Previous studies have found a processing difference between unaccusative sentences and unergative sentences. Theyargued that the difference is derived from a syntactic difference, i.e. an unaccusative sentence involves movement whereas anunergative sentence does not. In this study, we are going to show that those studies are uninterpretable due to uncontrolledstimuli and confounds in the materials. After examining their data anlysis, we argue that the effects they found does seem to bestable. This reopens the question whether there is a syntactic difference between unaccusative and unergative verbs.

The Unaccusative Hypothesis (UH) predicts that the subject of an unaccusative is mentally reactivated in the objectposition. Previous psycholinguistic studies have reported evidence of reactivation (Friedmann et al 2008, Koring et al 2012).However, these studies did not equate the unaccusative and unergative stimuli, resulting in confounds which jeopardize theirconclusions. We reexamined UH with two Visual World Paradigm experiments carefully controlled for the potential confoundsin the previous studies. On each trial, participants (n=40; n=52) saw 4 black-and-white drawings and heard a sentence. In thetest condition, but not the control condition, one image was semantically related to subject of the sentence. We measured theproportion of looks to the target image at three time regions after the verb onset and found a robust match-effect (p’s<.05)but no differences between the unaccusative and unergative conditions. We will discuss the consequences of our findings forsyntactic theory.