Research Report The role of category learning in the acquisition and retention of perceptual expertise: A behavioral and neurophysiological study Lisa S. Scott a, ⁎ , James W. Tanaka b , David L. Sheinberg c , Tim Curran d, ⁎ a Department of Psychology, University of Massachusetts, 413 Tobin Hall/135 Hicks Way, Amherst, MA 01003, USA b Department of Psychology, University of Victoria, Canada c Department of Neuroscience, Brown University, USA d Department of Psychology, University of Colorado, USA ARTICLE INFO ABSTRACT Article history: Accepted 13 February 2008 Available online 4 March 2008 This study examined the neural mechanisms underlying perceptual categorization and expertise. Participants were either exposed to or learned to classify three categories of cars (sedans, SUVs, antiques) at either the basic or subordinate level. Event-Related Potentials (ERPs) as well as accuracy and reaction time were recorded before, immediately after, and 1- week after training. Behavioral results showed that only subordinate-level training led to better discrimination of trained cars, and this ability was retained a week after training. ERPs showed an equivalent increase in the N170 across all three training conditions whereas the N250 was only enhanced in response to subordinate-level training. The behavioral and electrophysiological results distinguish category learning at the subordinate level from category learning occurring at the basic level or from simple exposure. Together with data from previous investigations, the current results suggest that subordinate-level training, but not basic-level or exposure training, leads to expert-like improvements in categorization accuracy. These improvements are mirrored by changes in the N250 rather than the N170 component, and these effects persist at least a week after training, so are conceivably related to long-term learning processes supporting perceptual expertise. © 2008 Elsevier B.V. All rights reserved. Keywords: Perceptual expertise Categorization Event-related potential 1. Introduction Recent studies of perceptual expertise and categorization have used training studies to further our understanding of the behav- ioral and neural mechanisms contributing to the acquisition of visual perceptual expertise (Gauthier and Tarr, 1997; Gauthier et al., 1999; Gauthier et al., 1998; Rossion et al., 2002; Rossion et al., 2004; Scott et al., 2006; Tanaka et al., 2005). The use of training studies allows for more precise control over the amount and quality of visual experience needed to obtain perceptual expertise. Although researchers do not expect to be able to equate the acquisition of expertise in the laboratory to real- world expertise, training in a laboratory setting allows for better manipulation of factors contributing to perceptual learning and generalization. Results of perceptual training studies have lead to several important conclusions about how people learn to BRAIN RESEARCH 1210 (2008) 204 – 215 ⁎ Corresponding authors. E-mail address: lscott@psych.umass.edu (L.S. Scott). URL: http://people.umass.edu/lscott (L.S. Scott). 0006-8993/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2008.02.054 available at www.sciencedirect.com www.elsevier.com/locate/brainres