Perceptual awareness and motor expertise in the temporal dynamics of adaptation to unexpected tempo changes.

Adaptation to unexpected tempo step changes may vary with perceptual awareness and motor expertise across the post-change time course. This study examined how trial-level Detection and motor expertise, operationalised as professional dance training, were associated with post-change adaptation. Two finger-tapping experiments used unexpected step changes from a 500-ms baseline inter-stimulus interval: near-threshold perturbations (± 10 ms) in Experiment 1 and supra-threshold perturbations (± 50, ± 100, and ± 150 ms) in Experiment 2. Forty adults completed Experiment 1 (21 dancers and 19 non-dancers), and 32 completed Experiment 2 (16 dancers and 16 non-dancers). Inter-tap interval (ITI), relative asynchrony (RA), and phase correction response (PCR) were analysed using linear mixed-effects models. In Experiment 1, Detection-related differences in continuation ITI and RA occurred primarily among non-dancers. In the + 10-ms deceleration condition (+Δt), the Detection-related PCR contrasts were opposite in direction between groups, but only non-dancers showed a reliable difference, with lower PCR in detected than in not-detected trials. In Experiment 2, both groups generally produced continuation ITIs close to the new target intervals. Expertise-related differences were selective and most consistently observed in RA in the - 100-ms acceleration condition (-ΔT), whereas PCR varied with perturbation direction and magnitude but did not differ between dancers and non-dancers. Perceptual awareness and motor expertise were associated with condition- and measure-specific patterns of adaptation to unexpected tempo step changes rather than a uniform adaptation advantage.