To lay the theoretical foundation for the present research, an extensive literature review for all the involved concepts and variables shall be conducted. It is necessary to do so, to clarify what is meant with each term and also illustrate the results of prior research efforts in the respective domains. Firstly, the dependent variable will be looked at and followingly the independent variable will be talked about. In a next step, the two variables will be looked at together, meaning it will be reviewed if and how previous research combined both elements in a single study and what these findings imply for the research at hand. As a result of this review, first hypotheses can be established. Followingly, the mediator variable will be introduced, which will enable us to further add to our hypothesis. Next, the moderator variables will be illustrated, which will allow for a further hypotheses. Lastly, drawing from past research, we will introduce control variables, which will help us to eventually achieve more concise research findings.
Work Engagement
It was not until the recent decade, that the concept of work engagement has started to attract increasing research interest (Sonnentag, 2011). The rising interest is likely to be explained twofold. Firstly, it can be explained by the increased focus on research surrounding
“Positive Psychology” instead of negative concepts. For example, prior research focus was directed more on “engagement’s” negative counterpart issue, burnout (Schaufeli, Salanova, González-romá, & Bakker, 2002). Second, the rising importance of employee’s psychological connection with their job, created a need for more research in the field. In the modern economy, companies rely heavily on this connection, to foster the full potential and capabilities of their employees, and ultimately gain a competitive edge (Bakker & Leiter, 2010).
Connected to the above-mentioned rise in research, is the emergence of a wide variety of different takes on the specifics of the concept “engagement”. Therefore, although the term engagement has become quite popular and is widely used throughout various literature, it is important to note that there exists no universally agreed-upon definition for the term.
The first time the concept “engagement” in a business context, received a scholarly definition was towards the end of the last century. Kahn (1990) defined engagement at work as the “harnessing of organization members’ selves to their work roles: in engagement, people employ and express themselves physically, cognitively, emotionally and mentally during role performances”(p. 694). The above definition emphasizes that engaged employees identify with
their job on several layers, which allows them to perform without any cognitive dissonance.
The importance of this psychological connection, is once again emphasized by Kahn in a later publication, where he elaborates that engagement can be considered as a result of psychological presence at work. (Kahn, 1992) It is important to highlight that Khan examined engagement in relation to an employee’s job role. Later scholars, who still draw on Kahn’s work, changed their perspective and focus specifically on an employee’s work activity (Maslach, Schaufeli, &
Leiter, 2001; Schaufeli et al., 2002). These scholars examine work engagement as the counterpart of burnout and accordingly consider engaged employees “characterized by energy, involvement, and efficacy.”(Maslach et al., 2001, p. 416) Three distinct dimensions, constituting work engagement were established, which have proven to be widely agreed upon to be vital to constitute the term. These three aspects are vigor, dedication and absorption (Schaufeli et al., 2002; Schaufeli & Bakker, 2010). Therefore, for the remainder of this work, the following definition of the term work engagement is utilized. Work engagement describes
“a positive, fulfilling, work-related state of mind that is characterized by vigor, dedication, and absorption” (Demerouti & Bakker, 2008; Schaufeli et al., 2002, p. 74).
Studies about work engagement have found compelling evidence for the importance of the construct in today’s business world. Employees with high levels of work engagement were repeatedly found to perform better at their job (Halbesleben & Wheeler, 2008; Salanova et al., 2005). More specifically, further studies found, that engaged employees tend to exhibit higher levels of creativity and productivity as well as commitment to their organization (Demerouti &
Bakker, 2008). Additionally, it was found, that work engagement has not only benefits of temporary nature, such as allowing employees to perform better in the present, but also valuable long term consequences, such as higher life satisfaction and a decrease in ill-health (Shimazu, Schaufeli, Kamiyama, & Kawakami, 2015).
Employee Chronotypes / Morningness
Although research interest and initiatives about the concept of Morningness-Eveningness or Chronotypes has only started to increasingly gain popularity in the recent decade, the concept itself was already discovered and started to be examined in the second half of the 20th century. Both the above mentioned terms refer to individual’s circadian rhythm, or in other words, biological clock. The circadian rhythm is a biological process describing an individual’s tendency to sleep and be active during certain time frames throughout a 24-hour window (Adan et al., 2012; Tankova et al., 1994; Vink, Vink, Groot, Kerkhof, & Boomsma, 2001). Depending on when an individual experiences the highest levels of alertness throughout
the day he is classified to belong to a specific chronotype or morningness-eveningness dimension. Generally, three distinct categories are differentiated which are used to classify an individual as either a morning, neutral or evening person (Adan et al., 2012). Since these chronotypes are typically assessed by utilizing a continuous scale, scholars also refer to the degree of morningness in a person. The higher the degree of morningness, the more clearly the person can be classified as a morning person.
