Coordination effort in joint action is reflected in pupil size.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Human-Computer Interaction

Background:

• Humans naturally form teams to tackle visual tasks, often dividing labor to manage cognitive load.
• Coordinating actions in collaborative tasks requires significant mental effort.
• Pupil size is a known physiological indicator of mental effort.

Purpose of the Study:

• To investigate if pupil size can detect the coordination effort involved in collaborative visual tasks.
• To differentiate between effort in self-initiated strategy formation versus externally assigned roles.

Main Methods:

• Participants engaged in a multiple object tracking (MOT) task.
• Two conditions were tested: a main experiment with self-determined division of labor and a control experiment with pre-determined roles.
• Pupil size was monitored as a measure of cognitive effort.

Main Results:

• Pupil size significantly increased when participants devised their own division of labor strategy compared to performing the MOT task alone.
• No significant increase in pupil size was observed in the control experiment where labor division was pre-determined.
• This suggests pupil dilation reflects the effort associated with active coordination.

Conclusions:

• Pupil size serves as a reliable physiological marker for detecting coordination effort in human-human and human-computer collaboration.
• The findings expand the understanding of pupil size as an index of mental effort across diverse cognitive tasks.
• This research has implications for designing more intuitive and responsive collaborative systems.