The Development of Induction: From Similarity-Based to Category-Based

The Development of Induction: From Similarity-Based to Category-Based Anna V. Fisher (fisher.449@osu.edu) Department of Psychology & Center for Cognitive Science The Ohio State University 208B Ohio Stadium East, 1961 Tuttle Park Place Columbus, OH 43210 USA Vladimir M. Sloutsky (sloutsky.1@osu.edu) Center for Cognitive Science The Ohio State University 208C Ohio Stadium East, 1961 Tuttle Park Place Columbus, OH 43210 USA members of the same categories share many unobservable properties. According to another position, young children perform induction (as well as categorization) by detecting multiple correspondences, or similarities, among presented entities (e.g., see Jones & Smith, 2002; McClelland & Rogers, 2003; Sloutsky & Fisher, in press-a; Sloutsky, 2003). Because members of a category often happen to be more similar to each other than they are to nonmembers, young children are more likely to induce unobserved properties to members of the category. One such similarity-based model, SINC (abbreviated for Similarity, Induction, and Categorization) was proposed recently by Sloutsky and colleagues (Sloutsky et al., 2001; Sloutsky, 2003, Sloutsky & Fisher, in press-a). Under this view, conceptual knowledge (i.e., knowledge that that members of the same category share many unobservable properties) is a product of learning and development rather than an a priori assumption. In short, under the former view, induction is category- based (i.e., it is a product of categorization), whereas under the latter view, induction is a product of computation of similarity. One of the goals of this research is to distinguish between these positions. Traditionally, inductive inference in children has been studied directly, by asking participants to perform inductive generalizations and assessing their performance. However, this approach may not be an optimal way of examining representations underlying performance on induction tasks. An alternative framework has been recently suggested (Sloutsky & Fisher, in press-b). In this framework, representations underlying induction performance are studied by examining memory traces formed in the course of Induction. Participants are first presented with sets of pictures of familiar animals, and are asked to make inductive inferences about these animals. Later participants are given a surprise recognition memory test, in which they are presented with some old pictures (i.e., pictures they had previously reasoned about in the induction task), and some Critical Lures (i.e., “new” pictures that belong to the same category as “old” pictures). If participants perform induction in a similarity-based manner, they should form Abstract The ability to perform inductive generalizations has been demonstrated to develop very early in life. We argue that while adults use their conceptual knowledge when performing induction, young children perform induction by computing the similarity among presented entities. We further argue that this differential processing underlying children’s and adults’ induction results in different memory traces, and affects accuracy on a subsequent memory test. Experiment 1 demonstrates that while performing induction decreases memory accuracy of adults and 12-year-olds, it does not affect memory accuracy of 5-, and 7-year-olds. In Experiment 2, 5- and 7-year- olds were trained to perform category-based induction, which resulted in a decrease of their memory accuracy. In Experiment 3, a delayed transfer task was used to examine whether 5- and 7- year-olds could retain their learning over time. Overall, results of the reported experiments point to a developmental trend from similarity-based to category-based induction. Introduction The ability to make inductive generalizations is undoubtedly crucial for humans, for not only does it facilitate acquisition of new knowledge and skills, but also aids survival: “our knowledge that leopards can be dangerous leads us to keep a safe distance from jaguars” (Sloman, 1993, p.321). It has been demonstrated that infants and very young children can perform simple induction tasks (Gelman & Markman, 1986; Sloutsky, Lo, & Fisher, 2001, Welder & Graham, 2001). The process underlying this basic ability is, however, still open to debate. According to one view, children’s inductive generalizations are driven by a priori conceptual assumptions (Keil, Smith, Simons, & Levin, 1998, Gelman & Hirschfeld, 1999). Under this view, which has traditionally been referred to as a naive theory position, even early in development, induction is driven by the category assumption – a belief that entities are members of categories, and members of the same category have much in common. Thus, in the course of induction, children first identify presented entities as members of categories, and then perform inductive inferences on the basis of this categorization, because they presumably believe that