Abstract
The current study employed a rapid adaptation procedure to investigate the response profile of the early face-sensitive N170 ERP component to human and animal faces. Adaptors (S1) consisting of full faces, isolated eye regions and eyeless faces of humans, apes, dogs and cats were rapidly followed by a full human face as test stimulus (S2). All stimuli were equated in luminance, contrast and spatial frequencies. In response to adaptor stimuli (S1), human faces yielded significantly lower N170 amplitudes than human eyes, as classically reported, whereas no difference was found between animal eyes and faces. In response to S2 and in line with the adaptation mechanism, an attenuation of N170 amplitude was found for all types of face-related adaptors relative to house adaptors irrespective of species. Eye stimuli elicited stronger adaptation than face stimuli for humans, apes and cats, but not for dogs. These results support a differential role of eyes in early face processing for humans compared to animal species. Their significance is discussed in light of a recent model of face processing stipulating eye- and face-selective neuronal populations (Itier, 2007).
Canada Research Chair (CRC) program, Canadian Institutes for Health Research (CIHR), Canada Foundation for Innovation (CFI) and the Ontario Research Fund (ORF).