1. Introduction
Effort-reward imbalance (ERI) refers to a work condition characterized by high effort and low reward and is used to assess job stress. The concept of ERI is based on the idea of social exchange, where individuals provide their labor and hope to be rewarded for it [
1]. According to the ERI model, the time and effort individuals put into their work are compensated with money, respect, and opportunities for career advancement. Individuals feel stressed when they do not receive what they deserve in exchange for what they give. Therefore, ERI reduces job motivation and satisfaction [
2], organizational commitment [
3], and increases levels of burnout [
4], absenteeism [
5], and turnover [
6,
7]. To make matters worse, ERI may have adverse effects on an individual's physical or mental health [
8]. Previous studies have shown that ERI increases the risk of cardiovascular disease [
9], including metabolic syndrome (MetS) [
10], coronary heart disease [
11], diabetes [
12,
13], and depressive symptoms [
14]. Among these, MetS refers to a group of risk factors for cardiovascular disease and type 2 diabetes, including central obesity, impaired glucose metabolism, insulin resistance, dyslipidemia, and hypertension. It has been suggested that prolonged exposure to work stress, such as ERI, may lead to metabolic syndrome (MetS) by activating the autonomic nervous system (increased heart rate and blood pressure) and increasing the release of cortisol [
10]. Alternatively, some studies suggest that ERI increases the risk of MetS and other diseases through the deterioration of lifestyle factors such as unhealthy diet [
15,
16]. Furthermore, the risk of ERI is not equal for all workers. A meta-analysis by Zhang et al. [
17] showed that the incidence of ERI among nurses has gradually increased over time, and that the incidence of ERI is higher among Asian nurses, as well as among nurses in certain departments such as operating rooms, emergency departments, pediatrics, and ICUs [
17]. These differences are likely because nurses in these departments have a heavier daily workload [
18,
19] and endure more work pressure than nurses in other departments [
20]. This means that we need to better understand what ERI is, as well as identify and care for occupations where ERI occurs.
In this study, we will review how ERI is related to similar concepts such as "passion exploitation" and "intrinsic motivation," and how workers adapt to exploitation. We will then state three remaining challenges for ERI research and present specific research proposals.
2. ERI and Passion Exploitation
The imbalance between effort and rewards has been discussed by other researchers under a different concept called passion exploitation. Passion exploitation refers to the practice of employers exploiting employees’ motivation by forcing them to work unreasonably long hours and at low wages. In Japan, the term “passion exploitation (yarigai sakusyu)” is said to have been first used by Honda [
21]. Today, companies that engage in such practices are called “exploitative enterprise (black kigyo)” in Japan and are often discussed in relation to collectivism and peer pressure, which are characteristic of Confucian societies including Japan [
22]. However, similar practices are seen worldwide. For example, Lyons [
23] provides evidence showing how information and technology (IT) ventures in the United States create a family-like atmosphere to tame and exploit obedient employees. Furthermore, it has been made clear that such practices do not target all workers to the same extent. Previous studies have used experimental methods to measure the degree to which people can empathize with the characters in stories, and have shown that loyal [
24] and generous [
25] people are more likely to be targets of passion exploitation. Interestingly, these studies depict how many exploited workers are exploited not because they are forced to be exploited, but because they want to be exploited. For example, a boss targets a loyal subordinate and gives them work that goes beyond their original role, while the targeted subordinate believes that taking on such extra work is a virtue and willingly takes on the extra work to gain a reputation for being loyal. In this way, passion exploitation is established with the consent of both the organization and the employee, even though it involves a "vicious cycle of suffering" [
25]. The results of a recent meta-analysis also show that people tend to view passionate workers as justified in accepting poor treatment (e.g., degrading tasks unrelated to the job description or unpaid overtime) [
26], mainly based on the belief that for passionate workers, the work is its own reward. This suggests that passion may lead to the acceptance of poor and exploitative treatment of workers [
26]. ERI and passion exploitation are similar concepts, but strangely, there is little discussion in the discussion of ERI about the possibility that employees may willingly fall into the imbalance trap.
3. Passion Exploitation and Intrinsic Motivation
Looking at it from another perspective, the theory of passion exploitation emphasizes the negative aspects of the classic psychology theory of intrinsic motivation [
27]. The theory of intrinsic motivation was incorporated into human resource management theory on the premise that extrinsic motivation such as money alone is insufficient to bring out the performance of employees. Therefore, the appeal of this theory in organizational psychology is that it brings out efforts beyond what is provided by rewards. Incidentally, one method of bringing out intrinsic motivation from employees is the theory of transformational leadership [
28], which aims to raise employees' awareness and bring out performance beyond what is provided by the work they are instructed to do. To put it a little more daringly, the theories of intrinsic motivation and transformational leadership are positive views of efforts beyond rewards from the perspective of management, while ERI and the theory of passion exploitation are negative views from the perspective of employees.
