1. Introduction

Perceived overqualification has been a hot topic in the field of organizational behavior in recent years and has become very common with the spread of education. In addition, in the current era of open innovation, the demand for innovative behaviors by enterprises is increasing day by day. Therefore, this study intended to link the two to explore the relationship between them. Based on self-evaluation theory and face theory, taking enterprise employees as the research object, this paper discusses the impact of perceived overqualifications on employees’ innovative behavior and the internal mechanism and examines the first-order and high-order moderating effects of ability–face pressure and length of service in turn. The results showed that perceived overqualifications had a positive impact on employees’ innovation behavior, and felt trust had a mediating role in the relationship. Ability face pressure played a negative moderating role in the impact of felt trust on innovative behavior and played a negative moderating role in the impact of perceived overqualifications on innovative behavior. With the increase in the length of service, the negative moderating effect of ability face pressure on the relationship between perceived overqualifications and employees’ innovative behavior weakened.

The theoretical contributions of this study are as follows: first, to verify the positive influential relationship between perceived overqualification and innovative behavior, and to obtain the mediating mechanism of felt trust between perceived overqualification and employee innovative behavior based on self-evaluation theory, enrich the research on the positive effect of perceived overqualification, identify the mediating mechanism between perceived overqualification and innovative behavior, and help companies recognize the inner mechanism of perceived overqualification. This study provided theoretical support for the maximization of talent utilization. Second, we discovered the boundary effects between perceived overqualification and innovative behavior and between felt trust and innovative behavior, and extended the literature on perceived overqualification by exploring the ability face pressure of employees at work based on face theory, and studied the ability face pressure of employees as a moderating variable, which was verified to clarify the boundary effects of overqualification of employees in the process of their ultimate effect on innovation behavior, and provides a new perspective for exploring the factors influencing employees’ innovative behavior. Third, in the research process, the factor of employees’ length of service was added, and it was argued that employees’ ability face pressure may be influenced by the length of service. Therefore, a higher-order adjustment model was constructed, and length of service was used as a higher-order adjustment variable to explore the ultimate effect on overqualification and innovative behavior, which enriched the literature on perceived overqualification and length of service, where the length of service no longer appeared as only a statistical variable.

In the current business market with many talented people, there is a phenomenon that occurs where the supply of talents exceeds the demand for jobs, and coupled with the outbreak of SARS-CoV-2, the enterprise economy is seriously threatened and there are a large number of layoffs, which undoubtedly aggravates the imbalance between supply and demand in the talent market, resulting in a large number of talented people being unable to find suitable jobs, and the overqualification of employees becomes a very common phenomenon ^[1]. Therefore, combined with the quantity and quality of talents and the status quo of enterprises recruiting employees, the study of overqualification is not only beneficial to the physical and mental development and career development of employees but is also beneficial to enterprises’ reasonable development of talents to obtain sustainable development.

Overqualification means that employees think that their ability and knowledge exceed the needs of their positions. At present, there are differences in the research views on perceived overqualifications. Most of them focus on the negative impact of perceived overqualifications. Some scholars believe that the sense of overqualification will reduce employees’ work engagement, self-efficacy, job satisfaction, work performance, team performance, and organizational citizenship behavior, and lead to anti-productive behavior due to unfairness, feeling deprived, or feeling that the mismatch between the employee and job will lead to negative employee output ^[2][3][4][5].

However, the previous positive research on perceived overqualifications is relatively lacking. Some studies start from the theory of relative deprivation and believe that employees with a sense of perceived overqualifications will work harder and achieve high task performance in order to get rid of relative deprivation, while other studies are based on psychological contract theory ^[6][7][8]. However, this is not sufficient, especially in the context of open innovation, where the market is complex and changing and competition is fierce since employees’ innovative behavior is the basis and key for companies to gain a competitive advantage and achieve sustainable development ^[9]. For enterprises, innovation is the first productive force that can help them gain a sustainable competitive advantage and achieve sustainable business development. Therefore, it is crucial to explore the relationship between the influence of overqualification and innovation behavior and the inner mechanism and to rationalize the use of talents and stimulate the innovation behavior of employees. In view of this, this study was based on a new perspective, namely, self-evaluation theory, to explore the positive relationship between perceived overqualification and employees’ innovative behavior, the mediating mechanism, and the boundary conditions based on face theory. This study also aimed to expand the research perspective of the intermediary mechanism between the perceived overqualifications and employees’ innovative behavior and enrich the research on the boundary conditions of the perceived overqualifications and employees’ innovative behavior.