One of the first tools created to measure these dimensions is the Morningness-Eveningness Questionnaire (MEQ), which was developed in the 1970s by Horne and Östberg.
(Horne & Ostberg, 1976) The developed questionnaire for the first time allowed to scientifically assess these dimensions and conduct research on the topic. Since then also other measurement tools have been developed, which are commonly used to conduct research in this field, such as the Munich Chronotype Questionnaire (MCTQ) and the Composite Scale of Morningness (CSM) (Roenneberg, Wirz-Justice, & Merrow, 2003; Smith, Reilly, & Midkiff, 1989). While all these tools represent valid methods to measure individuals’ circadian rhythms, there exist some difference between the different measurement tools. For instance, the MCTQ was found to collect additional information on sleep-wake behavior under natural conditions. (Zavada, Gordijn, Beersma, Daan, & Roenneberg, 2005).
Most of the present research involving individuals’ preferences for certain sleeping patterns, focuses on topics belonging to the fields of medicine or psychology. Several studies have found links between chronotypes and behavioral problems as well as general life satisfaction and physical health. (Gau et al., 2007; Randler, 2008a, 2011b; Susman, Dockray, Schiefelbein, Herwehe, Heaton, & Dorn, 2007) However, with the increasing popularity of research surrounding chronotypes, more studies emerge inspecting general and transferable traits such as cognitive performance or academic and career success.(Beşoluk, Önder, & Deveci, 2011; Preckel, Lipnevich, Schneider, & Roberts, 2011; Randler & Frech, 2009; Vollmer et al., 2013) Additionally, few studies try to explore how a chronotype could affect the role of individuals as employees. However, mentioned research only examined general perceived employability of individuals (Sõõru, Hazak, & Rebane, 2018)
The above-mentioned traits are naturally of particular interest to businesses, since they are closely related to employee performance and therefore potential monetary gains for a company. While some first research links certain chronotypes or more specifically morningness, to career boosting personality traits such as proactivity (Bakker et al., 2012; Randler, 2009), the specific influence of chronotypes on employees at the workplace remains largely unresearched.
Work Engagement & Sleeping Patterns
Research examining the relationship between sleep patterns and work engagement remains very little to almost non-existent. While a validation study of work engagement discovered a moderate relationship between sleep disturbances and work engagement (Hallberg
& Schaufeli, 2006), the specific reasons behind this correlation were not explored. Another study focused on examining a link between sleep hygiene and work engagement, but didn’t put its focus on employee’s chronotypes (Barber, Grawitch, & Munz, 2013). Consequently, there still exists a big need for research combining the concepts of work engagement and employee chronotypes.
The relationship between employee chronotypes and work engagement is particularly interesting to research, as it might be able to explain how employees with a morning chronotype achieve higher levels of success at the workplace, as discovered in prior research (Yam et al., 2014). Work engagement could constitute the missing link between the belongingness to a certain chronotype and performance at the workplace. The suspected higher level of work engagement among morning chronotype employees could be explained by morning people reaching their peak cognitive performance early in the day during the traditional work hours, whereas evening employees reaching their peak cognitive performance levels only after traditional work times have already ended (Dijk, Duffy, & Czeisler, 1992).
Since work engagement and morningness are both linked to similar personality traits, such as proactivity (Bakker et al., 2012; Randler, 2009), the relationship between the two variables is highly likely to be positive.
Consequently, H1 and H2 can be stated as follows:
H1: Morningness is positively related to work engagement.
H2: Employees with a Morningness-Chronotype experience higher levels of work engagement than Evening-chronotype employees.
