Judging another person's facing direction using peripheral vision

M. Pusch, J. M. Loomis
2010 Journal of Vision  
Two psychophysical experiments are reported, one dealing with the visual perception of the head orientation of another person (the "looker") and the other dealing with the perception of the looker's direction of eye gaze. The participant viewed the looker with different retinal eccentricities ranging from foveal to far peripheral viewing. On average, judgments of head orientation were reliable even out to the extremes of peripheral vision (90º eccentricity), with better performance at the
more » ... rmance at the extremes when the participant was able to view the looker changing head orientation from one trial to the next. In sharp contrast, judgments of eye gaze direction were reliable only out to 4º eccentricity, signifying that the eye gaze social signal is available to people only when they fixate near the looker's eyes. While not unexpected, this vast difference in availability of information about head direction and eye direction, both of which can serve as indicators of the looker's focus of attention, is important for understanding the dynamics of eye gaze behavior. Like so many facets of non-verbal communication, signaling by eye gaze is phenomenologically transparent, allowing the perceiver to effortlessly know much about the other's attentional focus, intentions, and desires (Baron-Cohen 1995; Tooby and Cosmides 1995) . Contrasting with the phenomenological transparency of eye gaze signaling is its computational complexity. Just being able to perceive the other person's attentional focus ("joint attention") is a computational feat. It requires perceiving the distance and direction to the other's head, perceiving the orientation of the other's head, perceiving the orientation of the eyes within the other's head, and then, on the basis of these, constructing the line in space representing the other's gaze direction. Any object perceived to be on this line, which also requires distance perception, is then a candidate for the other's attentional focus. Because of the intimate connection between visual perception and eye gaze processing, the dynamics of eye gaze behavior reflect the social signals that are and are not perceptible to the interactants. Thus, a full understanding of social interaction mediated by eye gaze requires psychophysical research to elucidate which signals can be sensed by the interactants. So far, there has been a modicum of research, mostly by vision scientists, devoted to the psychophysics of gaze direction, whether the eyes are directly observed or just the head (
doi:10.1167/1.3.288 fatcat:6ian6jfurncf7c2w6e34wfzqs4