The contribution of short-term memory for serial order to early reading acquisition: Evidence from a longitudinal study

Early reading acquisition skills have been linked to verbal short-term memory (STM) capacity. However, the nature of this relationship remains controversial, since verbal STM, like reading acquisition, depends upon the complexity of underlying phonological processing skills. This longitudinal study addressed the relation between STM and reading decoding acquisition by distinguishing between STM for item and STM for order information, based on recent studies showing that STM for item information recruits underlying phonological representations, but not STM for order information. If there is a specific link between STM and reading decoding acquisition, STM for order information should be an independent predictor of reading decoding acquisition. Tasks maximizing STM for serial order or item information, measures of phonological abilities and reading tests were administered to children followed from kindergarten through 1st grade. We observed that order STM capacity but not item STM capacity predicted independent variance in reading decoding abilities one year later. These results highlight the specific role of STM for order in reading decoding acquisition, and argue for a causal role of order STM capacity in reading acquisition. Mechanisms relating STM for order information and reading acquisition will be discussed.