Testing the automaticity of syntax using masked visual priming

Language comprehension proceeds at a very fast pace. It is argued that context influences the speed of language comprehension by providing informative cues for the correct processing of the incoming linguistic input. Priming studies investigating the role of context in language processing have shown that humans quickly recognise target words that share orthographic, morphological, or semantic information with their preceding primes. How syntactic information influences the processing of incoming words is however less known. Early syntactic priming studies reported faster recognition for noun and verb targets (e.g., apple or sing) following primes with which they form grammatical phrases or sentences (the apple, he sings). The studies however leave open a number of questions about the reported effect, including the degree of automaticity of syntactic priming, the facilitative versus inhibitory nature, and the specific mechanism underlying the priming effect—that is, the type of syntactic information primed on the target word. Here we employed a masked syntactic priming paradigm in four behavioural experiments in German language to test whether masked primes automatically facilitate the categorization of nouns and verbs presented as flashing visual words. Overall, we found robust syntactic priming effects with masked primes—thus suggesting high automaticity of the process—but only when verbs were morpho-syntactically marked (er kau-t; he chew-s). Furthermore, we found that, compared to baseline, primes slow down target categorisation when the relationship between prime and target is syntactically incorrect, rather than speeding it up when the prime-target relationship is syntactically correct. This argues in favour of an inhibitory nature of syntactic priming. Overall, the data indicate that humans automatically extract abstract syntactic features from word categories as flashing visual words, which has an impact on the speed of successful language processing during language comprehension