Simulating SLI: general cognitive processing stressors can produce a specific linguistic profile

Area of Science:

• Developmental Psychology
• Linguistics
• Cognitive Science

Background:

• Specific Language Impairment (SLI) is a developmental disorder affecting language acquisition.
• The underlying causes of SLI are debated, with processing deficits being a prominent hypothesis.
• Understanding SLI requires modeling its characteristic linguistic patterns.

Purpose of the Study:

• To investigate if cognitive processing demands can induce SLI-like grammatical errors in children with typical language.
• To test the hypothesis that processing deficits contribute to SLI.

Main Methods:

• A grammaticality judgment task was administered to 6-year-old children with typically developing language.
• Cognitive stress was manipulated by compressing speech rate and increasing memory load (redundant verbiage).
• Performance on noun and verb morphology was analyzed under different cognitive loads.

Main Results:

• Children performed near-perfectly at normal speech rates.
• Speech compression (50% rate) induced patterns of errors similar to SLI, with poor performance on verb morphology (past -ed, 3rd person -s) but good performance on noun morphology (plural -s).
• Increased memory load also produced a similar SLI-like error pattern.

Conclusions:

• Inducing SLI-like performance through cognitive stress supports the processing deficit hypothesis for SLI.
• Cognitive processing demands may play a crucial role in the language difficulties observed in SLI.
• This study provides evidence that SLI may stem from limitations in cognitive processing rather than solely linguistic deficits.