Forgiving lark, resentful owl: Self-control mediates the relationship between chronotype and forgiveness.

Considerable evidence shows that nocturnal chronotypes have increased odds of mental health problems, poor academic performance, and impairment in executive functions. Although the cognitive and health costs of evening-oriented preference are well-documented in the literature, little is known about its interpersonal costs. In this article, we propose that people with a preference for an evening chronotype show a lower tendency to forgive following an interpersonal offense because of their lower self-control ability. Three studies using independent samples and complementary measures reveal that morning-evening preference plays a role in the emergence of forgiveness, which provides support for our theoretical perspective. In Study 1, we found that evening-type students were less forgiving when responding to a transgression than morning-type students. Employing a longer measure of forgiveness and a more representative population, Study 2 replicated our initial findings and supported our hypothesis regarding the mediating role of self-control. To circumvent methodological issues associated with self-report data, Study 3 used a behavioral measure of forgiveness and revealed that chronotype can also predict actual forgiving behavior in a laboratory setting. Together, these findings suggest that diurnal preference towards eveningness not only imposes threats on people's health, but can also incur interpersonal costs.