title: Size determines whether specialized expert processes are engaged for recognition of faces.
abstract: Many influential models of face recognition postulate specialized expert processes that are engaged when viewing upright, own-race faces, as opposed to a general-purpose recognition route used for nonface objects and inverted or other-race faces. In contrast, others have argued that empirical differences do not stem from qualitatively distinct processing. We offer a potential resolution to this ongoing controversy. We hypothesize that faces engage specialized processes at large sizes only. To test this, we measured recognition efficiencies for a wide range of sizes. Upright face recognition efficiency increased with size. This was not due to better visibility of basic image features at large sizes. We ensured this by calculating efficiency relative to a specialized ideal observer unique to each individual that incorporated size-related changes in visibility and by measuring inverted efficiencies across the same range of face sizes. Inverted face recognition efficiencies did not change with size. A qualitative face inversion effect, defined as the ratio of relative upright and inverted efficiencies, showed a complete lack of inversion effects for small sizes up to 6°. In contrast, significant face inversion effects were found for all larger sizes. Size effects may stem from predominance of larger faces in the overall exposure to faces, which occur at closer viewing distances typical of social interaction. Our results offer a potential explanation for the contradictory findings in the literature regarding the special status of faces.
authors: Department of Medicine, University of British Columbia, Vancouver, Canada.
authors: Nan
authors: N
authors: Yang
authors: Graduate Program in Neuroscience, University of British Columbia, Vancouver, CanadaDepartment of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
authors: Fakhri
authors: F
authors: Shafai
authors: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada.
authors: Ipek
authors: I
authors: Oruc
mesh_terms: D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology; D005145:Face; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*; D055815:Young Adult
keywords: configural processing; contrast threshold; efficiency; face recognition; holistic; ideal observer; piecemeal; scale invariance; size