No significant relationship found between spontaneous motor tempo, heartbeat, and individual alpha frequency: an analysis of internal tempos

Many theories of time perception propose the existence of an internal pacemaker, and studies across behavioral, physiological, and neuroscience fields have explored this concept. Specifically, Spontaneous Motor Tempo (SMT), the most comfortable and natural tapping tempo for each individual, is thought to reflect this internal pacemaker’s tempo. Changes in heart rate are also linked to time estimation, while Individual Alpha Frequency (IAF), the peak in the alpha range (8–13 Hz) observed in EEG, is reported to reflect the brain’s temporal processing. Despite the associations of SMT, heart rate, and IAF with intrinsic tempo, their interrelations remain unexplored. In this pre-registered study, we measured SMT, IAF, and heart rate in 32 healthy university students aged 18–21 and examined how these variables relate to each other. During the experiment, participants sat with their eyes closed for 5 min while we recorded their EEG and heart rate. They then tapped the space key with their ind...