Human sensitivity to eye contact in 2D and 3D videoconferencing

Gaze awareness and eye contact serve important functions in social interaction. In order to maintain those functions in 2D and 3D videoconferencing systems, human sensitivity to eye contact and gaze direction needs to be taken into account in the design of such systems. Here we experimentally investigate human perception of eye contact and gaze direction in 2D and 3D, using a within-subjects design. Our results indicate that the disparity between the optical axis of the camera and the looking direction of a looker (a photographed face) should be at most 1.2° in horizontal direction, and 1.7° in vertical direction to support eye contact. Maximum tolerable offsets for the perception of eye contact are independent of (monoscopic or stereoscopic) display conditions. Asymmetric sensitivity to eye contact is explained by the underestimation of the vertical component of a looker's gaze direction.