Embodied Responses to Harmony and (Poly)Rhythm: An Integrated Ratio-Based Perception-Action Framework

Harmony and rhythm perception have traditionally been treated as separate perceptual phenomena in auditory cognitive science. Yet, both involve inherently oscillatory and periodic structures. Converging evidence suggests that harmonic and rhythmic patterns that can be described in terms of (approximate) low-order integer relationships are often perceived differently from those characterized by more complex relations. In harmony, small integer frequency ratios (e.g., 2:1 for the octave, 3:2 for the perfect fifth) are related to perceived consonance and ease of auditory encoding. Similarly, rhythmic patterns whose component durations can be expressed by simple ratios (e.g., 2:1, 3:1) as well as polyrhythms based on simple ratios (e.g., 2:3, 3:4) are more readily detected, produced, and remembered than those based on more complex ratios. In this paper, we ask whether these perceptual and processing advantages reflect underlying shared mechanisms across harmonic and rhythmic domains. Furthermore, we explore whether and how these advantages extend into the motor domain. Grounding on neural resonance theory, we propose an integrated ratio-based framework that links the perceptual salience of low-order integer relationship in rhythm and harmony to enhanced sensorimotor synchronization.