An integrative approach towards understanding the psychological and neural basis of congenital prosopagnosia

Faces have distinctive evolutionary and social significance and, therefore, it is not surprising that face perception is probably the most developed visual perceptual skill in humans. At an input level, faces are perceptually similar homogeneous exemplars drawn from a single class and are all composed of essentially the same local elements (e.g., two eyes, a nose, cheeks and amouth) in the same spatial layout (e.g., eyes above the nose). Despite this fundamental visual similarity, individual faces convey a large amount of critical information upon which we, as human observers, rely heavily for social interaction and communication. A quick look at a person’s face reveals valuable information such as age, gender, emotional state, gaze direction, and useful speech cues. We can also identify individuals accurately and rapidly across radically different viewing conditions (e.g. lighting, vantage points) and structural changes of the face as the person ages or conveys different expressions. Moreover, notwithstanding some in- dividual differences (Rotshtein et al., 2007), we can represent the unique identity of an almost unlimited number of faces and, when presented with a familiar face, can easily come upwith the name of the person as well as other relevant biographical information that pertains to the individual.