Component processes in free-viewing visual search: Insights from fixation-aligned pupillary response averaging

Area of Science:

• Cognitive Psychology
• Neuroscience
• Ophthalmology

Background:

• Pupil size changes are potential indicators of cognitive processes during visual search.
• Previous research is limited by methodological confounds and lack of literature.

Purpose of the Study:

• To investigate cognitive processing during free-viewing visual search for multiple targets.
• To examine pupil size changes as a reliable measure of cognitive effort and memory accumulation.

Main Methods:

• Employed a novel synthesis of experimental methods and averaging techniques.
• Utilized whole-trial and fixation-aligned pupil analysis.
• Controlled for experimental confounds and corrected eye-movement measurement error.

Main Results:

• Pupil analysis showed significant effects of button pressing and target presence in non-self-terminated trials.
• Fixation-aligned pupil responses revealed transient modulations after initial target fixations.
• Pupil responses differed between initial fixations on targets and distractors, and subsequent refixations.

Conclusions:

• Pupil size changes reliably reflect cognitive processing during visual search.
• Findings provide insights into task-related processing and underlying neural activity.
• This study establishes a more reliable methodology for pupil-based cognitive research.