In an organization, trust between leaders and employees also affects employees’ innovative behavior ^[10]. Although trust is mutual, i.e., employees trust in leaders and leaders trust in employees, most of the current research focuses on employees’ trust in leaders and relatively little attention is paid to leaders’ trust in employees, that is, felt trust ^[11][12]. Therefore, it is necessary to explore the influence of employees’ felt trust on their behavior from the trusted side ^[13]. The theory of self-evaluation points out that individuals will be influenced by the social environment and social information, and constantly conduct self-recognition and evaluation, which ultimately affects their attitudes and behaviors ^[14], especially when the information comes from important people in the organization (such as leaders) and is positive information, leading to the effect of self-evaluation being more obvious ^[15]. In particular, for employees with perceived overqualifications, under the premise of mismatches between an employee and their job, the trust of superiors may have an important impact on self-perceptions and evaluations, which, in turn, affect their attitudes and behaviors ^[16]. Therefore, based on self-evaluation theory, this study explored the influence mechanism of felt trust on perceived overqualifications and innovative behavior and further verified the explanation logic based on self-evaluation theory.

In the workplace, employee behavior can also be affected by stress ^[17]. According to face theory, employees will be affected by the ability face pressure at work and will be disturbed by the thinking of “don’t lose face” at work ^[18]. In terms of the theory, although some scholars have discussed perceived overqualification and employee innovation behavior, it is not enough. Based on face theory, there are few studies that analyze the moderating effect of ability face pressure between the perceived overqualifications and employees’ innovative behavior, and the relationship between felt trust and employees’ innovative behavior.

In addition, the literature studying employee behavior in the field of organizational behavior has more often used the length of service as a control variable, but the length of service also has an impact on employees’ work experience, interpersonal relationships, and skills ^[19]. As moderating variables in this study, the size of the ability face pressure is closely related to the employee’s work experience, interpersonal relationships, and other factors ^[18]. Therefore, this study included length of service to explore its higher-order moderating effect. By establishing a three-dimensional interaction model, this study not only explored the influence of perceived overqualifications on employees’ innovative behavior and felt trust on employees’ innovative behavior but also explored the moderating effect of ability face pressure on it, as well as the synergistic moderating effect of length of service.

Since the research variable of this study was employees’ perceived overqualification and innovative behavior, it needed to be analyzed from employees’ data; therefore, this study used a questionnaire to carry out the research and the obtained findings were processed using SPSS 25.0 and AMOS 24.0 to test the hypotheses of this study through the data structure via analysis and finally draw conclusions.

21. Perceived Overqualification and Innovative Behavior

Perceived overqualifications refer to the level of knowledge, skills, experience, and ability that an individual possesses that exceeds the requirements of the current job, which is a situation of underemployment [2]. Perceived overqualifications can be divided into two types: subjective perception and objective perception. Among them, subjective perceived overqualification is an individual’s self-perceived belief that the level of knowledge and ability they possess is higher than that required for the job ^[1][20][1,20]. In the existing organizational behavior research, subjective perceived overqualification is more often studied. Because this study mainly investigated the influence of excess qualification on employees’ innovative behavior, the concept of perceived overqualification was chosen. Employee innovative behavior refers to the new ideas, new products, new services, or new methods that employees generate in their work that are meaningful to the enterprise [21], and it is also a key topic of current organizational management research. In the face of the complex and changeable external business environment, the continuous emergence of employees’ innovative behavior is an important guarantee for the company to maintain its competitive advantage and obtain sustainable development [9].

Many articles on perceived overqualification show that the sense of perceived overqualification is a negative feeling, but it also indicates that employees have knowledge and abilities above the job requirements ^[22][23][22,23]. The high work ability of employees can stimulate some positive behaviors, such as improving innovation ability and improving task performance ^[24][25][24,25]. First, perceived overqualified employees are capable of divergent thinking, drilling, and reflection, thus promoting the innovation process [26]; second, perceived overqualified employees can complete the tasks assigned by the organization in a shorter time, and thus have free time to think and explore, discover existing deficiencies, generate new ideas, and then enhance innovative behavior. Third, perceived overqualified employees are easily dissatisfied with their existing jobs, which sometimes motivates them to engage in more interesting and challenging jobs, such as innovative behaviors, to enhance their sense of accomplishment [27].

32. Mediating Effect on Perceived Overqualification and Innovative Behavior

Felt Trust

Felt trust refers to the perception of one party’s willingness to take risks for the actions of another party [28]. When employees perceive that their superiors have assigned them an important task that is directly related to the development of the enterprise, they will feel trusted by their superiors. Since only the superiors know whether they truly trust the subordinates or not, any information regarding being trusted by the superiors from the perspective of the subordinates is regarded as “felt trust” [13].

