The aim of the present study was to test whether morningness–eveningness is related to the six dimensions of temperament postulated in the Regulative Theory of Temperament: briskness (BR), perseveration (PE), sensory sensitivity (SS), emotional reactivity (ER), endurance (EN), and activity (AC). A sample of 581 undergraduates (age: 21.92 ± 2.54; 381 female) completed the Morningness–Eveningness Questionnaire (MEQ) and the Formal Characteristics of Behaviour – Temperament Inventory. Data was analysed using linear and quadratic hierarchical regressions. The MEQ scores exhibited linear associations with BR and EN and quadratic relationships with PE, ER and AC. Morningness was related to high levels of EN, BR and AC and low levels of PE and ER, while eveningness was associated with low levels of EN, ER, BR and PE and high levels of AC. Subjects in the middle of the morningness–eveningness dimension exhibited high levels of PE and ER, low levels of AC, and average levels of EN and BR. Morningness was related to the most advantageous temperament profile, and temperament is discussed as a possible mediator between morningness–eveningness and mood and affective disorders.
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The morningness–eveningness dimension is a variable belonging to individual differences, describing individual preferences for functioning at various times of the day. Individuals differing in morningness–eveningness display differing circadian phasing of many physiological and psychological circadian rhythms. Individuals with different morningness–eveningness levels also vary in many more individual characteristics than simply their circadian phase position.
Particularly consistent relationships have been shown for morningness–eveningness and affective functioning. Eveningness was associated with a disadvantageous diurnal mood profile, consisting of low energy and pleasance and high tension (Jankowski & Ciarkowska, 2008), which was similar to the profile of individuals with depressive symptoms (Wirz-Justice, 2008). Therefore, it is not surprising that eveningness has been associated with depression (Chelminski, Ferraro, Petros, & Plaud, 1999) and other affective disorders ( [Ahn et al., 2008] and [Murray et al., 2003]). Consequently, greater eveningness was associated with lower life satisfaction (Jankowski, 2012). The above observations seem to have crucial importance in studying morningness–eveningness, as they imply that individual circadian preference may influence key measures of human wellbeing and happiness.