Spatial statistics of gaze fixations during dynamic face processing

Abstract

Social interaction involves the active visual perception of facial expressions and communicative gestures. This study examines the distribution of gaze fixations while watching videos of expressive talking faces. The knowledge-driven factors that influence the selective visual processing of facial information were examined by using the same set of stimuli, and assigning subjects to either a speech recognition task or an emotion judgment task. For half of the subjects assigned to each of the tasks, the intelligibility of the speech was manipulated by the addition of moderate masking noise. Both tasks and the intelligibility of the speech signal influenced the spatial distribution of gaze. Gaze was concentrated more on the eyes when emotion was being judged as compared to when words were being identified. When noise was added to the acoustic signal, gaze in both tasks was more centralized on the face. This shows that subject's gaze is sensitive to the distribution of information on the face, but can also be influenced by strategies aimed at maximizing the amount of visual information processed.

The National Institute on Deafness and other Communication Disorders (grant DC-00594), the Natural Sciences and Engineering Research Council of Canada, the EJLB Foundation, and the Canadian Institutes of Health Research supported this work. MP holds a New Investigator Award from the Canadian Institutes of Health Research. JB holds an Ontario Graduate Scholarship and the Brian R. Shelton Graduate Fellowship.

We are grateful to June Lam, Mike Yurick, and Dave Hoffmann for help with this study.