The Mediating Role of Processing Speed in the Relationship between Fluid Reasoning and Working Memory among Children with Dyslexia

Working memory is the most important predictor of fluid reasoning. Working memory and fluid reasoning as two complicated cognitive functions have a significant correlation. A large number of studies have confirmed the strong association between working memory and fluid reasoning; however, the hidden variables between them are still unknown. The aim of the present study was to identify the mediating role of processing speed in the relationship between fluid reasoning and working memory among children with dyslexia. This research was a descript4e-correlational study. The statistical population included all students with dyslexia in Mashhad schools, of whom 205 students were selected using convenience sampling method. For collecting data, the Wechsler Intelligence Scale for children–Fourth Edition and the Tehran- Stanford-Binet Intelligence Scale were administered. The results of the study showed that: (1) working memory has a significant association with fluid reasoning (P=0/04), (2) only 26/2% of changes in fluid reasoning were influenced by processing speed and working memory, (3) only 11.8% of changes in verbal fluid reasoning were influenced by processing speed and verbal and non-verbal working memory, (4) only 18.2% of changes in non-verbal fluid reasoning were influenced by processing speed and verbal and non-verbal working memory. The present study suggested a significant association between working memory and fluid reasoning but the mediating role of processing speed in the relationship between fluid reasoning and working memory among children with dyslexia hadn’t been confirmed.