Are Greebles like faces? Using the neuropsychological exception to test the rule

Abstract

Which image geometries count as face-like and which do not? Across multiple experiments [Vision Research 37 (12) (1997) 1673; Journal of Cognitive Neuroscience 11 (4) (1999) 349; Psychological Science 13 (3) (2002) 250], novel objects called Greebles have been used to argue that face-specific effects can be obtained with non-face stimuli under certain situations, in particular with expert observers. However, this claim depends on the argument that these non-face stimuli are not a priori treated by the face processing system. To address this question, CK, a neuropsychological patient well-known for exhibiting severe visual object agnosia and dyslexia but intact face processing, was tested with Greebles. CK performed poorly on Greebles, indicating that his intact face-specific abilities do not extend to include Greebles. These results suggest that insofar as CK is relying on face-specific visual processes, these processes do not a priori treat Greebles as faces.