Using Microsaccades to Estimate Task Difficulty During Visual Search of Layered Surfaces

Area of Science:

• Cognitive Science
• Neuroscience
• Human-Computer Interaction

Background:

• Cognitive load significantly impacts visual attention and eye movements.
• Microsaccades, small rapid eye movements, are sensitive to cognitive processes.
• Visual search tasks provide a paradigm to study cognitive load and visual behavior.

Purpose of the Study:

• To develop and validate an approach using microsaccade dynamics to measure cognitive load during visual search.
• To investigate the relationship between task difficulty and microsaccade behavior in a layered surface visual search task.
• To differentiate between ambient and focal phases of visual search and their impact on microsaccade activity.

Main Methods:

• Utilized a visual search task on a layered surface with free eye movement.
• Employed Krejtz's K coefficient to distinguish between ambient and focal phases of visual search.
• Analyzed microsaccade dynamics (magnitude and rate) in relation to task difficulty, segmented by ambient/focal phases.

Main Results:

• Validated Krejtz's K coefficient for quantifying visual search phases.
• Found that during the focal phase, microsaccade magnitude significantly increased with task difficulty.
• Observed a significant decrease in microsaccade rate during the focal phase as task difficulty increased.

Conclusions:

• Microsaccade dynamics, particularly during the focal search phase, serve as a reliable indicator of cognitive load.
• The combination of Krejtz's K coefficient and microsaccade analysis offers a promising tool for real-time cognitive activity assessment.
• This approach can be applied to develop effective tools for monitoring cognitive engagement during tasks.