Instruction-based learning difficulties in developmental dyslexia

Individuals with developmental dyslexia often experience difficulties in skill acquisition, attributed to atypical cortico-striatal networks. But while extensive research has focused on the formation of familiar stimulus–response (S–R) associations in dyslexia, less attention has been given to the ability to form novel S–R associations, which occurs very rapidly with few practice trials following verbal instructions. Instruction-based learning refers to the unique human ability to rapidly acquire and implement new behaviors based on verbal guidance, a process that has been shown to promote the development of skill expertise. In this study, we examined how university students with and without dyslexia learn to implement verbally instructed familiar and novel S–R rules across number and letter domains. Our results show that individuals with dyslexia demonstrate a reduced ability to implement S–R rules compared to neurotypicals, especially for novel S–R associations. Most significantly, individuals with dyslexia did not show the expected performance improvement during the first practice trials of novel S–R rules seen in the neurotypical group. These findings indicate difficulties in the ability to rapidly learn verbally instructed novel S–R associations among individuals with dyslexia, which may have implications for the development of expertise in novel domains.