2.1. Emotional Intelligence as Research Theory
Researchers have studied the concept of intelligence and emotions for many years. Certain emotions may support certain types of thinking. In this sense, positive emotions can generally lead to better decision-making and increase productivity [
18,
19]. The concept of emotional intelligence was introduced to the literature by Mayer [
20,
21]. Both intelligence and emotion are active in all mental processes. In a way, emotion and intelligence are in a mutual relationship in mental activities [
22]. Emotional intelligence has been defined as a type of intelligence that includes the ability of individuals to observe and understand their own and others’ emotions and to use their emotions as a guide to their behavior [
23,
24]. To be qualified as emotionally intelligent, individuals must be skilled in defining, understanding, using, and regulating their emotions [
25,
26]. Goleman defines emotional intelligence as being able to take action, move on despite problems, control impulses, regulate mood, control negative thoughts, empathize, and hope [
27]. Bar-on considered emotional intelligence as non-cognitive intelligence and described the term (EI) as a set of emotional, personal, and interpersonal talents, skills, and abilities that influence one’s capacity to deal with daily challenges [
28]. Emotional intelligence is regarded as the whole of interrelated emotional competencies, skills, and facilitators that determine how much we understand and express ourselves, how we understand and relate to others, and our capacity to cope with problems [
29].
Emotional intelligence enables individuals to understand and evaluate their own and other people’s emotions and use information about emotions effectively in daily and professional life. Accordingly, persons can be classified as “emotionally intelligent” if they can control their emotions as they like and accomplish the required results in their professional or private lives [
30,
31]. Thanks to emotional intelligence, the development of individuals’ thoughts are ensured by reasoning about emotions [
17]. Hence, the basic assumption under the concept of emotional intelligence is the capability to take into account, organize and express emotions and analyze the emotions of others correctly. Furthermore, a person’s resilience in the face of rapid changes and problems and the ability to cope with them. Emotional intelligence enables people to deal with adversity such as COVİD-19 pandemic conditions by strengthening their decision-making abilities, communication skills, and psychological resilience [
16]. It serves as a basis for developing feelings in a healthy manner, allowing individuals to manage different circumstances effectively and thus also helps relieve post-traumatic stress disorders (PTSD) [
14,
15,
32].
2.2. Emotional Intelligence and Depression
The literature reveals that emotional intelligence is a coping trait for physical and mental disorders such as depression, anxiety, and stress [
33,
34,
35,
36,
37]. Depression is a disease that is very common among people, may differ with age, and is characterized by changing symptoms [
38,
39]. It has a symptom cluster that can occur in a wide range, from normal sadness to severe psychotic symptoms [
40]. Individuals suffering from this condition have difficulty performing normal daily activities. Their social and occupational functionality is impaired, appetite deterioration and sleep problems are observed, attention may decrease, and slowness in thinking may be experienced. In addition, symptoms such as self-harming behaviors, suicide attempts, reduced libido, pessimism, guilt, and decreased self-confidence can be seen. There are some social, economic, emotional, and biological reasons for the emergence of depression. For example, age, gender, race, marital status, social environment, socioeconomic level, negative life experiences, loss of a loved one, family problems, and physical problems affect depression levels in individuals [
41].
Emotional intelligence empowers the fight against many individual and social problems. Emotional intelligence strengthens the fight against addiction by increasing individuals’ emotion and problem-focused coping skills [
42]. Similarly, studies in the literature show that there is a relationship between emotional intelligence and depression. Many studies have found that emotional intelligence reduces depression [
43,
44,
45,
46]. A study found that students who could not physically go to school during the COVID-19 period in India used their emotional intelligence capacity to cope with the educational problems they experienced [
47]. Since EI is higher in women than in men, an increase in EI does not cause a decrease in depression in women as much as in men [
43]. While a study found a negative relationship between emotional intelligence and depression, the moderator effect of gender was found in the relationship. While low emotional intelligence led to higher depression in men, the same result did not occur in women [
48]. A high level of emotional intelligence was connected to reduced levels of anxiety and depression and improved social and physical health levels in studies of university students and adolescents in Spain [
49,
50]. Emotional intelligence may reduce not only depression but also suicidal thoughts and behaviors. A study conducted among nursing students found a negative relationship between emotional intelligence and suicidal ideation and suicide risk, which emerge with depression and stress [
51]. Another study conducted with nursing students found that emotional intelligence minimized the students’ stress levels, and thus their perceived social support and mental health status were better [
52]. There are similar results in many studies in the literature [
53,
54,
55]. A study conducted with the elderly in the USA observed that as emotional intelligence increased, the risk of being exposed to depression decreased. Therefore, the rising emotional intelligence made a beneficial contribution to the current depression of the elderly over the age of 65 [
56]. Emotional intelligence was higher, especially in the elderly; therefore, it helps alleviate depression more quickly [
56].
