Short term memory in high-functioning adult dyslexics : isolating the deficit

The overall aim of this thesis was to provide a detailed characterisation of impaired and unimpaired performance in dyslexia. One of the core areas of Interest in dyslexia research has been short term memory (STM). Typically, attempts to understand the nature of dyslexic's STM deficits have attempted to localise impairments in dyslexics to one or more components of working memory model (e.g. Smith-Spark, Fisk, Fawcett & Nicolson 2003). However, inconsistent results have led to the conclusion that dyslexics have general STM deficits as they have not been localised to an area of the working memory model (Everatt, Weeks & Brooks 2007). Three subsections of the thesis looked at performance in different areas of STM. The first chapter established that performance on verbal STM tasks by dyslexics' showed a typical pattern of recall. The findings consistently demonstrated that dyslexics had quantitatively deficited performance, however qualitatively performance was equivalent to that of the control groups. The findings also suggest that dyslexics were not able to adapt strategies (e.g. passive, serial) for encoding information which would allow optimal recall on basic verbal STM tasks. The second chapter looked at memory for items with similar and different semantic characteristics, to establish the stability and use of these characteristics when encoding. Findings showed dyslexic and control groups demonstrated use of semantic encoding strategies. Dyslexic participants performed comparably to controls on those verbal STM tasks that promoted semantic encoding. The third chapter demonstrated that dyslexics did not have a deficit on a non-verbal serial recall task designed to minimize the possibility of verbal re-coding (Parmentier et al., 2006). The results again establishing that the pattern of recall interference was the same across groups. To conclude, the experiments reported in this thesis have provided convincing evidence that dyslexics' short term memory deficit is isolated to verbal short term memory which is not supported by semantic strategies.EThOS - Electronic Theses Online ServiceGBUnited Kingdo