Development of Semantic Knowledge and Its Role in the Development of Category-Based Reasoning

Development of Semantic Knowledge and Its Role in the Development of Category-Based Reasoning Karrie E. Godwin (kegodwin@andrew.cmu.edu) Carnegie Mellon University, Department of Psychology, 5000 Forbes Avenue, Pittsburgh, PA 15213 USA Bryan J. Matlen (bmatlen@cmu.edu) Carnegie Mellon University, Department of Psychology, 5000 Forbes Avenue, Pittsburgh, PA 15213 USA Anna V. Fisher, (fisher49@andrew.cmu.edu) Carnegie Mellon University, Department of Psychology, 5000 Forbes Avenue, Pittsburgh, PA 15213 USA Abstract Prior research indicates a protracted developmental course in category-based reasoning. One possible explanation for the development of this ability is the gradual reorganization of semantic knowledge. To measure development of semantic knowledge we developed a new paradigm, the Semantic Space task, which uses distance in a two-dimensional space to infer semantic similarities between two objects. Using this paradigm we examined development of semantic knowledge in young children (preschoolers, kindergarteners, and first-grade children) and in adults. We also examined whether conceptual organization as measured by the Semantic Space task is predictive of children’s scores on a category-based reasoning task. The findings point to the possibility that development of semantic knowledge plays an important role in the development of category-based reasoning. Keywords: Semantic Space; Concepts; Cognitive Development Introduction Category-based reasoning is a critical cognitive ability that enables an individual to generalize from the known to the unknown (Hayes, Heit, & Swendsen, 2010; Proffitt, Coley, & Medin, 2000). For example, upon learning that a chicken has 39 pairs of chromosomes, one may infer that a dove also has 39 pairs of chromosomes because chickens and doves are the same kind of animal (i.e., birds). Prior research indicates that children’s category-based reasoning undergoes a protracted developmental course (e.g., Badger & Shapiro, 2012; Fisher, Matlen, & Godwin, 2011; Godwin, Matlen, & Fisher, in press; Fisher, 2010; Fisher & Sloutsky, 2005; Sloutsky, Kloos, & Fisher, 2007), with marked improvements in category-based reasoning apparent between 4 and 6 years of age. However, it is not clear what factors underlie this improvement. One possible explanation for the development of category-based reasoning is representational change: the gradual accretion and reorganization of domain-specific knowledge (Goswami & Brown, 1989, 1990; Rattermann & Gentner, 1998). Representational change has been identified as a factor that fosters cognitive development in a wide array of domains such as numerical development (e.g., Opfer & Siegler, 2007), problem solving (e.g., Karmiloff-Smith, 1986), and analogical reasoning (e.g., Gentner, Rattermann, Markman, & Kotovsky, 1995). One of the few studies to examine the relationship between semantic development and category-based reasoning was conducted by Chi, Hutchinson, and Robin (1989). Chi et al. classified 6-year-old children as either dinosaur experts or novices, based on their pre-test performance. Subsequently, the children completed an inference task about dinosaurs. The stimuli were digitally modified in order to create novel dinosaurs for both experts and novices. Chi et al. found that children who were classified as domain experts tended to make category-based inferences about the novel dinosaurs (e.g., “he is probably a good swimmer … cause duckbills are good swimmers”, p. 48). In contrast, children who were classified as dinosaur novices tended to make inferences based on a salient attribute (e.g., [the dinosaur] “could walk real fast cause he has giant legs”, p. 49). These findings can be taken to suggest that category-based induction is a function of one’s domain knowledge (also see Gobbo & Chi, 1986). There is also converging evidence suggesting that representational change may play a role in semantic development. First, multidimensional scaling studies have investigated people’s ability to classify familiar objects. These studies provide evidence of advancement in classification from initially classifying objects according to more concrete characteristics to utilizing more abstract features when making groupings (e.g., Howard & Howard, 1977; Saltz, Seller, & Sigel, 1972). For example, preschool- age children are likely to classify familiar animals on the dimension of size, whereas school-age children are more likely to classify animals along the dimensions of domesticity and predativity. Second, studies on the development of priming suggest that associative priming (e.g., faster responding to the word ‘banana’ after ‘monkey’ is presented) appears early in development whereas semantic priming (e.g., faster responding to the word ‘banana’ after ‘cherry’ is presented) develops during the school years (McCauley, Weil, & Sperber, 1976; Arias-Trejo & Plunkett, 2011). Finally, work in cognitive modeling points to a gradual developmental progression in conceptual organization from relatively undifferentiated (e.g., groupings including a penguin, a trout, and an alligator) to more differentiated groupings (Kemp & Tenenbaum 2008; Rogers &