs within the tasks.
- Recorded and analyzed microsaccade directions in relation to attentional shifts.
Main Results:
- Microsaccade directions were not random.
- Microsaccade directions showed a direct correlation with the directions of covert attention shifts.
- This correlation was consistent across the two experimental tasks.
Conclusions:
- Microsaccades may be linked to covert attention shifts, challenging the notion of randomness.
- Subliminal activation of the oculomotor system by covert attention might trigger microsaccades.
- Findings provide new insights into the interplay between attention and eye movement control.