Time-of-day variation in motivation for everyday behaviors: A cluster-based approach to understanding individual differences.

Motivation governs everyday behavior and is often disrupted in psychiatric conditions, yet how motivation varies within the day, and how these patterns differ between individuals remains unclear. Here, we examined diurnal patterns of momentary subjective motivation for everyday activities, their translation into behavior, and how these patterns vary by trait-based measures linked to motivation. At baseline, 538 participants (424 women, 112 men, 2 non-binary, aged 18-77 years) completed questionnaires indexing psychiatric traits associated with altered motivation, revealing four clusters differing in appetitive motivation, and depressive features with varying levels of goal-directed behavior. Participants (n = 410) then completed ecological momentary assessments between ∼08:00 and 23:00, reporting momentary motivation for, and recent engagement in, everyday behaviors. Across clusters, motivation for recovery (rest, being alone) outweighed motivation for activity (socializing and exercise), creating a "motivational gap" (defined as the relative difference between recovery-oriented and activity-oriented motivations) that was largest in the morning and late evening and smallest around mid-day, with cluster-specific differences. Momentary motivation translated into subsequent behavior, with the strength of this coupling varying by time-of-day and motivational cluster. These findings identify diurnal motivation as an underrecognized source of individual variabilit in motivational state and behavioral.