Infants' Expectations about Object Label Reference

Article excerpt

Abstract The aim of this research was to examine whether infants at the early stages of lexical development were sensitive to the word-category linkage. In Experiment 1, 16-to 19-month-old infants were requested to match a target with either a basic-level or a thematic match, with or without a novel label. Stimuli were presented using the preferential looking paradigm. Infants in the Novel Label condition looked significantly longer at the basic-level match than infants in the No Label condition. In Experiment 2, infants were presented with a target, followed by a basic-level match and a superordinate-level match with or without a novel label. Again, infants in the Novel Label condition looked significantly longer at the basic-level match than infants in the No Label condition. Taken together, these findings indicate that infants initially assume that novel words label basic-level categories and thereby do honour the word-category linkage.

Young children are amazingly adept word learners. Anglin (1993) recently estimated that between the ages of 18 months and 6 years, children acquire five to six new words a day. A large number of the words acquired during the infancy period refer to object categories (Benedict, 1979; Nelson, 1973). Most of these early object words refer to basic-level (e.g., dog) as opposed to superordinate-level (e.g., animal) or subordinate-level (e.g., collie) categories (Anglin, 1977; PoulinDubois & Graham, 1994). For the majority of infants, first words are acquired slowly, over the course of several months. Then around 18 months of age, many infants experience an accelerated period of lexical acquisition termed the vocabulary spurt (Goldfield & Reznick, 1990; Nelson, 1973; Reznick & Goldfield, 1992).

Infants' rapid acquisition of novel words is a remarkable feat considering the formidable demands of the word-learning task. Upon hearing a new word, infants must link the word to the appropriate referent and then generalize that word to other instances of the referent. This task is extremely complex when one considers the highly inductive nature of the word mapping task - even in ostensive labelling situations, there is a multitude of possible referents for any new word. Given children's success at word learning, many researchers have argued that lexical development is guided by biases or constraints that facilitate word learning (e.g., Golinkoff, Mervis, & Hirsh-Pasek, 1994; Markman, 1989,1992). These biases are proposed to simplify the process of word learning by limiting the number of possible referents a child must consider when confronted with a new word.

One word-learning bias that has received a great deal of empirical scrutiny in recent years is the taxonomic assumption or the word-category linkage (Markman, 1989; Waxman & Hall, 1993). According to this bias, children assume that a novel word refers to members of the same kind or taxonomic category, and not to objects that are related spatially or thematically (Markman,1992). That is, when taught a new label for an object (e.g., a dog), children will extend that new label to another object in the same taxonomic category (e.g., another dog or animal) rather than to an object that is spatio-temporally related to the original object (e.g., a doghouse). In the present experiments, we examined the nature of the word-category linkage at the early stages of lexical development. Specifically, we examined whether infants who are provided with a novel label will attend longer to basic-level matches than infants who do not hear a novel label. A second goal was to examine infants' initial assumptions about the categorical level of a novel word when faced with a choice between superordinate- and basic-level matches.

The notion of a linkage between nouns and taxonomic categories was first proposed by Markman and Hutchinson (1984). They presented 3- and 4-year-old children with a series of target objects (e. …