The automatic neural processing of musical pitch categorization: evidence from mismatch negativity

While the categorical perception (CP) of musical pitch is often attributed to systematic musical training, prior work suggests that long-term experience, such as language background, can also shape pitch processing. However, it remains unclear whether musical pitch CP undergoes automatic neural processing at the pre-attentive stage. This study utilized event-related potentials (ERPs) to investigate the automatic neural representation of musical pitch CP in Mandarin-speaking non-musicians. We employed a passive auditory oddball paradigm, presenting standard, within-category, and between-category deviant tones from two pitch continua to 26 participants while recording the mismatch negativity (MMN). The results revealed that between-category deviants elicited a significantly larger MMN amplitude compared to within-category deviants. Furthermore, despite previous behavioral studies indicating varying categorization strengths across different pitch registers, the MMN-indexed categorization effect showed no significant difference between the two continua. These findings provide neurophysiological evidence for automatic categorical perception of musical pitch in non-musicians, supporting a two-stage model where early sensory processing is robust to variations that affect later, attention-dependent cognitive categorization.