Introduction
The functioning of the human body depends on numerous factors because of its complexity. It can be represented as a sophisticated system impacted by various aspects and depending on their change. An enhanced understanding of how these factors might promote specific changes in the body’s work and influence a person is vital for the increased quality of life and higher productivity levels. Thus, the circadian rhythm is one of the fundamental concepts regulating the life of a person. The sleep-wake cycle and its repetitions establish the basis for human activities and people’s ability to achieve planned goals. It also means that the concepts of morningness and eveningness acquire the top priority as they describe specific behavioral patterns of an individual, peculiarities of his/her biological and psychological processes, and activity peaks. For this reason, numerous attempts are made to analyze these phenomena and acquire an enhanced vision. There is also a tendency to consider morningness and eveningness as a single construct, which becomes an issue for disputes.
Circadian Rhythms
A person’s circadian rhythm, or so-called biological clock, has always been an issue for discussion and investigation. Researchers have always been trying to determine the correlation between physical time and activity peaks peculiar to various individuals (Harvey et al., 2014). It is also linked to the sleep-wake cycle originating within an organism and depending on various factors influencing individuals’ preferences linked to rest and activity periods. The differences in these patterns result in the emergence of early birds and night owls, or people who are most active at night or during day hours. The given cycles are usually associated with the body temperature peaks and other changes in the physiological processes (Miyazaki et al., 2018). At the same time, a better understanding of the cycle requires in-depth research and work with representatives of these two cohorts. That is why the concepts of morningness and eveningness acquire the top priority.
Morningness
As stated previously, some individuals are more active during the daytime or morning periods. For this reason, the concept of morningness is used to describe this cohort. It refers to individuals who have preferences for morning or daytime activities (Roy et al., 2021). They do most of their tasks during the early hours, which is also linked to the changes in their body temperatures (Roy et al., 2021). The assessment of diurnal preferences or timing of sleep is usually performed using specific questionnaires promoting a better vision of how individuals spend their days and the peculiarities of their circadian cycles (Zielińska et al., 2021). Thus, there is also research showing the correlation between morningness and specific preferences, features, and abilities of a person (Zielińska et al., 2021). For instance, morning-type individuals are less pessimistic, have lower stress or depression levels, and demonstrate better school performance (Zielińska et al., 2021). It means that the biological clock might influence various activities and play an essential role in people’s lives and careers.
Eveningness
Eveningness is another concept introduced to describe specific preferences regarding sleep-wake patterns. In general, the term can be defined as the individual’s preference for being most active and alert during late hours or in the evening (Roy et al., 2021). It is also linked to biological rhythms and body temperature. Investigations show that people with this characteristic have a tendency toward the growth of their temperature during the second half of the day and show more interest in various activities (Ágoston et al., 2019). This pattern of sleep-wake distribution also influences personal features, reactions, and preferences. For instance, the evening type individuals more often have sleep and mood problems, irregular wake habits, and are more addicted to caffeine (Ágoston et al., 2019). It means that the given peculiarity of the circadian cycle becomes an essential step towards a better understanding of individuals, their psychology, and behaviors.
Thus, the distribution of time for activity and rest regarding the period forms the circadian preference of an individual and his/her specific reactions. The existing body of evidence shows that morning and evening types have specific preferences and personality types. The first category is usually more open, while the second one prefers loneliness and isolation (Ágoston et al., 2019). Moreover, there are other factors linked to the specific characteristics of these issues. In such a way, the enhanced understanding of morningness and eveningness is necessary for various fields, including psychology, biology, and medicine. That is why there are also numerous debates about the topic and how it should be treated.
Single Construct
From the definitions, it is also possible to understand that morningness and eveningness can be viewed as two aspects of a sleep-wake cycle. For this reason, there is a tendency toward seeing these issues as a single construct that is critical for understanding behavioral patterns, the psychology of individuals, and changes in their biological rhythms (Miyazaki et al., 2018). The existing questionnaires focus on researching the morningness-eveningness dyad by collecting information about sleep and activity patterns and processing it to acquire a better understanding of how a person behaves (Miyazaki et al., 2018). In such a way, by merging these two concepts, researchers start to view them as a single entity and acquire new opportunities to investigate their impacts. At the same time, there are also some disadvantages linked to the given perspective on the two concepts that should also be considered to realize possible barriers for further investigation and research.
