Young children and adults use lexical principles to learn new nouns.

In two experiments, adults and children were tested in an object-selection task that examined whether Ss would (a) map a novel word onto a previously unnamed object and (b) extend the newly learned word to another exemplar. Experiment 3 was a control study. Ss overwhelmingly selected the novel object as the referent for the novel term, even though the new label was never explicitly linked to the novel object. Ss also extended the new term and allowed it to preempt yet another novel label from applying to the just-named object. The existence of several lexical principles and the power of indirect word learning is supported. Consider the problem that faces the language-learning child, arguably an alien among expert speakers. How is the child to decide what a new word means? As Quine (1960) noted, there are an infinite number of logical possibilities for the meaning of a new term, none of which can be unambiguously attested to by ostensive naming. Yet, children do not seem to give equal weight to these alternatives. If they did, two well-known phe-nomena would probably not exist: (a) fast mapping, or one-trial