Fig. 4.

Results of two permutation tests comparing the (A) onset and (B) offset of eye contact to 1,000, randomly chosen, 9-s moments in each conversation, per dyad. The distributions depicted above were created by taking the pupillary synchrony value at the “onset” and “offset” point (position 5) of each randomly chosen moment in the conversation. The true pupillary synchrony values for the onset and offset of eye contact are represented by the red horizontal lines in each figure. Pupillary synchrony at the onset of eye contact is significantly higher than would be expected by chance, and pupillary synchrony at the offset of eye contact is significantly lower than would be expected by chance.