Does Conceptual Information Take Precedence Over Perceptual Information Early in Development? Evidence From Perseveration Errors

Does Conceptual Information Take Precedence Over Perceptual Information Early in Development? Evidence From Perseveration Errors Anna V. Fisher (fisher49@andrew.cmu.edu) Department of Psychology, Baker Hall 345-I 5000 Forbes Ave, Pittsburgh, PA 15213 USA Abstract Generalization is a fundamental cognitive process; however mechanisms of generalization early in development remain contested. According to one theoretical position, from very early in development conceptual information takes precedence over perceptual information. According to the alternative position, effects of conceptual knowledge have a protracted developmental course. The goal of the present research was to examine directly whether 3- to 5-year-old children privilege conceptual information over perceptual information. Participants were presented with triads of objects in which category membership conflicted with appearance similarity. Half of the children were first asked to sort pictures by category membership and then switch to sorting by similarity; the order of tasks was reversed for the other half of the children. A strong asymmetry in perseveration errors was observed across all three age groups: there was a marked decrease in accuracy when children were asked to switch form sorting by similarity to sorting by category membership, whereas the decrease was less pronounced when children were asked to switch from sorting by category membership to sorting by similarity (particularly for 4- and 5- year-old children who exhibited virtually no decrease in accuracy in the latter condition). Keywords: Categorization, Cognitive Cognitive Flexibility, Perseveration. Development; Introduction Generalization is a fundamental cognitive process because it allows us to acquire new knowledge by extending known to the unknown. Humans exhibit remarkable generalization abilities very early in development. For example, 3- and 4- month-old infants can learn to categorize artificial dot patterns (Bomba & Siqueland, 1983) as well as naturalistic stimuli (Quinn, Eimas, & Rosenkrantz, 1993); by 10 months of age infants are capable of performing simple generalizations about object properties, such as pattern of motion (Rakison, & Poulin-Dubois, 2002; Baldwin, Markman, & Melartin, 1993); 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. There is little disagreement in the literature that perceptual factors influence both early and mature generalization (for review see Murphy, 2002). For instance, French, Mareschal, Mermillod, & Quinn (2004) demonstrated that 3- and 4-month-old infants form a representation of the category “cat” that excludes dogs, and a representation of the category “dog” that includes cats. The basis for this asymmetry was infants’ sensitivity to the distribution information of perceptual features (such as leg length, head width, ear separation, etc.) and the fact that feature distribution of the category “cat” is subsumed within the feature distribution of the category “dog”. Therefore, the asymmetry was reversed when infants were presented with a set of stimuli in which the inclusion relationship of the feature distributions was reversed (French, et. al., 2004). When children learn their first words, they extend new words to refer to correct objects or overextend new words to refer to items perceptually similar to correct objects (Huttenlocher & Smiley, 1987). Importantly, perceptual similarity effects are also well documented in mature generalization (Malt, 1994; Sloman, 1993; Osherson, Smith, Wilkie, Lopez, & Shafir, 1990; Nosofsky, 1984; Rips, Shoben, & Smith, 1973). There is also little disagreement that mature generalization is often influenced by conceptual factors, such as knowledge of the taxonomic hierarchies, expertise in a particular domain, or knowledge of an object’s function (Heit & Rubinstein, 1994; Proffitt, Coley, & Medin, 2000; Wisniewski, 1995). However, while conceptual effects in mature generalization are well documented, the developmental course of these effects remains unclear. One possibility is that early in development generalization processes are driven primarily by the low-level mechanisms of perception, attention, and memory, with conceptual factors emerging as an important influence on generalization later in development (McClelland, & Rogers, 2003; Rakison, 2003; Sloutsky, & Fisher, 2004; Sloutsky, 2003; Samuelson, & Smith, 2000; Smith, 2000). However, it has been argued that perceptual factors alone are insufficient to explain early generalization, and conceptual factors (e.g., knowledge of the ontological status of the object) permeate learning from early infancy (Booth & Waxman, 2002; Gelman, 2003). Furthermore, it has been suggested that when perceptual and conceptual information are in conflict, conceptual information “takes precedence” over perceptual information (Booth & Waxman, 2002; Gelman & Markman, 1986; Gelman, 2003). The goal of the present research was to address the question whether young children privilege conceptual information over perceptual information using a task traditionally used to examine cognitive flexibility - a Dimension Change Card Sorting (DCCS) task, which is a simplified version of the Wisconsin Card Sort Test (Berg, 1948). In the DCCS task children are presented with a set