Monday, February 28, 2011

Statistical Learning in Children With Specific Language Impairment

Evans, J.L., Saffran, J.R., & Robe-Torres, K. (2009). Statistical learning in children with specific language impairment. Journal of Speech Language and Hearing Research, 52, 321-335.

This study examines statistical learning in children with specific language impairment (SLI), a difficulty acquiring language despite otherwise typical development generally. Statistical learning is a time of implicit learning – learning without awareness – that involves tracking patterns of regularities over input (such as strings of syllables).

Children with either SLI or typical development engaged in a drawing task while strings of syllables were played either for 21 or 42 minutes. The syllable strings contained predictable sequences of syllables (“words”) but were otherwise word boundaries were no otherwise marked by prosodic pattern or pauses. After 21 minutes, the typically developing children showed significant learning while the SLI group performed at chance levels. After 42 minutes, the performance of the two groups did not differ reflecting learning on the parts of both groups. Analysis of response errors revealed that the children with SLI often chose a foil phonologically related to the target. It was suggested that the children with SLI may not have retained enough phonological detail to differentiate the target and foil items at test.

This paper was a pleasure to read. The study was well designed, and the paper well written. The results emphasize the protracted learning and need for repeated exposures by children with SLI.

Blogger: Lisa Archibald

Wednesday, February 9, 2011

The Etiology of Diverse Receptive Language Skills at 12 Years

Dale, P.S., Harlaar, N., Hayiou-Thomas, M., & Plomin, R. (2010). The Etiology of Diverse Receptive Language Skills at 12 Years. Journal of Speech, Language, and Hearing Research, 53, 982-992.

Substantial research has been conducted on earlier but not later stages of language development. Early child language research is not transferable, nor can it be applied to adolescents because of the large increase of qualitative and quantitative language skills that are developed, and continue to develop. Along with linguistic changes (e.g., lexicon, verbal reasoning, syntax, pragmatics, figurative language and literacy), there are consequential changes in cognition, academia and social experiences.

To study the etiology of language skills at 12 years of age, Dale et al. (2010) conducted a twin study (n = 4,892) comparing performance of twins with identical genetic complements (monozygotic) and those with differing genetic complements (dizygotic). Greater relationships between measures for the monozygotic vs. dizygotic twins reflect genetic contributions. The researchers measured vocabulary, listening grammar, figurative language, and making inferences using online measures.

A factor analysis revealed that all four language measures loaded on the same factor, a single language factor. Not surprisingly, genetics and shared environment both influenced these factors. As well, there were no significant differences between boys and girls that underlie the etiology of language development. These findings are also consistent with the generalist genes hypothesis.

This study employed a well-accepted research paradigm (twin study) with a large sample. The findings that genetics and environment contribute to language are consistent with current clinical and research views. The results of one language factor incorporating vocabulary, receptive grammar, figurative language, and making inferences suggests that improvements in one of these areas should lead to improvements in the other areas.

Blogger: Sarah Cloutier. Sarah is completing her Masters degree in Child and Youth Health, Health and Rehabilitation Sciences at The University of Western Ontario. She is studying behavioural measures of parent abilities, and familial and environmental factors that influence a broad spectrum of children and their language abilities. Sarah had also been a research assistant in the Language and Working Memory Lab with Dr. Lisa Archibald.