Face perception, perhaps the most highly developed visual skill in humans, is mediated by a distributed neural system in humans that is comprised of multiple, bilateral regions. We propose a model for the organization of this system that emphasizes a distinction between the representation of invariant and changeable aspects of faces. The representation of invariant aspects of faces underlies the recognition of individuals, whereas the representation of changeable aspects of faces, such as eye gaze, expression, and lip movement, underlies the (...) perception of information that facilitates social communication. The model is also hierarchical insofar as it is divided into a core system and an extended system. The core system is comprised of occipitotemporal regions in extrastriate visual cortex that mediate the visual analysis of faces. In the core system, the representation of invariant aspects is mediated more by the face-responsive region in the fusiform gyrus, whereas the representation of changeable aspects is mediated more by the face-responsive region in the superior temporal sulcus. The extended system is comprised of regions from neural systems for other cognitive functions that can be recruited to act in concert with the regions in the core system to extract meaning from faces. (shrink)

Facial appearance changes with age and health affecting skin color as well as facial and head hair. Yet somehow the brain is able to see past shared structure and dynamic deformations to focus on subtle details that distinguish one face from another. This article argues that the brain takes an efficient approach to this problem using prior knowledge about the structure of faces in its analysis. It employs intrinsic norms to focus on subtle variations in the shared face configuration that (...) differentiate one face from another. The study reviews evidence that the brain uses multiple norms to extract face identity that these norms are shaped by visual experience, and that norm-based coding is well-suited to meeting the challenges of image-based face perception mentioned above. By encoding faces with reference to stored perceptual norms the visual system can focus on what is unique to each individual, allowing for the discrimination of thousands of faces despite their similarity. (shrink)

This article discusses how research on the image-based analysis of facial images has informed this debate by demonstrating that a single representational system for facial identity and facial expression is not only computationally viable, but can simulate existing cognitive data demonstrating apparent dissociable processing of these two facial properties. It discusses the increasing number of cognitive studies that provide support for this view. Neuropsychological case studies of brain-injured patients and provide limited evidence for separate visual routes processing facial identity and (...) facial expression. It deals with neuroimaging studies addressing both facial identity and facial expression processing which shows that the fusiform gyrus contributes to the recognition of both facial properties. Research continues to reinforce the proposal that a common visual framework supports the representation of at least some aspects of facial identity and facial expression. (shrink)