Global face distortion aftereffects tap face-specific and shape-generic processes

Abstract

Face aftereffects are commonly used to investigate the mechanisms underlying face processing, based on the assumption that they tap processes involved specifically with face-level coding (e.g., face space). However, face aftereffects could potentially arise from many levels of the visual system, and recent research has shown that one figural aftereffect (eye height) has both face-level and shape-generic components. Another very widely used figural manipulation is global face distortion. Here we investigate whether a global face distortion aftereffect (vertical compression) transfers to nonface stimuli, and if so, to what extent. Arguing for a mid- or high-level shape-generic component to our face aftereffect, we found significant face-to-object transfer even after minimizing retinotopic components. Arguing for an additional face-specific component, we found, first, that face-to-face aftereffects were significantly larger than face-to-object aftereffects and second, that this occurred only when the adaptor face was whole and intact rather than scrambled. Our results argue that global face distortion aftereffects are a useful tool for investigating face-space but that, to do so unambiguously, requires developing methods to minimize or account for the shape-generic contribution.