Structure Mapping and Relational Language Support Children’s Learning of Relational Categories Dedre Gentner Northwestern University Florencia K. Anggoro College of the Holy Cross Raquel S. Klibanoff Learning relational categories—whose membership is defined not by intrinsic properties but by extrinsic rela- tions with other entities—poses a challenge to young children. The current work showed 3-, 4- to 5-, and 6-year-olds pairs of cards exemplifying familiar relations (e.g., a nest and a bird exemplifying home for) and then tested whether they could extend the relational concept to another category (e.g., choose the barn as a home for a horse). It found that children benefited from (a) hearing a (novel) category name in a relational con- struction and (b) comparing category members. The youngest group—3-year-olds—learned the category only when given a combination of relational language and a series of comparisons in a progressive alignment sequence. Relational categories are those whose membership is determined by a common relational structure rather than by common properties. For example, an exemplar of the barrier category must block some object or actor from its goal. Members of a relational category can differ widely in their intrinsic properties; for example, the barrier cate- gory can include a fence, a river, a canyon, or a mountain, or even poverty or lack of education (Asmuth & Gentner, 2005; Gentner & Kurtz, 2005; Goldwater, Goodman, Wechsler, & Murphy, 2009; Markman & Stilwell, 2001). Relational categories thus contrast with entity categories such as tulip or camel, whose members share many intrinsic properties. Relational categories play a key role in abstract thought. They occur frequently in everyday life (pet, parent, winner, accident); for example, Asmuth and Gentner (2005) estimated that relational nouns made up nearly half of the nouns in a rep- resentative corpus of adult vocabulary. They are especially prominent in mathematics and science (e.g., result, carnivore, pressure, equilibrium). Given the importance of relational categories, it is natu- ral to ask when and how they are learned by children. There is a reason to expect relational categories to be relatively late in acquisition. In general, rela- tional tasks and concepts are more difficult for chil- dren than are object concepts; for example, children solve object-matching tasks at an earlier age than relation-matching tasks (Gentner & Rattermann, 1991; Smith, 1984), and when given relation-match- ing tasks, children often match objects instead (Gentner & Toupin, 1986; Rattermann & Gentner, 1998; Richland, Morrison, & Holyoak, 2006). Fur- ther, children’s early word learning appears geared toward object-based categories (e.g., Gentner, 1982, 2006; Golinkoff & Hirsh-Pasek, 1990, 2008; Mark- man, 1989; Waxman & Markow, 1995). Finally, there is indirect evidence that relational nouns are acquired later than entity nouns: In the MacArthur Communicative Developmental Inventory, which serves as a reasonable upper-bound estimate of what children might know at a given age, entity nouns are plentiful even for the 8- to 16-month range, whereas relational nouns do not appear until the 17- to 30-month range. This research was supported by ONR Cognitive Science Pro- gram Award N00014-02-0040 and by NSF SLC Grant SBE- 0541957, the Spatial Intelligence and Learning Center (SILC). We are grateful to Kathleen Braun, Jennifer Palmer Hellige, Lauren Clepper, Steve Flusberg, Elise Krause, Katherine James, and Amie Wolf for their assistance with materials, data collection, and other stages of this project. We also thank three anonymous reviewers for their comments on earlier drafts. Correspondence concerning this article should be addressed to Dedre Gentner, Department of Psychology, Northwestern Uni- versity, 2029, Sheridan Road, Evanston, IL 60218-2710. Electronic mail may be sent to gentner@northwestern.edu. Child Development, July ⁄ August 2011, Volume 82, Number 4, Pages 1173–1188 Ó 2011 The Authors Child Development Ó 2011 Society for Research in Child Development, Inc. All rights reserved. 0009-3920/2011/8204-0012 DOI: 10.1111/j.1467-8624.2011.01599.x