One theory of facial recognition holds that a specialized area of the brain is specifically wired for the job. It is also thought that this region can integrate information about a visage all at once and that it can do so more quickly than can other areas of the brain that identify unfamiliar objects using a piecemeal approach. But recent findings have challenged this viewpoint by showing that car and bird experts use this face-centric region when analyzing objects associated with their specialty. Whether the same neural circuitry was at work in these instances, however, remained unknown.
In the new study, Isabel Gauthier of Vanderbilt University and her colleagues designed an experiment to try and better pin down the neurons being used to catalogue novel things. The scientists recruited 20 car experts and 20 car novices and showed them alternating images of automobiles and faces while monitoring their brain activity. The researchers asked the subjects to compare each face with the previously shown face, and each car with the previous car, to ensure that they were looking at a face while thinking about a vehicle and vice versa. The team found that the most car-savvy individuals recognized the cars as a whole, but their ability to process faces declined as a result. Vehicle neophytes, in contrast, used the slower piecemeal approach to categorize cars but saw no decrease in their ability to process faces. Gauthier says the findings indicate that "at least some of the same neural circuitry must be involved in identifying faces and other objects of extreme interest. "