Relationship between Professional Commitment and Subjective Well-being of College Students -- A Moderated Mediation Model

In order to explore the specific influence mechanism of professional commitment on subjective Well-being, this paper makes a research questionnaire based on professional commitment scale, subjective Well-being scale, academic Self-efficacy scale and social support scale, and surveys 356 college students nationwide. The obtained data are analyzed empirically using SPSS22.0 and Amos22.0. The results show that: (1) Professional commitment and academic Self-efficacy can positively predict subjective Well-being; (2) Academic Self-efficacy has a partial mediating effect on the relationship between professional commitment and subjective Well-being; (3) The moderating effect of social support occurs in the direct path of professional commitment’s influence on subjective Well-being and the indirect path of professional commitment’s influence on academic Self-efficacy. By constructing a moderated mediation model, this study reveals the mechanism of professional commitment on subjective Well-being, and provides reference for analyzing, predicting, shaping and correcting college students’ cognition and behavior, as well as helping to solve their psychological problems.


Proposal of Question
All human activities are not only for the sake of survival, the ultimate goal of which is to enjoy a better life. A good evaluation of life is not negligible content of a happy life. As a psychological term, subjective Well-being refers to the holistic assessment of life quality by evaluators according to their own criteria. It is an important psychological parameter reflecting the life quality of individuals in a society, with the basic characteristics of subjectivity, stability and wholeness [1]. Wanner Wilson's 1967 article, "Factors related to Self-reported Happiness," can be regarded as a watershed in happiness research. Until then, people had been content with simple descriptions of happiness. Discussion of subjective Well-being is mostly at the qualitative level. After that, people tend to combine qualitative and quantitative research. Research on happiness has reached a relatively mature level. Many theories on subjective Well-being have been put forward, such as comparison theory, goal theory and personality trait theory [2].
The concept of professional commitment comes from the study of organizational commitment and career commitment. Organizational commitment is first proposed by Becker. He believes that organizational commitment is a kind of feeling that employees are willing to devote themselves to work with the increase of "unilateral investment" (time, energy, money, etc.) in the organization [3]. With the further research on organizational commitment, Meyer & Allen directly extended their research results to the field of career commitment. They believe that career commitment refers to the psychological belonging of practitioners to their career, the obligation to work hard, and the willingness to continue to maintain the career identity [4]. Professional study is the career of college students and is their main activity. Commitment to professional study reflects college students' positive learning psychology, such as identification and love of their major, and their willingness to work hard and behave well. Therefore, professional commitment is a comprehensive indicator to measure the psychological status of college students. This is also an important source of college students' professional learning motivation, which directly affects college students' learning and life EED 2021 Volume 3 (2021) 2 quality and even their future career planning. At the same time, the study of college students' professional commitment is helpful to grasp the influence of college students' major on their psychological behavior from non-cognitive factors, and provide a new research perspective for analysis of college students' psychology.
As an important group in society, college students are in an important period of life development. In terms of current research, few scholars have studied the relationship between college students' career commitment and subjective Well-being and the specific mechanism of the two. However, the daily life of college students mainly revolves around professional learning, so the confidence brought by professional learning is bound to have a positive impact on the mental health of college students. Therefore, this paper chooses the relationship between college students' professional commitment and subjective Well-being as the research topic, and constructs academic Self-efficacy as the intermediary. Based on the mediation model where social support functions as a moderating factor (as shown in Figure 1), this study aims to explore the specific mechanism of action between college students' professional commitment and subjective Well-being, to provide practical support for analyzing, predicting, shaping and correcting college students' cognition and behavior, as well as helping to solve their psychological problems.

Sampling of Subjects
In order to make the questionnaire suitable for college students, after the questionnaire is formed, 50 students are randomly selected as the subjects to conduct small sample testing. According to the test results, the items that are unclear, incomprehensible or questionable are modified or deleted.
Subjects in formal studies are sampled by stratified global random sampling. A total of 348 college students are selected online as the study subjects. After eliminating the invalid questionnaires, there are 335 valid questionnaires with an effective rate of 96.26%. Among them, there are 143 boys and 192 girls; There are 69 freshmen, 134 sophomores, 91 juniors and 41 seniors; There are 113 students majoring Arts, 151 students majoring science and engineering, and 71 students majoring technical subjects; There are 64 students ranking in the top 20%, 136 students ranking in 20%-40%, 79 students ranking in 40%-60%, 32 students ranking in the bottom 20%-40% and 24 students ranking in the bottom 20%; there are 161 people had families in rural areas and 174 in urban areas; 182 of the students are the only child in their family and the rest 153 are not.