Furthermore, many studies have found an association between emotional intelligence and chronological age. A study conducted with 405 Americans aged 22–70 found a slightly significant positive relationship between emotional intelligence and age. The research found that older people had higher emotional intelligence than younger people. The findings reflected that emotional intelligence is the sum of the developmental skills acquired from the experiences encountered in life [
57]. Kafetsios discovered age-related changes in emotional intelligence capacities. The emotional intelligence of older respondents was higher [
58]. Similarly, many studies have found a positive relationship between age and emotional intelligence [
59,
60,
61]. However, there have also been studies that did not show a significant relationship between age and emotional intelligence, albeit very few [
62,
63]. Many studies revealed the association between socioeconomic environment and emotional intelligence. Studies observed that those with low socioeconomic status had lower education, health, and psychological resilience due to high risks, and therefore lower emotional intelligence [
64,
65,
66,
67]. However, it was also seen that as socioeconomic status increases, individuals’ emotional intelligence decreases because they are less dependent and less motivated to identify their feelings of struggling with difficulties [
68,
69,
70]. Studies have shown that low socioeconomic status reduces self-esteem, which gives individuals the ability to cope with problems [
71]. As a result, these individuals may have low emotional intelligence by experiencing emotional instability in life [
63]. According to the literature, the following hypotheses were proposed.
Hypothesis 1 (H1). Emotional intelligence has a negative relationship with depression.
Hypothesis 2 (H2). Age and emotional intelligence have a positive relationship.
Hypothesis 3 (H3). SES and emotional intelligence have a positive relationship.
2.3. Emotional Intelligence, Satisfaction with Life, and Depression as Mediator
Life satisfaction evaluates one’s life according to subjectively determined standards [
72,
73]. This concept is related to subjective well-being, which is defined as individuals’ emotional and cognitive evaluations of their lives [
12,
74,
75]. Thus, life satisfaction is the state of taking pleasure from life, finding life meaningful, and evaluating people’s lives positively in accordance with their own criteria [
75,
76,
77]. Life satisfaction differs from person to person. Factors such as health status, working life, economic level, psychological quality, education level, social environment, religion, spirituality, and perspective on the meaning of life affect satisfaction with life. People with high satisfaction with life may have the following attitudes [
12,
73,
78,
79]:
Enjoying activities in their daily life;
Having meaning and purpose in life, accepting the responsibilities of the past;
Having the belief that they can achieve the goals;
Accepting themselves as a valuable asset;
Expecting to be optimistic about life.
Emotional traits are an important influence in enhancing persons’ cognitive evaluations of their own life satisfaction [
80,
81,
82,
83]. Studies conducted with university students examined the relationship between emotional intelligence levels and life satisfaction and found a positive and significant relationship between them [
84,
85]. In another study, emotional intelligence was positively associated with psychological well-being or life satisfaction measures and negatively with indicators of psychological disorders [
36]. A negative relationship between life satisfaction and depression was also found [
86,
87]. Many studies determined that depression reduces satisfaction with life, and a negative relationship was revealed between them [
77,
86,
88,
89]. Moreover, the current literature has confirmed that the level of satisfaction with life decreased with the increase of depression of all segments of society, especially during extraordinary periods such as the COVID-19 pandemic [
90,
91,
92].
Hypothesis 4 (H4). Emotional intelligence has a positive effect on satisfaction with life.
Hypothesis 5 (H5). Depression has a negative effect on satisfaction with life.
While emotional intelligence is used as an independent variable in many studies, it is used as a mediator and moderator variable in some [
93,
94,
95,
96]. A study conducted by Magnano et al. [
97] revealed that individuals who better understand, access, and regulate their emotions are better at dealing with and adapting to challenging situations. According to some findings, the association between emotional intelligence and life satisfaction may be mediated by mental factors [
26,
98]. Moreover, due to the negative effect of emotional intelligence on psychological outcomes, stress and depression are used as mediators in many studies involving emotional intelligence [
26,
37,
99,
100]. Similarly, research revealed a significant role for depression as a mediator in the association between emotional intelligence and suicide risk in bullying victims [
101]. Studies showed the favorable association of emotional intelligence with life satisfaction. Furthermore, a significant link to life satisfaction from emotional intelligence via stress by controlling demographics was found in surveys [
37,
102,
103]. As a result, it is considered that emotional intelligence will lower the risk of depression and boost life satisfaction.
Hypothesis 6 (H6). Depression has a mediating impact on the effect of emotional intelligence on satisfaction with life.
