Uncovering Distinct Drivers of Covert Attention in Complex Environments With Pupillometry.

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Psychophysics

Background:

• Covert spatial attention, the ability to focus on locations without eye movements, is challenging to measure due to its hidden nature.
• The pupillary light response (PLR) has been used to indirectly assess covert attention, but previous methods required simple stimuli and focused on single attentional drivers.
• A need exists for methods capable of tracking covert attention dynamics with complex, naturalistic stimuli.

Purpose of the Study:

• To introduce and validate a novel pupillometric method for tracking multiple covert attention effects simultaneously using complex stimuli.
• To investigate the independent contributions of bottom-up, top-down, and pseudoneglect effects on pupillary responses during movie viewing.
• To demonstrate the utility of the Open-DPSM toolbox for analyzing covert attention dynamics.

Main Methods:

• Participants viewed movie clips while passively observing or covertly attending to cued locations (left, right, or both).
• Pupillary responses were recorded and analyzed using the Open-DPSM toolbox to assess the influence of luminance changes in attended regions.
• The study evaluated bottom-up (stimulus-driven), top-down (goal-directed), and pseudoneglect (left-side bias) effects on pupillary responses.

Main Results:

• The novel pupillometric method successfully tracked covert attention dynamics in complex visual stimuli.
• Three distinct effects of covert attention on pupil responses were confirmed: bottom-up (dynamic regions), top-down (cued direction), and pseudoneglect (left-side bias).
• These attentional drivers were found to contribute independently, without modulating each other's influence on pupillary responses.

Conclusions:

• The developed pupillometric method offers a robust approach for studying covert attention with complex, dynamic stimuli.
• Bottom-up, top-down, and pseudoneglect influences on covert attention operate independently, even in ecologically valid visual environments.
• The Open-DPSM toolbox provides a valuable resource for researchers investigating the neural and physiological underpinnings of spatial attention.