The head constituent plays a key role in the lexical boost in syntactic priming

• It’s not clear whether the lexical boost is limited to heads or not. • We conducted two large-scale syntactic priming experiments with Mandarin datives. • We found that only head repetition yielded a lexical boost in both experiments. • Our results support lemma-based residual activation account of language production. Accounts of language production make different predictions about the conditions under which structural priming should be enhanced by lexical repetition (the lexical boost). Repetition of the head verb strongly enhances structural priming of a sentence, but studies of English have found contradictory results regarding the effects of noun repetition. In two experiments, Mandarin participants read a prime sentence aloud and then produced a target picture description of a dative event. In Experiment 1, the verb was printed on the target picture, and we found that repetition of the verb enhanced priming (vs. no repetition) but repetition of the agent, theme, or recipient argument did not. In Experiment 2, both the agent noun and the verb were printed on the picture, and we found that verb repetition enhanced priming but agent repetition did not. These results indicate that the lexical boost is restricted to the head verb in Mandarin and therefore support lemma-based residual activation accounts of language production in which activation of a head leads to activation of its associated grammatical construction.