Producing filler-gap dependencies: structural priming evidence for two distinct types of combinatorial processes in production
A previous model of long-distance dependency production claims that speakers compose clause-taking verbs like believe and the complementizer of their complement clauses (that or the null complementizer) differently when there is a cross-clausal filler-gap dependency crossing the complementizer structure (e.g., Who did the breeder believe (that) the dog bit?) than when there is not (e.g., The breeder believed (that) the dog bit them.). This claim implicates two distinct structures headed by clause-taking verbs like believe. Under a certain assumption about the lexical boost effect, this model predicts that the lexical boost effect for the that priming occurs only when prime and target sentences both contain a cross-clausal filler-gap dependency or when neither does. In the current study, a computational model of structural priming implementing the core claims of the previous filler-gap dependency production model was built to show that this prediction coherently follows from the model. The prediction of the model was then tested in five recall based structural priming experiments. Speakers showed a larger complementizer priming when prime and target sentences share a clause-taking verb (i.e., the lexical boost effect). But the lexical boost effect was selective to when both prime and target sentences contained a cross-clausal filler-gap dependency (Experiment 3) and when neither did (Experiment 1). Critically, the lexical boost effect was absent when only either prime or target sentences contained a filler-gap dependency crossing the complementizer structure (Experiments 2, 4, and 5), confirming the prediction of the model.