How abstract is syntax? Evidence from structural priming

In 1990, Bock and Loebell found that passives (e.g., The 747 was radioed by the airport's control tower) can be primed by intransitive locatives (e.g., The 747 was landing by the airport's control tower). This finding is often taken as strong evidence that structural priming occurs on the basis of a syntactic phrase structure that abstracts across lexical content, including prepositions, and is uninfluenced by the semantic roles of the arguments. However, all of the intransitive locative primes in Bock and Loebell contained the preposition by (by-locatives), just like the passive targets. Therefore, the locative-to-passive priming may have been due to the adjunct headed by by, rather than being a result of purely abstract syntax. The present experiment investigates this possibility. We find that passives and intransitive by-locatives are equivalent primes, but intransitive locatives with other prepositions (e.g., The 747 has landed near the airport control tower) do not prime passives. We conclude that a shared abstract, content-less tree structure is not sufficient for passive priming to occur. We then review the prior results that have been offered in favor of abstract tree priming, and note the range of evidence can be considerably narrowed-and possibly eliminated-once effects of animacy, semantic event structure, shared morphology, information structure, and rhythm are taken into account.