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Morningness–Eveningness and Satisfaction with Life
Abstract
Individual differences in diurnal preferences and circadian rhythms are viewed as an interesting dimension of human personality.
Previous research has examined various psychological correlates of diurnal preference. Evening types reported psychological
and psychosomatic disturbances more frequently and intensively than morning types and morning types have a healthier lifestyle
than evening types. Depression was also related to eveningness as were bulimic behaviour and seasonal affected disorders (SAD).
Given these studies, one would expect a positive relationship between satisfaction with life or happiness (general well-being;
Diener etal. (J Pers Assess 49:71–75, 1985)) and morningness. There was a significant positive correlation between morningness and satisfaction with life (r=0.177; p=0.023; N=164).
... Morning and evening type individuals were found to differ in terms of many cognitive, psychological and physiological variables. For example, morningness was found to correlate with more stable personality (DeYoung et al. 2007), greater life satisfaction (Randler 2008), better sleep quality (Vollmer et al. 2017), greater well-being (Jankowski 2015), higher positive affect (Hasler et al. 2010;Biss and Hasher 2012), and higher alertness in the morning (Demirhan et al. 2019). In contrast, eveningness was found to correlate with depression (Merikanto et al. 2015), increased substance use (Arrona-Palacios et al. 2019), being in poor general health (Fabbian et al. 2016), lower alertness values early in the day (Díaz-Morales et al. 2007), and lower quality of life (Merikanto et al. 2016). ...
... Overall, outcomes of students' happiness may provide beneficial information to understand university students' academic achievement. Randler (2008) indicated that college students are more likely to have sleep deprivation and poor sleep quality. Some studies reported that decreased academic performance results from disturbed sleep (Gaultney 2010;El Hangouche et al. 2018). ...
... Díaz-Morales et al. (2015) have found M-type students to show better mood compared to N-types and E-Types. Similarly, Randler (2008) found a positive correlation between morningness and satisfaction with life. Rahafar et al. (2015) also found M-E Preference to correlate positively with Happiness. ...
Happiness, defined as the cognitive and emotional evaluations of individual's life as a whole, not only gives individuals positive emotions , but also has positive returns in many areas related to the individual's life. Therefore, the aim of the study was to examine the association of happiness with morningness-eveningness preference , sleep-related variables and academic performance in university students. 547 university students (80.4% female, 19.6% male) aged between 19 and 25 years participated in the study. Demographic Questionnaire, CSM and OHQ-SF were used as data collection instruments. Happiness correlated negatively with MSFsc and positively with both ME Preference and CGPA. Meanwhile, ME Preference and CGPA were associative factors of Happiness. Univariate two-way ANCOVA provided a significant two-way interaction. The pairwise comparisons indicated that M-type Achievers had higher happiness scores compared to M-type Underachievers. Similarly, E-type Achievers had higher happiness scores compared to E-type Underachievers. Meanwhile, Happiness scores of both Achievers and Underachievers significantly differed in ME Preference categories. Happiness scores of Achiever M-types differed significantly from Achiever N-types in favour of M-types. Underachiever N-types had higher happiness scores compared to Underachiever E-types. These results indicate that students' happiness scores increase depending on the increase in student's academic performance and the student's being an earlier chronotype. ARTICLE HISTORY
... M-types wake up early in the morning, reach their energy peak mentally and physically early in the day, and go to bed early. E-types, on the other hand, prefer getting up later in the morning, perform mentally and physically best in the late afternoon or evening; therefore, they are active during the evening/night, and go to bed late (Chung et al. 2008;Randler 2008). ...
... Persons with different chronotypes may vary in several physiological and psychological factors. For instance, E-types show lower satisfaction with life (Drezno et al. 2019;Randler 2008), a higher tendency for psychological symptoms (e.g. depression, anxiety) (Gulec et al. 2013;Wittmann et al. 2006), and lower quality of life (Gulec et al. 2013;Prieto et al. 2012) than M-types. ...
... Additionally, eveningness has also been associated with poorer mental health in other investigations (e.g., Giannotti et al. 2002). Also, Randler (2008) found that morningness is linked to enhanced life satisfaction. An explanation for the worse mental health of E-types could be that evening-types have more affective disturbances because their endogenous circadian rhythm does not fit into expected social schedules (social jetlag) (Wittmann et al. 2006). ...
Morningness-eveningness (chronotype) indicates the preferred time of intellectual and physical activity. This cross-sectional study had two main aims. The first aim was to explore associations among chronotype, quality of life, and relationship quality. The second aim of this study was to examine whether the similarities or discrepancies in chronotype between male and female members of the couples were linked to relationship quality. Both members of 143 couples (mean age = 39.44; SD = 10.11y) living together for at least 6 months completed measures of chronotype, marital stress, relationship satisfaction, dyadic coping, satisfaction with life, health-related quality of life, and quality of sleep. Variable-oriented (correlational) and person-oriented (cluster-analytic) analyses were conducted. Variable-oriented analyses showed that morningness was linked to better mental health, and fewer insomnia problems, but less frequent (self-perceived) stress communication for both genders. The discrepancy between the couple’s chronotype scores was positively related to the women’s sexual and general life satisfaction and more frequent (self-perceived) supportive dyadic coping by the partner. Moreover, ANOVA results showed that Evening-type (E-type) women had the highest mean score on sexual life satisfaction. According to cluster-analytic investigation, couples consisting of two morning-type members had the least frequent stress communication. On the other hand, these couples had better sleeping quality with less insomnia symptoms than couples with two E-type members. In summary, the present findings demonstrate that morningness holds both advantages and disadvantages for both general aspects of life and also the quality of relationships.
... Geographic closeness generally leads to similarity of climate and culture, which helps eliminate confounding factors that may lead to differences in lifestyle behaviors unrelated to city size. In contrast to traditional research investigating lifestyle patterns, where data collection methods include questionnaires and telephone interviewing [6], [7], [8], we leverage data from social media to make inferences about people's lifestyles. The wide adoption of social media brings researchers a new opportunity of studying natural, unconstrained human behavior at very large scales. ...
... Randler finds a significant positive correlation between "morningness" tendencies of people and satisfaction in life [7], and Monk [16] find that MT individuals appear to have more regular lifestyle than ETs. A positive correlation between eveningness and depression level is reported by Hasler et al. [17]. ...
Lifestyles are a valuable model for understanding individuals' physical and mental lives, comparing social groups, and making recommendations for improving people's lives. In this paper, we examine and compare lifestyle behaviors of people living in cities of different sizes, utilizing freely available social media data as a large-scale, low-cost alternative to traditional survey methods. We use the Greater New York City area as a representative for large cities, and the Greater Rochester area as a representative for smaller cities in the United States. We employed matrix factor analysis as an unsupervised method to extract salient mobility and work-rest patterns for a large population of users within each metropolitan area. We discovered interesting human behavior patterns at both a larger scale and a finer granularity than is present in previous literature, some of which allow us to quantitatively compare the behaviors of individuals of living in big cities to those living in small cities. We believe that our social media-based approach to lifestyle analysis represents a powerful tool for social computing in the big data age.
... A sociodemographic questionnaire was included for sample characterization. Other self-reportable questionnaires were: the Epworth Scale of Sleepiness (ESS) [27], Morningness-Eveningness Questionnaire (MEQ) [28], Stop-Bang Questionnaire (SBQ) [29], and Pittsburgh Sleep Quality Index (PSQI) [30]. Table 1 presents a review of the validated questionnaires for the Portuguese population and respective measures for internal consistency (Cronbach's alpha or Kuder-Richardson 20 for dichotomous items). ...
... Morningness-Eveningness Questionnaire (MEQ) is a self-assessment questionnaire used to evaluate the diurnal type. The main purpose of this questionnaire is to measure whether a subject circadian rhythm creates peak alertness in the morning, in the evening, or in between [28]. MEQ consists of 19 multiple-choice questions scored from 1 to 5 points [41]. ...
Introduction
Sleep is a crucial biological need for all individuals, being reparative on a physical and mental level. Driving heavy vehicles is a task that requires constant attention and vigilance, and sleep deprivation leads to behavioral and physiological changes that can develop sleep disorders which can put lives at risk.
Objectives
The main objectives of this study are to describe and evaluate sleep quality, excessive daytime sleepiness, circadian preference, and risk of suffering from obstructive sleep apnea in a population of Portuguese professional drivers.
Methods
To fulfill the objectives, 43 Portuguese professional drivers, between 23 and 63 years old, answered validated questionnaires: Epworth Sleepiness Scale, Morningness–Eveningness, Stop-Bang Questionnaire, and Pittsburgh Sleep Quality Index.
Results
Results indicated that older drivers tend to experience higher daytime sleepiness (11 ± 3.4; p = 0.002) and obstructive sleep apnea risk (4.5 ± 1.5; p = 0.03). Regarding sleep quality, the majority of drivers were classified with poor sleep quality (74.4%). It was possible to infer statistical differences between groups based on body mass index (p = 0.037), the type of route (p = 0.01), and physical activity (p = 0.005).
Conclusion
Drivers have an indifferent circadian preference and small-course drivers have a worse sleep health perception. Therefore, it is essential to implement prevention programs, promoting the basic rules for better sleep quality as well as identifying sleep disorders to minimize possible road accidents.
... The time at which one feels sleepy and wants to go to bed and the time they wake up in the morning vary between individuals: some people naturally prefer going to bed earlier in the evening and arising earlier in the morning, while others prefer a later sleep-wake schedule (Adan et al., 2012). Morning-and eveningoriented people differ not only in preferred timing of daily activities and sleep-wake patterns but also in psychological and behavioural characteristics including emotional functioning (Saalwirth & Leipold, 2021), satisfaction with life (Randler, 2008), and perceived social support (Walsh et al., 2022). ...
... To the best of our knowledge this is the first evidence presented of a causal effect of morningness on well-being. Thus, our results strengthen the numerous earlier findings reporting correlations between these two features (e.g., Randler, 2008) by providing evidence that morning preference not just accompanies, but indeed fosters subjective well-being. ...
Studies show that morningness is positively associated with subjective well-being. Our previous research investigated factors that could underlie this relationship, finding that the association between morningness-eveningness and subjective well-being can be partially attributed to the higher levels of perceived social support received by morning-oriented individuals. In the present study, we examine the longitudinal effects of perceived social support in mediating the relationship between morningness-eveningness and subjective well-being. Our results show that this mediating effect remains significant with respect to changes in well-being over a 6-month period. It seems that the causal effect of morningness on well-being may be partially mediated by the causal effect of social support. The findings provide further support for the conclusion that perceived social support is an important contributing factor to the greater well-being reported by morning-oriented individuals. Additionally, our results provide seminal evidence for the causal effect of morningness on well-being.
... In this sense, among the big five traits, conscientiousness seems to be the most strongly related with morningness, while agreeableness is highly unrelated to circadian type. Morning-types tend to be more active and stable, and they also show more indicators of psychological well-being (Randler, 2008). Accordingly, this variable might give some insight on how individuals adapt to the confinement situation in terms of underlying biological rhythms. ...
... Morningness is linked to responsibility and activity, and with less variability in sleep and eating patterns, so it might be easier for these individuals to adapt to the situation with a low impact on their mood and timings/schedules. Thus, in line with previous studies, morningness seems to be a protective factor for mental health and psychological well-being (Randler, 2008), also in times of sudden changes of routines and habits. On the other hand, being past-positive oriented seems to help reduce anxiety levels in times of isolation, in line with previous findings (Muro et al., 2015), which could be attributed to the fact that focusing on successful past achievements and memories might help individuals gain confidence in their ability to cope with the uncertainty. ...
The exceptionality of the Coronavirus-related quarantines motivated the design of a longitudinal study aimed at exploring how the confinement can affect psychological well-being. 205 participants (81% female) took part in the study. Personality, time perspective, and morningness were assessed at the beginning of the quarantine, along with levels of depression, anxiety, and satisfaction with life as mood and well-being indicators. A post measure was taken 2 weeks after the first data collection. Two weeks later, a supplementary follow-up measure was performed again. A significant increase in depression and anxiety was found between pre and post measures that remained stable at follow up, whereas life satisfaction was not affected. Past-negative temporal orientation and neuroticism were the highest risk factors for a decline in psychological well-being. Results are discussed in terms of how individual differences should be considered in assessing citizens' response to public health policies regarding isolation measures.
