Understanding completion entailments in the absence of agency cues.

This study investigated the role that agency information plays in children's early interpretations of grammatical aspect morphology, in particular, the progressive -ing and simple past forms. Fifty-nine children (two-, four- and five-year olds) were presented with a forced-choice sentence-to-scene matching task very similar to the one used by Weist and colleagues (Weist, 1991; Weist, Wysocka & Lyytinen, 1991; Weist, Lyytinen, Wysocka & Atanassova, 1997), except that here the scenes contained only information about the relative completion of the object of the event and no information about the state of the agent of the event. In contrast to previous research, the children here did not succeed at this object-oriented task until as late as age five; moreover, also contra previous work, when they did succeed, their performance tracked the formal entailments of grammatical aspect. Thus, subjects consistently matched the perfective sentence to the completed event (reflecting the perfective's entailment of completion) but never consistently matched the imperfective sentence to either scene (reflecting the imperfective's lack of entailments). It is argued that agent-oriented meaning, in particular, intentionality, has priority in the mapping process over object-oriented completion entailments.