Examining methodological influences on the rhythmic priming effect: A commentary on Kim, McLaren, and Lee (2024)

The rhythmic priming effect (RPE) refers to improved language performance (typically grammaticality judgements) following regular rhythmic primes compared to various control conditions. This effect has been observed primarily in French, but also in English and Hungarian. However, a recent implementation by Kim, McLaren & Lee (2024), aiming to replicate the RPE in English (Chern, Tillmann, Vaughan & Gordon, 2018), was not successful, inviting a discussion about the conditions under which the RPE could be observed. We here discuss features of Kim et al.'s (2024) implementation that might have reduced the probability of observing the RPE. Compared to Chern et al. (2018), and numerous other studies reporting the RPE, additional delays after the primes and before each sentence were introduced by Kim et al. (2024). This change might have limited beneficial prime effects, which persist, but decay over time. Further, their instruction to "relax and have some rest" might have reduced attentive processing of the primes and related entrainment. Finally, their sample was small (n =16 per experiment) and with a large age range for investigating typically developing children (7-12y), potentially reducing experimental effects due to development-related individual variations. These methodological changes and sample characteristics are discussed in relation to previous research on the RPE, and entrainment in general. This discussion prompts the need for future research to investigate conditions leading to the RPE, with the aim to shed light on underlying mechanisms. Better understanding the RPE will be critical for the use of rhythmic priming within clinical and educational settings.