Processing of perceptual information is more robust than processing of conceptual information in preschool-age children: Evidence from costs of switching Anna V. Fisher ⇑ Carnegie Mellon University, Department of Psychology, 5000 Forbes Ave., 335-I Baker Hall, Pittsburgh, PA 15213, United States article info Article history: Received 30 March 2010 Revised 29 January 2011 Accepted 30 January 2011 Available online 23 February 2011 Keywords: Generalization Categorization Cognitive flexibility Cognitive development abstract Is processing of conceptual information as robust as processing of perceptual information early in development? Existing empirical evidence is insufficient to answer this question. To examine this issue, 3- to 5-year-old children were presented with a flexible categoriza- tion task, in which target items (e.g., an open red umbrella) shared category membership with one test item (e.g., a folded umbrella) and perceptual characteristics with another test item (e.g., a red mushroom). Participants were instructed to either categorize stimuli by the same dimension (i.e., perceptual similarity or category membership) in both phases of the task, or switch from categorizing by one dimension to categorizing by the other dimension. Results pointed to a strong asymmetry in switch costs: conceptual switch costs were higher than perceptual switch costs. These results suggest that processing of perceptual information remains more robust than processing of conceptual information at least until 5 years of age. Ó 2011 Elsevier B.V. All rights reserved. 1. Introduction The ability to generalize from the known to the un- known is a fundamental cognitive ability: As Steven Sloman succinctly put it ‘‘our knowledge that leopards can be dangerous leads us to keep a safe distance from jaguars’’ (Sloman, 1993, p. 321). Humans exhibit remarkable generalization abilities very early in development. By 3 months of age, infants can learn novel categories consist- ing of artificial as well as naturalistic objects (Bomba & Siqueland, 1983; Quinn, Eimas, & Rosenkratz, 1993), by 10 months of age infants can perform simple generaliza- tions about object properties, such as the path of motion and sounds objects produce (Baldwin, Markman, & Melartin, 1993; Rakison & Poulin-Dubois, 2002), and by 24 months of age children readily extend known labels to novel objects (Booth & Waxman, 2002; Jones & Smith, 1998; Smith, Jones, & Landau, 1996). However, mechanisms of generalization early in development remain contested. Generalization may be influenced by a variety of factors. Consider the generalization in the example above: On what basis might one decide to keep away from jaguars based on the knowledge that leopards are dangerous? Leopards and jaguars belong to the same animal family referred to as ‘‘big cats’’; leopards and jaguars live in similar habitats (rainforest in Africa and South America, respectively); leopards and jaguars are both predators; leopards and jag- uars look similar to each other. Researchers in the field commonly divide possible factors that can influence gener- alization into two broad categories: perceptual factors and conceptual factors (e.g., Booth & Waxman, 2002; Gelman & Markman, 1986; Sloutsky, 2010). Perceptual factors are those that are directly observable and readily perceived by the organism (e.g., that leopards and jaguars look simi- lar); conceptual factors are characterized as those that 0010-0277/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.cognition.2011.01.015 ⇑ Tel.: +1 412 268 8656; fax: +1 412 268 2798. E-mail address: fisher49@andrew.cmu.edu Cognition 119 (2011) 253–264 Contents lists available at ScienceDirect Cognition journal homepage: www.elsevier.com/locate/COGNIT