Research Tools
(1) Professional commitment. The survey scale of scholar Lian Rong [5] is adopted. The scale contains 27 questions, including four dimensions of emotional commitment, continuing commitment, ideal commitment and normative commitment. The scale adopts a 5-level scoring method. "1" means strongly disagree, and "5" means strongly agree. The score is positively correlated with the level of students' professional commitment. Cronbach's α coefficient of Lian's scale is 0.927. In this study, the Cronbach's α coefficient is 0.860. The square sum of loads extracted for each problem by factor analysis is 56.51%.
(2) Subjective Well-being. The Subjective Well-being Index Scale (WBIS) compiled by scholar Campbell [6] is adopted. The scale consists of 9 questions, including two dimensions of general emotion (question 1 to 8) and life satisfaction (questions 9). The scale adopts 7-level scoring method. The sum of the average score of the former (weight 1) and the weighted score of the latter (weight 1.1) is the overall happiness index. The higher the total score, the greater the sense of happiness. In this study, the Cronbach's α coefficient of this scale is 0.807.
(3) Academic Self-efficacy. The academic Self-efficacy scale compiled by Liang et al. [7] of Central China Normal University is adopted. This scale is based on the relevant dimensions of the academic Self-efficacy questionnaire compiled by Pinirich and DeGroot, with a total of 22 questions. The scale includes two dimensions, which are Self-efficacy of learning ability (question 1 to 11) and Self-efficacy of learning behavior (question 12 to 22). The scale adopts a 5-level scoring method. "1" means totally inconsistent, and "5" means completely consistent. Scores are positively correlated with students' academic Self-efficacy. In this study, the Cronbach's α coefficient of this scale is 0.824. Through factor analysis, the information content of each problem is above 0.5. The square sum of extracted load is 63.5%.
(4) Social support. The survey scale of Jiang Ganjin [8] is adopted. The scale has 12 questions, including three dimensions of family support, friend support and other support. The scale adopts a 7level scoring method. "1" means strongly disagree, and "7" means strongly agree. In this study, the Cronbach's α coefficient of this scale is 0.897. The square sum of loads extracted by factor analysis is 57.1%.
Combined with the characteristics of the research object and content, this study synthesizes the above four scales and makes certain corrections and adjustments to finally form "The Questionnaire on College Students' Professional Commitment, Academic Self-efficacy, Subjective Well-being and Social Support", with a total of 76 questions.

Data Processing
In this study, SPSS22.0 statistical software and Amos22.0 are used for data analysis. The analysis specifically applies descriptive statistics, reliability and validity test, difference analysis, correlation analysis, stepwise regression analysis, path analysis, mediating effect test and moderating effect test.

Descriptive Statistics
The total scores of the four subscales and the scores of each dimension are shown in Table 1.

Reliability and Validity Test
The reliability analysis of 70 scoring questions in this questionnaire shows that Cronbach's α coefficient is 0.927, indicating that the questionnaire as a whole has a high reliability. Factor analysis is used to test the validity of the questionnaire, and the test data are shown in Table 2. According to the results, the coefficient result of KMO test for this questionnaire is high, which is 0.827, suitable for factor analysis. The information content extracted from each question is above 0.5. Factor analysis shows that the sum of squares of extraction load is 64.61%, which is in line with the standard that interpretation should be more than 50%. Therefore, the questionnaire has good validity as a whole.

Difference Test
In this study, the statistical methods of independent sample t test and variance analysis are used to test the differences of subjective Well-being of college students in different characteristics. The

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Volume 3 (2021) 4 results show that the subjective Well-being of college students has statistically significant differences in family location (see Table 3) and whether they are the only child or not (see Table 4).

Correlation Analysis among Professional Commitment, Learning Engagement and Selfefficacy of Career Choice
The correlation analysis between the three variables of professional commitment, subjective Wellbeing and academic Self-efficacy is carried out in pairs, and Tables 5, 6 and 7 are obtained. The results show that all variables are significantly correlated at the significance level of 99%, and the correlation coefficients are all above zero, so they are all positively correlated.

Regression Analysis among Professional Commitment, Learning Engagement and Selfefficacy of Career Choice
The dimensions of professional commitment and academic Self-efficacy are taken as independent variables, and the total score of subjective Well-being is taken as dependent variable. The Stepwise analysis method is used for analysis, and the results are shown in Table 8. According to the analysis of the table, emotional commitment, learning behavior and continuing commitment can predict the total score of subjective Well-being and its dimensions respectively.

