Dyslexia and the failure to form a perceptual anchor.
In a large subgroup of dyslexic individuals (D-LDs), reading difficulties are part of a broader learning and language disability. Recent studies indicate that D-LDs perform poorly in many psychoacoustic tasks compared with individuals with normal reading ability. We found that D-LDs perform as well as normal readers in speech perception in noise and in a difficult tone comparison task. However, their performance did not improve when these same tasks were performed with a smaller stimulus set. In contrast to normal readers, they did not benefit from stimulus-specific repetitions, suggesting that they have difficulties forming perceptual anchors. These findings are inconsistent with previously suggested static models of dyslexia. Instead, we propose that D-LDs' core deficit is a general difficulty in dynamically constructing stimulus-specific predictions, deriving from deficient stimulus-specific adaptation mechanisms. This hypothesis provides a direct link between D-LDs' high-level difficulties and mechanisms at the level of specific neuronal circuits.
Ahissar
Merav
M
Department of Psychology, Hebrew University, Jerusalem 91904, Israel. msmerava@mscc.huji.ac.il
Lubin
Yedida
Y
Putter-Katz
Hanna
H
Banai
Karen
K
D000223:Adaptation, Psychological; D000293:Adolescent; D002648:Child; D003071:Cognition / Q000502:physiology*; D004410:Dyslexia / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D007859:Learning Disabilities / Q000503:physiopathology / Q000523:psychology; D011939:Mental Recall / Q000502:physiology*; D012718:Set, Psychology; D013067:Speech Perception / Q000502:physiology*