... Miller et al. (2015) employed an ecological momentary assessment method in healthy middle-aged adults and demonstrated that evening-types experienced delayed timing of peak positive affect (PA) and blunted amplitude of PA compared to morning-types. Compared to eveningness, several key factors which foster or protect subjective happiness are reported to be related to morningness, such as higher satisfaction with life (Randler 2008), health-related quality of life (Suh et al. 2017), emotional intelligence (Antúnez et al. 2013), resilience, optimism (Antúnez et al. 2015), emotion regulation (Antúnez 2020), locus of control, conscientiousness trait (Jackson and Gerard 1996;Lenneis et al. 2021), and physical activity (Vitale and Weydahl 2017). In sum, these results support a positive association between morningness and a high level of subjective happiness, and also between eveningness and a low level of subjective happiness. ...
... As shown as the change of R 2 in Table 5, diurnal preference explained about 3% of the variance for subjective happiness in women. The magnitude of diurnal preference is in line with previous studies, which reported small to moderate partial correlations (Díaz-Morales et al. 2013;Drezno et al. 2019;Jankowski 2012;Randler 2008). We reconfirmed these findings and complemented them via both subjective and objective measures which allowed us to observe the individual's diurnal preference and also their behavior. ...
Research on mental health in working populations has predominantly focussed on negative outcomes, while studies on the positive aspects of life remain very limited, especially in Japan. Although morningness has recently been considered a factor for being happy, the role of sleep characteristics as it relates to the association between morningness and happiness has not been substantiated. The aim of this study is to investigate the associations between diurnal preference and level of subjective happiness in healthy, full-time, daytime workers in Japan. We also tested the moderation effect of sleep parameters on the relationship between diurnal preference and subjective happiness. This is an exploratory analysis from the cross-sectional data of the SLeep Epidemiology Project at the University of Tsukuba (SLEPT Study). Subjective happiness was evaluated using a single-item question. Diurnal preference was assessed using the Morningness-Eveningness Questionnaire (MEQ), in which higher scores indicate greater tendency to have morning preference. The participants underwent assessment of sleep parameters for 7 consecutive days using a waist-worn actigraphy device and kept a sleep diary. Sleep parameters investigated were subjective sleep quality, sleep disturbance, daytime sleepiness, weekend oversleep, total sleep time, sleep onset time, wake time, and sleep efficiency. A total of 205 males (average 42.6 ± 10.4 years) and 272 females (41.1 ± 9.8 years) were eligible for analysis. Hierarchical liner regression analysis was used to show the relationships of subjective happiness with MEQ score, and the sleep parameters. Further, moderation analysis was conducted by adding the interaction between MEQ score and the sleep parameters. After adjusting for age, psychological distress, self-rated health, and occupational stress, we found that subjective happiness was significantly associated with higher MEQ score and sleep efficiency but only in female. The moderating role of sleep parameters was not found. We discussed the implications of the obtained results and a possible strategy to maintain and improve subjective happiness of female workers who have evening preference.
... Multiple studies show that morningness-eveningness is associated with various features of both physical and psychological functioning, including physical efficiency (Adan et al., 2012), emotional functioning (Saalwirth & Leipold, 2021), mood (Jankowski & Ciarkowska, 2008), satisfaction with life (Randler, 2008), as well as personality or cognitive intelligence (Gorgol et al., 2020). ...
... Fourth, our study was based on a sample of Polish adults. The observation of a similar effect in different cultures, taking into account both the present and previous studies(Randler, 2008), could provide evidence that the studied effect may be culturally independent and thus broadly generalisable. Unavailability of sociodemographic information that may influence both an individual's SWB and their real or perceived social support (such as marital status, socioeconomic level, or occupation), and the inability to statistically control for such effects, may be another limitation of the study. ...
Studies show that morningness preference and subjective well-being are positively related. However, little is known about potential factors that may underpin this association. In the present study, we explored the mediational role of general social support and its facets (family, friends, and significant other) in the relationship between morningness–eveningness and subjective well-being. The present study was conducted with a sample of 1,067 adults (51% women), with a mean (SD, range) age of 36.41 (9.95, 18–55) years. Our results corroborated earlier findings that morningness was positively associated with both subjective well-being and social support. Controlling for age and gender, we obtained significant mediation effects, showing that the association between morningness–eveningness and subjective well-being might stem, at least in part, from the higher levels of social support received by morning-oriented individuals. This may lead to the conclusion that social support is an important antecedent of the greater well-being reported by morning-oriented individuals.
... Many additional factors, such as social, cultural and environmental zeitgebers do modulate and determine chronotype (Randler and Diaz-Morales 2007). The prevalence of early chronotype is more among the humans living in the tropical regions as compared with those of the temperate regions (Randler 2008a(Randler , 2008b. The individuals also shift from morningness to eveningness over the process of aging from puberty to old age Randler 2008aRandler , 2008c. ...
... Gau and Soong (2003) studied school students and discovered that at the age of 9-11 years, prevalence of morningness is more as compared with those at the age of 11-14 years. Morning type individuals are found to be more satisfied with their life (Randler 2008b). According to Roeser et al. (2012) as compared to evening type, the morning type adolescents show higher health-related quality of life and lesser symptoms of insomnia. ...
The sleep requirement of humans varies as a function of the country they live in, and their chronotype, gender, ethnicity, physiological state, and lifestyle. An interaction between the circadian clock (process C) and the sleep-wake homeostasis (process S) regulates sleep in humans. The Suprachiasmatic nuclei (SCN) – the master clock, measures the length of the solar day and through appropriate neuroendocrine mechanisms promotes sleep in the night. In this mini-review, we made an attempt to summarize findings of earlier studies dealing with the distribution pattern of chronotypes, sleep quality, and behavioral sleep patterns in human populations. The review is based on 203 relevant papers that we picked up from the databases, such as PubMed, Scopus, and Google Scholar. The review reveals the paucity of information on sleep behavior in humans in densely populated countries, like China and India. In addition, a clear message emerged from the review of the literature, i.e. the studies on the distribution of chronotypes and their problems associated with sleep quality, the behavioral sleep pattern, and diseases are critically limited and are far from complete. We recommend that this is the area that needs to be investigated extensively and intensively.
... Another dimension of temporal preferences is morningness -eveningness, which reflects individual differences in the preferences for situating one's activities during the daytime (Cavallera & Giudici, 2008). Empirical studies tend to find higher well-being in morning-oriented individuals (Randler, 2008), although the exact causes of this association (physiological or social) are yet to be investigated. ...
... The finding that self-employed individuals have higher levels of job satisfaction than employees has been consistently demonstrated across Europe (e.g. Blanchflower & Oswald, 1998;Blanchflower, 2000, Benz & Frey 2004, 2008, Clark & Senik, 2006, as well as in the USA and Canada (Hundley, 2001;Benz and Frey, 2004). Benz andFrey (2004, 2008) explain that it is the factor of work autonomy that is primarily responsible for higher levels of job satisfaction amongst the self-employed. ...
In this review questions such as " What is a good use of time? " , " How can one achieve satisfaction with their time? " and " How can one's relationship with time contribute to their well-being? " are raised and discussed with regard to empirical research on various aspects of positive psychology of time. This paper differs from traditional approach to thinking about time in organisations in three substantial ways. Firstly, it reviews the existing empirical research on time use, focusing on the implications of this research for organizations and individuals. Secondly, it highlights the limitations of believing that time is infinitely stretchable and defined good time use as one that results in increased well-being, rather than productivity at the expense of well-being. Thirdly, although the workplace is in the centre of the paper, we view time use from a broader perspective of life and work-leisure balance. A range of evidence is considered, based on both objective and subjective time use studies, suggesting specific measures to increase well-being through time use, first of all, at workplace, but also touching on other domains, such as media, leisure, etc. Based on Self-Determination Theory, we argue that good time use results from choosing activities that help people to satisfy their basic needs and are directed at intrinsic goals (helping other people, establishing relationships, developing and growing as a person, maintaining health and balance in one's life). A pathway to increase basic need satisfaction and, as a result, happiness associated with good time use, is by supporting autonomy: giving people more opportunities for choosing and working towards goals that are self-congruent and intrinsic, benefitting both themselves and societies.
... Clocks&Sleep 2024, 6 313 The differences between MTs and ETs extend beyond sleep and wake timings, encompassing a range of behavioral and psychological traits as well [6]. A later chronotype was associated with sleep deprivation, lower sleep quality, reduced perceived quality of life and life satisfaction, and an increased risk for mood disorders and depression [7][8][9][10][11][12][13]. A plausible explanation for these effects is the necessity for evening-preference individuals to conform to the conventional morning-oriented social schedule, whether it pertains to school or work hours. ...
Chronotype reflects the morningness–eveningness preference over a 24 h period. Significant data indicate meaningful differences between evening types (ETs) and morning types (MTs) in behavior, personality traits, health, and well-being. This study explores the interactions between chronotype, sleep, personality, and life satisfaction among 254 undergraduate college students (mean age 23.79 ± 1.85). Using online questionnaires, the participants provided demographic information and completed assessments, including the Morningness–Eveningness Questionnaire (MEQ), the Pittsburg Sleep Quality Index (PSQI), a shortened version of the Big Five Inventory (BFI-10), and a life satisfaction uniscale measure. The results revealed a significant association between chronotype and both life satisfaction and sleep quality, where ETs exhibited poorer outcomes compared to MTs. Additionally, the chronotype correlated with agreeableness and conscientiousness, with later chronotypes linked to reduced scores in these personality traits. A key finding in this study was revealed in a mediation analysis in which sleep quality was found to mediate the relationship between chronotype and life satisfaction. The mediation analysis highlighted sleep quality as a crucial process connecting chronotype to life satisfaction. The findings emphasize the importance of addressing sleep quality in interventions aimed at enhancing life satisfaction and overall well-being among ETs. Overall, our results provide valuable insights into the intricate relationships between chronotype, personality, sleep quality, and subjective well-being.
... Chronotypes and changes in depression, anxiety, and stress levels are associated due to various reasons. One of these reasons may be life satisfaction (Randler, 2008). In this study, life satisfaction levels were higher in the morning-type participants than that in the evening-type participants (p \ .05). ...
Chronotype is defined as individuals’ preferences regarding the timing of their sleep and wake cycle. An individual’s chronotype is associated with many factors such as age, sex, and lifestyle. This study was conducted to evaluate the relationship between chronotype and emotional eating,depression, anxiety, stress, body weight, eating disorder risk, and life satisfaction in university students. This present study included 511 Turkish university students with a mean age of 20.0 ± 1.93 years. The anthropometric measurements (body weight, and height) were recorded. Additionally, the Morningness-Eveningness Questionnaire (MEQ), the Emotional Eater Questionnaire (EEQ), the Sick, Control, One stone, Fat, Food (SCOFF) Questionnaire, the Depression, Anxiety, Stress Scale-21 (DASS-21), and the Contentment with Life Assessment Scale (CLAS) were used to collect data. The evening-type individuals had significantly higher total EEQ and DASS-21 subscale scores than the morning-type individuals. The morning-type individuals had significantly higher total CLAS scores than the evening-type individuals. There was no significant difference between the groups in terms of their SCOFF total scores and BMI values. This showed that chronotype is related to emotional eating, depression, anxiety, stress, and life satisfaction in university students, but there is not related to the risk of eating disorders and BMI. The regulation of the circadian system will be useful for improving eating behavior and mood, as well as weight loss programs. It is thought that further long-term follow-up studies with different samples would contribute to this field.
... The chronotype determines preferred wake-and bedtimes as well as preferred daytime periods to perform physical and cognitive activities (Walsh et al., 2021). As the chronotype distribution can be categorized as a psychological construct (Horne & Östberg, 1977;Randler, 2008), self-rated psychometric questionnaires are used commonly to detect a person's chronotype (Adan et al., 2012). ...
Objectives
The coronavirus disease (COVID-19) had a major impact on sleep and training behavior in adolescent athletes. A crucial sleep parameter is midsleep time, which illustrates the midpoint between sleep onset and offset. The aim of this investigation was to examine the impact of chronotype, age, sex, pandemic phase, weekend, and training habits on midsleep time. The sample consisted of German elite adolescent basketball athletes ( N = 91, 15.75 ± 1.15 years, female = 39.46%).
Method
Data were collected through a 10-day subjective monitoring program during three different pandemic phases, with more severe restrictions in phase 1. In total, 1146 measurement points were analyzed. A linear mixed model approach was used for the evaluation.
Results
A negative linear association between chronotype and midsleep time was revealed. A negative effect was identified for phases 2 and 3. The weekend parameter showed a positive effect, which may illustrate the occurrence of social jetlag. The main finding of this investigation is that a morning chronotype distribution was associated with earlier midsleep timing throughout the entire survey period.
Conclusion
The results acknowledge that chronotype is one of the main influencing parameters for midsleep time. The study represents a useful contribution to the research of chronotype and sleep behavior in athletes, with a focus on the major impact of the COVID-19 pandemic.
