Abstract
Humans are sensitive to the gaze direction of others, and use this visual information to guide attentional, emotional, and social processes. To accurately judge the direction of another's gaze, it is necessary to represent not only the position of the eyes in isolation, but also the orientation of the head. Thus, gaze perception depends on an integrative process, where multiple combinations of head orientation and eye position produce the same gaze direction in a head-view invariant manner. We tested for such representations by applying a novel combination of multivariate searchlight mapping and correlation-based representational similarity analysis to human functional MRI data. A group analysis showed that response patterns in right anterior superior temporal sulcus (STS) extract a code for gaze direction in a manner that is not reducible to coding of the component head/eye cues in isolation (N = 18, random effects. all ps < 0.05, FWE-corrected for the anatomically-defined right STS region). Furthermore, this STS gaze direction code showed a graded similarity structure, with sensitivity to fine-grained distinctions between adjacent gaze directions. Our results show that anterior STS forms a late stage of social visual processing, where face features are integrated to form a perceptually-relevant gaze direction code. These findings exemplify how the representation of faces in anterior temporal regions becomes sensitive to perceptually-relevant dimensions, such as gaze direction, through invariance to intermediate-level features, such as head view.
This work was supported by the United Kingdom Medical Research Council (grant U.1055.02.001.0001.01 to A.J.C studentship U.1055.01.011.00001.01 to J.D.C), and the Wellcome Trust (077029 to J.B.R.).