Structural Equation Model of Professional Commitment, Academic Self-efficacy and Subjective Well-being
According to the results of correlation analysis, the pairings of the four dimensions of professional commitment, the two dimensions of academic Self-efficacy and the two dimensions of subjective Well-being are significant (P < 0.01). Therefore, it is suitable to construct structural equation model. After model fitting, each path coefficient is shown in Figure 2.
The results show that all path coefficients reach the significant level. Among them, the path coefficient of professional commitment to subjective Well-being is 0.64; The path coefficient of professional commitment to academic Self-efficacy is 0.68; The path coefficient between academic BCP Education & Psychology

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Volume 3 (2021) 6 Self-efficacy and subjective Well-being is 0.26. The mediating effect is 0.18; The mediating effect rate is 21.6%.  The main fitting indexes are shown in Table 9. χ 2 , χ 2 /df, GFI, AGFI and RMSEA all fall within the recommended range, indicating that the model is well fitted.

Analysis of Moderation Effect
Social support is introduced into the original mediation model as the moderating variable (as shown in Figure 3), and the three possible paths that the moderating variable may have effect on are analyzed with the help of Amos. In path 1, the P value of interaction term on the dependent variable BCP Education & Psychology

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Volume 3 (2021) 7 academic Self-efficacy is less than 0.001, indicating that social support has a significant moderating effect in path 1. In path 2, the P value of interaction term on the dependent variable subjective Wellbeing is less than 0.001, indicating that social support has a significant moderating effect in path 2. In path 3, the P value of interaction term on the dependent variable subjective Well-being is less than 0.001, indicating that social support has a significant moderating effect in path 3. Therefore, the moderating effect of social support occurs in the three pathways 1,2 and 3. Through verification, it is found that the moderating effect in the model is significant only when the moderating effect in the two pathways occurs simultaneously, while in other conditions the effect is not significant. Based on the results above, relevant models are constructed and Amos is used for testing. The path coefficients obtained are shown in Table 10. Currently, the P value of the interaction term on academic Selfefficacy is less than 0.001 and less than 0.001 on subjective Well-being. Through the moderation effect test, all the fitness indexes of this model pass the test standard. Therefore, the final model of this study is obtained, as shown in Figure 3.

Discussion
Based on previous theoretical studies, this study combines academic Self-efficacy as a mediating variable and social support as a moderating variable to construct a moderated mediation model based on the interaction between professional commitment and subjective Well-being. This model not only reveals how professional commitment affects subjective Well-being (the mediating effect of academic Self-efficacy), but also explores under what conditions professional commitment has a more significant impact on subjective Well-being (the moderating effect of social support). The results enrich the relationship among professional commitment, subjective Well-being, academic Self-efficacy and social support of college students, thus having theoretical and practical value in helping college students shape and correct cognition, improve their own happiness and protect their mental health.

The Overall Situation of College Students' Professional Commitment and Subjective Wellbeing
This paper makes an overall analysis of the current situation of college students' professional commitment and subjective Well-being (Table 1). Through data analysis and comparison with previous studies, it is found that in terms of professional commitment, the current college students' professional commitment is relatively high in all dimensions. Among them, normative commitment is the highest and continuing commitment is the lowest. On average, however, there is little difference between the two. Emotional commitment and ideal commitment are in the middle. This may be related with the increasingly improved university application system, education system and social ethos that values education. In addition, the current parents' educational background is relatively high, and they generally attach importance to education. Meanwhile, with the high openness of of internet information, college students can get in touch with the norms and requirements of their majors in advance and conveniently. This will be more conducive to improving the sense of responsibility and identity of the college students for their major.
In terms of subjective Well-being, on the one hand, overall, the current subjective Well-being of college students is above average. In the dimension of general emotion index, the positive emotion of college students is greater than the negative emotion, which indicates that the general emotion index of college students is relatively high, and they have a basically positive attitude towards personal happiness. In the selection of positive emotions, college students' high selection rate of optimism, confidence and value reflects the young people's yearning for the future, positive optimism and the pursuit of their own value. In the dimension of life satisfaction, the main life content of college students is learning. Contemporary college students are basically born after 2000, more than half being the only child. In addition, college students generally have good family conditions and enjoy high economic level and rich life materials, so the economic pressure is small. Therefore, college students can devote themselves to study. They are optimistic about the successful completion of their studies, so college students have a high degree of study and life satisfaction. On the other hand, the results of difference analysis show that the subjective Well-being of college students is significantly different in the location of their family and whether they are the only child in family. The life satisfaction and total happiness index of college students from rural areas are significantly lower than those from urban areas. This is related to regional differences between urban and rural areas. College students from rural areas shoulder greater life pressure, so their life quality is not high. At the same BCP Education & Psychology

