What children learn from adults’ utterances: An ephemeral lexical boost and persistent syntactic priming in adult–child dialogue

•Children showed persistent syntactic priming and a brief lexical boost in dialogue.•This pattern did not differ significantly from adult controls in the same task.•Children but not adults showed cumulative priming effects.•The same mechanism may underlie immediate syntactic priming and long-term syntactic learning.•Different mechanisms underlie the lexical boost versus long-term learning of verb–structure links. We show that children’s syntactic production is immediately affected by individual experiences of structures and verb–structure pairings within a dialogue, but that these effects have different timecourses. In a picture-matching game, three- to four-year-olds were more likely to describe a transitive action using a passive immediately after hearing the experimenter produce a passive than an active (abstract priming), and this tendency was stronger when the verb was repeated (lexical boost). The lexical boost disappeared after two intervening utterances, but the abstract priming effect persisted. This pattern did not differ significantly from control adults. Children also showed a cumulative priming effect. Our results suggest that whereas the same mechanism may underlie children’s immediate syntactic priming and long-term syntactic learning, different mechanisms underlie the lexical boost versus long-term learning of verb–structure links. They also suggest broad continuity of syntactic processing in production between this age group and adults.