Humans often perform visual tasks together, and when doing so, they tend to devise division of labor strategies to share the load. Implementing such strategies, however, is effortful as co-actors need to coordinate their actions. We tested if pupil size – a physiological correlate of mental effort – can detect such a coordination effort in a multiple object tracking task (MOT). Participants performed the MOT task jointly with a computer partner and either devised a division of labor strategy (main experiment) or the labor division was already pre-determined (control experiment). We observed that pupil sizes increase relative to performing the MOT task alone in the main experiment while this is not the case in the control experiment. These findings suggest that pupil size can detect a rise in coordination effort, extending the view that pupil size indexes mental effort across a wide range of cognitively demanding tasks.

人们经常一起执行视觉任务，并且这样做时，他们倾向于设计分工策略来分担负担。但是，由于合作者需要协调其行动，因此实施此类策略非常费力。我们测试了瞳孔大小（即精神努力的生理相关因素）是否可以在多对象跟踪任务（MOT）中检测到这种协调努力。参与者与计算机合作伙伴共同执行了MOT任务，并设计了一项分工策略（主要实验）或已经预先确定了分工（对照实验）。我们观察到，在主要实验中，相对于仅执行MOT任务，瞳孔大小会增加，而在对照实验中情况并非如此。这些发现表明，学生的规模可以检测出协调能力的提高，