On-line processing of wh-questions in children with G-SLI and typically developing children.

TLDR: The findings indicate that G-SLI children fail to establish reliably a syntactic filler-gap dependency and instead interpret wh-questions via lexical-thematic information, which supports the CGC hypothesis, according to which G- SLI children have a particular deficit in the computational system affecting syntactic dependencies involving 'movement.

Abstract: Background: The computational grammatical complexity (CGC) hypothesis claims that children with G(rammatical)-specific language impairment (SLI) have a domain-specific deficit in the computational system affecting syntactic dependencies involving ‘movement’. One type of such syntactic dependencies is filler-gap dependencies. In contrast, the Generalized Slowing Hypothesis claims that SLI children have a domain-general deficit affecting processing speed and capacity. Aims: To test contrasting accounts of SLI we investigate processing of syntactic (filler-gap) dependencies in wh-questions. Methods & Procedures: Fourteen 10;2–17;2 G-SLI children, 14 age-matched and 17 vocabulary-matched controls were studied using the cross-modal picturepriming paradigm. Outcomes & Results: G-SLI children’s processing speed was significantly slower than the age controls, but not younger vocabulary controls. The G-SLI children and vocabulary controls did not differ on memory span. However, the typically developing and G-SLI children showed a qualitatively different processing pattern. The age and vocabulary controls showed priming at the gap, indicating that they process wh-questions through syntactic filler-gap dependencies. In contrast, G-SLI children showed priming only at the verb. Conclusions: The findings indicate that G-SLI children fail to establish reliably a syntactic filler-gap dependency and instead interpret wh-questions via lexical– thematic information. These data challenge the Generalized Slowing Hypothesis account, but support the CGC hypothesis, according to which G-SLI children have a particular deficit in the computational system affecting syntactic dependencies involving ‘movement’. As effective remediation often depends on aetiological insight, the discovery of the nature of the syntactic deficit, along side a possible compensatory use of semantics to facilitate sentence processing, can