Research Article View-Specific Coding of Face Shape

ABSTRACT—Monkey and human cortex contain view-spe-cific face neurons, but it remains unclear whether they code face shape. We tested the view specificity of face-shape coding by inducing figural face aftereffects at one viewpoint (3/4 left) and testing generalization to different viewpoints (front view and 3/4 right). The aftereffects were induced by adaptation to consistent figural distor-tions (contracted or expanded), which shifts the distortion perceived as most normal toward the adapting distortion. The strong aftereffect that was observed at the adapting view was significantly and substantially reduced for both front-view test faces and mirror-image (3/4 right) test faces, indicating view specificity. The limited transfer across mirror views is strong evidence of view specificity, given their figural similarity. The aftereffects survived a size change between adaptation and test faces (Experi-ment 2), a result that rules out low-level adaptation as an explanation. These results provide strong evidence that face-shape coding is view-specific. Human face identification is remarkably robust to changes in viewpoint considering that the images projected on the retina by two different faces seen from the same view are more similar than the images projected by the same face seen at different views. A single exposure to a face from one viewpoint can be sufficient for recognition of this face at other views (Bruce, Valentine, & Baddeley, 1987; Bülthoff & Edelman, 1992), al-though subtle decrements in recognition can occur as test views are rotated away from learned views (Liu & Chaudhuri, 2002; Newell, Chiroro, & Valentine, 1999; Troje & Bülthoff, 1996; Troje & Kersten, 1999). A central question in face and object perception is whether this robustness to changes in viewpoint reflects underlying view-invariant representations or the use of multiple view-specific representations (e.g., Biederman & Bar