Impaired statistical learning in developmental dyslexia

Purpose: Developmental dyslexia (DD) is commonly thought to arise from phonological impairments. However, an emerging perspective is that abyjhhyjnm more general procedural learning deficit, not specific to phonological processing, may underlie DD. The current study examined if individuals with DD are capable of extracting statistical regularities across sequences of passively experienced speech and nonspeech sounds. Such statistical learning is believed to be domain-general, to draw upon procedural learning systems, and to relate to language outcomes. Method: DD and control groups were familiarized with a continuous stream of syllables or sine-wave tones, the ordering of which was defined by high or low transitional probabilities across adjacent stimulus pairs. Participants subsequently judged two 3-stimulus test items with either high or low statistical coherence as being the most similar to the sounds heard during familiarization. Results: As with control participants, the DD group was sensitive to the transitional probability structure of the familiarization materials as evidenced by above-chance performance. However, the performance of participants with DD was significantly poorer than controls across linguistic and nonlinguistic stimuli. In addition, readingrelated measures were significantly correlated with statistical learning performance of both speech and nonspeech material. Conclusion: Results are discussed in light of procedural learning impairments among participants with DD. Fundamental language skills, such as reading, are learned early in life and are culturally dependent. One psychological process that has been suggested to be involved in learning to read is the ability to detect statistical regularities. Reading involves the mapping between phonology, the sounds of the language, and orthography, their arbitrary visual forms. The correspondence between phonology and orthography is complex in languages such as English. For example, the vowel “e” is pronounced as /ɛ/ in a word such as bed but as /i/ when paired with an “a” as in bead. Although many of these correspondences are taught explicitly in learning to read, learning models emphasize.