Out of sight, but not out of mind: 21-month-olds use syntactic information to learn verbs even in the absence of a corresponding event.

By 27 months of age, toddlers hearing a novel verb in transitive syntax are able to (1) establish an initial representation for the verb based on its syntactic properties alone, even in the absence of a relevant visual scene, and (2) retrieve this representation later when a candidate causative referent comes into view. This ability is important considering that over 60% of the verbs that mothers produce in conversations with their children refer to events that are not currently observable. Here, we advance this finding in two ways. First, we demonstrate the same ability in 21-month-olds, who do not yet show mastery of transitive structures in their own productions. Second, we use analyses of toddlers’ eye gaze to explore the time-course with which they process the novel verb and assign its referent when candidate scenes become available. These results (1) provide the first evidence that 21-month-olds establish a representation of a novel verb's meaning from syntax alone, and (2) establish that they process and assign meaning to novel verbs with a similar time-course to that for novel nouns. The findings are thus relevant to our understanding of both word learning and lexical processing of novel words.