Linguistic and Conceptual Influences on Adjective Acquisition in 24- and 36-Month-Olds Toben H. Mintz University of Southern California Two hundred forty English-speaking toddlers (24- and 36-month-olds) heard novel adjectives applied to familiar objects (Experiment 1) and novel objects (Experiment 2). Children were successful in mapping adjectives to target properties only when information provided by the noun, in conjunction with participants’ knowledge of the objects, provided coherent category information: when basic-level nouns or superordinate-level nouns were used with familiar objects, when novel basic-level nouns were used with novel objects, and—for 36-month-olds—when the nouns were underspecified with respect to category (thing or one) but participants could nonetheless infer a category from pragmatic and conceptual knowledge. These results provide evidence concerning how nouns influence adjective learning, and they support the notion that toddlers consider pragmatic factors when learning new words. This study investigated aspects of word learning surrounding toddlers’ interpretation of novel adjectives. In general, when learn- ing a word’s meaning by observing its use in context, one of the many problems learners face is determining which of an infinite set of possible meanings is the correct one (see Gleitman, 1990, and Quine, 1960, among others). Fortunately, learners can make use of a number of different biases, cues, and pieces of information that facilitate the selection of the correct interpretation by restrict- ing the hypothesis space of meanings. For example, human learn- ers appear to be biased to interpret novel nouns as referring to whole objects, rather than pieces or parts; but if the learner already has a name for the object, then he or she might posit a part interpretation or an interpretation at a different taxonomic level (Clark, 1997; Markman, 1990). For words of all grammatical categories, being able to observe a word’s use over multiple utterances in different situations helps to rule out some interpre- tations and support others (e.g., Gleitman & Gleitman, 1997; Mintz & Gleitman, 2002; Pinker, 1984). In the case of verbs, possibilities often need to be further limited. In such cases, learners can rely on structural properties of the sentence to constrain possible meanings, a process called syntactic bootstrapping (Gleitman, 1990; Landau & Gleitman, 1985). For example, verbs with sentential complements (e.g., know in, “Sally knows that George is a thief”) are generally mental state verbs: that is, verbs of knowledge or perception. The general idea is that aspects of the linguistic context can help a learner restrict the range of possible meanings of a target word (Fisher, Hall, Rakowitz, & Gleitman, 1994; Gillette, Gleitman, Gleitman, & Lederer, 1999; Gleitman, 1990; Landau & Gleitman, 1985; Naigles, 1990). In learning the meaning of a novel adjective, children may be able to rely on similar kinds of cues from other elements of the sentence to help restrict the set of possible meanings. When an adjective occurs in a sentence, it generally modifies a noun (e.g., “Look at that stoof car!”) or is predicated of one (e.g., “That car is stoof !”). Hence, an interesting question arises as to whether, in principle, the noun could facilitate the interpretation of a novel adjective by restricting the set of candidate meanings and, further- more, whether young children are influenced by the noun in interpreting a novel adjective. Information Carried by the Noun That Is Relevant to Interpreting Adjectives One situation in which the noun can restrict possible meaning candidates is in the case of relative adjectives. Relative adjectives refer to properties that vary along a scale, such as size and weight. Whether or not the property denoted by a relative adjective accu- rately describes an object depends crucially on how the object is construed, or categorized, by the speaker, because establishing the category construal determines the comparison class against which relative adjectives are evaluated. For example, big is interpreted differently when applied to mice than when applied to animals. In contrast, nonrelative adjectives (also called absolute adjectives), such as striped, are not interpreted differently. To illustrate the distinction, consider the sentence in Example 1a below, in which a novel adjective is used to describe a 6-in.-long mouse. Because the object is categorized as a mouse, stoof could mean BIG, because Toben H. Mintz, Departments of Psychology and Linguistics, and Program in Neuroscience, University of Southern California. This research was supported in part by Grant HD040368 from the National Institute of Child Health and Human Development, by the Zum- berge Faculty Research Innovation Fund at the University of Southern California, and by an equipment grant from the Intel Corporation. Portions of this research were presented at the 2003 biennial meeting of the Society for Research in Child Development in Tampa, FL. Thanks are due to the parents and children who participated in this research. I would also like to thank Emily Bowen, Nuria Giralt, Christy Harding, Lewis Lawyer, and Laura Steenberge for their help in the col- lection and analysis of the data and Laura Siegel for helpful comments on a draft of this article. Discussions with Amit Almor, Lila Gleitman, Kathy Hirsh-Pasek, Raquel Klibanoff, Maryellen MacDonald, and Sandy Wax- man helped shape some of the ideas in this article. Correspondence concerning this article should be addressed to Toben H. Mintz, Department of Psychology, SGM-501 MC-1061, University of Southern California, Los Angeles, CA 90089 –1061. E-mail: tmintz@usc.edu Developmental Psychology Copyright 2005 by the American Psychological Association 2005, Vol. 41, No. 1, 17–29 0012-1649/05/$12.00 DOI: 10.1037/0012-1649.41.1.17 17