Structural encoding of human and schematic faces: Holistic and part-based processes

The range of specificity and the response properties of the extrastriate fa ce area were investigated by comparing the N170 event-related potential (ER P) component elicited by photographs of natural faces, realistically painte d portraits, sketches of faces, schematic faces, and by nonface meaningful and meaningless visual stimuli. Results showed that the N170 distinguished between faces and nonface stimuli when the concept of a face was clearly re ndered by the visual stimulus, but it did not distinguish among different f ace types: Even a schematic face made from simple line fragments triggered the N170. However, in a second experiment, inversion seemed to have a diffe rent effect on natural faces in which face components were available and on the pure gestalt-based schematic faces: The N170 amplitude was enhanced wh en natural faces were presented upside down but reduced when schematic face s were inverted. Inversion delayed the N170 peak latency for both natural a nd schematic faces. Together, these results suggest that early face process ing in the human brain is subserved by a multiple-component neural system i n which both whole-face configurations and face parts are processed. The re lative involvement of the two perceptual processes is probably determined b y whether the physiognomic value of the stimuli depends upon holistic confi guration, or whether the individual components can be associated with faces even when presented outside the face context.