Abstract
Perception of mutual gaze direction is an important, nonverbal communication cue in social interactions. Individuals with hemianopia (without neglect) often show a visuo-spatial bias towards the side of the hemifield loss in perceptual tasks. We investigated whether such biases also manifest in judgements of mutual gaze direction. Participants adjusted the eye position of a life-size virtual head on a monitor at a 1-m distance until (1) the eyes appeared to be looking straight at them; or (2) the eyes were perceived to be no longer looking at them (to the right and left), providing a measure of the gaze cone width (the range of gaze directions that are perceived as 'being looked at'). Contrary to expectations, neither participants with left hemianopia (n = 10) nor right hemianopia (n = 10) differed from age-similar, normally-sighted controls (n = 22) in their judgments of straight ahead gaze direction (p = 0.34). Gaze cone widths also did not differ between hemianopes and controls (p = 0.30). However, hemianopes' judgments were more variable than those of controls, especially when gaze of the virtual head was directed toward their blind hemifield (p = 0.01). Interestingly, four participants with left hemianopia and neglect history (not included in the main analyses) demonstrated a rightward shift in their perception of gaze direction and had an asymmetric gaze cone (wider on the blind side), although the overall width was similar to that of participants without neglect history. In summary, participants with hemianopia without neglect history did not show any spatial biases in gaze judgements, although biases were present on a line bisection task. However, residual neglect, not detected on traditional pencil and paper tests, appears to manifest in simulations of more real world tasks, as reported for collision judgments in a simulated walking task (Houston et al., 2015).
Meeting abstract presented at VSS 2018