Coordination effort in joint action is reflected in pupil size

Basil Wahn*, Veera Ruuskanen, Alan Kingstone, Sebastiaan Mathôt

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)
78 Downloads (Pure)


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.

Original languageEnglish
Article number103291
Number of pages8
JournalActa Psychologica
Publication statusPublished - Apr-2021


  • Computers
  • Humans
  • Pupil


Dive into the research topics of 'Coordination effort in joint action is reflected in pupil size'. Together they form a unique fingerprint.

Cite this