Prototype-referenced shape encoding revealed by high-level after effects

We used high-level configural aftereffects induced by adaptation to realist ic faces to investigate visual representations underlying complex pattern p erception. We found that exposure to an individual face for a few seconds g enerated a significant and precise bias in the subsequent perception of fac e identity. In the context of a computationally derived 'face space,' adapt ation specifically shifted perception along a trajectory passing through th e adapting and average faces, selectively facilitating recognition of a tes t face lying on this trajectory and impairing recognition of other faces. T he results suggest that the encoding of faces and other complex patterns dr aws upon contrastive neural mechanisms that reference the central tendency of the stimulus category.