Abstract
The eyes of other people subserve two core functions in human social cognition: gaze perception and facial identity recognition. Here we report four experiments that investigate whether various aspects of gaze processing can be intact when identity processing is impaired in developmental prosopagnosia (DP). Experiment 1 (N = 102 DPs, 97 controls) measured perception of strabismus, which requires judgment of gaze direction from the two eyes. Experiment 2 (N = 101 DPs, 97 controls) measured the Wollaston illusion (whereby perceived eye gaze is pulled by head rotation), which requires perceptual integration of eye and head direction. Experiment 3 (N = 45 DPs, 45 controls) measured gaze discrimination and gaze adaptation, which reflects sensitivity to gaze direction and its sensory representations. Experiment 4 (N = 18 DPs, 22 controls) measured serial dependence in gaze perception, which reflects temporal integration of gaze direction and its perceptual stability. Despite their severe and lifelong deficits at recognising identity, DPs showed normal gaze processing across all experiments. These results demonstrate the functional specificity of gaze processing and imply that gaze perception is carried out by dedicated mechanisms not used for processing identity. Our findings align with models of face processing that posit distinct pathways for gaze and identity analysis, and further clarify the selectivity of face processing dysfunctions in developmental prosopagnosia.