Preschool-aged children develop awareness of the words theydo and do not know. Awareness of one’s lexicon mayencourage word learning if children pay more attention to thedefinition of unknown words. Here, we tested 3-4-year-oldchildren (N = 91) on a word learning task embedded in an e-book. When a novel word was read, children were eitherasked if they knew the word, asked a question about thestoryline, or asked no question. Then they were given adescription without visual input and asked to identify thereferent’s picture from three choices. Participants who wereasked if they knew a word before being provided with thedefinition identified more referents than children in the otherconditions. Children’s word learning was predicted by short-term memory.

We used a between-subjects selective trust paradigm to investigate whether 3-year-olds (N=28) and 5-year-olds (N=28)evaluate the quality of informants definitions for familiar and unfamiliar words. 3-year-olds did not choose the informativedefiner (silly=goofy) over the circular definer (silly=silly) for familiar or unfamiliar words. In contrast, 5-year-olds en-dorsed the informative definer for familiar (M=.71, t(12)=2.38, p=.04) and unfamiliar (M=.82, t(14)=3.41, p=.004) words.Additionally, 5-year-olds in the unfamiliar word condition chose to learn new information from the informative definer,such as asking about novel words (p¡. 001) and novel object functions (p¡.001). The unfamiliar word condition may haveelicited better performance than the familiar word condition because the contrast between the two informants was moreobvious. We are currently investigating whether 3- and 5-year-olds prefer an informant who uses familiar words to definenovel words (meager=small) to one that uses other novel words (meager=paltry).