No abstract

L. Markson and P. Bloom (1997) concluded that there was evidence against a dedicated system for word learning on the basis of their finding that children remembered a novel word and a novel fact equally well. However, a word-learning system involves more than recognition memory; it must also provide a means to guide the extension of words to additional exemplars, and words and facts may differ with regard to extendibility. Two studies are reported in which 2-4-year-old children learned novel words and novel facts for unfamiliar objects and then were asked to extend the words and facts to additional exemplars of the training objects. In both studies, children extended the novel word to significantly more category members than they extended the novel fact. The results show that by 2 years of age, children honor the necessary extendibility of novel count nouns but are uncertain about the extendibility of arbitrary facts.

A B S T R A C TWhen presented with a pair of objects, one familiar and one unfamiliar, and asked to select the referent of a novel word, children reliably demonstrate the disambiguation effect and select the unfamiliar object. The current study investigated two competing word learning accounts of this effect : a pragmatic account and a word learning principles account. Two-, three-and four-year-olds were presented with four disambiguation conditions, a word/word, a word/fact, a fact/word and a fact/fact condition. A pragmatic account predicted disambiguation in all four conditions while a word learning principles account predicted disambiguation in the word/word and fact/word conditions. Results indicated that children disambiguated in word/word and fact/word conditions and two-year-olds disambiguated at above chance levels in the word/word condition but at BELOW chance levels in the fact/fact condition. Because disambiguation varied both as a function of age and condition these findings are presented as challenges to a pragmatic account of the disambiguation effect.Young children display a reliable tendency to reserve a single word for a single object

Studies show that children trust previously reliable sources over previously unreliable ones (e.g., Koenig, Clément, & Harris, 2004). However, it is unclear from these studies whether children rely on accuracy or conventionality to determine the reliability and, ultimately, the trustworthiness of a particular source. In the current study, 3- and 4-year-olds were asked to endorse and imitate one of two actors performing an unfamiliar action, one actor who was unconventional but successful and one who was conventional but unsuccessful. These data demonstrated that children preferred endorsing and imitating the unconventional but successful actor. Results suggest that when the accuracy and conventionality of a source are put into conflict, children may give priority to accuracy over conventionality when estimating the source's reliability and, ultimately, when deciding who to trust.

Past studies show that a referential context is important for successful word learning. Still in question, however, is the success of word learning in the absence of a referential context. In this study 2-year-olds were presented with novel words in the absence of a speaker and therefore in the absence of a referential context. Findings revealed that word learning was successful across the experimental trials at rates greater than chance and at rates greater than in the control trial. Findings demonstrated that the absence of a speaker and the referential context provided by a speaker did not result in unsuccessful word learning. It is concluded that a referential context is not necessary for successful word learning.