Compared with employees with perceived underqualification, employees with perceived overqualification are more likely to be valued by their superiors because of their higher level of ability and knowledge and are more likely to be entrusted with important responsibilities by their superiors, thus increasing the level of felt trust. On the other hand, employees with perceived overqualification can complete the tasks assigned by the organization in a short time, thus having some leisure time, further promoting the entrustment of heavy responsibilities by the superiors, and improving the felt trust level of employees.

On the other hand, self-evaluation theory points out that the formation of an individual’s self-evaluation will be affected by the social environment and social information in which they live [14]. When social information is positive and originates from important members of the organization (such as superior leaders), the influence of individuals will be further increased [15]. According to trust-related research, leaders are an important source of social information for employees at work, and trust itself is a positive message. Therefore, when employees feel that they are trusted by their superiors, they are more likely to use this information for self-evaluation, which further affects their attitudes and behaviors [14]. Most studies showed that felt trust can significantly stimulate employees’ organizational citizenship behavior, innovative behavior, and individual performance ^[13][28][29][13,28,29]. Due to positive feedback information, employees will show more behaviors expected by their superiors, such as innovative behavior ^[21][27][21,27].

In summary, employees with a sense of perceived overqualification have a relatively high level of knowledge and ability to complete their work and they are able to complete the tasks assigned by the organization more quickly, have spare time to do other tasks, increase the possibility of their superiors assigning important tasks, and promote the perception of being trusted. On the other hand, employees who feel the trust of their superiors as positive feedback will stimulate more innovative behavior.

43. The Moderating Effect of Ability Face Pressure 

Ability Face Pressure

“Face” is a social psychological construct rooted in a culture that is the internal self-esteem and self-image of the individual, as well as social respect and identity that the individual constantly seeks [18]. In a social culture that values face, individuals will attach great importance to their social status in the interpersonal network; therefore, they are very sensitive to the recognition and evaluation from others [30], and thus, face pressure is generated. Zhu believed that face pressure refers to the psychological process of negative self-perceptions perceived by individuals after receiving certain social feedback [31]. Therefore, this study explored the moderating influence of face pressure and regards face pressure as a continuous psychological process. Face pressure is divided into three types: ability face pressure, autonomous face pressure, and communicative face pressure. Among them, ability face pressure is feedback on personal ability [18]. Ability face pressure, also known as “perceived face threat based on ability,” is a result of the perceived possibility and potential risk of losing face due to the individual’s desire for others to recognize their own abilities, achievements, and status [31].

Ability face pressure itself, as a pressure source, is the negative self-competence awareness of employees based on the social feedback they perceive in the organization ^[32], which has an obvious impact on work. According to face theory, individuals are threatened with “losing face” at work. When employees face social evaluations, such as their overqualifications and felt organizational trust, their final behavior must be affected by the ability face pressure ^[33].能力面对压力本身，作为压力源泉，是员工基于他们在组织中感知到的社会反馈而产生的消极的自我能力意识[32]，这对工作有明显的影响。根据面子理论，个人在工作中受到"丢面子"的威胁。当员工面临社会评价时，比如他们的资历过高和感受到组织的信任，他们的最终行为必须受到能力面对压力的影响[33]。

For employees with high ability face pressure, they will pay special attention to social respect and recognition, and generate negative self-ability awareness through self-perception ^[32]. When employees are trusted by their superiors to a greater extent, they are more inclined to take care of themselves not to “lose face,” while innovative behavior itself is risky and the generation of new ideas may not necessarily be valued and recognized by the company ^[34][35], thus reducing the generation of innovative behaviors. Similarly, when employees have the perception of overqualifications, they tend to “not lose face,” which reduces risk-taking behavior and reduces innovation.对于面临压力能力高的员工，他们会特别注重社会的尊重和认可，通过自我认知产生消极的自我能力意识[32]。当员工在更大程度上受到上级的信任时，他们更倾向于照顾自己不要"丢面子"，而创新行为本身就是有风险的，新想法的产生可能不一定得到公司的重视和认可[34，35]，从而减少了创新行为的产生。同样，当员工有超额资格感时，他们往往会"不丢面子"，这减少了冒险行为，减少了创新。