... Importantly, chronotype has also marked consequences for human well-being and flourishing. Namely, research indicates that morningness is associated with higher satisfaction with life, construed as a subjective evaluation of the quality of life-based on personal criteria set by individuals [6][7][8]. ...
The associations between morningness-eveningness, conscientiousness, and religiosity have not been investigated to date. The aim of the present research was to provide evidence for the relationships between these dimensions. Moreover, we tested whether the well-established link between morningness and life satisfaction could be explained by elevated religiosity of morning-oriented individuals and whether this relationship may be mediated by conscientiousness. The investigation was conducted on two independent samples of Polish adults (N = 500 and N = 728). Our results corroborated earlier findings that morningness was positively associated with both conscientiousness and satisfaction with life. We also found evidence for a significant positive association between morningness and religiosity. Moreover, controlling for age and gender, we obtained significant mediation effects showing that the association between morningness-eveningness and satisfaction with life might stem, at least in part, from the higher religiosity among morning-oriented individuals, also when conscientiousness was included in the model. It means that more morning-oriented individuals may benefit from higher psychological well-being thanks to both personality characteristics and attitudes towards religion.
... Besides associations with differences in sleep-wake patterns, morningness-eveningness is related to many other physical and psychological features such as temperament (Gorgol et al. 2022c), mood (Jankowski and Ciarkowska 2008), satisfaction with life (Randler 2008), cognitive performance (Díaz-Morales and Escribano 2015) or affective functioning (Gao et al. 2019). Morningness-eveningness is also associated with the Big Five personality traits; morningness is positively related to conscientiousness and eveningness to neuroticism (Randler et al. 2017b). ...
Morningness-eveningness refers to individual differences in the sleep-wake cycle. Research indicates that morningness-eveningness is associated with the Big Five (neuroticism, extraversion, openness to experience, agreeableness, conscientiousness) and the Big Two (alpha-stability, beta-plasticity) personality factors. However, the latter has not yet been tested within the multidimensional approach to morningness-eveningness. In the present study, we have adapted the Morningness-Eveningness-Stability-Scale improved (MESSi) to Polish (https://osf.io/rcxb5) to explore the associations between its subscales (morning affect, eveningness, distinctness) and the Big Two personality traits in a sample of 1106 participants (559 women and 547 men) aged 18 to 55 (M = 36.26, SD = 9.90). In bivariate correlations, morning affect was positively related to alpha-stability and beta-plasticity, distinctness was correlated negatively with alpha-stability and beta-plasticity, while eveningness was positively correlated only with beta-plasticity. Furthermore, the confirmatory factor analysis supported the original three-factor structure of the Polish version of MESSi, while the associations with affect and the symptoms of depression and anxiety attested to its validity. Overall, the present study provides the first evidence for the associations between MESSi subscales and the Big Two personality traits, as well as shows a good fit of the three-factor structure of MESSi in the Polish population.
... Further, there is evidence of a link between chronotype and suicidal ideation in adolescents and young adults (Bradford et al. 2021;Chan et al. 2020), but not between chronotype and suicide attempt among undergraduate students without a psychiatric diagnosis (Lester 2015). Further, a study on German university students (n = 164) showed that being an evening type is associated with lower quality of life (Randler 2008). The same association was demonstrated to be independent of age in a sample of Polish residents (n = 349; ages 13-59 years) (Jankowski 2012). ...
Individual preferred timing of sleep and activity patterns, known as circadian preference, ranges from definitely morning types to definitely evening types. Being an evening type has been linked to adverse sleep and mental health outcomes. This study aimed to explore the associations between circadian preference and self-reported sleep, depression, anxiety, quality of life, loneliness, and self-harm/suicidal thoughts. Data stem from a national survey of students in higher education in Norway (the SHoT-study). All 169,572 students in Norway were invited to participate, and 59,554 students (66.5% women) accepted (response rate = 35.1%). Circadian preference was associated with sleep and mental health outcomes in a dose-response manner. For both genders, being an evening type (either definitely evening or more evening than morning) was associated with an increase in age-adjusted relative risk (RR-adjusted; range = 1.44 to 2.52 vs. 1.15 to 1.90, respectively) across all outcomes compared with definitely morning types. Overall, the present study provides further evidence that evening circadian preference is associated with adverse sleep and mental health outcomes in young adults. As such, future efforts to improve sleep and mental health in young adults should consider their circadian preferences.
... For instance, given that certain features of emotional intelligence (Stolarski and Jankowski 2015) proved significantly higher among E-types, it would be interesting to test whether these differences reflect a more general way of dealing with negative emotional consequences of eveningness. Following the positive psychology approach (Seligman and Csikszentmihalyi 2014) it would also be essential to seek the factors that would allow E-types to compensate for their lower well-being (Randler 2008). One such dimension could be extraversion, which has been shown to moderate the link between morningness and life satisfaction (Drezno et al. 2019). ...
Due to the undeniably morning orientation of the social clock, the evening chronotype can be associated with negative consequences, both at the affective and cognitive levels. Evening-oriented individuals are more susceptible to affective disorders, show poorer educational achievements and consume stimulants more often than morning-oriented individuals. However, little is known about potential factors that may attenuate or amplify these negative emotional consequences of the evening preference. Thus, our aim was to examine whether personality traits interplay with chronotype in predicting depressive symptoms. We assessed the Big Five and the Big Two personality traits, morningness-eveningness and depressive symptoms in an online sample of 913 Polish individuals (468 females, 445 males), aged 18–35 (M = 26.34, SD = 5.15). Eveningness, higher neuroticism, lower conscientiousness and lower alpha-stability were associated with higher depressive symptoms. The magnitude of the association between eveningness and depressive symptoms decreased with higher conscientiousness and alpha-stability, as well as with lower neuroticism. In conclusion, high neuroticism, low conscientiousness and low alpha-stability increase the risk of depressive symptoms, particularly among evening chronotypes. The patients’ chronotypes and personality traits should be taken into account in both the prevention and diagnostics of depression.
... However, in this study, respondents with a score in the bottom 20% were identified as evening-type, and those with a score in the top 20% were identified as morning-type (Prat and Adan, 2013). Thus, those with a score of 26 or lower were classified into the evening-type group, those with a score of 41 or higher were classified into the morning-type group, and those with a score in-between were classified into the intermediate-type group (Randler, 2008). ...
Circadian rhythms have been known to be associated with bipolar disorders. There are many cases in which hypomanic symptoms are not recognized as indicators of an illness. This study aimed to determine the correlation between the experience of lifetime hypomanic symptoms and circadian typology of university students. A total of 8,562 university students participated in the study. The participants completed the Composite Scale of Morningness (CSM) for circadian typology and Mood Disorder Questionnaire (MDQ). Chi-square test and analysis of variance were performed, and the post-hoc result was computed using the FDR adjusted p-values. Overall, the MDQ score was higher in the evening-type group. There was no significant difference between the intermediate-type group and morning-type group for male students. In the evening-type group, the positive response rate was significantly higher for 10 out of 13 items in the MDQ. The evening-type group was more likely to experience hypomanic symptoms. This study showed that circadian and seasonal characteristics related to circadian typology are associated with lifetime hypomanic symptoms. Hence, further investigation is needed to determine the eveningness trait, as it could be a trait marker of bipolar spectrum disorder.
... Thus, those with a score of 26 or lower were classi ed into the evening-type group, those with a score of 41 or higher were classi ed into the morning-type group, and those with a score in-between were classi ed into the intermediate-type group. (Randler 2008) Mood Disorder Questionnaire (MDQ) MDQ is a 3-part self-report questionnaire used to screen for Bipolar Spectrum Disorder (BSD). Part 1 is composed of 13 items that look into whether the respondents experienced manic or hypomanic episodes in their lifetime , Miller et al. 2004), part 2 asks whether those manic or hypomanic episodes or behaviors were demonstrated during the same period, and part 3 assesses on a 4-point scale whether the respondents had any functional impairment due to the illness. ...
BACKGROUND: Circadian rhythms have been known to be associated with bipolar disorders. There are many cases in which hypomanic symptoms are not recognized as an illness. This study aimed to determine the correlation between the experience of lifetime hypomanic symptom and circadian type of university students.
METHODS: A total of 8,562 university students participated in the study. The participants completed the Composite Scale of Morningness (CSM) for circadian typology and Mood Disorder Questionnaire (MDQ). Chi-square test and analysis of variance were performed, and the post-hoc result was computed using the FDR adjusted p-values.
RESULTS: Overall, the MDQ score was high in the evening-type group. There was no significant difference between the intermediate-type group and morning-type group for male students. In the evening-type group, the response rate was significantly higher in 10 out of 13 items in MDQ.
CONCLUSIONS: The evening-type group was more likely to experience hypomanic symptoms. This study shows that circadian and seasonal characteristics related to circadian types are associated with lifetime hypomanic symptoms. Hence, further investigation is needed to determine the eveningness, as it could be a trait marker of bipolar spectrum disorder.
... Chronotype is often conceptualized as a psychological construct or trait [6][7][8]. In this framework, questionnaires assessing diurnal preferences and classifying individuals into types according to a score were developed (e.g., the Morningness-Eveningness Questionnaire, MEQ, [9]). ...
The Munich ChronoType Questionnaire (MCTQ) has now been available for more than 15 years; its original publication has been cited 1,240 times (Google Scholar, May 2019); its online version, which was available until July 2017, has produced almost 300,000 entries from all over the world (MCTQ database). The MCTQ has gone through several versions, has been translated into 13 languages and has been validated against other more objective measures of daily timing in several independent studies. Besides being used as a method to correlate circadian features of human biology with other factors – ranging from health issues to geographical factors – the MCTQ gave rise to quantifying old wisdoms, like “teenagers are late” and has produced new concepts, like social jetlag. Some like the MCTQ’s simplicity and some view it critically; it is time to have a self-critical view on the MCTQ, to address some misunderstandings and give some definitions about MCTQ-derived chronotype and the concept of social jetlag.
... Our findings are also in line with previous studies showing that lower sport participation and physical activity are associated with eveningness (Klimentidis et al. 2018;Vera et al. 2018). In terms of negative personality traits, eveningness has been correlated with impulsiveness, low life satisfaction, higher novelty seeking, lower harm avoidance, neuroticism, and psychoticism (Adan et al. 2010;Caci et al. 2004;Mecacci and Rocchetti 1998;Randler 2008). In this study, psychoticism and extraversion were found to be higher in an evening-type cluster but neuroticism showed no difference between chronotypes. ...
Evening-oriented sleep timing preferences have been associated with risk of diabetes, cardiovascular diseases, obesity, psychiatric disorders, and increased mortality. This research aims to explore the relationship between diurnal preferences (chronotype), daily habits, metabolic health, and mortality, using longitudinal data from The University of Manchester Longitudinal Study of Cognition in Normal Healthy Old Age (6375 participants at inception, recruited in the North of England) with a long follow-up period (up to 35.5 years). Mixed models were used to investigate the influence of aging, socio-demographic, and seasonal factors on sleep timing. Results show that sleep timing shifted towards earlier time with aging. Test seasons influence chronotype of older adults but working schedules challenge seasonality of sleep timing. Moreover, the season of birth may set chronotype in adulthood. Individual chronotype trajectories were clustered using latent class analysis and analyzed against metabolic health and mortality. We observed a higher risk of hypertension in the evening-type cluster compared to morning-type individuals (Odds ratio = 1.88, 95%CI = 1.02/3.47, p = .04). Evening-type cluster was also associated with traits related to lower health such as reduced sport participation, increased risk of depression and psychoticism personality, late eating, and increased smoking and alcohol usage. Finally, Cox regression of proportional hazards was used to study the effects of chronotype on longevity after adjusting for sleep duration, age, gender, smoking, alcohol usage, general health, and social class. The survival analysis (82.6% censored by death) revealed that evening-type chronotype increased the likelihood of mortality (Hazard ratio = 1.15, 95%CI = 1.04/1.26, p = .005). Taken together, chronotype is influenced by aging and seasonal effects. Evening-type preference may have detrimental outcomes for human well-being and longevity.
... Chronotype is often conceptualized as a psychological construct or trait [6][7][8]. In this framework, questionnaires assessing diurnal preferences and classifying individuals into types according to a score were developed (e.g., the Morningness-Eveningness Questionnaire, MEQ, [9]). ...