Advantages and Disadvantages
As stated previously, there are some advantages linked to considering morningness and eveningness a single construct. First of all, it provides researchers an opportunity to conduct research in the given field, focusing on two aspects simultaneously. For instance, Lipnevich et al. (2017) delve into the correlation between the given dyad and the Big Five factors of personality. In the study, they research both characteristics and how they impact such features as openness, extravert, or introvert patterns (Lipnevich et al., 2017). Moreover, viewing morningness and eveningness as a single construct helps to develop unified tools necessary for investigating the sleep-wake cycle and discussing results. In such a way, the given decision can be viewed as a step promoting in-depth research in the given field and offering new chances for investigators.
At the same time, there are also some important disadvantages of considering these two issues as a single construct. For instance, Lipnevich et al. (2017) conclude that morningness and eveningness have different influences on the factors of personality. The first one is linked to extrovert behavioral patterns, while the second one correlates with introvert preferences (Lipnevich et al., 2017). It proves that these circadian preferences influence individuals differently and promote the emergence and development of various responses. For this reason, it is vital to consider and investigate both these aspects separately instead of focusing on a single construct. Otherwise, the scope of research will be too broad, and researchers will face numerous challenges when conducting the study. The attempt to work with the broader audience and investigate numerous factors at the same time might deteriorate outcomes and reduce their credibility. For this reason, it is necessary to consider this aspect when speaking about merging the ideas of morningness and eveningness into a single construct.
Conclusion
In such a way, the discussed concepts are essential for a better understanding of sleep-wake patterns and their influence on individuals’ behaviors, psychology, and major personality traits. The research by Lipnevich et al. (2017) shows that morningness and eveningness impact academic activity, conscientiousness, and personality traits. At the same time, it is vital to continue investigation of the given field to ensure new data demonstrating how circadian preference and specific chronotype influence individuals and their functioning in different situations. However, I believe that better results can be attained if these two aspects are viewed as different constructs that should be researched separately.
My assumption rests on several factors linked to the circadian cycle and its investigation. First of all, the analyzed sources show that morningness and eveningness are broad concepts affecting individuals in their own ways. Moreover, the scope of differences is significant, and much effort is needed to understand what traits and characteristics emerge under the influence of these factors. For this reason, it is necessary to conduct studies focusing on these aspects separately. Second, although creating a single construct offers opportunities for using unified research tools, the results might be too broad and require additional clarification. For this reason, I believe it is necessary to view morningness and eveningness as two different constructs.
References
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Harvey, C. J., Gehrman, P., & Espie, C. A. (2014). Who is predisposed to insomnia: a review of familial aggregation, stress-reactivity, personality and coping style.Sleep Medicine Reviews, 18(3), 237–247.
Lipnevich, A. A., Credè, M., Hahn, E., Spinath, F. M., Roberts, R. D., & Preckel, F. (2017). How distinctive are morningness and eveningness from the Big Five factors of personality? A meta-analytic investigation.Journal of Personality and Social Psychology, 112(3), 491–509.
Miyazaki, R., Ando, H., Hamasaki, T., Higuchi, Y., Oshita, K., Tashiro, T., & Sakane, N. (2018). Development and initial validation of the Morningness-Eveningness Exercise Preference Questionnaire (MEEPQ) in Japanese university students. PloS One, 13(7), e0200870.
Roy, C., Monsivais, D., Bhattacharya, K., Dunbar, R., & Kaski, K. (2021). Morningness-eveningness assessment from mobile phone communication analysis. Scientific Reports, 11(1), 14606.
Zielińska, A., Stolarski, M., & Jankowski, K. S. (2021). Moral foundations in chronotypes: morningness predicts conservative morality.Chronobiology International, 38(8), 1143–1150.