Developmental associations between verbal and visual short-term memory and the acquisition of decoding skill

This study longitudinally investigated the relationships between verbal and visual short-term memory (STM) and the acquisition of decoding from the pre-reading through the early acquisition stages in 63 Hebrew-speaking children. Test waves occurred in kindergarten, first grade and second grade. IQ, visual and verbal STM and decoding ability were assessed. The data indicated that while both verbal and visual STM in kindergarten were significantly correlated to later decoding skill, pre-reading visual STM was a stronger predictor. The results further showed that pre-reading performance on the WISC-R Block Design test predicted later decoding ability, while performance on the WISC-R Vocabulary test did not. Lastly, decoding skill in grade 1 was found to predict only visual in grade 2. These results indicate that visual parameters may make a crucial contribution to the acquisition of decoding skills. The size of pre-reading visual STM capacity appears to play a role in this process. The relationship between visual STM and decoding may be bidirectional, as learning to decode appears to develop visual STM. It is suggested that either language-related or task-related factors may account for these counter-to-mainstream results.