Effects of Visual Cues on the Lexical Boost Effect in Structural Priming, 2017-2021

Four structural priming experiments used a sentence fragment completion task in which participants had to complete both prime and target sentence fragments. We manipulated (1) the prime structure (prepositional object or double object eliciting ditransitive structure, e.g., the cleaner showed the ladder to ... or the cleaner showed the apprentice ...) and (2) whether a word in the prime was repeated in the target. Target fragments consisted of a subject noun phrase followed by a verb (e.g., A painter lent …), which participants could complete as either a prepositional object or double object structure. In Experiments 1 and 2, we manipulated the repetition of the subject noun, whereas in Experiments 3 and 4, we manipulated the repetition of the ditransitive verb. We used two different tasks in order to investigate whether structural priming was affected by whether participants could see the prime when completing the target. In Experiments 1 and 3, participants received booklets and provided hand-written completions to the sentence fragments, so they could see the prime and target simultaneously. In Experiments 2 and 4, participants typed responses to the sentence fragments that appeared one-by-one on a computer screen, so they could not see earlier fragments and completions. As the dependent variable, we scored whether participants completed the target fragments with a prepositional object or double object structure.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/the apprentice the ladder), 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 subject noun, the last two from the head verb. The noun boost only arose when participants could see the prime, suggesting that re-inspecting the prime acted as a cue, boosting the activation of its structure. In contrast, the verb repetition boost occurred regardless of whether or not participants could still see the prime. These results suggest that the noun repetition boost is a strategic effect that only occurs when the simultaneous visibility of the prime and target makes the noun repetition explicit, whereas the verb repetition boost is task-independent. We conclude that structures are associated with the head verb but not normally with non-head nouns.