Task-dependent effects in the lexical boost

In structural priming, head verb repetition between prime and target leads to enhanced priming: the lexical boost effect (Pickering & Branigan, 1998). A boost from a non-head noun has, however, been more elusive (Carminati et al, 2019; Scheepers et al. 2017). To determine whether the lexical boost is affected by explicit memory (e.g., Chang et al, 2006), we tested for a lexical boost using ditransitive structures (e.g., the cleaner showed the ladder to the apprentice), when participants could still see the prime while completing a target (Experiments 1 & 3) or not (Experiments 2 & 4); the first two experiments tested for a boost from the head verb, the last two from the subject noun. The verb related boost occurred regardless of whether or not participants could still see the prime. Critically, the noun boost only arose when participants could see the prime. This suggests that, unlike the verb related boost, the noun-related boost is a strategic effect that only occurs when the simultaneous visibility of the prime and target makes the noun repetition explicit, boosting activation of the prime structure. We conclude that structures are associated with the head verb but not normally with nonhead nouns.