Investigating domain-general short-term memory for order versus specific item memory in developmental dyslexia

Recent findings suggest that people with dyslexia experience difficulties with the learning of serial order information during the transition from short- to long-term memory. At the same time, models of short-term memory increasingly incorporate a distinction of order and item processing. This work aims to investigate whether serial order processing deficiencies in dyslexia can be traced back to a selective impairment of short-term memory for serial order, and whether this impairment also affects processing beyond the verbal domain. In three studies, dyslexic children in Italy, good and poor reading school children in Germany and a sample of adults in Belgium participated in 2 x 2 experiments in which short-term recognition performance for order and item information was assessed, using both verbal and nonverbal material. The findings indicate that, irrespective of the type of material, children and adult participants with dyslexia recalled the individual items with the same accuracy as the matched control group, whereas the ability to recognize the serial order in which those items were presented appeared to be affected in the dyslexic groups. This work concludes with the assumption that dyslexia is characterized by a selective impairment of serial order short-term memory and discusses the implications of these findings for current theoretical views on dyslexia and its associated dysfunctions.