A comparative case study of face recognition: the contribution of configural and part-based recognition systems, and their interaction.

Understanding the interaction between the configural and part-based systems in face recognition is the major aim of this study. Specifically, we established whether configural representation of faces contribute to aspects of face recognition that depend on part-based processes, such as identifying inverted or fractured faces. Using face recognition tasks that require part-based or configural processing, we compared the results of CK--a man who has object agnosia and alexia [Moscovitch, M., Winocur, G., & Behrmann, M. (1997). What is special about face recognition? Nineteen experiments on a person with visual object agnosia and dyslexia but normal face recognition. Journal of Cognitive Neuroscience, 9(5), 555-604] but normal upright face recognition, to those of DC--a man who has prosopagnosia but normal object recognition. CK was normal at recognizing faces if configural processing was sufficient, but poor at recognizing faces that were modified so as to alter their gestalt, and require part-based processing (Moscovitch et al.). DC was impaired at recognizing upright faces and his performance declined in all tasks involving recognition of modified faces, including those that depend on part-based and on configural processing. Nevertheless, DC was normal on tasks involving perception of generic faces and face imagery. These results show that although configural face perception can proceed without part-based processing, the reverse is not the case. Our results suggest that the configural system is always necessary for face recognition, and appears to support what remains of face identification even in prosopagnosic people who have an intact part-based system.