Developmental and individual differences in performance on phonological synthesis tasks

This study was conducted in order to examine the role of individual differences in working memory and lexical access in accounting for age and reading skill related differences in performance on phonological synthesis tasks. The performance of 28 kindergarten, first-, and second-grade children with normal reading skills, as well as that of 28 reading-disabled second graders, was compared under four testing conditions. The testing conditions were formed by completely crossing rate of presentation of phoneme strings with type of stimulus to be blended (real or nonword). Both independent variables affected performance on the blending tasks, with better performance obtained at faster presentation rates and with real words. There was a developmental discontinuity in overall performance, with the kindergarten children obtaining substantially lower scores than the first or second graders. In the comparison of second-grade good and poor readers, there was a significant interaction between groups, presentation rates, and type of stimulus. The findings are discussed in terms of their implications for a general model of performance on the sound blending task, as well as their value for interpreting individual differences on the task.