The Munich ChronoType Questionnaire (MCTQ) has now been available for more than 15 years and its original publication has been cited 1240 times (Google Scholar, May 2019). Additionally, its online version, which was available until July 2017, produced almost 300,000 entries from all over the world (MCTQ database). The MCTQ has gone through several versions, has been translated into 13 languages, and has been validated against other more objective measures of daily timing in several independent studies. Besides being used as a method to correlate circadian features of human biology with other factors—ranging from health issues to geographical factors—the MCTQ gave rise to the quantification of old wisdoms, like “teenagers are late”, and has produced new concepts, like social jetlag. Some like the MCTQ’s simplicity and some view it critically. Therefore, it is time to present a self-critical view on the MCTQ, to address some misunderstandings, and give some definitions of the MCTQ-derived chronotype and the concept of social jetlag.
... Chronotype (or circadian phase preference) corresponds to an individual characteristic that reflects preferences for a given period of day.➢ People can be classified into morning-, intermediate-, or evening-types when this preference occurs in the morning, around the middle of the day, or in the evening, respectively ➢ Circadian preferences play a crucial role in a wide variety of human abilities and markers (for a review, see Adan et al. 2012), as well as in people's satisfaction with life(Jankowski 2012;Randler 2008) making it relevant that it be properly assessed.➢ The MESSi is a self-report instrument that has been recently proposed to overcome limitations of previous instruments of the kind and includes a new dimension (Distinctness).➢ ...
... -morningness thus explained less than 3 percent of the variance in life satisfaction after controlling for age and sex of participants. Similarly, small-moderate partial correlations are common in the associated literature [13][14][15][16]. Jankowski [17] used a within-subject design to monitor changes in well-being associated with a shift towards Polish summer time among students aged between 19 and 31 years. ...
Individuals with a circadian preference for mental and physical activity later in the day ("Evening types") are consistently found to fare worse on most facets of well-being than individuals with a circadian preference for mental and physical activity earlier in the day ("Morning types"). Several explanatory hypotheses of this association between chronotype and well-being have been proposed, including shared genetic, biological, developmental, and psychosocial mechanisms. This paper presents a critical summary of these explanatory mechanisms and offers suggestions for their integration in an interdisciplinary biopsychosocial framework.
... Extensive research has documented correlates of morningness-eveningness. Morningness is associated with the big five personality dimension of conscientiousness (Tsaousis 2010), and with better academic achievement at university (Önder et al., 2014;Randler and Frech 2006), and at school (Eberspach et al., 2016). Morningness is also associated with positive affect and subjective health (Biss and Hasher 2012), better sleep quality and more well-being (Howell et al. 2008), and more life satisfaction (Randler 2008). Eveningness, in contrast, is associated with poorer sleep quality (Bakotic et al. 2017;Carciofo et al. 2014), more impulsivity (Caci et al. 2005), more use of drugs, such as alcohol and nicotine (e.g., Bakotic et al. 2017;Suh et al. 2017;Wittmann et al. 2006), more negative moods (Díaz-Morales et al. 2015), and with more psychological distress or disorder (Au and Reece 2017;Taylor and Hasler 2018). ...
Individual differences in time of day preference have important correlates. Morningness is associated with greater well-being, while eveningness is associated with more maladaptive behaviors, psychological distress, and disorder. The availability of valid, reliable, questionnaire scales is central to this ongoing research. The recently developed Morningness–Eveningness-Stability-Scale improved (MESSi) utilizes items from previously established scales to assess the dimensions of Morning Affect (MA), Eveningness (EV), and amplitude of diurnal variation/distinctness (DI). The current study developed a Chinese version of the MESSi scale. A sample of 767 Chinese university students completed the translated MESSi, the reduced Morningness-Eveningness Questionnaire (rMEQ), and scales assessing sleep quality, positive and negative affect, the big five personality dimensions, and life satisfaction. An independent sample of 80 undergraduates completed the MESSi twice over a 14–19 day period. Exploratory and confirmatory factor analysis both supported the original three-factor structure of the MESSi, with the subscales of MA, EV, and DI. Internal consistency and test–retest reliability were acceptable/good, and expected correlations with other measures were found, including: MA correlated positively with the rMEQ, conscientiousness, positive affect, and life satisfaction; EV correlated negatively with rMEQ and conscientiousness; DI correlated positively with poor sleep quality, negative affect, and neuroticism. Overall, the results support the validity and reliability of the Chinese version of the MESSi.
... Finally, in accordance with our assumptions, morning types showed higher satisfaction with school than evening types. This finding is well aligned with prior findings according to which morning types show better mood in school and a higher general satisfaction with life than evening types (Randler, 2008). We found no differences in school satisfaction between high or low M-E types. ...
This paper investigates a quadrant-based typology of circadian preference including morning (M) types (high morningness, low eveningness), evening (E) types (low morningness, high eveningness), low M-E types (low morningness and low eveningness), and high M-E types (high morningness and eveningness). In Study 1, a latent class analysis of circadian preference was conducted using a representative sample of 1022 9th grade students (50.00% females; mean age: 14.98 years) and relations to academic outcomes were investigated. A 4-class solution comprised 39% evening types, 21% morning types, 27% low M-E types, and 13% high M-E types. There were no gender differences in the frequency of morning or evening types. More females were low M-E types and more males were high M-E types. Lower academic performance related to having an evening preference. In Study 2, test-criterion evidence of the typology was examined based on data from sleep diaries of 129 9th to 10th grade students (44.96%; mean age: 15.6 years). Types did not differ in sleep duration. Findings supported the well-known differences in sleep timing and behavior between morning and evening types; high M-E types and low M-E types did not differ in their sleeping behavior.
... It may also be possible that morning-type individuals have certain personality traits that are related to self-compassion (Randler et al. 2017;Sisneros 2017). It is worth mentioning that social and working schedules are more aligned with biological rhythms of the morning-types, which might reinforce a more dispositional tendency to positive affect and well-being (Randler 2008)and this may include self-compassion which is an alternative way of embrace suffering without suppression or avoidance. However, we do not have sufficient evidence to fully justify this finding. ...
It is well established in the literature that morning-type individuals present better health indicators than evening-types. Mindfulness is considered an adaptive self-regulation skill associated with well-being and physical and mental health. However, there is scarce studies that relate chronotype and mindfulness. Thus, in this research, our aim was to study the relationship between chronotype and mindfulness-related variables. For this purpose, a sample composed of 483 participants from the community was recruited through an online survey and invited to fill out the Five Facet Mindfulness Questionnaire, the Self-Compassion Scale, and the Composite Morningness Scale. Regarding mindfulness measure, the results indicated that morning-types presented higher levels of “acting with awareness” than intermediate and evening-types. Additionally, as to self-compassion measure, morning-types presented higher levels of “mindfulness” and “overall self-compassion” than intermediate and evening-types. The remaining associations examined were not statistically significant. In sum, the morning-types showed higher scores in some of the mindfulness and self-compassion scales which seem to suggest that this morningness tendency may function as protective factor concerning eventual disorders´ development. Nonetheless, more systematic studies are needed to better understand this association and subsequently foster changes for psychological intervention.
... This individual difference is relevant in a variety of domains. For example, it has been related to affective conditions (e.g., Randler et al., 2012;Oginska and Oginska-Bruchal, 2014), to health-related behaviors and problems (e.g., Fabbian et al., 2016;Suh et al., 2017), and to satisfaction with life (e.g., Randler, 2008;Jankowski, 2012). Chronotype also relates in different ways to various characteristics of personality (e.g., Lipnevich et al., 2017;Randler et al., 2017b). ...
Assessing morningness-eveningness preferences (chronotype), an individual characteristic that is mirrored in daily mental and physiological fluctuations is crucial given their overarching influence in a variety of domains. The current work aimed to investigate the best factor structure of an instrument recently presented to asses this variable: the Morningness-Eveningness-Stability-Scale improved (MESSi). For the first time, the originally-proposed three-factor structure was pitched against a uni- and a two-factor solution. We also aimed to establish that the best-fitting model would be invariant in relation to sex and age, two variables that influence chronotype. A Confirmatory Factor Analyses on the data obtained from a sample of 2096 German adults (age: 18-76; M = 25.5, SD = 7.64) revealed that the originally-proposed three-factor structure of the MESSi—Morning Affect, Eveningness, and Distinctness—was the only one to achieve acceptable fit indicators. Furthermore, each scale obtained good internal consistency. In order to assess age invariance, following the literature on development and chronotype, our sample was divided into three age groups: 18-21 years, 22-31 years, and 32 years or older. Full measurement invariance of the three-factor model was found for sex and age. Regarding differences between sexes, females did not differ significantly from males in Morning Affect, but scored significantly lower on Eveningness and higher on Distinctness; this last result has been consistent across validation studies of the MESSi. With respect to age differences, our oldest group scored lower on Eveningness and Distinctness than the other two age-groups; the intermediate group (age: 22-31) scored lower on Morning Affect than both the younger and older-age groups. Additionally, both Eveningness and Distinctness were negatively correlated with age. This latter relation has been consistently reported in other validation studies. Our results reinforce the idea that the MESSi assesses three different components of chronotype in a reliable manner and that this instrument can be used to explore sex and age differences.
... The peak of the intermediate-types arises in the middle of the day (Adan et al. 2012). A large body of research has demonstrated that circadian preferences play a crucial role in a wide variety of human abilities and markers (for a review, see Adan et al. 2012), as well as in people's satisfaction with life (Jankowski 2012;Randler 2008). ...
This work reports the initial psychometric characterization of the Morningness-Eveningness-Stability-Scale improved (MESSi) for Portuguese young-adults (N=466). A Confirmatory Factor Analysis confirmed a three-factor model (i.e., Morning Affect, Eveningness and Distinctness) in our data, as originally proposed. Furthermore, construct validity evidence in relation to external variables (i.e., morningness/eveningness and satisfaction with life), as well as adequate reliability (i.e., internal consistency and test-retest reliability), were found. Finally, sex-based invariance and between-sex differences were investigated for the three subscales, as were correlations with age. Results point to the suitability of the MESSi for multi-cultural research on relevant and multiple aspects of chronotype.
... The interindividual differences in the phase of biological and behavioral patterns are genetically based and controlled by an endogenous circadian pacemaker, although other factors such as social and cultural influences might also contribute at determining differences in behavioral rhythms [33,34]. The chronotype differences are reflected in timing of sleep [35], peak of cognitive abilities [36], academic performance [37], personality [38], and more generally well-being [39]. Nevertheless, the propensity toward diurnal or evening preferences can vary in different life periods, perhaps due to modifications in the secretion levels of gonadal hormones throughout the life span [40]. ...
Circadian rhythms influence our daily behavior. Individuals display preferences for activity at certain time of day and this circadian phenotype can be summarized with the concept of “chronotype” or circadian typology (CT). The chronotypes differ in the timing of many physiological and psychological variables. Individuals with an early circadian phase are morning-types (M-types), those with a delayed circadian phase are evening-types (E-types), and those with an intermediate circadian phase are neither-types (N-types). Nevertheless, the propensity toward morning or evening preferences can vary during the life. In particular, adolescence can represent a crucial time in which the sleep–wake cycle tends to become delayed. The circadian rhythm desynchronization is common in modern society and lead to negative health effects, not only for physical health, but also for cognitive and affective function. One of the most important variables that show a defined circadian rhythm is melatonin; human melatonin levels increase at night, but the acrophase of melatonin occurs earlier in M-type than in E-type. Aim of this review, after providing a description of the methods for detecting the CT, analyzes the propensity toward morning or evening preferences in different life periods and the interactions between melatonin and physiological functions associated to physical activity. Exercise, performed in morning or in evening sessions, can adjust circadian rhythm, supporting its application as a treatment for the circadian rhythm desynchronization, for example, resulting from jet lag or shift work. Interindividual differences should also be taken into account in case of changes of the circadian rhythms parameters of different variables that can influence health also in relation to sport.
... Previous studies indicated that eveningness was positively related to lower self-esteem, higher depression, hostility, psychopathy, and psychoticism (Hsu et al. 2012;Jonason et al. 2013;Randler 2011) which were linked to cyberbullying perpetration. Gau et al. (2007) and Randler (2008c) also reported that individuals with higher eveningness were less satisfied with their lives and they were having more emotional and behavioral problems. It is not surprising that individuals show cyberbullying behaviors via online games, social media, or mobile phones when considering the relationship between eveningness and depression, emotional and behavioral problems, and technological dependencies. ...
Cyberbullying is one of the important negative issues among adolescents and youngsters. Victims of cyberbullying perpetration have been reported to suffer many psychological and emotional problems that can lead them as far to suicide. The purpose of the present study was to investigate the associations of cyberbullying perpetration with gender, personality traits, chronotype, and sleep quality. Three hundred and fifty-three freshman and sophomore university students from Turkey (45.9% (n = 162) female and 54.1% (n = 191) male) completed a questionnaire that included Cyberbullying Scale, Big-5 Inventory, Composite Scale of Morningness, and Sleep Quality Scale. The most conspicuous result of the study was that chronotype and sleep quality were significant predictors of cyberbullying perpetration. Evening-type students had significantly higher scores on cyberbullying scale than neither-type students and morning-type students, and also neither-type students had higher scores on cyberbullying scale than morning-type students. Further, poorer sleep quality, being male, higher extraversion, higher neuroticism, and lower conscientiousness were related to higher cyberbullying perpetration.
