The state of the onion: Grammatical aspect modulates object representation during event comprehension

The present ERP study assessed whether grammatical aspect is used as a cue in online event comprehension, in particular when reading about events in which an object is visually changed. While perfective aspect cues holistic event representations, including an event's endpoint, progressive aspect highlights intermediate phases of an event. In a 2 × 3 design, participants read SVO sentences describing a change-of-state event (e.g., to chop an onion), with grammatical Aspect manipulated (perfective "chopped" vs progressive "was chopping"). Thereafter, they saw a Picture of an object either having undergone substantial state-change (SC; a chopped onion), no state-change (NSC; an onion in its original state) or an unrelated object (U; a cactus, acting as control condition). Their task was to decide whether the object in the Picture was mentioned in the sentence. We focused on N400 modulation, with ERPs time-locked to picture onset. U pictures elicited an N400 response as expected, suggesting detection of categorical mismatches in object type. For SC and NSC pictures, a whole-head follow-up analysis revealed a P300, implying people were engaged in detailed evaluation of pictures of matching objects. SC pictures received most positive responses overall. Crucially, there was an interaction of Aspect and Picture: SC pictures resulted in a higher amplitude P300 after sentences in the perfective compared to the progressive. Thus, while the perfective cued for a holistic event representation, including the resultant state of the affected object (i.e., the chopped onion) constraining object representations online, the progressive defocused event completion and object-state change. Grammatical aspect thus guided online event comprehension by cueing the visual representation(s) of an object's state.