Cross-domain and cross-sensory effects of rhythm on language development

Rhythmic abilities are deeply rooted in the human brain. They originated from our need for social interaction and bonding and have evolved hand-to-hand with communication and linguistic abilities across ages. In the ontogenetic evolution, first experiences with rhythm occur already in the womb, with different rhythmic sources being available to the human fetus. Among sensory modalities, vestibular, tactile, and somatosensory perception (Provasi et al., 2014, VTS) seems to play a crucial role in early rhythm processing, with neural coupling dynamics allowing for VTS and sensorimotor influences on auditory encoding (Trainor et al., 2009; Phillips-Silver and Trainor, 2005; Tichko et al., 2021). However, a restricted corpus of studies specifically focused on VTS and sensorimotor abilities in rhythm and language development. Therefore, the present work aimed at investigating the role of the body through VTS and sensorimotor rhythmic abilities in language development. Specifically, VTS rhythmic abilities will be firstly assessed through a custom made, vibrotactile tool for music perception specifically designed for infants and toddlers based on the recent advances in the field of human-computer interaction, as illustrated in Study 1 (Section 4.1). In Study 2 (Section 4.2), early linguistic abilities will be investigated in the same cohort of infants, specifically testing the role of phonological and prosodic features of speech. Then, the link between rhythmic and linguistic abilities will be explored be- tween the two tasks, to investigate whether the former might be informative about the latter. In Study 3 (Section 4.3), cross-domain (i.e, from music to language) benefits resulting from rhythmic exposure across sensory modalities (i.e., from VTS to auditory signals) will be tested through a rhythmic priming paradigm. Therefore, Chapter 4 will investigate VTS rhythmic abilities and their link as well as their effect on the emerging linguistic abilities of infants and toddlers. In the following Chapter, the effect of sensorimotor rhythmic abilities on complex linguistic behaviors including reading and writing skills will be examined in young adults (Chapter 5). Specifically, the effect of sensorimotor synchronization to an external beat will be evaluated while administering two screening tasks for developmental dyslexia: lexical decision and dictation under phonological suppression in Study 4 (Section 5.1) and Study 5 (Section 5.2). Therefore, Chapter 5 will provide insights into the role of sensorimotor rhythmic abilities in literacy skills with possible implications for early screening and training practices for neurodevelopmental disorders. Together, Chapter 4 and Chapter 5 together will bring evidence on the role of VTS experiences and sensorimotor abilities across language development. In conclusion, Chapter 6 will provide a general interpretation and discussion of the present findings with original insights on the cross-domain and cross-sensory effects of rhythm in language development.