In contrast, when employees’ ability face pressure is low, they pay less attention to the “face” of their abilities. When they perceive positive external support, such as trust from superiors, they will make better use of their own resources to exert their value, and then stimulate innovative behaviors ^[13][36][37]相比之下，当员工的能力面对压力较低时，他们对自己能力的"面子"关注较少。当他们感受到积极的外部支持，例如来自上级的信任时，他们会更好地利用自己的资源来发挥自己的价值，然后激发创新行为[13，36，37]; when employees perceive they are overqualified, they will use resources and their talents to explore and discover at work to bring out their greater value and promote innovative behaviors ^[27].当员工认为自己资历过高时，他们会在工作中利用资源和才能进行探索和发现，以发挥更大的价值并促进创新行为[27]。

54. Synergistic Moderating Effect of Length of Service on Ability Face Pressure服务年限对能力面临的协同调节作用

Length of Service服务期限

Length of service is the length of time an employee has worked since entering an organization, where the length of service can have an important impact on employees’ perceptions, self-evaluations, attitudes, and even behaviors ^[38]. In most previous studies, length of service existed only as a control variable, but some scholars showed that the length of service is not only an important control variable but may also play an important role in the causal influence relationship between empirical studies ^[39]. Ability face pressure weakens the positive effect of felt trust, perceived overqualifications, and employees’ innovative behavior服务年限是员工自进入组织以来工作的时间长度，其中服务时间长短会对员工的感知，自我评估，态度甚至行为产生重要影响[38]。在以往的大多数研究中，服务年限仅作为对照变量存在，但一些学者表明，服务年限不仅是一个重要的控制变量，而且还可能在实证研究之间的因果影响关系中发挥重要作用[39]。能力面对压力会削弱感觉信任、感知到的超额资格和员工创新行为的积极影响; however, this effect also depends on the length of time the employee has been with the organization ^[40]. Because new employees who have been working for a shorter time are less familiar with the work environment and less experienced in their work, they may not be able to achieve immediate innovative behavior ^[41].然而，这种影响也取决于员工在组织中的时间长度[40]。由于工作时间较短的新员工对工作环境的熟悉程度较低，工作经验不足，因此他们可能无法立即实现创新行为[41]。

Older employees who have been in the organization for a longer time tend to have a higher level of work experience, as well as better interpersonal relationships, a higher level of organizational belonging, and organizational commitment ^[42]. Combined with the analysis of face theory, with the increase in the length of service, the interpersonal relationship of employees in the organization is strengthened, the proficiency and experience of the work are improved, and the negative feedback received is reduced. This also inadvertently slows down the perception of employee ability face pressure, which naturally weakens the moderating effect of ability face pressure. In addition, this study argued that as employees work for longer and longer, employees with a sense of overqualification do not treat their work negatively and reduce their work commitment and innovation. In contrast, due to the longer length of service, they become more familiar with their work, they receive more resources and support, they can finish their work and still have spare time for exploration and discovery, and their commitment to innovation will be higher, which, in turn, stimulates innovative behavior ^[43].在组织中工作时间较长的年长员工往往具有更高水平的工作经验，以及更好的人际关系，更高水平的组织归属感和组织承诺[42]。结合面子理论的分析，随着服务时间的增加，组织内员工的人际关系得到加强，工作的熟练程度和经验得到提高，收到的负面反馈减少。这也无意中减慢了员工对能力面压力的感知，自然而然地削弱了人脸能力压力的调节作用。此外，这项研究认为，随着员工工作的时间越来越长，具有超额资格感的员工不会消极地对待他们的工作，并减少他们的工作承诺和创新。相比之下，由于服务时间较长，他们对自己的工作越来越熟悉，他们获得了更多的资源和支持，他们可以完成工作，仍然有空闲时间进行探索和发现，他们对创新的承诺会更高，这反过来又会刺激创新行为[43]。

For employees who work for a shorter time, interpersonal relationships are weaker because they are not familiar enough with the work environment and their work, and their surrounding colleagues are also more unfamiliar. In this uncertain environment, employees may have a lower degree of job completion and pay special attention to the evaluation and feedback of those around them. According to face theory, employees will attach great importance to their social status in the interpersonal network and are sensitive to the recognition and evaluation of others, especially in an uncertain environment, which undoubtedly affects the ability face pressure, thus ultimately reducing the occurrence of innovative behavior.对于工作时间较短的员工来说，人际关系较弱，因为他们对工作环境和工作不够熟悉，周围的同事也更不熟悉。在这种不确定的环境中，员工的工作完成程度可能较低，并特别注意周围人的评价和反馈。根据人脸理论，员工会非常重视自己在人际网络中的社会地位，对他人的认可和评价很敏感，尤其是在不确定的环境中，这无疑会影响面对压力的能力，从而最终减少创新行为的发生。