Are non-native structural preferences affected by native language preferences?

A structural priming experiment investigated whether bilingual speakers’ processing of their non-native language (L2) depends entirely on their experience of L2, or whether it is also affected by their experience of the native language (L1). German-L1 and Spanish-L1 proficient speakers of English (and English-L1 controls) described pictures of dative events after reading unrelated sentences that had a Prepositional Object (PO) or Double Object (DO) structure. Participants in all three groups were more likely to produce DO descriptions after reading DO sentences than PO sentences. Crucially, Spanish-L1 speakers, whose L1 allows PO but not DO structures, showed the same pattern of priming as German-L1 speakers, whose L1 allows both structures. Additionally, the groups showed no difference in their baseline preference for DO structures. We suggest that in proficient bilinguals, processing in L2 is not affected by L1 experience and L1 preferences, and propose a model to account for our findings.