While morningness (a preference for rising earlier in the day) is associated with positive affect and life satisfaction, eveningness is correlated with negative emotionality, poor sleep, less self-control, and more procrastination. The current study investigated inter-relationships between morningness–eveningness; bedtime, academic, and exercise procrastination; mind wandering; sleep quality; self-control; and depressive symptoms. An online survey including questionnaire measures of these variables was completed by 306 university students (aged 18–51 years; mean = 20.36, SD = 4.001; 34 male). Morningness correlated with more self-control and better sleep quality—eveningness correlated with more bedtime, academic, and exercise procrastination; depressive symptoms; and mind wandering. All forms of procrastination negatively correlated with self-control and sleep quality, and positively correlated with depressive symptoms and mind wandering, although more strongly with spontaneous than deliberate mind wandering. Mediation effects were found—bedtime procrastination (BP) between eveningness and spontaneous mind wandering (MW); spontaneous MW between BP and sleep quality; sleep quality between BP and depressive symptoms; self-control between depressive symptoms and academic procrastination. A path model of these inter-relationships was developed. This study adds to a growing body of research indicating that interventions to reduce bedtime procrastination may bring about improvements in wellbeing and academic achievement.
Sleep and circadian rhythm disruption (SCRD) is common in schizophrenia patients, who also typically experience impaired social functioning. While various factors influence social functioning in schizophrenia, the specific impact of sleep and circadian rhythm disruption remains unclear. This study aimed to investigate the connection between chronotype and social functioning in remitted schizophrenia patients, examining the mediating roles of depression and sleep quality. The study included 185 patients diagnosed with schizophrenia based on DSM-5 criteria. After categorizing the patients into morningness, eveningness, or intermediate chronotypes using the Morningness-Eveningness Questionnaire(MEQ), they were assessed with the Positive and Negative Syndrome Scale(PANSS), Calgary Depression Scale for Schizophrenia(CDSS), Personal and Social Performance Scale(PSPS) and Pittsburgh Sleep Quality Index(PSQI). The eveningness chronotype group showed higher CDSS and PSQI scores and lower PWBS and PSPS-Total scores than the other groups (p < 0.05). A hierarchical linear regression model assessed MEQ, PSQI, and CDSS scores' effects on PSPS total scores. MEQ scores' significance diminished when CDSS scores were included. Eveningness chronotype, particularly with increased depressive symptoms, negatively impacts social functioning in remitted schizophrenia patients.These findings contribute to the understudied area of chronotype in schizophrenia and its impact on social functioning, including its interaction with sleep..
Well-established correlates of morningness-eveningness include those of morningness with more future Time Perspective (TP), and eveningness with more present TP. However, research into these relationships has used unidimensional measures of morningness-eveningness. So, the current study aimed to further understanding by assessing associations between TP and the separate components of Morning Affect (MA: alertness/sleep inertia after awakening) and Distinctness (DI; amplitude of diurnal variations of functioning), in addition to Eveningness (EV; time-of-day preference). Chinese university students (N = 299, aged 18–25, 94 males, 205 females) completed an online survey with questionnaire measures of TP, MA, DI, EV, and other measures including mind wandering, conscientiousness, life satisfaction, positive and negative affect, and sleep quality. Previously demonstrated correlations were replicated, including positive correlations between Future TP, conscientiousness, and life satisfaction, and Past-negative TP and more negative affect. MA positively correlated with Future TP, and negatively correlated with Past-negative TP and Deviation from Balanced Time Perspective (DBTP); DI positively correlated with Past-negative TP, and with DBTP, and negatively correlated with Future TP; EV positively correlated with Present-hedonistic TP, and negatively correlated with Future TP. The EV-Future TP association was mediated by MA. Path models were consistent with the view that the relationship between EV and less Future TP may involve impaired functioning and reduced self-control/self-regulation associated with experiencing lower Morning Affect. This research shows relationships between time perspectives and specific components of circadian functioning, indicating the value of component-level analysis and the limitations of research utilising unidimensional measures of morningness-eveningness.
Chronotype represents the preference for evening or morning hours for mental and physical performance and viewed as a stable human behavioral trait and personality feature. Chronotype relates to many biological, social, and psychological aspects. Depression, anxiety, and health problems are associated with eveningness in the clinical and non-clinical populations. At the same time, morningness demonstrates a positive relationship with well-being (Randler, 2008a). Many studies show that age and sex is a significant predictor of time-of-day preference (Adan et al., 2012). This study is attempted to investigate the association between life-satisfaction and morningness-eveningness and explore age and sex differences. Two hundred thirty-eight persons participated in this study; age distribution was: 17–28 years. The reduced Morningness–Eveningness Questionnaire was used to measure chronotype preferences, and Social frustration and life satisfaction scale were used to assess the subjective level of life satisfaction. Age differences were found for chronotype demonstrating the tendency to eveningness for young adults (23–28 age) than for students (18–22 age), but no sex differences in morningness-eveningness were found. Eveningness negatively correlates with all life-satisfaction dimensions, but this association differs depending on sex and age. In general, the morningness-eveningness preferences seem to be dependent on age more than sex, but the life satisfaction influenced by both factors. We may report the existence of association between eveningness and life satisfaction, which is much more reliable for men and younger persons.
Morningness is associated with well-being, better sleep quality, and more conscientiousness, while eveningness is associated with negative emotionality, poorer sleep quality, and less conscientiousness. The current study aimed to further understanding of associations with conscientiousness by assessing specific behavioural indicators of conscientiousness, morningness-eveningness, and also the Morning Affect and Distinctness (amplitude of diurnal variation) aspects of circadian functioning. A survey of Chinese university students (N = 369, aged 18–30, mean = 19.48, SD = 1.922; 108 males, 261 females), included the Morningness-Eveningness-Stability-Scale, measures of conscientiousness, mindfulness, life satisfaction, aspects of sleep, and the Behavioural Indicators of Conscientiousness (BIC) scale. Morningness and Morning Affect were positively correlated with life satisfaction, mindfulness, better sleep quality, more conscientiousness, and with BIC including Hardworking, Self-control, and Punctuality. Distinctness showed negative correlations with these variables. Negative correlations between Eveningness and conscientiousness, and the BIC subscales of Hardworking and Cleanliness were no longer significant after controlling for Morning Affect. Mediation analysis showed that the associations between Eveningness and conscientiousness/BIC were mediated by Morning Affect. These results extend previous research by showing associations between circadian functioning and specific behavioural indicators of conscientiousness, and suggest that low Morning Affect may provide a mechanism for the relationship between Eveningness and conscientiousness.
Studies show that eveningness preference and depressive symptoms are positively related. However, little is known about possible factors that could reduce this association. In the present study, we examine the moderating effects of religiosity on the relationship between eveningness and depressive symptoms. The main analyses were conducted on a group of 606 individuals (300 women and 306 men) aged 18 to 36 years (M = 29.00, SD = 4.95). The participants completed the Composite Scale of Morningness, the Patient Health Questionnaire-9, and the Centrality of Religiosity Scale. Our results confirmed earlier findings that eveningness was positively related to depressive symptoms. The magnitude of this association decreased with higher religiosity. This lead to the conclusion that religiosity may act as a protective factor against elevated depressive symptoms among evening-oriented individuals.
Circadian rhythms are modulated by age. The timing of the circadian clock under real-life conditions (i.e., chronotype) is progressively delayed during adolescence. However, schools start very early in the morning, when the adolescent’ clock is still not prepared to be awake. Consistently, the misalignment between early school timing and late chronotypes leads to poor sleep: both short and out-of-time, which is associated with adverse consequences for health and cognitive and academic performance. This situation worsens in some countries due to cultural differences: Argentinian adolescents have even later chronotypes than most of their peers around the globe. Later school start times are associated with better sleep and a lower impact of chronotype on academic performance. Several strategies are suggested to evaluate and to mitigate the consequences of the misalignment between chronotype and school timing. Importantly, local studies and interventions are the key to understand and improve adolescents’ education and well-being.
While the social cost of problematic alcohol use has been examined, limited information exists on the private cost incurred by consumers. Using Icelandic panel data and the compensating income variation (CIV) method we estimate this individual private cost. We examine results using different measures of problematic alcohol use, two non-linear functional forms for income, and two utility proxies. We estimate the yearly individual cost, or CIV, to be 4–62 thousand USD. These estimates are considerably higher if not adjusted for income endogeneity. Results suggest that the CIV method is highly sensitive to model specifications in two areas: (i) The modelling of income; log-transformation contrasted with a piecewise-linear form shows that high-income groups affect full sample CIVs substantially, highlighting differences between mean and median value-estimates. This raises ethical questions on the trade-off between utilitarian policies based on means and largely driven by high-income groups, versus policies guided by median values that benefit most individuals. (ii) The choice of utility proxy; the CIV using happiness is substantially higher than that obtained using life satisfaction. This highlights the need for policy makers to consider whether their objectives should focus on cognitive measures of subjective well-being or affective measures.
Drawing on three sets of data provided by 338 Anglican clergy serving in the Church in Wales, 484 Presbyterian clergy serving in the Church of Scotland, and 422 Salvation Army Officers serving in the UK, this study reports the development of a 10-item instrument designed to provide independent measures of preference for morning activity (the Lark preference) and preference for evening activity (the Owl preference) appropriate for use among clergy. The thesis is then tested that these preferences predict individual differences in clergy work-related psychological health, as assessed by the Francis Burnout Inventory, after taking into account the effects of personal factors (sex and age) and personality factors (extraversion and neuroticism). The data demonstrated that clergy who displayed the Lark preference were less likely to suffer from emotional exhaustion, suggesting a clear and consistent linkage between preferences for mornings and lower vulnerability to burnout.
This chapter describes the effects of objective reality in terms of personal factors such as genetics, biology, health, drugs, life events, and the physical environment on the subjective aspects of quality of life (hedonic wellbeing, life satisfaction, and eudaimonia). With respect to biology, wellbeing research is discussed in relation to genes; hormones; stress, anxiety, and depression; food, sex, and drugs; sleep, physical exercise, obesity, body image, and diurnal preference. With respect to health, research is discussed in reference to how both physical and mental health influence wellbeing at large. Research is also discussed covering drugs and substance abuse and their effects on wellbeing. Focusing on life events, two research streams are discussed: facilitating adaptation to negative events and mitigating adaptation to positive events. Finally, the wellbeing effects of the physical environment (seasonal variation, climate, and weather; the natural environment; environmental pathogens; and resource scarcity) are highlighted.
ًاستهدفت هذه الدراسة استكشاف العلاقة بين التفاؤل وكل من السعادة، والرضا عن الحياة، فضلا عن فحص العلاقة
بين التشاؤم والسعادة، والرضا عن الحياة. أجابت عينة متاحة (ن = 225 ) من طلبة جامعة الإسكندرية وطالباتها عن
القائمة العربية للتفاؤل والتشاؤم، ومقياسي التقدير الذاتي لكل من السعادة، والرضا عن الحياة، ولم تكشف النتائج
عن فروق دالة إحصائًيا بين الجنسين في كل متغيرات الدراسة، في حين استخرجت ارتباطات دالة إحصائًيا بين التفاؤل
وكل من السعادة، والرضا عن الحياة (موجبة)، وبين التشاؤم وكل من السعادة، والرضا عن الحياة (سالبة). وكشف
تحليل المكونات الأساسية عن عامل ثنائي القطب لدى الجنسين، سمي: "الحياة الطيبة في مقابل التشاؤم". وخلصت
هذه الدراسة، إلى أن التفاؤل أحد المتغيرات المهة في الحياة النفسية الطيبة، وهو الموضوع الأساسي في علم النفس الايجابي
The importance of positive word of mouth (WOM) and repurchasing in competitive online retail environments demands their further study. Although customer satisfaction has been found to drive positive WOM and repurchasing, limited research has explored what type of customers feel more satisfied with online shopping. It was anticipated that the convenient nature of online shopping would better match the conscientious personality traits of customers with earlier sleep and wake times. Data collected from 334 Indian college students participating in this study using a snowball sampling method were analysed by multiple regression. As hypothesised, based on self-congruency theory, customers with earlier sleep and wake times were found to feel more satisfied with online shopping, which in turn enhanced their positive WOM and increased repurchase intention. Theoretical and managerial implications are discussed.