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Volume 3 (2021) 9 time, family background is also easy to cause inferiority, and the satisfaction of learning and life is naturally low. The overall emotional index of college students who are the only child in family is higher than those who are not. This may be because college students from one-child families can enjoy better economic conditions and the attention and love of parents and elders. As a result, they are more sensitive to emotional feelings, and coupled with more love for the only child in the family. What is more, the only child college students also feel more positive emotions.

Relationship between Professional Commitment and Subjective Well-being
This paper makes a correlation analysis of four dimensions of professional commitment and two dimensions of subjective Well-being of college students (Table 5). It can be seen from Table 5 that professional commitment and its four dimensions are significantly positively correlated with subjective Well-being and its two dimensions. The relationship between the two can be explained by one of the main theories of subjective Well-being, the goal theory. Brunstein et al. believe that when a person can pursue goals in the way of value and independent choice and reach the feasible degree, subjective Well-being will increase. The higher the professional commitment of college students, the higher the sense of identity and love of their major. Students subjectively believe that the major itself has a good employment prospect, that is, the major is in accord with their ideal goal. Thus, this kind of psychology can bring students happy and satisfied experience of study and life, and produce more positive emotions. In addition, the main effect of professional commitment on college students' subjective Well-being is supported by the results of regression analysis ( Table 8). The regression analysis shows that affective commitment, learning behavior and continuing commitment are the predictors of subjective Well-being. Among them, emotional commitment dimension of professional commitment is the most important predictor of the subjective Well-being of college students. This shows that if the teaching reform in colleges and universities can increase students' sense of identity with their majors and form positive career motivation, it will help reduce the negative learning psychology of college students, improve their subjective Well-being and benefit their mental health [5].

Mediating Role of Academic Self-efficacy in Professional Commitment and Subjective
Well-being Academic Self-efficacy refers to an individual's judgment and confidence on his ability to successfully complete academic tasks, which is composed of Self-efficacy of learning ability and learning behavior. The former refers to an individual's assessment of his or her ability to complete school, achieve good grades and avoid academic failure. The latter refers to the evaluation of students on whether their learning behaviors can achieve their learning goals and the estimation of their behavior results [9]. This study finds that college students' professional commitment could indirectly predict subjective Well-being through academic Self-efficacy, which is a mediating variable. This result shows that if college students love their chosen major and are full of passion and love for professional learning, they will be more serious and hard-working in study and invest more in it. The result of active engagement is improved academic performance. The better the academic performance, the higher the academic Self-efficacy. Because the most important source of information that academic Self-efficacy obtains is the previous experience of academic success or failure, students with good grades mostly get successful experience, thus having a high sense of Self-efficacy [10]. Students with high academic Self-efficacy have a positive attitude towards their ability to complete their studies, and there are more positive emotions. In terms of life satisfaction, since learning satisfaction is an important part of college students' subjective Well-being, these students' life satisfaction will be higher. As a result, these students have higher subjective Well-being. In contrast, students with low academic Self-efficacy hold a negative attitude towards their learning ability. The subjective Well-being of these students is obviously low [11].

The Moderating Effect of Social Support on Professional Commitment and Subjective Well-being
Social support is the resources and help those students can get from the outside world when they feel anxious or nervous [12], reflecting the connection between variables and external factors in the original simple mediation model. In this paper, family support, friend support and other support are mainly used to cover the main sources of help students get from outside. The results of data analysis show that the relationship between professional commitment and subjective Well-being is moderated by different levels of social support. Social support affects the relationship between the two, and the moderating effect occurs in the two relationship paths between (1) professional commitment and academic Self-efficacy and (2) professional commitment and subjective Well-being. When the level of social support is high, the influence degree of subjective Well-being and academic Self-efficacy is greater. That is, students in both groups with the same level of professional commitment generate more positive self-estimation when they experience more social support (such as parental care, teachers' praise, and classmates' support). Students will have increased confidence to overcome difficulties and form positive evaluation of their own ability, thus having a higher sense of academic Self-efficacy, and then they can develop a higher subjective Well-being.

