In this single case study we analyze the treatment focused on arithmetical text problems with a multiplicative structure that was offered to Lu., a 7.8-years-old child who had been diagnosed with mild mental retardation and a genetic anomaly (cariotype 47 XYY) associated with learning disabilities and language delay. Our main aim is to analyze the longitudinal learning profile of our target child in order to identify both the major sources of difficulties interfering with effective learning and the internal cognitive constructions linked to his acquisitions. We deploy qualitative observations tracking the longitudinal changes in the procedures that Lu. applied to the tasks and in adult-child interactive talk.
We identified three types of cognitive difficulties interfering with effective learning of solving arithmetical text problems: sensitivity to interference effects in verbal working memory, difficulties with complex coordination of sequential actions, slow automatization. The longitudinal analysis of the adult-child interactive talk showed that the child’s talk changed from being almost exclusively focused on giving simple answers, to producing descriptions and anticipation of computations or procedures. It is likely that this use of language provided Lu. with an abstract representational format that triggered an internal reorganization and conceptualisation of the acquired problem-solving procedures.