Job Satisfaction
With the backing of a large body of research, job satisfaction is considered one of the most comprehensively researched concepts in industrial and organizational psychology (Spector, 1997). While this notion indicating the importance of the concept already held true towards the end of the last century, it still continues to play an important role in human resource
related research today. This can be largely attributed to the construct’s self-explanatory nature as well as clear importance for companies looking to retain their human capital. While the term job satisfaction is readily understood by people in and outside of academia, its academic definition and understanding used in this study, should still be pointed out. Originally, job satisfaction was defined as “the pleasurable emotional state resulting from the appraisal of one’s job as achieving or facilitating the achievement of one’s job values” (Locke, 1969, p. 316). To further simplify, job satisfaction expresses the degree to which employees like their jobs (Spector, 1997). As research surrounding the concept increased, several causing factors for the occurrence of job satisfaction (Connolly & Viswesvaran, 2000; Judge, Thoresen, Bono, &
Patton, 2001; Loher, Noe, Moeller, & Fitzgerald, 1985) as well as work behaviors resulting out of the existence of job satisfaction have been established (Bakotić, 2016; Judge et al., 2001; Lu et al., 2016; Tett & Meyer, 1993).
Morningness, Job Satisfaction & Work Engagement
Similarly, to work engagement, job satisfaction has only been researched very scarcely in relation to morningness. However, due to job satisfaction being a concept positively correlated to work engagement (Alarcon & Edwards, 2011; Lu et al., 2016; Yeh, 2013), similar conclusions can be drawn. As hypothesized above, people high in morningness are personality and behavior wise more likely to experience high levels of work engagement. Consequently, people with high levels of morningness should also be more likely to exhibit higher levels of job satisfaction. To support this notion, a previous study already found that the higher the morningness among employees, the higher the job satisfaction (Moreno et al., 2012).
Considering the implications of this finding, evening-type employees should experience significantly lower levels of job satisfaction compared to their morning-type employee counterparts.
Consequently, H3 can be stated as follows:
H3: Employees with a Morningness-Chronotype experience higher levels of job satisfaction than Evening-type employees.
The relationship between job satisfaction and work engagement remains unclear. While the positive relationship between the two constructs is well-established (Alarcon & Lyons, 2011;
Garg, Dar, & Mishra, 2018; Lu et al., 2016; Yeh, 2013), it isn’t clear which concept precedes which in a work setting. Reason for that is likely the close relationship found between those
concepts. The close relationship even led to research examining if the two concepts are in fact separate constructs (Alarcon & Lyons, 2011), which was confirmed. While previous research generally followed the notion, that job satisfaction is the result of work engagement (Alarcon
& Edwards, 2011; Andrew & Sofian, 2012; Lu et al., 2016; Maslach et al., 2001; Saks, 2006;
Yeh, 2013) , other studies discovered, that job satisfaction could very well also be a predictor for work engagement (Abraham, 2012; Johnson, 2000; Macey, Schneider, Barbera, & Young, 2011; Singh, 2017). Since the possible predictive nature of job satisfaction on work engagement is a rather counterintuitive finding, it has led to a call for more research across different populations and backgrounds to gain a clearer understanding. The present research aims to follow this call and therefore wants to examine whether job satisfaction acts as a mediator in the relationship between morningness and work engagement.
Consequently, H4 can be stated as follows:
H4: Job satisfaction mediates the relationship between morningness and work engagement.
Big Five Personality Dimensions
The big five personality dimensions shall be used as a moderator in the investigation of the relationship between employee chronotypes and work engagement. The big five personality dimensions, stemming from the Big Five Model introduced and popularized by John, Costa &
McCrae (1990; 1992), are Extraversion, Conscientiousness, Agreeableness, Neuroticism and Openness to Experience. Some earlier studies have already started to investigate potential connections between the “Big Five” personality dimensions and chronotypes (DeYoung, Hasher, Djikic, Criger, & Peterson, 2007; Hogben, Ellis, Archer, & Schantz, 2009; Randler, 2008b). While mentioned studies were conducted in different countries with different populations and naturally produced different results, all of those studies found convincing evidence, that Morningness was associated with higher levels of Agreeableness and Conscientiousness.
Further, Agreeableness is likely to positively influence high levels of work engagement, as a person high in Agreeableness tends to avoid conflicts and is motivated to maintain harmonious relationships with their peers (Gleason, Jensen‐Campbell, & Richardson, 2004).
Consequently, mentioned persons are likely to fully dedicate themselves to their tasks at work.
As a result, Agreeableness should act as a moderator that strengthens the positive relationship between morningness and work engagement.
Especially Conscientiousness could constitute an interesting moderator for the research at hand as it was not only repeatedly found to be linked to morningness but also traits closely related to work engagement. Conscientiousness was found to be a consistent predictor for performance across various situations at work (Barrick, 2005). Employees with high levels of Conscientiousness tend to exhibit positive work related behavioral traits such as being well-organized, goal oriented, hard-working and highly motivated (Costa & McCrae, 2008). Since these behavioral traits are highly indicative of high levels of work engagement, it can be assumed that Conscientiousness is likely to significantly impact mentioned concept. Previous conducted research supports this notion, by finding that Conscientiousness contributes to higher levels of performance by boosting work engagement (Bakker, Demerouti, & ten Brummelhuis, 2012)
Conscientiousness linking the two previously unrelated concepts of employee chronotypes and work engagement should therefore result in being a moderator that is strengthening the positive relationship between morningness and work engagement.
