Neural correlates of music-syntactic processing in two-year old children

• We observed neurophysiological correlates of music-syntactic processing in 30-month-olds.
• This indicates that children of that age process harmonic sequences according to complex syntactic regularities.
• These representations of music-syntactic regularities must have been acquired before and stored in long-term memory.
• Similar to syntax processing in language, these processes are highly automatic and do not require attention.

Music is a basic and ubiquitous socio-cognitive domain. However, our understanding of the time course of the development of music perception, particularly regarding implicit knowledge of music-syntactic regularities, remains contradictory and incomplete. Some authors assume that the acquisition of knowledge about these regularities lasts until late childhood, but there is also evidence for the presence of such knowledge in four- and five-year-olds. To explore whether such knowledge is already present in younger children, we tested whether 30-month-olds (N = 62) show neurophysiological responses to music-syntactically irregular harmonies. We observed an early right anterior negativity in response to both irregular in-key and out-of-key chords. The N5, a brain response usually present in older children and adults, was not observed, indicating that processes of harmonic integration (as reflected in the N5) are still in development in this age group. In conclusion, our results indicate that 30-month-olds already have acquired implicit knowledge of complex harmonic music-syntactic regularities and process musical information according to this knowledge.