Speech recognition is a complex human behavior in the course of which listeners must integrate the detailed phonetic information present in the acoustic signal with their general linguistic knowledge. It is commonly assumed that this process occurs effortlessly for most people, but it is still unclear whether this also holds true in the case of developmental dyslexia (DD), a condition characterized by perceptual deficits. In the present study, we used a dual-task setting to test the assumption that speech recognition is effortful for people with DD. In particular, we tested the Ganong effect (i.e., lexical bias on phoneme identification) while participants performed a secondary task of either low or high cognitive demand. We presumed that reduced efficiency in perceptual processing in DD would manifest in greater modulation in the performance of primary task by cognitive load. Results revealed that this was indeed the case. We found a larger Ganong effect in the DD group under high than under low cognitive load, and this modulation was larger than it was for typically developed (TD) readers. Furthermore, phoneme categorization was less precise in the DD group than in the TD group. These findings suggest that individuals with DD show increased reliance on top-down lexically mediated perception processes, possibly as a compensatory mechanism for reduced efficiency in bottom-up use of acoustic cues. This indicates an imbalance between bottom-up and top-down processes in speech recognition of individuals with DD.
Bibliographical noteFunding Information:
This study is part of the research conducted at the University of Haifa by Hadeer Derawi, as partial fulfillment of her requirements for a PhD degree under the supervision of Yafit Gabay. This research was supported by a grant from the National Institute of Psychobiology in Israel to YG (2111819) and by a grant from the German Research Foundation (Grant RE 3047/1-1) to ER. The project was initiated while ER was at the Institute of Phonetics at Ludwig Maximilian University, Munich, Germany. The authors declare no conflict of interest.
© 2021, The Author(s).
- Developmental dyslexia
- Dual task
- Ganong effect
- Lexical bias
- Speech perception
- Spoken word recognition
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Developmental and Educational Psychology
- Arts and Humanities (miscellaneous)