Also, the personality dimension Neuroticism, is likely to have a significant impact on the relationship between morningness and work engagement. Previous research indicated, that people with low scores in the Neuroticism dimension, or in other terms with high emotional stability, are morning people (DeYoung et al., 2007). Additionally, it should be assumed that people, who are considered to be emotionally stable, find it easier to enter a positive, work-related state-of mind, which constitutes the basis of high levels of work engagement (Demerouti
& Bakker, 2008; Schaufeli et al., 2002). This is congruent with previous findings in this area of research, that state that low level of Neuroticism are connected to higher levels of work engagement (Langelaan, Bakker, van Doornen, & Schaufeli, 2006). Consequently, the personality dimension Neuroticism should act as a moderator that is weakening the positive relationship between morningness and work engagement.
The impact of the personality dimension, Extraversion, is a bit more challenging to hypothesize, due to mixed findings surrounding the concept. While older research has found links between Extraversion and eveningness (Adan, 1992; Neubauer, 1992), more recent research couldn’t replicate these findings (DeYoung et al., 2007; Jackson & Gerard, 1996;
Randler, 2008b). However, looking at previous studies, investigating the links between Extraversion and work engagement, credible support for a positive association between the two concepts has been found (Langelaan et al., 2006). Consequently, Extraversion should constitute a moderator, which strengthens the positive relationship between morningness and work engagement.
Similar, to Extraversion, Openness to new experience also hasn’t been consistently linked to either the dependent or independent variable of this study. While some prior research simply couldn’t detect a significant relationship with chronotype or work engagement (Kim, Shin, & Swanger, 2009; Randler, 2008b), other more recent research did find a positive association between Openness to new experience and work engagement (Woods & Sofat, 2013;
Zaidi, Wajid, Zaidi, Zaidi, & Zaidi, 2013). Although not consistently found, this connection seems reasonable, as people scoring high in this dimension are often connected to traits such as being intelligent and creative in their problem solving approach (John, 1990), which should allow them to easily reach a mental state as described under work engagement. Consequently, Openness should constitute a moderator, which strengthens the positive relationship between morningness and work engagement.
Consequently, H4 to H8 can be stated as follows:
H5: Agreeableness strengthens the positive relationship between morningness and work engagement.
H6: Conscientiousness strengthens the positive relationship between morningness and work engagement.
H7: Neuroticism weakens the positive relationship between morningness and work engagement.
H8: Extraversion strengthens the positive relationship between morningness and work engagement.
H9: Openness to new experience strengthens the positive relationship between morningness and work engagement.
It is important to note, that the above-mentioned studies, examining the connections between the “Big Five” personality domains and chronotypes, were almost completely conducted in western cultures and populations. Thus, the research at hand, which is focusing on an Asian population, will provide valuable insights on whether there exist any cultural differences or if the previous found results can also be confirmed in the present sample.
Control Variables
To be able to draw a true, cause-effect relationship about the above outlined variables, certain control variables in the hierarchical regression analysis will be used. Firstly, the variable age will be controlled for. A large body of research has found evidence for the effect of age on
an individual’s chronotype. More specifically, there exists a well-observed correlation between increasing age and morningness (Adan et al., 2012; Kim, Lee, Kim, Cho, Lee, & Cho, 2010;
Merikanto, Kronholm, Peltonen, Laatikainen, Lahti, & Partonen, 2012). Gender will serve as a second control variable for the present investigation. Throughout several studies a difference between men and women has been observed regarding their chronotype (Adan & Natale, 2002;
Caci, Deschaux, Adan, & Natale, 2009; Randler, 2011b). Women were more frequently found to belong to a morning chronotype while men belong more often to an evening chronotype.
Lastly, when testing the moderating effect of personality dimensions on the relationship between morningness and work engagement, with the help of a hierarchical regression, job satisfaction is controlled for to avoid any confounding effect. At this point, it is important to point out, that the variable job satisfaction is both used as a control variable as well as a mediator.
This can be done, since Moderation and Mediation analysis in this study are run separately.