Social behaviours have been proposed to follow circadian patterns across the course of the day, but empirical support is mixed. As a within-subject test of circadian effects on everyday behaviour, we conduct an experience-sampling study with a near-representative population of 285 Americans (7405 observations). Prosocial behaviour and empathy were both somewhat more frequent in the morning (d = 0.08). However, these non-linear patterns only described morning-type participants; evening-types had consistent (and lower) rates of prosocial behaviour and empathy across time-of-day. These patterns were explained by morning-types reporting more social opportunities earlier in the day. These findings suggest that small, within-subject diurnal effects on social behaviour occur in daily life, and that some circadian effects may be driven by situation selection.

有人提议在一天当中遵循社会昼夜节律的行为，但经验支持是混杂的。作为一项昼夜节律对日常行为影响的受试者内部测试，我们对一个具有代表性的285名美国人进行了一项经验抽样研究（7405个观察结果）。亲社会行为和同理心在早晨都比较频繁（d = 0.08）。但是，这些非线性模式仅描述了早晨型参与者。在一天中，晚上型的亲社会行为和同理心率保持一致（且较低）。早上的类型报告了当天早些时候更多的社交机会，从而解释了这些模式。这些发现表明，日常生活中对社会行为的日间影响很小，而且某些生物钟的影响可能是由情况选择引起的。