Use of Speaker's Gaze and Syntax in Verb Learning.

Speaker eye gaze and gesture are known to help child and adult listeners establish communicative alignment and learn object labels. Here we consider how learners use these cues, along with linguistic information, to acquire abstract relational verbs. Test items were perspective verb pairs (e.g., chase/flee, win/lose), which pose a special problem for observational accounts of word learning because their situational contexts overlap very closely; the learner must infer the speaker's chosen perspective on the event. Two cues to the speaker's perspective on a depicted event were compared and combined: (a) the speaker's eye gaze to an event participant (e.g., looking at the Chaser vs. looking at the Flee-er) and (b) the speaker's linguistic choice of which event participant occupies Subject position in his utterance. Participants (3-, 4-, and 5-year-olds) were eye-tracked as they watched a series of videos of a man describing drawings of perspective events (e.g., a rabbit chasing an elephant). The speaker looked at one of the two characters and then uttered either an utterance that was referentially uninformative (He's mooping him) or informative (The rabbit's mooping the elephant/The elephant's mooping the rabbit) because of the syntactic positioning of the nouns. Eye-tracking results showed that all participants regardless of age followed the speaker's gaze in both uninformative and informative contexts. However, verb-meaning choices were responsive to speaker's gaze direction only in the linguistically uninformative condition. In the presence of a linguistically informative context, effects of speaker gaze on meaning were minimal for the youngest children to nonexistent for the older populations. Thus children, like adults, can use multiple cues to inform verb-meaning choice but rapidly learn that the syntactic positioning of referring expressions is an especially informative source of evidence for these decisions.