User portrait analysis is one of the key points in human behavior analysis. It is important to describe or guess user's characteristics through rational methods in business analysis. In this paper, we use the user details records data set from a mobile operator to analyze the preference of users with different brand phones for different APPs and propose the concept of mobile Internet life personas (MILP) and the latent MILP indexing (LMILPI) model for the analysis of users' MILP. At the same time, we build user portrait analysis framework based on the latent semantic indexing (LSI) theme model, LMILPI model, and association rule mining. On the one hand, we analyze users' preference for APP content when using different mobile brands. On the other hand, we analyze the relationship among mobile brands, user access time, and MILPs to describe users' Internet behavior. Our research shows that there is a difference between users who use different brands of mobile phones: 1) users who use different brand phones have different preferences for different APPs. However, if mobile brand marketing methods or target users are same or similar, the APP preference of these brands will be similar; 2) MILPs are different between users who use different brands of mobile phones, but the MILPs displayed on Android platform are similar even though brands are not same, while the MILP displayed on iPhone is quite different from MILPs on Android; and 3) MILPs' importance will be changed by mobile phone brands and time periods. The analytical framework which we propose can provide commercial solutions such as application recommendations, market strategy formulation, Internet access, and other fields.
How circadian rhythms affect socio-economic behaviour is little explored but is a promising area of research that could suggest considerable changes in policy making, social norms and individual decision making. This article presents a pilot study of perceived restrictions that sleep patterns set on the employment options of creative research and development professionals. The study is based on ordered probit and ordinary least squares regression modelling on a sample of 153 creative R&D employees from Estonia, with chronotype, sleep duration and various individual and work characteristics as explanatory variables. We find that evening type individuals and those who sleep more hours feel that sleep restricts their work options more than other employees do. Given that there is some genetic background to both morning-evening preference and sleep hours and they are therefore difficult to change, individuals of different chronotypes and with different sleep behaviour may not have equal options in finding employment in creative R&D work.
Abstract
Background & Aim: Caring is the nature of nursing and plays an important role in the promotion of patients’ health level, process of recovery and their satisfaction. Difference in the performance and behavior among circadian types may influence nurses’ performance such as caring for patients. Accordingly, this study aims to determine the relationship between circadian types and nurses’ caring behaviors.
Material & Methods: This is a descriptive-correlational study. A total of 573 nurses were selected from different wards of hospitals affiliated to Tehran University of Medical Sciences through cluster sampling. Data was collected by Morningness Eveningness Questionnaire (MEQ) and Caring Behaviors Inventory (CBI) and analyzed by Spearman test and partial correlation using SPSS-PC (v. 16).
Results: The findings showed that most of the sample (%57.9) was of intermediate type. Subscales of professional knowledge and skill, and positive connectedness from CBI had the most and least scores respectively. After adjustment for age and work experience, there was no significant association between circadian types and caring behaviors.
Conclusion: The results did not provide enough evidence regarding the existence of a relationship between circadian types and nurse caring behaviors. Accordingly, conducting a same study by controlling the variables of age and work experience is recommended.
Background
Current research yields inconclusive results regarding the similarity of couples’ chronotypes. It seems that relationship satisfaction is not connected to the similarity of chronotypes.
Objectives
The present paper focuses on a moderating factor leading to an explanation of these results. Does autonomy and attachment of a couple have a moderation effect on the connection between the similarity of chronotypes and a couple’s satisfaction?
Material and methods
For the implementation 442 subjects (219 males, 222 females and one “not specified”; mean age 26,46) completed an online survey. The chronotypes were determined via the Morningness-Eveningness Questionnaire (D-MEQ), relationship satisfaction by the Life Satisfaction Questionnaire (FLZ) and autonomy and attachment with the Couple Climate Scale (PKS).
Results
There was no moderation effect due to a couple’s autonomy and attachment on the connection between the similarity of chronotypes and partnership satisfaction. It seems that there is no link between the similarity of chronotypes and partnership satisfaction. Furthermore there were almost as many couples with similar chronotypes as different chronotypes.
Discussion
These results raise the question of whether chronotypes have an impact on relationship satisfaction at all. The results can be explained by social conventions. Many people can’t live according to their chronotype, so differences in the natural sleep-wake pattern of couples are hardly apparent. To show the potential impacts of chronotypes on partnerships and personality traits there is a demand for future research.
Using data from an Icelandic health-and-lifestyle survey carried out in 2007, 2009, and 2012, we employ a compensating income variation (CIV) approach to estimate the monetary value sufficient to compensate individuals for the presence of various sub-optimal health conditions. This method is inexpensive and easy on subjects and has been applied to several desiderata that do not have revealed market prices. The CIV literature is, however, still limited in its application to health and thus information about its suitability is limited. With the aim of shedding light on the method́s appropriateness we thus provide a broad-view analysis including a spectrum of diseases and conditions that can be held up against more traditionally used methods CIV for physical conditions vary greatly, but paralysis, fibromyalgia, chronic back pain, rheumatoid arthritis, urinary incontinence, severe headache and thyroid disease were among those consistently associated with substantial well-being reductions. Mental-health results using this method should be read with caution. The societal value of health interventions is multidimensional, including for example increased productivity in the population. However, one of the main positive aspects of increased health is undoubtedly the increased well-being of the treated subjects. Such quality-of-life effects should thus preferably be taken into account. For this reason, information on the value individuals place on recovery from various sub-optimal health conditions is useful when it comes to prioritizing scarce capital in the health sector. It is therefore vital to estimate the importance individuals place on various health states and hold them up against each other. Furthermore, this paper has scientific value as it sheds light on attributes of a potentially useful method in health evaluations.
Personality, mood, and psychophysiological correlates of Home and östberg's (1976) Morningness-Eveningness Questionnaire (MEQ) are reported. State data were collected at both morning and evening times of day. MEQ score was related to personality traits associated with psychopathology—trait anxiety in males and psychoticism in females. The best explanation of these correlations is that personality and subject sex affect attention to zeitgebers or time of day cues. MEQ score was related to extroversion only in female subjects. A between-subjects study showed that morningness was positively associated with high energetic arousal in the morning, as predicted, but the MEQ did not predict physiological arousal measures reliably. A subsequent within-subjects study demonstrated sex differences in interactive effects of time of day and morningness-eveningness in mood states related to psychological disorder. The MEQ predicted two somewhat independent circadian rhythms—one related to arousal, and one to depression. It is concluded that personality may be linked to morningness-eveningness through associations between personality traits and cognitive and social factors affecting the entrainment of circadian rhythms to the sleep-wake cycle.
Humans show pronounced individual differences in circadian orientation. Transcultural comparisons are interesting since biological (or environmental) factors together with cultural ones may contribute to differences in morningness–eveningness. We compared Spanish and German undergraduates using the Composite Scale of Morningness (CSM) to assess circadian preferences. Confirmatory and multiple groups confirmatory factor analysis were used to assess factor structure and structural invariance across countries. The results showed that a three-factor model of morningness best characterises the CSM structure of both samples. Partial factorial invariance (factor loadings) across countries was demonstrated for the factors ‘morningness’ and ‘morning alertness’. Scores of both factors were higher in German students. Potential cultural and biological explanations for the differences are discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Morningness, or the preference for morning or evening activities, is an individual difference in circadian rhythms with potential applications in optimizing work schedules, sports performance, and academic achievement. This study addressed some neglected issues in morningness research. First, we propose a morningness self-report measure, the Preferences Scale, to remedy deficiencies in existing scale content and format. Second, because little is known about group or population differences in morningness, we collected data from university students in six countries. Both classical and structural equation modeling (SEM) analyses indicated that the psychometric properties of the Preferences Scale are adequate and comparable with an established morningness instrument, the Composite Scale. The SEM analyses also showed considerable group consistency in the morningness construct. However, mean differences were found across countries, suggesting that people in more temperate climates perceive themselves to be more morning-oriented than their peers in less temperate climates.
This paper reviews studies which have dealt with the relationship between morningness-eveningness (circadian typology) and other individual differences such as age, sex, personality dimensions and work schedule of their subjects. It appeared that the changes in the morningness-eveningness preference covaried with the age related changes in the internal body clock. An older age was associated with morningness while younger subjects tended towards eveningness, the critical age for the circadian typology change was 50 years. Sex-related differences are too small to be reflected in the scores on circadian typology questionnaires, although women were ahead of men by 1 hr in their circadian rhythms. The results on work schedule proved its role as a synchronizer modifying the morningness factor. The morningness dimension and extraversion are probably related through the impulsivity subdimension, which is closely associated with brain activation. Further research is needed to clarify the relationship between morningness and other personality dimensions (neuroticism, psychoticism), because the results are inconclusive. The influence of circadian typology on the tolerance to shift work and life habits are also discussed. The results with regard to shift work revealed the importance of morningness in determining human tolerance and health complaints. As regards life habits, there were differences in various aspects related to carcadian typology especially psychoactive substances consumption.
In an attempt to study the relationship between ageing and personality and the morningness-eveningness dimension two experiments were carried out. In experiment I, an Italian version of the Morningness-Eveningness Questionnaire (MEQ) was administered to 435 Ss ranging in age from 20 to 79 yr, and divided in to six age groups. In comparison with younger people older S tended to display greater Morningness-Eveningness scores. These results suggest that ageing relates to a shifting toward morningness. In Experiment II the Eysenck Personality Questionnaire (EPQ) and the MEQ were administered to 233 Ss (20–29 yr). Morning-types had significantly higher N scores and tended to be insignificantly more introverted. Evening-types had significantly higher N scores and tended to be insignificantly more extraverted. The present findings are consistent with reports of a tendency for morning-types to be introverted and for evening-types extraverted. However, they do provide some evidence of individual differences on the neuroticism and psychoticism dimensions of personality between the two diurnal types.
An English language self-assessment Morningness-Eveningness questionnaire is presented and evaluated against individual differences in the circadian vatiation of oral temperature. 48 subjects falling into Morning, Evening and Intermediate type categories regularly took their temperature. Circadian peak time were identified from the smoothed temperature curves of each subject. Results showed that Morning types and a significantly earlier peak time than Evening types and tended to have a higher daytime temperature and lower post peak temperature. The Intermediate type had temperatures between those of the other groups. Although no significant differences in sleep lengths were found between the three types, Morning types retired and arose significantly earlier than Evening types. Whilst these time significatly correlated with peak time, the questionnaire showed a higher peak time correlation. Although sleep habits are an important déterminant of peak time there are other contibutory factors, and these appear to be partly covered by the questionnaire. Although the questionnaire appears to be valid, further evaluation using a wider subject population is required.
Morningness-eveningness preference (morning-, intermediate-, evening-type) or circadian typology is the individual difference that most clearly explains the variations in the rhythmic expression of biological or behavioral patterns. The aim of this study was to analyze gender difference in morningness-eveningness preference using the Horne and Ostberg questionnaire in the largest university student population selected so far (N = 2135), with an age range 18-30 yr. Morningness-eveningness questionnaire (MEQ) score distribution closely correlated to the normal curve (range 17-78, mean = 48.25; SD = 10.11), with 338 (15.84%) morning-types, 1273 (59.62%) intermediate-types, and 524 (24.54%) evening-types. The men and women differed significantly in their mean scores (p < 0.0001) and distribution per circadian typology (p < 0.00001), with the men presenting a more pronounced eveningness preference. Three factors were identified by factor analysis: time of greatest efficiency (I), sleep time/sleep phase (II), awakening time/sleep inertia (III). The MEQ items sensitive to gender differences were essentially those included in factor I and factor II. The results are discussed in relation to recent models of circadian regulation of the sleep-wake cycle.
This article reports the development and validation of a scale to measure global life satisfaction, the Satisfaction With Life Scale (SWLS). Among the various components of subjective well-being, the SWLS is narrowly focused to assess global life satisfaction and does not tap related constructs such as positive affect or loneliness. The SWLS is shown to have favorable psychometric properties, including high internal consistency and high temporal reliability. Scores on the SWLS correlate moderately to highly with other measures of subjective well-being, and correlate predictably with specific personality characteristics. It is noted that the SWLS is Suited for use with different age groups, and other potential uses of the scale are discussed.
