Pupil Sizes Scale with Attentional Load and Task Experience in a Multiple Object Tracking Task.

Area of Science:

• Cognitive psychology
• Neuroscience
• Human-computer interaction

Background:

• Previous research links attentional load to pupil size changes.
• Limited studies explore fine-grained effects of attentional load and task experience on pupil size.

Purpose of the Study:

• To investigate how varying attentional load and task experience influence pupil size.
• To assess the utility of pupillometry for measuring cognitive states in visuospatial tasks.

Main Methods:

• Participants performed a covert object tracking task with 0-5 objects.
• Attentional load was manipulated by the number of tracked objects.
• Task experience was assessed over three consecutive experimental days.

Main Results:

• Pupil size positively correlated with increased attentional load.
• Consistent pupil size reductions were observed across experimental days, indicating learning.
• A model incorporating attentional load and task experience best predicted pupil size modulations, outperforming models including task performance.

Conclusions:

• Pupillometry is a sensitive measure for quantifying attentional load in real-time.
• Pupil size changes reflect task experience and learning in visuospatial contexts.
• This method offers a non-invasive approach to assess cognitive states during complex tasks.