Eye-contact facilitates effective interpersonal exchange during social interactions, but can be a considerable source of anxiety for individuals with social phobia. However, the relationship between the fundamental spatial range of eye-contact perception and psychiatric traits is, to date, unknown. In this study, I analyzed the eye-contact spatial response bias and the associated pupil response, and how they relate to traits of social interaction disorders. In a face-to-face situation, 21 pairs of subjects were randomly assigned to be either viewers or perceivers. (...) The viewer was instructed to gaze either at the perceiver’s eyes, or at a predetermined point, and the perceiver was asked to indicate whether eye-contact had been established or not. I found that the perceptual volume is much larger than the actual volume of eye-contact, and that the subjective judgment of eye-contact elicited greater pupil dilation in the perceiver. Furthermore, the relationship between behavioral performance and social anxiety traits was identified. These findings provide new indications that internal traits related to lower social anxiety are potentially related to a restriction of spatial response bias for eye-contact. (shrink)