Humans show large differences in the preferred timing of their sleep and activity. This so-called "chronotype" is largely regulated by the circadian clock. Both genetic variations in clock genes and environmental influences contribute to the distribution of chronotypes in a given population, ranging from extreme early types to extreme late types with the majority falling between these extremes. Social (e.g., school and work) schedules interfere considerably with individual sleep preferences in the majority of the population. Late chronotypes show the largest differences in sleep timing between work and free days leading to a considerable sleep debt on work days, for which they compensate on free days. The discrepancy between work and free days, between social and biological time, can be described as 'social jetlag.' Here, we explore how sleep quality and psychological wellbeing are associated with individual chronotype and/or social jetlag. A total of 501 volunteers filled out the Munich ChronoType Questionnaire (MCTQ) as well as additional questionnaires on: (i) sleep quality (SF-A), (ii) current psychological wellbeing (Basler Befindlichkeitsbogen), (iii) retrospective psychological wellbeing over the past week (POMS), and (iv) consumption of stimulants (e.g., caffeine, nicotine, and alcohol). Associations of chronotype, wellbeing, and stimulant consumption are strongest in teenagers and young adults up to age 25 yrs. The most striking correlation exists between chronotype and smoking, which is significantly higher in late chronotypes of all ages (except for those in retirement). We show these correlations are most probably a consequence of social jetlag, i.e., the discrepancies between social and biological timing rather than a simple association to different chronotypes. Our results strongly suggest that work (and school) schedules should be adapted to chronotype whenever possible.
Comprehensive data for children's time of day preference were collected with school children from 8 through 16 years of age (n = 989) using the Children's Morningness-Eveningness Preferences (CMEP) scale. Strong evidence was found that children's optimal time of day preference shifts toward evening at about 13 years of age. Additionally, gender and ethnic differences in time of day preference were also examined. There was no gender difference, but there was a tendency for ethnic differences among older children. An implication of these findings is that a mismatch between older children's time of day preferences and school start time may have a negative effect on their school performance and this effect could be greater for some ethnic groups than for others.
A 16-item scale to measure optimism-pessimism was developed and administered to 160 subjects to investigate differences in personality traits as related to circadian rhythm functioning. Evening types were significantly more pessimistic than morning types. Other results showed that men and women did not differ significantly with respect to either optimism-pessimism or morningness-eveningness. Finally, while increased age was mildly correlated with morningness, it appeared to have little relationship to optimism-pessimism.
This article reports the development and validation of a scale to measure global life satisfaction, the Satisfaction With Life Scale (SWLS). Among the various components of subjective well-being, the SWLS is narrowly focused to assess global life satisfaction and does not tap related constructs such as positive affect or loneliness. The SWLS is shown to have favorable psychometric properties, including high internal consistency and high temporal reliability. Scores on the SWLS correlate moderately to highly with other measures of subjective well-being, and correlate predictably with specific personality characteristics. It is noted that the SWLS is suited for use with different age groups, and other potential uses of the scale are discussed.
The SWLS consists of 5-items that require a ratingon a 7-point Likert scale. Administration is rarely morethan a minute or 2 and can be completed by interview(including phone) or paper and pencil response. The in-strumentshouldnotbecompletedbyaproxyansweringfortheperson.Itemsofthe SWLSaresummedtocreatea total score that can range from 5 to 35.The SWLS is in the public domain. Permission isnot needed to use it. Further information regardingthe use and interpretation of the SWLS can be foundat the author’s Web site http://internal.psychology.illinois.edu/∼ediener/SWLS.html. The Web site alsoincludes links to translations of the scale into 27languages.
Several self-evaluation instruments have been developed for identifying the individual circadian typology. The use of these instruments suggests the idea that the morningness-eveningness dimension could be considered as a continuum between two extremes. Aim of the present work is to support such an idea by means of external criteria. A sample of 222 subjects was administered the Morningness-Eveningness Questionnaire (MEQ). Six typologies were considered: definitely morning, moderately morning, intermediate-morning, intermediate-evening, moderately evening, and definitely evening. Body temperature, and subjective alertness readings were collected at 08:00, 14:00, and 23:00 in counterbalanced order. As regards subjective alertness a significant interaction (ANOVA) between circadian typology and time of day was found. At 08:00 the recorded values of subjective alertness gradually increased starting from the definitely evening extreme typology to the definitely morning one, vice-versa at 23:00. These results seem to support the idea that the morningness-eveningness dimension could be considered as a continuum between two extremes: morning-evening preference. Nevertheless, this is especially true for subjective alertness. Suggestions about how to use the MEQ are put forward.
Pupils shift their time of day preferences from morningness to eveningness during the age of puberty. Therefore, early school start times may have a negative influence on school functioning, adolescent health and on grade point average. Here, we show that morningness – eveningness influences school performance as measured by the final school leaving/university entrance certificate. One hundred and thirty-two university students aged between 20 and 22 years participated in our study. We found a highly significant positive correlation between the average grading of the final exam and the morningness score, suggesting that pupils with morning preferences performed better in school achievement. Evening types seem at a serious disadvantage because the final exams are used for university entrance decisions.
The Composite Scale of Morningness is widely used and was translated into several languages. The aim of this study was to validate the German CSM scale and to present first results based on a sample of pupils and university students. The sample consisted of a total of 3745 persons (63.8% females). Mean age was 15.9 ± 4.0 (SD) years with a range from nine to 52 years. Cronbach's α coefficient was 0.84 and the inter-item correlations were all positive with an average value of 0.296 and a range between 0.112 and 0.764. Based on the eigenvalue-greater-than-one criterion a three factor solution was provided. After rotation, eigenvalues were 3.40 (26.2%), 2.36 (18.2%), and 1.61 (12.4%). As an external validation, I used the German translation of the morningness – eveningness questionnaire (MEQ). The correlation was high (r = 0.89). To investigate differences in morningness/eveningness in pupils and students a sub-sample was used (N = 3577; mean age 15.4 ± 3.0, range 10 – 22). Using age classes as factors revealed significant differences [one-way ANOVA: F(12, 3564) = 31.352; P
Measurements of physiological, biochemical and psychological variables at two or more
different times of day reveal substantial inter-individual differences. This paper reviews studies
which have dealt with these differences in terms of the morningness-eveningness, personality
(introversion-extraversion), age or sex of their subjects. Studies of individual differences in the
response of the circadian system to disturbance (e.g. shift work) are also discussed. The most
reliable differences were observed in association with the morningness-eveningness factor. From
the studies reviewed here it appeared that several rhythm parameters covarled consistently as a
function of morningness-eveningness, suggesting underlying differences in the intrinsic period of
the circadian system. It is argued that the differences in rhythm parameters associated with the
personality dimension of introversion-extraversion are the result of exogenous influences. The
results with regard to age-related and sex-related differences were not sufficient to allow conclusions
to be made.
Während die gesundheitsbezogene Lebensqualität Erwachsener zunehmend erforscht ist, wird die Lebensqualität gesunder und chronisch
kranker Kinder und Jugendlicher erst jüngst thematisiert. In der vorliegenden Arbeit werden in der Literatur publizierte Arbeiten
zum Thema gesundheitsbezogene Lebensqualität von Kindern ausgewertet hinsichtlich Schwerpunkten und Methoden der Forschung.
Der Überblick zeigt, dass empirische Arbeiten bisher rar sind, die vorhandenen Messinstrumente zur Lebensqualität von Kindern
werden beschrieben. Verstärkte Forschungsaktivitäten sind notwendig, um die Erfassung der Lebensqualität von Kindern in der
Prävention, den Gesundheitswissenschaften, in Therapieevaluation und Rehabilitation einsetzen zu können.
While health-related quality of life of adults is increasingly researched, the quality of life of healthy and chronically
ill children and adolescents has only recently been addressed. The present paper analyses published articles on children's
health-related quality of life, identified from medical and psychological sources according to focus and methodology in research.
The review shows that empirical work is short and describes available instruments for the assessment of quality of life in
children. Increased research activities are necessary to include quality of life assessment of children in prevention, public
health, treatment evaluation and rehabilitation
The aim of this study was to explore associations between chronotype and sleep–wake variables on the one hand and personality on the other in a large and gender balanced sample based on the big five inventory, encompassing the factors extraversion, neuroticism, openness, agreeableness and conscientiousness. 1231 participants (652 female, 579 male) responded to the composite scale of morningness (CSM) as a measure of chronotype and to a short version of the big five inventory (Rammstedt & John, 2007). Morningness correlated positive with agreeableness and conscientiousness, even when controlling for age and when examining gender separately. Neuroticism was related to eveningness only in females and in adolescents (10–17 years). In adults (18–47) only conscientiousness correlated with morningness. Positive correlations existed between agreeableness and conscientiousness and sleep length on weekdays and on weekends. Misalignment correlated significantly negative with agreeableness and conscientiousness but positive with extraversion.
This exploratory study investigates the relationship between morning and evening types and creative thinking as defined by Guilford’s factorial hypothesis. The research was carried out on a sample of 120 subjects, 52 males and 68 females aged between 19 and 76. The data show that evening-disposition is correlated with the ability to apply divergent thinking strategies to visual content. There was no significant difference between men and women but many differences were found with respect to age group. These findings suggest the need for in-depth studies to investigate morning and evening types and their relationship with creative thinking.
Little is known about the causes of the wide variability in circadian rhythms in humans. We present the first report of genetic influence on a circadian phenotype, the morningness-eveningness disposition. Two hundred and five pairs of adult monozygotic reared-together twins, and 55 pairs of adult monozygotic and 50 pairs of adult dizygotic reared-apart twins completed a morningness-eveningness questionnaire. Biometrical model-fitting showed that genetic variability accounted for about 54% of the total variance in morningness-eveningness; age contributed to 3% of the variance; and the remaining variance was explained by nonshared environmental influences and measurement error. Shared rearing environmental effects were not significant. The husband-wife correlation for morningness-eveningness was 0.25. This correlation appears to be due largely to assortative mating (the tendency of like to marry like) at the time of marriage rather than a consequence of cohabitation during marriage.
Sixty-one men and 50 women measured their own skin conductance hourly throughout one working day as well as recording drug intake and activities; they also completed the EPQ, I7 and Morningness-Eveningness questionnaires. As expected, self-reported Morning types showed higher skin conductance in the morning and Evening types in the evening. Introverts appeared as more highly aroused than extroverts, but particularly so in the morning; by midnight the two personality types had converged in skin conductance. Sociability, rather than impulsiveness, seemed to be the component of extraversion responsible for this interaction. Women showed higher conductance in the early morning, men in the afternoon and evening. Indications were that activity was determining arousal rather than the other way about, and that drug use was socially rather than neurologically motivated.
A group of 232 adult subjects was administered the Morningness-Eveningness Questionnaire to assess their individual circadian typology and a battery of questionnaires of personality and psychological and psychosomatic disorders (Beck Depression Inventory; Bortner Type A Scale; Eysenck Personality Questionnaire; Jenkins Activity Survey; Middlesex Hospital Questionnaire; Strelau Temperament Inventory). Significant correlations between circadian typology scores and data relative to personality, psychosomatic disorders, and stress-prone behaviour were found. Evening types reported psychological and psychosomatic disturbances more frequently and intensively than morning types, and showed more problems in coping with environmental and social demands. The relevance of the morningness-eveningness dimension for research on stress and cardiovascular diseases is discussed.
Gender differences in circadian typology and in biological rhythms have been revealed by using biological measurements but results based on self-report questionnaires are inconclusive. I applied meta-analytical tools to examine gender differences in morningness. I searched different databases for studies presenting values for morningness in males and females. Fifty-two studies were identified from which 11 used the composite scale of morningness CSM, 29 the morningness–eveningness-questionnaire MEQ, and eight the morning/evening questionnaire M/E. Most studies (51.9%) were carried out with students. There was no significant publication bias. Taken together, the meta-analysis suggests a weak but significant effect of gender on morningness (overall effect size E = 0.097 under a fixed effects model and E = 0.0845 under a random effects model). Girls and women were significantly more morning oriented than boys and men. Further, standard deviations of mean age of the subjects had a significant effect on effect sizes suggesting that large standard deviations, and thus a large age range within a study, produced smaller effect sizes. Focusing on student samples revealed higher effect sizes (E = 0.196). With regard to the different questionnaires, the CSM produced the largest effect sizes, followed by the MEQ.
Two questionnaires for the measurement of individual differences in circadian phase position (morningness-eveningness) were psychometrically evaluated and compared: the widely used Morningness-Eveningness Questionnaire (MEQ) by Horne and Östberg (International Journal of Chronobiology, 4, 97–110, 1976) and the Marburger questionnaire by Moog (Night and shift work: biological and social aspects. Oxford: Pergamon Press, 1981). Further instruments given to the sample (113 undergraduate students) were the EPI and a 2-week sleep/waking diary. In addition, two groups of extreme morning and evening types measured their own oral temperature throughout several days. Both circadian rhythm questionnaires proved reliable and valid (with respect to sleep/waking behaviour and oral temperature), although some deficiences were found for the MEQ with regard to its multidimensionality, skewness of distributions and a negative correlation with neuroticism. In line with previous research, a weak negative relationship of morningness-eveningness with extraversion was observed for both questionnaires. Impulsivity, rather than sociability, seemed to be the component responsible for this association. Effects of sex and age were only partially in line with previous findings.