However, in recent years, even from the perspective of management, research has emerged that takes a reflective view of intrinsic motivation [
29,
30]. Among them, there are concerns about the "moralization of intrinsic motivation" [
29]. The gist of this argument is as follows: the normative pressure to do what one likes encourages people to pursue work that is satisfying for oneself and others, but at the same time, it can lead to the neglect of uninteresting tasks. Furthermore, it can elicit discriminatory attitudes toward people who do not appear to be intrinsically motivated or who have different types of motivation, which can affect the overall cohesion within the organization [
29]. Consistent with this "moralization" theory, other researchers have found that passion for work is easily linked to overconfidence and lack of cooperation [
30]. Thus, intrinsic motivation is not a panacea. Moreover, considering the above discussion, there may be many cases where intrinsically motivated employees are also victims of ERI and passion exploitation. It may be that employees are exhausted when they are intrinsically motivated for a long time, and one day suddenly take negative actions such as quitting their jobs, complaining about physical and mental health problems, or taking actions that disrupt teamwork. If that is the case, the boundary between ERI and intrinsic motivation is unclear, and it is possible that existing management and psychology research has not yet fully met the expectations of the world.
4. Three Remaining Issues for ERI Research
Previous research has revealed that, from the employee's perspective, ERI is related to negative economic behavior and mental and physical illness, and that passion exploitation is related to the personality of the person being exploited. At the same time, from the manager's perspective, discussions have emerged that emphasize the negative aspects of intrinsic motivation. These suggest that management that relies on the passion and hard work of individual employees may be successful in the short term, but is difficult to sustain in the long term. Therefore, future research is needed to increase the sensitivity of labor and management to ERI and passion exploitation. Specifically, research is needed to (1) deepen understanding of ERI and passion exploitation, (2) identify the types of jobs in which these are likely to occur, and (3) identify the extent to which ERI and passion exploitation are acceptable or unacceptable by jobs. Below, we will look at these three points in order.
First, many studies claim that ERI and passion exploitation cause stress, but do not clarify the mechanism. Why is it the "imbalance" between effort and reward, not effort, that is critical? If the problem is the amount of stress on the mind and body, it is effort that is critical, and reward should not be relevant. However, in recent years, there has been a trend of an increase in studies that claim that balance is important. For example, the results of a meta-analysis using data from 11 independent cohort studies conducted in six European countries between 1985 and 2005 showed that people with an imbalance between effort and reward at work have a higher risk of coronary heart disease, and that this is unrelated to the job strain experienced [
11]. Unfortunately, however, most studies only deterministically claim that imbalance is the cause of stress and avoid delving deeper into this cause.
A clue to this problem may be the fact that indigenous people who live by hunting and gathering rarely suffer from diseases that often accompany imbalance, such as cancer, cardiovascular disease, high blood pressure, and type 2 diabetes [
31]. These diseases began to develop when agriculture became established in our lives and we began to live a settled life [
31]. According to Ratey & Manning [
31], our brains and bodies have hardly changed since Homo sapiens, known as modern humans, appeared in Africa about 200,000 years ago [
31]. If we live a hunting-centered life like theirs, we would not need to worry about imbalance because we would only put in effort that is commensurate with the reward. If we get hungry, we attack animals to survive, and if we are full, we will not hunt any more until we are hungry again. Our minds and bodies may be programmed to live by hunting. However, modern humans often go against this biological law and make efforts for rewards that are not necessary in the immediate future. For example, it may be because, even if gaining a good reputation in an organization is not important now, it is predicted to be related to future promotion opportunities. As a result, sometimes people make efforts beyond the expectations of the organization reflected in the reward (long overtime hours, working on holidays, etc.), which puts extra strain on their mind and body, or they consume excessive alcohol and sweet foods to soothe their strained mind and body, which causes further mental and physical disorders. In this way, humans' vulnerability to the social systems they have created may be the cause of their susceptibility to mental and physical breakdown due to the imbalance between effort and reward. Therefore, to tackle this unsolved problem, it may be necessary to incorporate perspectives from different fields such as evolutionary biology.
