Rhythm Perception as an Early Constraint on Reading Development: A Mediated and Proficiency-Dependent Pathway

Purpose: A growing body of evidence suggests that rhythm abilities play an important role in reading development. However, how rhythm supports reading and how its role changes across acquisition remain to be fully specified. In this study, we tested whether rhythm perception contributes to reading fluency via phonological decoding and/or lexical access, and whether this pathway varies as a function of reading proficiency. Method: Three-hundred and five Portuguese-speaking primary school children (167 girls; age: M = 8.49 ± 1.17 years, range 6.35–11.20) completed measures of rhythm perception, pseudoword reading (phonological decoding), word reading (lexical access), and text reading fluency. Serial mediation and moderated mediation analyses were conducted. Results: Rhythm perception was positively associated with all reading measures. The relation between rhythm perception and reading fluency was fully mediated by pseudoword reading, both directly and sequentially through word reading. Moderated mediation analyses revealed that these indirect effects were present only among children with lower reading proficiency and diminished as proficiency increased. No direct effect of rhythm perception on reading fluency remained once phonological skills were accounted for. Conclusion: Together, these findings suggest that rhythm perception acts as an early functional constraint on reading fluency, supporting reading primarily through phonological decoding during early stages of acquisition. Accordingly, rhythm-based mechanisms scaffold phonological learning rather than sustain proficient reading, highlighting rhythm perception as a developmentally specific contributor and a potential target for early support.