Eppur non si muove : Experimental evidence for the Unaccusative Hypothesis and distinct ɸ-feature processing in Basque

The Unaccusative Hypothesis (UH) has been extensively studied in linguistics, but, to date, it has not been tested by means of ERPs. The present study aimed to experimentally test the UH hypothesis in Basque and determine what the electrophysiological correlates are of the processing of unergative versus unaccusative predicates; it also aimed to investigate distinctness in phi-feature processing. We generated eight conditions to compare unergative and unaccusative predicate sentence processing involving phi-feature violations in grammatical and ungrammatical sentences. Participants responded faster to sentences containing unaccusative predicates compared to unergative predicates. All conditions elicited a N400-P600 interaction. Overall, the negativity elicited by person violations was larger than the negativity elicited by number violations in both types of predicates. Intransitives differed regarding the size of the positivity elicited by phi-feature violations: unaccusatives elicited a larger positivity for number than for person feature violations, but unergatives elicited a larger positivity for person than for number.