Perceptual Expertise

The study of perceptual expertise addresses the acquisition of perceptual skills that generalize across objects in a domain, such as the ability to recognize birds, to match handwriting samples, or to interpret x-rays or weather maps. Although perceptual expertise in many domains is rare (e.g., few people can match fingerprints), most people [Page 778]acquire some kind of expertise, such as the ability to recognize characters of a writing system or to learn new faces. The majority of studies on perceptual expertise have been done in visual domains, although perceptual expertise can be acquired in other modalities, as found in the work of a som-melier or a music critique. Topics discussed in this entry include: different kinds of perceptual expertise, the study of facelike expertise, facelike expertise with nonface objects, and questions for future perceptual expertise research.

The skills studied in perceptual expertise studies can be distinguished from those typically investigated in research on perceptual learning, which reflects improvements that are highly specific to the trained stimulus and the conditions of training. For example, improvements in detecting low-contrast vertical bars in the right visual field may not transfer to performance with horizontal bars in the same location or to vertical bars in the left visual field. In contrast, a bird expert may learn new species of birds on a trip abroad more efficiently than a novice would. However, the mechanisms underlying perceptual learning may be the same as those involved in perceptual expertise. For instance, perceptual learning could reflect early stages of perceptual expertise, but this is still unknown.

The processes studied under the rubric of perceptual expertise also differ from those that underlie expertise of a more abstract nature, although real-world experts likely generally acquire both perceptual and more semantic knowledge about objects. For instance, a car expert may learn to distinguish cars from photographs, but also learn about the history of the car designs. In contrast to knowledge that can be verbalized, perceptual expertise is not accessible explicitly for the expert to report. A doctor may be able to discuss with colleagues the rules by which she makes a given diagnosis, but her ability to discriminate different kinds of rashes effortlessly is not something that she can explain. Indeed, there is some evidence from studies of face expertise that verbalizing can impair expert performance by leading them to use nonoptimal strategies.