319 10 Children’s Eye Movements during Listening: Developmental Evidence for a Constraint-Based Theory of Sentence Processing JOHN TRUESWELL LILA GLEITMAN Many comprehension studies of grammatical development have focused on the ultimate interpretation that children assign to sentences and phrases, yielding somewhat static snapshots of children’s emerging grammatical knowledge. Studies of the dynamic processes underlying children’s language comprehension have to date been rare, owing in part to the lack of online sentence processing techniques suitable for use with children. In this chapter, we describe recent work from our research group, which examines the moment-by-moment inter- pretation decisions of children (age 4 to 6 years) while they listen to spoken sen- tences. These real-time measures were obtained by recording the children’s eye movements as they visually interrogated and manipulated objects in response to spoken instructions. The first of these studies established some striking develop- mental differences in processing ability, with the youngest children showing an inability to use relevant properties of the referential scene to resolve temporary grammatical ambiguities (Trueswell, Sekerina, Hill, & Logrip, 1999). This find- ing could be interpreted as support for an early encapsulated syntactic proces- sor that has difficulty using non-syntactic information to revise parsing commit- J.M. Henderson & F. Ferreira (Eds.) Interface of Vision, Language & Action