Spontaneous motor tempo over the course of a week: The role of the time of the day, chronotype, and arousal

The spontaneous motor tempo (SMT) or internal tempo describes the natural pace of predictive and emergent movements such as walking or hand clapping. One of the main research interests in the study of the spontaneous motor tempo relates to factors affecting its pace. Previous studies suggest an influence of the circadian rhythm (i.e., 24-h cycle of the biological clock), physiological arousal changes, and potentially also musical experience. This study aimed at investigating these effects in participants‘ everyday life by measuring their SMT four times a day over seven consecutive days, using an experience sampling method. The pace of the SMT was assessed with a finger-tapping paradigm in a selfdeveloped web application. Measured as the inter-tap interval, the overall mean SMT was 650 ms (SD = 253 ms). Using multi-level modelling (MLM), results show that the pace of the SMT sped up over the course of the day, and that this effect depended on the participants’ chronotype, since participants tending towards morning type were faster in the morning compared to participants tending towards evening type. During the day, the pace of the SMT of morning types stayed relatively constant, whereas it became faster for evening-type participants. Furthermore, higher arousal in participants led to a faster pace of the SMT. Musical sophistication did not influence the SMT. These results indicate that the circadian rhythm influences the internal tempo, since the pace of SMT is not only dependent on the time of the day, but also on the individual entrainment to the 24-h cycle (chronotype).自发性运动节律（spontaneous motor tempo, SMT）或称内在节律，指行走、拍手这类预测性与自发性运动的自然节奏。自发性运动节律研究的核心议题之一，是探讨影响其节奏的各类因素。既往研究表明，昼夜节律（即生物钟的24小时周期）、生理唤醒水平变化及潜在的音乐训练经历均可对其产生影响。本研究采用经验抽样法，让参与者在连续7天内每日四次测量自身的自发性运动节律，旨在探究上述因素在日常生活中的作用。自发性运动节律的节奏通过参与者在自研网页应用中完成的手指敲击范式进行评估，以敲击间隔时长作为测量指标，整体平均自发性运动节律时长为650毫秒（SD=253毫秒）。采用多层模型（multi-level modelling, MLM）分析结果显示，自发性运动节律的节奏在一日内呈加快趋势，且该效应受参与者的睡眠时型（chronotype）影响：相较于夜型倾向者，晨型倾向者在晨间的节律更快。日间时段中，晨型参与者的自发性运动节律相对稳定，而夜型参与者的节律则逐渐加快。此外，参与者的生理唤醒水平越高，其自发性运动节律的节奏越快。音乐素养并未对自发性运动节律产生显著影响。上述结果表明，昼夜节律会影响内在节律：自发性运动节律的节奏不仅取决于当日时段，还与个体对24小时周期的节律同步性（即睡眠时型）相关。