Syntactic complexity and musical proficiency modulate neural processing of non-native music.

In music, chords are organized into hierarchical structures on the basis of musical syntax and the syntax of Western music can be implicitly acquired by listeners growing up in a Western musical culture. Here, we investigated whether Western musical syntax of different complexities can be implicitly acquired by non-native listeners growing up in China. This study used electroencephalography (EEG) to measure how the neural responses to musical sequences that either follow a simple rule, i.e., finite state grammar (FSG), or a complex rule, i.e., phrase structure grammar (PSG), are affected. We tested three groups of Chinese listeners who varied in their proficiency and experience in Western music. Only the high-proficiency group had received formal Western musical training, whereas the low- and moderate-proficiency groups varied in their degree of exposure to Western music. The results showed that in the FSG condition, the event-related potentials (ERPs) evoked by regular and irregular final chords were not significantly different in the low-proficiency group. In contrast, in the moderate- and high-proficiency groups, the irregular final chords evoked an ERAN-N5 biphasic response. In the PSG condition, however, only the high-proficiency group showed an ERAN-N5 biphasic response evoked by irregular final chords. This study provides evidence that although simple structures of Western music, such as FSG, can be acquired by long-term implicit learning, the acquisition of more complex structures, such as PSG, merely from exposure to western music may not be as easy.