Implications
First, the high level of professional commitment and subjective Well-being of college students is attributed to the "people-oriented" education reform in China. Since the 18th National Congress of the Communist Party of China, the central Government has launched a new round of reform of the examination and enrollment system. The pilot reform of the examination and enrollment system is launched in 2014 and fully advanced in 2017. By 2020, a modern education examination and enrollment system with Chinese characteristics has been basically established, and an examination and enrollment mode featuring classified examination, comprehensive evaluation and multiple admissions has been formed. The mode of the new college entrance examination enables students to identify themselves and position themselves before entering the university in order to choose a combination of disciplines, and have a directional grasp of their future major choice. In addition, the guidance on students' major selection before the college entrance examination and the continuous strengthening of the professional and vocational education for students after enrollment in colleges and universities all over the country have continuously improved the overall level of professional commitment of Chinese college students. Students are more confident in their professional study and more satisfied with their study and life. Therefore, the subjective Well-being of college students has been improved. However, the survey shows that the difference between urban and rural college students' subjective Well-being is still significant. This requires colleges and universities to be more targeted when conducting psychological counseling, focusing on low-income families and poor college students. Colleges and universities should not only rely on the implementation of the financial aid system in the national policy to alleviate economic difficulties, but also vigorously carry out effective psychological help. Colleges and universities can open mental health knowledge courses extensively to popularize mental health knowledge, so that they can master the basic knowledge and moderating methods of mental health. By doing so, the psychological problems of poor college students can be solved in a professional, scientific and humane way [13].
Besides, professional commitment and its four dimensions are positively correlated with subjective Well-being and its two dimensions. Moreover, the regression analysis shows that emotional commitment, learning behavior and continuing commitment are the predictors of college students' subjective Well-being. Therefore, various parties can take college students' majors as the entry point and enhance students' professional commitment to improve their subjective Well-being. For example, colleges and universities can further optimize the structure of majors and try to explore and establish majors that meet the needs of society and the development needs of college students. Combined with the characteristics of local colleges and universities, it is necessary to adjust the majors with difficulty BCP Education & Psychology

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Volume 3 (2021) 11 in employment or limited employment, and build some majors with strong service and application. This meets the needs of students and improves their emotional commitment. Meeting the needs of the society, it also enhances students' ideal commitment because the related majors have good employment prospects. In addition, government departments should further reform the mode of major enrollment and establish a flexible system of major selection. In terms of changing majors after entering the university, the university are encouraged to give students more rights and freedom to make their own decisions by allowing some students to choose majors again after entering the university. Thus, the motivation and interest of professional learning of college students can be mobilized, the college students' level of professional commitment can be raised, and their happiness can be improved.
What is more, colleges and universities should educate college students about their outlook on life, values and career, so that they can set up lofty life ideals and achievement goals. At present, many popular theories to explain subjective Well-being are essentially goal theories. These theories believe that subjective Well-being arises from the satisfaction of needs and the realization of goals. For example, according to Maslow's hierarchy of needs theory, people's subjective Well-being at this level will be improved after their low-level needs are satisfied, and then they will pursue a higher level of happiness. It is generally believed that people's positive emotions are closely related to whether they have goals or not, and the lack of goals and pursuits in life will produce negative emotions and unhappiness [14]. Therefore, in order to improve the subjective Well-being of college students, the most important measure is to strengthen the education of their outlook on life and values, to enable them to establish lofty life ideals, and guide them to make continuous efforts to achieve their goals, thus improving their own happiness in the process of becoming talents.
Finally, social support is mainly embodied in substantive support, emotional support, cognitive information support and verbal guidance support [15]. Colleges and universities should improve college students' mental health by realizing various types of social support to improve college students' subjective Well-being. For example, the infiltration of mental health consciousness can be strengthened, and a highly unified mental health cognition can be formed. In the past a long period of time, colleges and universities regard basic theoretical knowledge learning as the point of education, but ignore the existence of college students' mental health problems. Colleges and universities can guide teachers and students to form a highly unified cognition of mental health by adjusting the period proportion of mental health course education. In addition, colleges and universities can also innovate the traditional mental health education methods and enrich the content of mental health education. Based on the main causes of college students' mental health problems and the adaptability of traditional mental health education content and form in the new period, colleges and universities should enrich and diversify mental health education content while innovating the mode of mental health education, so that the current requirements of college students can be met. For example, teachers can jointly analyze the hot topics widely discussed in internet communication with students, and students can express their personal opinions anonymously. Afterwards, teachers can analyze the problems existing in students' psychological cognition and provide verbal guidance and support according to students' opinions and expressions.