2.4. Age and Family Type as Moderators
The relationship between satisfaction with life, depression, and age varies according to the studies. In some studies, there is no significant relationship between age and satisfaction with life and depression while there is a significant relationship in others. A person may have different expectations, activities, and challenges that may influence life satisfaction and depression in each period [
75,
77,
104]. Therefore, it is possible to have different life satisfaction and depression in different life periods. Contrary to expectation, in a study conducted with 3287 people during the COVID-19 pandemic period, the depression levels of young people were significantly higher than the elderly due to not being able to go to school, increased career anxieties, and inability to socialize [
84]. Although the pressure on young people increases during the COVID-19 pandemic, generally, young people are exposed to intense depression between the ages of 20–24, and depression decreases as age increases [
105,
106]. However, when health-related problems rise, depression increases significantly in the elderly. Depression may be caused by phenomenological differences between older and younger people and the link between age and psychomotor development [
107]. Physical sickness, life experiences, lack of social support, and isolation are linked to depression, the most prevalent but treatable psychological disorder in senior years [
108,
109]. Adolescence is a developmental period that is marked by significant physical and psychological changes. Therefore, decline in life satisfaction during adolescence must be viewed as a developmental process [
110]. In a study conducted with students, a negative correlation was found between age and satisfaction with life. However, no significant relationship was found in the sample in the same study, with no upper age limit obtained on the internet [
111]. There are studies in the literature that find that satisfaction with life increases as age advances [
112,
113].
There may be differences between extended and nuclear family structures regarding family resources, parental support, communication opportunities between family members, use of financial resources, and socioeconomic status [
114]. Extended families are expected to have less material and more interaction opportunities, whereas the opposite is expected in nuclear families. The number and quality of contacts between family members can have an impact on their personalities and psychologies. Individuals adapt their own emotions and behaviors in line with their social environment, parents’ expectations, and the quality of their emotionality, attitudes, and relationships with their parents [
115]. The extent and nature of the interactions between family members may affect individuals’ characters and psychologies. Therefore, emotional intelligence, depression, and satisfaction with life may vary according to the family structures of individuals. A study conducted in Pakistan found that a suitable family environment with cohesiveness, supportive and caring family atmosphere, parents’ education levels, and children’s networks of friends positively correlated with emotional intelligence [
115]. Studies found no difference in emotional intelligence between nuclear and extended family members [
116,
117]. Emotional intelligence was lower in broken, authoritarian, and neglectful families than in nuclear, extended, and democratic families [
118]. In studies, fewer mental problems were discovered as the family grew. In this sense, mental health issues are mostly observed in single-parent families, then nuclear and lastly extended families [
119]. In extended families with good parent and grandparent relationships and support, it was observed that family members have less depression and higher life satisfaction when their problems are shared [
120,
121,
122,
123].
There are studies with different results. Investigations revealed that intact and nuclear family members had fewer psychological symptoms than extended family members in Sweden [
124,
125]. Family size, life satisfaction, and depression may vary according to society. For example, those living in extended families may have preferred to live in a nuclear family if they migrated to other countries and married [
126]. Other studies observed that life experiences and relationships in the family impact depression and the life satisfaction of individuals [
127,
128,
129,
130]. In a study conducted in Turkey, depression and life satisfaction of individuals did not differ according to extended and nuclear families [
131]. A study in Pakistan found the depression of the elderly living in a nuclear family was almost twice that of those living in an extended family [
132]. However, due to women’s workload in the extended family, women were more depressive than in nuclear families, whereas children in extended families had more positive values [
133]. Thus, according to the studies, family type influences emotional intelligence, depression, and life satisfaction. Therefore, the following hypotheses were proposed.
Hypothesis 7 (H7). Age has a moderating role in the effect of emotional intelligence and depression on satisfaction with life.
Hypothesis 8 (H8). Family type has a moderating role in the effect of emotional intelligence and depression on satisfaction with life.
2.5. The Context of This Study
This study investigated the effect of adults’ emotional intelligence levels on depression and life satisfaction during the COVID-19 pandemic. Emotional intelligence is the ability to think about, organize, express, and accurately assess one’s own emotions, as well as the emotions of others. It is easy for people with high emotional intelligence to understand their own and others’ emotional states and manage difficult processes. Thus, individuals can use their emotional skills actively in their private and professional lives. In addition, emotional intelligence strengthens individuals’ resilience and ability to cope with rapid changes and problems, especially in today’s complex and depressive modern life. Thus, while individuals’ resistance against the problems they encounter in life increases, their satisfaction with life increases along with it.
In the study, it was assumed that emotional intelligence increases satisfaction with life levels by reducing the depression of individuals. For this purpose, the conceptual model depicted in
Figure 1 was designed. In the conceptual model, direct, indirect, and moderation analyzes were used. In addition, the
t-test and ANOVA test were performed to determine the differences between groups. Finally, hypotheses for each relationship were defined and tested. Accordingly, emotional intelligence reduces depression, and decreased depression increases satisfaction with life. It was assumed that these relationships vary according to age level and family type.