Abstract
Perceived gaze direction plays a significant role in successful communication between two people (Otsuka, S. et al., 2014). Specifically, eye contact provides information about the type of interaction taking place and regulates behavior accordingly (Tomonaga & Imura, 2010). Previous studies using two-dimensional face models displayed on flat monitors have shown two phenomena: a repulsive effect that causes gaze direction to be perceived shifted opposite to head orientation, and an attractive effect that causes a bias towards head orientation (Gibson & Pick, 1963). Here, using virtual reality, we determined whether or not the two effects persist when faces and their components (eyes) are perceived in three dimensions (3D). In an immersive 3D world, a model is presented with a combination of three head and seven pupil orientations, along with four eye types: Normal (white sclera, grey iris, black pupil), inverted (grey sclera, white iris, black pupil), pupil-only (white sclera, black pupil, absence of the iris) and no pupil (white sclera, grey iris, absence of the pupil). We observed a significant repulsive effect in each head rotation in almost all conditions (Wilcoxon Rank Test, p < .05), except for the inverted eyes (p > .156). Reaction times were not significantly different between the normal, no pupil and pupil-only conditions (Kruskal-Wallis, p > .043). However, they were significantly longer in the inverted eyes condition relative to the others (p ≤ .001). The slope of the psychometric function was not significantly different between conditions (Kruskal-Wallis, p = .247). This indicates that task difficulty across conditions was similar. Our results demonstrate that the repulsive effect of head orientation on perceived gaze direction is also present when using 3D virtual displays. Moreover, they suggest that the repulsive effect is caused by the high contrast between the white sclera and the tissue surrounding the eye aperture.
Acknowledgement: CIHR, Autism Research Chair Ontario, NSERC, CFI