Effects of prosodic and lexical constraints on parsing in young children (and adults).

Prior studies of ambiguity resolution in young children have found that children rely heavily on lexical information but persistently fail to use referential constraints in online parsing (Trueswell, Sekerina, Hill & Logrip, 1999; Snedeker & Trueswell, 2004). This pattern is consistent with either a modular parsing system driven by stored lexical information or an interactive system which has yet to acquire low-validity referential constraints. In two experiments we explored whether children could use a third constraint-prosody-to resolve globally ambiguous prepositional-phrase attachments ("You can feel the frog with the feather"). Four to six years olds and adults were tested using the visual world paradigm. In both groups the fixation patterns were influenced by lexical cues by around 200ms after the onset of the critical PP-object noun ("feather"). In adults the prosody manipulation had an effect in this early time window. In children the effect of prosody was delayed by approximately 500 ms. The effects of lexical and prosodic cues were roughly additive: prosody influenced the interpretation of utterances with strong lexical cues and lexical information had an effect on utterances with strong prosodic cues. We conclude that young children, like adults, can rapidly use both of these information sources to resolve structural ambiguities.