Using eye movements to get a glimpse at child sentence processing: An interactive and probabilistic account of parsing development
Many comprehension studies of grammatical development have focused on the ultimate interpretation that children assign sentences and phrases, resulting in somewhat 'static' snapshots of children's emerging use of grammatical knowledge. Studies of the dynamic processes underlying language comprehension are much rarer, owing in part to the lack of on-line sentence processing techniques suitable for use with children in the preschool and early school years. In this talk, I will present some work from my lab which examines the moment-by-moment interpretation decisions of children, age four years and older, by recording their eyegaze as they visually interrogate and manipulate objects in response to spoken instructions. The first of these studies established some striking developmental differences in processing ability, with the youngest children showing an inability to use relevant properties of the referential scene to resolve local syntactic ambiguities (Trueswell, Sekerina, Hill & Logrip, 1999). Rather than suggest that this pattern supports a modular theory of syntactic processing, I provide evidence from a series of follow-up experiments that indicate that this pattern arises from a developing interactive processing system. Under this account, adult and child sentence comprehension is inherently a 'perceptual guessing game', in which multiple probabilistic cues are used to recover detailed linguistic structure. These cues, e.g., lexical-distribution evidence, verb semantic biases, referential scene information, come 'on-line' (become automatized) gradually over the course of development, with more reliable and easier-to-track evidential cues to structure developmentally preceding less reliable and more-difficult-to-track cues. I will conclude that appearances of modularity in a processing system are likely to arise out of patterns of informativity in the input when imposed on a probabilistic device, rather than out of predetermined constraints on a system�s architecture.
Reference: Trueswell, J.C., Sekerina, I., Hill, N.M. & Logrip, M.L. (1999). The kindergarten-path effect: studying on-line sentence processing in young children. Cognition 73, 89-134.