Presenter Name:Erica Flaten

School/Affiliation:McMaster University

Co-Authors:Laurel J Trainor

Abstract:

Adults asked to imagine an ambiguous rhythm in one metrical interpretation or another show more energy at frequencies corresponding to their metrical interpretation Previously, we presented 7-month-olds with an ambiguous 6-beat rhythm and found SSRs with peaks at the beat, duple (groups of 2 beats), and triple (groups of 3 beats) meter frequencies. We investigated 6-month-olds’ (N = 24) SSR and mismatch responses (MMR) to an ambiguous 6-beat rhythm. Infants were primed to hear the rhythm in either duple or triple meter by adding accents to every second or every third beat, respectively. Following priming, test trials consisted of 16 repetitions of the ambiguous unaccented pattern. To elicit MMR, pitch deviants occurred on either beat 4 (strong beat in triple meter) or beat 5 (strong beat in duple meter) of the unaccented pattern. SSR results showed peaks at all frequencies present in the unaccented pattern. Instead of a negative, adult-like MMR, we found positive MMRs which, in frontal left channels, were larger for the strong beat vs the weak beat in the duple group. In line with our hypothesis, this shows that some internalization of the duple meter lead to a difference in processing deviants that occur on strong beats. Further, we found that the MMR was larger overall for those in the duple group compared to the triple group in frontal right sites. These results indicate infants can impose a top-down internally generated metrical structure on ambiguous auditory rhythms, an ability that would aid early language and music learning.