Real-world fluctuations in motivation drive effort-based choices

Subjective experiences, like feeling motivated, fluctuate over time. However, we usually ignore these fluctuations when studying how feelings predict behaviour. Here, we examine whether naturalistic ups and downs in states influence the subjective value of choices. In a novel microlongitudinal design (N = 155, included timepoints = 3344, tasks = 845, mean timepoints per person = 26.4), we assessed the link between state fluctuations and effort-based choices using smartphone-based, momentary assessments over 15 days. Task-based willingness to exert effort for reward was specifically boosted when people felt more motivated (than they normally do). This naturalistic state-behaviour coupling was significantly strengthened in individuals with higher trait apathy. Computational modelling revealed that the fluctuations in state changed and preceded sensitivity to reward, thereby driving choices. Our results show that typical, day-to-day fluctuations in feelings and cognition are tightly linked, and critical to understanding fundamental human behaviours in the real-world.