Blame it on the "night owls": Perceived discrimination partly mediates the effects of morningness-eveningness on positive and negative affect.

The well-established effects of evening preference on diminished well-being and poorer mental health are usually explained in terms of common genetic bases of eveningness and negative emotionality and/or the discrepancy between biological and social clocks, experienced far more frequently by the Evening-types. However, recent studies provide evidence for the negative stereotyping of evening chronotypes which may lead to unexpectedly pronounced social stigma and its consequences. The present article provides a seminal empirical analysis of the role of perceived chronotype-related discrimination in the association between morningness-eveningness and both positive affect and negative affect. The study was conducted on a gender-balanced sample of 768 individuals aged between 18 and 56 years who filled measures of morningness-eveningness, positive and negative affect, as well as a modified version of the Perceived Devaluation Discrimination scale, tentatively labeled Perceived Chronotype-Related Discrimination scale (https://osf.io/urs8x/), developed to measure the sense of chronotype-based discrimination. Conducted analyses provided evidence for a positive association between eveningness and perceived discrimination. Moreover, perceived discrimination partly mediated the associations between morningness-eveningness and both positive affect and negative affect, explaining 18% and 29% of these effects, respectively. Hence, our results provide initial evidence for yet another mechanism through which chronotype may impact emotional functioning, namely the experience of chronotype-based stigmatisation.