Growing into the groove: Developmental changes in the pleasurable urge to move to music.

Groove - the pleasurable urge to move to music - provides a behavioral index of how perceptual, motor, and reward systems are engaged and coupled by rhythm. Although groove has been widely studied in adults, little is known about its developmental trajectory. We examined how groove evolves across early to mid-adolescence using a cross-sectional (N = 290) and longitudinal design (N = 105). Participants aged 11-15 rated their urge to move to music stimuli varying in low, moderate, and high levels of rhythmic and harmonic complexity. Across both studies, groove showed the well-established inverted U-shaped relationship with rhythmic complexity, peaking at moderate levels; however, this pattern varied by age. In the cross-sectional study, groove declined with age selectively at high levels of rhythmic complexity. The longitudinal study revealed a comparable decline over time for high rhythmic as well as harmonic complexity levels. These findings indicate that adult-like groove patterns emerge during early adolescence. More broadly, they suggest two complementary developmental processes: broader predictive priors that drive curiosity for highly complex structures in early adolescence, and increasing engagement with moderately complex structures that facilitate sensorimotor coupling and social coordination in mid adolescence.