The impact of visual complexity on visual short-term memory in children with specific language impairment

Many studies have assessed visual short-term memory (VSTM) abilities in children with specific language impairment (SLI), with contrasting results: some studies observed preserved VSTM capacities, while others reported impaired VSTM. The present study explores the hypothesis that the complexity of the visual information to be encoded and stored might underlie these discrepancies. Four VSTM conditions were administered to a group of 15 children with SLI, as well as to two groups of typically developing children, matched for chronological age and for VSTM capacity for visually simple stimuli, respectively. The stimuli to be remembered varied in their visual similarity and in the number of their visual features. Across the four VSTM conditions, children with SLI showed significantly reduced performance relative to an age-matched control group, and they were more strongly affected by visual similarity and number of features when compared to a control group matched for VSTM capacity for visually simple stimuli. The present results support the hypothesis that stimulus complexity is a determining factor of the poor VSTM performances in children with SLI.