Abstract
Most animals look at each other to signal threat or interest. In humans, this social interaction is usually punctuated with brief periods of mutual eye contact. Deviations from this pattern of gazing behaviour generally make us feel uncomfortable and are a defining characteristic of clinical conditions such as autism or schizophrenia, yet it is unclear what constitutes normal eye contact. Here, we measured, across a wide range of ages, cultures and personality types, the period of direct gaze that feels comfortable and examined whether autonomic factors linked to arousal were indicative of people's preferred amount of eye contact. Surprisingly, we find that preferred period of gaze duration is not dependent on fundamental characteristics such as gender, personality traits or attractiveness. However, we do find that subtle pupillary changes, indicative of physiological arousal, correlate with the amount of eye contact people find comfortable. Specifically, people preferring longer durations of eye contact display faster increases in pupil size when viewing another person than those preferring shorter durations. These results reveal that a person's preferred duration of eye contact is signalled by physiological indices (pupil dilation) beyond volitional control that may play a modulatory role in gaze behaviour.
Highlights
Eye contact occurs during most animal interactions, often signalling either threat or interest [1,2]
We provide the very first large-scale quantification of preferred direct gaze duration and relate this measure to eye tracking, physiological, demographic and personality indices
We find that changes in pupil size are indicative of a participant’s experience of preferred duration of eye contact
Summary
Eye contact occurs during most animal interactions, often signalling either threat or interest [1,2]. Given the importance of eye contact in human (and non-human) social interactions, as well as the fact that abnormal eye contact is used as a diagnostic tool for clinical symptoms such as autism and schizophrenia [14], it is surprising that ‘normal’ eye contact behaviour remains so ill defined This is hampered by the fact that gaze behaviour between two people is highly dynamic; any explicit characterization of gaze behaviour must quantify its spatio-temporal characteristics. Using behavioural methods, we measure the amount of time an actor can look at a participant without it feeling uncomfortable for the participant ( called ‘preferred gaze duration’, PGD) and examine if this depends on participant personality traits. Behavioural and physiological measures were combined with basic demographics and personality questionnaires to determine whether trait characteristics influenced gazing behaviour
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