Data from: Pupil dilation as an index of preferred mutual gaze duration

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.

绝大多数动物会通过对视传递威胁或意图信号。对人类而言，这类社交互动通常会穿插短暂的相互注视。偏离此类注视行为模式的表现通常会引发不适感，同时也是自闭症、精神分裂症等临床病症的典型特征之一，但目前学界尚未明确正常目光接触的界定标准。本研究在覆盖广泛年龄层、文化背景与人格类型的群体中，量化了人们感到舒适的直接注视时长，并探究了与唤醒水平相关的自主神经因素是否能够反映个体偏好的注视时长。令人意外的是，我们发现个体偏好的注视时长并不取决于性别、人格特质或外貌吸引力这类基础特征。不过本研究亦发现，反映生理唤醒状态的细微瞳孔变化，与个体感到舒适的注视时长存在显著相关。具体而言，相较于偏好较短注视时长的个体，偏好更长注视时长的个体在观察他人时，瞳孔尺寸会出现更快的扩张。本研究结果显示，个体偏好的注视时长可通过不受意志控制的生理指标（瞳孔扩张）进行表征，此类指标或可对注视行为发挥调节作用。