Neural Evidence for Linguistic Statistical Learning is Independent of Rhythmic and Cognitive Abilities in Neurotypical Adults: A Registered Report

Objective: Statistical Learning (SL) is an essential mechanism for speech segmentation. Importantly, individual differences in SL ability are associated with language acquisition. For instance, better SL correlated with a larger vocabulary size and impaired SL was found in populations with language impairments. The aim of the current study is to contribute to uncovering the underpinnings of such individual differences in auditory SL for word segmentation. We hypothesized that individuals with better musical – specifically rhythmic – abilities would show better SL for speech segmentation. Methodology: Participants were exposed to an artificial language consisting of trisyllabic nonsense words. Recent methodological innovations allow online assessment of SL via electroencephalography (EEG) measures of neural entrainment to the words and syllables in the auditory signal. The current study used this EEG method to measure individual SL performance during exposure. Aiming to assess individual differences, we linked the neural measure of SL to a battery of tests assessing possible individual differences by measuring rhythmic, musical, and cognitive abilities, as well as vocabulary size. Preregistered Stage 1 protocol: https://osf.io/2y6sx (date of in-principle acceptance: 01/12/2023). Results: We replicated earlier work, finding both online (neural) and offline (behavioral) evidence of SL in our sample. In contrast to our expectations regarding individual differences, we found no effects of rhythmic ability on the measurements of SL. Evidence regarding working memory remained inconclusive. Finally, we found moderate evidence for a small correlation between vocabulary size and a neural, but not behavioral, measure of SL. Overall, our results suggest that linguistic SL is largely independent from abilities in other cognitive domains, including rhythmic processing and musical abilities, at least as measured within a in a sample of healthy, typically developed adults.