Adaptation to other people's eye gaze reflects habituation of high-level perceptual representations.

Our sense of where another person is looking depends upon multiple features of their face, relating to both the deviation of their eyes and the angle of their head. In this way, gaze direction is a higher-level perceptual property that is dependent on holistic processing of lower-level visual cues. A key paradigm in social perception research is sensory adaptation, which has been used to probe how properties like gaze direction are encoded in the visual system. Here we test whether sensory adaptation acts on higher-level, perceptual representations of gaze direction, or occurs to lower-level visual features of the face alone. To this end, participants were adapted on faces that evoke the Wollaston illusion, in which the direction that the face appears to look differs from its veridical eye direction. We compared across sets of images that were exactly matched in the lower-level features of the face image, but perceptually distinct due to differences in the conjunction of head and eye direction. The changes in participants' perception of gaze direction following adaptation were consistent with habituation having occurred to the perceived gaze direction of the Wollaston faces, where this is dependent on integration of eye direction and head direction, rather than to lower-level sensory features of the face alone. This constitutes strong evidence for adaptable representations of other people's gaze direction in the visual system that are abstracted from lower-level facial cues.