This study is an adaptation and standardization of Horne and Östberg's questionnaire for the Spanish population. The variables age (17–50) and work hours were studied in subjects from the student community and in workers with different work schedules (morning, afternoon, morning-afternoon and night). At the same time, information was collected from the EPQ questionnaire in order to correlate preferences and the personality dimensions extraversion and neuroticism, and determine the relationship between them. Use of the Morningness-Eveningness Questionnaire (MEQ) produces differential results in the study of individual differences and rhythmicity, and it is a variable which should be considered in studies in this field. Hence the interest in the possible use of the questionnaire in Spanish as a tool for future research. For this purpose we have selected a broad sample of individuals which enables us to generalize about the results, and we have given consideration to sex, age, work schedule and personality traits in the MEQ scores, and their relative priority. The results corroborate the discoveries of previous researchers who studied these parameters separately, and confirm the importance of work schedule and age over personality of the subjects.
Humor research has focused on relationships between humor and various personality traits. As personality and morningness-eveningness, as well as personality and humor, are related based on genetics and neurobehavioral function, one might also expect a relationship between humor and chronotype. 197 students responded to the Composite Scale of Morningness as a measure of chronotype, the Sense of Humor Questionnaire and a 10-item version of the Big Five Inventory. Individuals scoring as evening types reported a greater sense of humor than morning individuals, with higher morningness scores. In a stepwise linear regression, Extraversion, Agreeableness, Openness, and Chronotype each accounted for a significant amount of variance in sense of Humor scores. That is, the relationship between scores on Sense of Humor and evening orientation was significant after controlling for personality dimensions. Eveningness was related to sense of Humor scores in women but not in men. Social but not cognitive humor was predicted by eveningness.
Effects of depression and age on the Horne-Ostberg morningness-eveningness scale in human volunteers were assessed. Thirty-nine healthy outpatients with current DSM-IIIR depression, free of recent substance abuse or confounding medications, were compared to 39 age- and sex-matched controls. Patients reported greater 'eveningness' than controls (P = 0.014, Wilcoxon signed-ranks test). There was multimodality in the distribution of Horne-Ostberg scale scores in the depressed group, but a normal distribution in controls. Pearson's correlation of age vs. Horne-Ostberg score was positive (r = 0.42-0.55). Depression and age influence the Horne-Ostberg score. Potential multimodality of circadian phase in the depressed group deserves further study.
Circadian rhythms, cyclic fluctuations in many physiological and psychological functions, are thought to influence adjustment to shiftwork. A widely acknowledged individual difference in circadian rhythms, commonly called morningness, indicates preferences associated with morning or evening activities. Various self-report instruments have been developed to measure morningness, although little measurement data have been published for these scales. Because morningness scales are being used to select workers for night shiftwork, psychometric evaluations of these scales are needed. Psychometric assessments of undergraduate responses (N = 501) on three widely used scales indicate internal (interitem) measurement deficiencies in all three. Therefore, a 13-item scale was developed that distills the best items from two of these scales. Relationships between the new composite scale and external criteria are comparable with or stronger than similar relationships between the published scales and external criteria.
This article is a survey study, followed by an experimental study, examining the differences of sleep-wake habits and sleep electroencephalographic (EEG) variables between morning and evening type subjects (Ss). In the survey study, the Japanese version of the Horne and Ostberg Morningness-Eveningness Questionnaire and Life Habits Inventory (LHI) were administered to approximately 1,500 university students. The survey results showed that the two types were significantly different from each other in terms of retiring and arising time, sleep latency, mood on arising, nap, adequate amount of sleep, number of times of staying awake all night, and variability in bedtime, arising time, and sleep length. These results suggested that evening type Ss had more irregular and/or flexible sleep-wake habits than morning type Ss. In the experimental study, 10 morning and 11 evening type Ss were selected from the population included in the survey study, and polysomnograms were obtained. The results showed that only in rapid eye movement (REM) latency did morning type Ss significantly differ from evening type Ss. REM latency might be related to personality factors, particularly to neuroticism and anxiety.
Circadian variability in depression has not been well characterized with respect to the "eveningness-morningness" dimension.
The "eveningness-morningness" dimension, as measured by the Home and Ostberg questionnaire, was examined among a student population (n = 1617) that was named as "depressive". Three depression scales (BDI, GDS-SF, and CESD) were used to determine "depressiveness". The Horne and Ostberg questionnaire was used to measure the degree of "eveningness-morningness". It was hypothesized that there would be negative and significant correlations between the scores on the Horne and Ostberg questionnaire and the depression scales. Consequently, it was expected that there would be a significantly higher number of evening types than the morning types among the participants identified as "depressives".
There were significant, negative correlations between the Horne and Ostberg questionnaire scores and the responses on the 3 depression scales (for BDI r= -.174, GDS-SF r= -.182, CESD r = -.176, all p < .001). Also, a significantly higher incidence of evening types than of the morning types among the "depressive" students was found (chi2 = 11.18, p < .01). Limitations: It is uncertain to what extent these data generalize to clinical populations.
"Depressive" college students are more likely to be evening types.
Research examining various psychological correlates of circadian type (also known as diurnal preference) has been, over the years, quite expansive. A notable omission within this research program would appear a systematic exploration of the relation between intelligence and morningness-eveningness. The present study redressed this imbalance. 420 participants performed two self-report inventories assessing circadian type, as well as measures of intelligence from two psychometric batteries: CAM-IV and the ASVAB. The results indicate that, contrary to conventional folk wisdom, evening-types are more likely to have higher intelligence scores. This result is discussed in relation to current theories concerning the nature of human cognitive abilities.
The bipolar dimension of morningness-eveningness refers to the preferred times of day for achieving various activities (i.e. the phase of the circadian clock). It is validated from a biological point of view, associated with at least one gene and heritable through an epistatic mechanism. It has been used as a proxy to study the relationships between the circadian system, personality and psychopathology: there is a correlation between the evening orientation and depression, extraversion and, probably, impulsivity. Furthermore, there is a possible relationship with temperament in children as theorized by Thomas and Chess. In this paper, we expanded on the hypothesis that impulsive subjects are low in morningness by performing a factor analysis of the Composite Scale of Morningness, Cloninger's temperament and character inventory, and Spielberger's trait anxiety inventory in a sample of 129 males. The results can probably be extended to women. Morningness is negatively correlated with novelty seeking (which includes an impulsivity facet), positively correlated with persistence, and independent of character dimensions and trait anxiety. Future research may focus in the involvement of the circadian system in these personality dimensions and facets, and the benefits of adding chronotherapic manipulations in the treatment of the personality disorders.
Between childhood and adulthood, we go through puberty and adolescence. While the end of puberty is defined as the point of cessation of bone growth (epiphyseal closure; girls: 16 y; boys: 17.5 y), the end of adolescence (∼19 y) is defined less clearly, by a mixture of physical, psychological, social, and mental measures [1]. One conspicuous property of adolescence is the apparently unsaturable capacity to stay up late and to sleep in. Investigating ‘chronotypes’ we observed an abrupt change in the timing of sleep at around the age of 20 and propose this change as the first biological marker of the end of adolescence.
The Composite Scale of Morningness (CSM) is a psychometrically sound instrument available in several languages, including French, aimed at arranging individuals along a continuum from high "eveningness" to high "morningness." On the other hand, impulsivity is involved in many personality disorders and is thought to be orthogonal to venturesomeness, which can be seen as a component of the broader construct of sensation seeking. We hypothesized that evening-type subjects would be more impulsive than morning-types. Self-administered questionnaires were distributed to students, and only complete forms were analyzed (194 males and 358 females). A four-way analysis of covariance showed significant effects of age, gender and impulsivity, but not venturesomeness, on morningness in the sense of a higher degree of eveningness in more impulsive subjects. In addition, the correlation coefficients in both genders were similar to those reported in smaller samples. Our findings deserve further interest because, regardless of gender, they suggest a possible physiopathological approach to impulsivity that may be accessible by circadian interventions such as midday bright light exposure or pharmacological treatments.
It has been suggested that being an "evening type" might enhance susceptibility to non-seasonal and seasonal affective disorders (SAD). In a survey and a prospective study, we examine the relationship between mood seasonality and circadian typology. In the survey study, the Morningness-Eveningness Questionnaire (MEQ) and the Seasonal Pattern Assessment Questionnaire (SPAQ) were administered to 1715 university students from Spain and Italy. In the prospective study, 18 subjects, selected from the Italian sample, self-assessed their mood monthly for over a year. A slight but significant negative correlation between the MEQ score and the Global Seasonality Score was found in the survey study, with a significantly higher incidence of evening versus morning types among the students with seasonal depression. These results were not replicated when the Spanish sample was analysed separately. In the prospective study, evening types did not present a higher annual range of mood variations than morning types. Caution should be exercised in ascribing eveningness as a risk factor in SAD since other underestimated factors, including social-cultural conditions, might be involved in the pathogenesis of mood seasonality.
Morningness scales have been translated into several languages, but a lack of normative data and methodological differences make cross-cultural comparisons difficult. This study examines the psychometric properties and factor structure of the Composite Scale of Morningness (CSM) in samples from five countries: France (n = 627), Italy (n = 702), Spain (n = 391), Thailand (n = 503), and Australia (n = 654). Strong national differences are identified. A quadratic relationship between age and CSM total score was apparent in the Australian data with a downward trend after age 35 yrs. There was no age effect in any sample in the range from 18 to 29 yrs. Factor analysis identified a three-factor solution in all groups for both men and women. Tucker's congruence coefficients indicate that: (1) this solution is highly congruent between sexes in each culture, and (2) a morning affect factor is highly congruent between cultures. These results indicate there are national differences in factorial structure and that cut-off scores used to categorize participants as morning- and evening-types should be established for different cultural and age groups.
Individual variation in the phase and amplitude of human circadian rhythms is well known, but the impact of heritable factors on such variation is less clear. We estimated the narrow-sense heritability for selected circadian and sleep timing, quality, and duration measures among related members of the Hutterites, an endogamous, religious community (n=521 participants). "Morningness-eveningness" (M/E), a stable trait reflecting circadian phase, was evaluated using the Composite Scale (CS). Subjective sleep measures were assessed using the Sleep Timing Questionnaire. Initial analyses reconfirmed the impact of age on M/E. Previously reported correlations between M/E scores and the sleep measures were also noted, demonstrating the construct validity of the questionnaires among the participants. Following corrections for age, gender, and colony of residence, significant narrow-sense heritability was noted for M/E (23%). The heritability for subjective sleep measures (related to timing, duration, and quality) were statistically significant for all but one variable, and varied between 12.4% and 29.4%. Thus, significant heritable influences on human circadian phase and subjective sleep indices can be detected through family-based studies. In view of the impact of circadian malfunction on human health, it may be worthwhile to map genetic factors impacting circadian and sleep variation.
Gender differences in morningness eveningness assessed by selfreport questionnaires: a meta-analysis Morningness in German and Spanish students: a comparative study Correlation between morningness–eveningness and final school leaving exams
- C C Randler
- J F Dí-Morales
- C Randler
- D Frech
Randler, C. (2007b, in press). Gender differences in morningness eveningness assessed by selfreport questionnaires: a meta-analysis. Personality and Individual Differences Randler, C., & Dí-Morales, J. F. (2007, in press). Morningness in German and Spanish students: a comparative study. European Journal of Personality. doi: 10.1002/per.632. Randler, C., & Frech, D. (2006). Correlation between morningness–eveningness and final school leaving exams. Biological Rhythm Research, 37(3), 233–239.
Gender differences in morningness eveningness assessed by selfreport questionnaires: a meta-analysis. Personality and Individual Differences Morningness in German and Spanish students: a comparative study
- C Randler
Randler, C. (2007b, in press). Gender differences in morningness eveningness assessed by selfreport
questionnaires: a meta-analysis. Personality and Individual Differences
Randler, C., & Díaz-Morales, J. F. (2007, in press). Morningness in German and Spanish students: a
comparative study. European Journal of Personality. doi: 10.1002/per.632.
Morningness-eveningness dimensions: Is it really a continuum? Personality and Individual Differences
- V Natale
- P C Cicogna
Inter-individual differences in the human circadian system: a review
- G Kerkhof
- G. Kerkhof
Kerkhof, G. (1985). Inter-individual differences in the human circadian system: a review. Biological Psychology, 20, 83-112.