[PS-2.4] Impaired statistical learning in dyslexia is manifested in a less efficient use of morphology

Kimel, E. & Ahissar, M.

The Hebrew University of Jerusalem

We studied the interrelation between word structure (morphology), literacy and vocabulary acquisition in dyslexia using a novel paradigm of auditory vocabulary acquisition, and a reading task. In both, novel words were presented either with or without familiar morphological structure. If an effective utilization of stimuli statistics poses the main difficulty for individuals with dyslexia (IDDs), they might benefit less than good readers from regularities in spite of their online difficulties. However, if impaired short-term memory and poor phonological decoding pose the main impediments to IDDs, they are expected to compensate for these difficulties with a greater reliance on linguistic regularities, to reduce online load. For vocabulary acquisition, IDDs showed a reduced benefit from familiar structure for recall, but their benefit from familiar structure to recognition did not significantly differ from controls'. In reading, IDDs' benefit from structure familiarity was significantly smaller than controls'. However, when asked to read fast, morphological structure was found to be beneficial to IDDs' reading rate. These results imply that the utilization of morphological word regularities is less efficient in dyslexia, though under some experimental conditions it is accessible and beneficial.