A dual mobile eye tracking study on natural eye contact during live interactions.

Human eyes convey a wealth of social information, with mutual looks representing one of the hallmark gaze communication behaviors. However, it remains relatively unknown if such reciprocal communication requires eye-to-eye contact or if general face-to-face looking is sufficient. To address this question, while recording looking behavior in live interacting dyads using dual mobile eye trackers, we analyzed how often participants engaged in mutual looks as a function of looking towards the top (i.e., the Eye region) and bottom half of the face (i.e., the Mouth region). We further examined how these different types of mutual looks during an interaction connected with later gaze-following behavior elicited in an individual experimental task. The results indicated that dyads engaged in mutual looks in various looking combinations (Eye-to-eye, Eye-to-mouth, and Mouth-to-Mouth) but proportionately spent little time in direct eye-to-eye gaze contact. However, the time spent in eye-to-eye contact significantly predicted the magnitude of later gaze following response elicited by the partner's gaze direction. Thus, humans engage in looking patterns toward different face parts during interactions, with direct eye-to-eye looks occurring relatively infrequently; however, social messages relayed during eye-to-eye contact appear to carry key information that propagates to affect subsequent individual social behavior.