Fine-grained time course of verb aspect processing

Abstract

Sentence processing is known to be highly incremental. Speakers make incremental commitments as the sentence unfolds, dynamically updating their representations based on the smallest pieces of information from the incoming speech stream. Less is known about linguistic processing on the sub-word level, especially with regard to abstract grammatical information. This study employs the Visual World Paradigm to investigate the processing of grammatical aspect by Russian-speaking adults (n = 124). Aspectual information is encoded relatively early within the Russian verb which makes this an ideal testing ground to investigate the incrementality of grammatical processing on the sub-word level. Participants showed preference for pictures of ongoing events when they heard sentences involving Imperfective verbs, and for pictures of completed events when they heard sentences involving Perfective verbs. Crucially, the analysis of the participants' eye-movements showed that they exhibited preference for the target picture already before they heard the end of the verb. Moreover, the latency of this effect depended on where the aspectual information was encoded within the verb. These results indicate that the processing and integration of grammatical aspect information can happen rapidly and incrementally on a fine-grained word-internal level. Methodologically, the study draws together a set of analytical techniques which can be fruitfully applied to the analysis of effect latencies in a wide range of studies within the Visual World eye-tracking paradigm.

Fig 1. Visual display: ‘Grandma planting a flower’.

Fig 2. Looks to ongoing event and completed event pictures.

Proportions of looks to the Ongoing Event (left panel) and Completed Event (right panel) pictures in 50 ms time bins starting from verb onset by condition (Imperfective vs Perfective). The vertical dashed blue lines represent the average verb offset. Shaded areas represent significant clusters identified via a cluster-based permutation analysis.

Fig 3. Looks to target and competitor pictures.

Proportion of looks to the Target and Competitor pictures at 150 time points sampled at 120Hz starting from 200 ms after the verb onset. The vertical dashed blue line represents the average verb offset (731 ms). The vertical solid red line represents the upper estimate of effect latency (525 ms), i.e., the earliest time point with above chance looks to the Target picture after applying the Holm-Bonferroni correction for multiple comparisons (α = 0.05).

Fig 4. Prefixal vs Suffixal aspectual marking.

Proportions of looks to the Target and Competitor pictures in Trials involving verbs with Prefixal and Suffixal aspectual marking starting from 200 ms after the verb onset. The vertical dashed blue lines represent the average verb offsets in the two conditions (706 ms for the Prefixal items and 755 ms for the Suffixal items). The vertical solid orange lines represent the estimates of effect latency (475 ms for the Prefixal items and 666 ms for the Suffixal items).