Mechanisms of Ensemble Face Processing: Extraction of Summary, but not Single, Identity Shows Sensitivity to Non-Frontal Global Viewpoints

The recognition and perception of faces – both alone and in groups – is an important biological function, enabling humans to effectively engage with one another socially. This thesis describes viewpoint and identity interactions in processing face ensembles, helping vision scientists to understand the cognitive mechanisms taking place. I manipulated viewpoint or identity across two experiments. The first experiment had participants report an average or single viewpoint or identity, and the second experiment had participants report an average identity or a single identity across a wide range of viewpoints. I find that efficiency in average – but not single – identity extraction decreases as viewpoints are progressively non-frontal. Viewers also extract summary viewpoint better than a single viewpoint, and this ability also decreases as global viewpoints are non-frontal. The implications in the face ensemble processing system, general ensemble processing models, and future research are discussed below.