Secondly, there is a lack of research on what types of occupations are more susceptible to imbalance and the economic behavior and health problems caused by imbalance. The theory of passion exploitation shows that young people with low status are more likely to be exploited [
23] and that women tend to be more exploited than men [
32]. In addition, Dragano et al.'s [
11] meta-analysis shows that the association between effort-reward imbalance and coronary heart disease is stronger in employees with low socioeconomic status compared to those with high status, and in younger participants than older participants. However, most studies have shown little interest in the differences in imbalance and its impact by occupation, except for some such as Zhang et al. [
17], which dealt with the awareness of nurses by department. At present, results that provide hints for clarifying the relationship between the two have been partially shown by researchers with a gender inequality perspective. For example, a study conducted in Sweden from 2008 to 2014 found that women work longer hours and spend more time on unpaid work than men. The study also showed that the association between increased unpaid work hours and increased progression of depressive symptoms was stronger for women than for men [
33]. However, the gender gap may be more deeply rooted in countries with large gender gaps. For example, in Japan, many people view childcare and caregiving as work that women should do at home for free, even though it is hard work, which may be the reason why wages in these industries are kept low [
34]. Therefore, if there was objective information on the actual situation of exploitation by country and industry, it would be useful information to attract the necessary support for these people. For example, a large-scale survey using the ERI would contribute to collecting such evidence.
Finally, there is a lack of analysis from the perspective of managers on what level of imbalance is acceptable. If imbalance always leads to negative economic behavior and mental and physical disorders in employees, managers would want to avoid it. However, for many years, intrinsic motivation and leadership theory have been major themes on how to draw out efforts beyond compensation, and it is true that managers have used these discussions as a reference in their management. This means that there is a certain benefit to imbalance, at least from the manager's perspective. If ERI and the exploitation of motivation were completely harmful, managers would have abandoned them a long time ago. In other words, if it does not bring negative results to management, managers should rather want some imbalance. At first glance, the idea of "research to find acceptable imbalance" seems arrogant. However, relying on words such as intrinsic motivation and transformational leadership because one does not want to be seen as a manager who tolerates imbalance is like managers who use positive “symbols” such as “challenging” in their recruitment strategies to hide poor working conditions [
35], and thus conceals the truth. In the first place, if it becomes clear in what types of jobs imbalance is likely to be harmful, it will be beneficial for workers as well, as it will make irrational exploitation more noticeable. However, if a study to clarify tolerance to ERI adopts a randomized controlled trial (RCT) or the like, there is a risk of ethical problems arising, as participants will be subject to exploitation for a certain period. Therefore, it would be preferable to conduct a case-control study in which participants who have experienced economic behavior such as job loss or mental and physical disorders are asked about the causes of their experiences, or a cross-sectional study using a standardized questionnaire. Furthermore, to promote this type of research, it would be desirable for researchers from sociology, ethics, and public health, who have the perspective of workers, as well as business and economics, who have the perspective of managers, to become more involved in research on ERI and passion exploitation.
Regarding the third issue, we will consider in more detail what kind of participants should be recruited to measure tolerance to ERI. For example, expatriates who are dispatched to overseas subsidiaries may be in a position where they have low tolerance for imbalance. Their mission is to complete the tasks given to them by the headquarters during their three- to five-year term. If expatriates are given excessive authority, the activities of the local subsidiary will diverge from the headquarters' intentions and lose unity, resulting in a "principal-agent problem" [
36]. Japanese companies are particularly sensitive to this problem, and as a result, they are known to be more reluctant to localize than companies in other developed countries [
37]. In addition, as previous research has revealed that intrinsic motivation and passion can easily lead to overconfidence and lack of cooperation [
29,
30], it is possible that the excessive enthusiasm of expatriates, who need to work cooperatively with local personnel while understanding and respecting the local culture, may interfere with daily management. Therefore, in a situation where imbalance (or efforts beyond the headquarters' expectations reflected in working conditions) occurs, it is thought that trouble will arise and the work performance of expatriates will decline. Problems such as early return home during the term, deterioration of health, and suicide due to expatriate maladjustment [
38] may also be caused by imbalance.
On the other hand, the opposite of expatriates are unpaid or paid volunteers. Paid volunteers are people who work part-time on a voluntary basis for less than the norm. In many cases, the amount of compensation is less than the minimum wage [
39]. For them, their intrinsic motivation to help others and demonstrate their abilities is what drives them. Therefore, it is thought that performance will not decline even if there is a discrepancy between effort and compensation. Of course, the fact that performance does not decline does not justify the imbalance. Many paid volunteers are in a serious situation where there is a shortage of people to carry out the work and the supply cannot keep up with the demand (according to an interview survey conducted by the author at a non-profit organization that handles paid volunteers). This shows the limits of relying on people who can work solely for intrinsic motivation, and even if they are not dissatisfied, it means that there is no small significance in improving treatment to fill the supply-demand gap. The same would apply to fields such as nursing care and childcare, which are exhausted by a shortage of workers. Therefore, it is believed that knowing what kind of mentality people who currently take on paid volunteer duties have, and how they differ from the opposite end of the spectrum, expatriates, will be meaningful in improving the perceptions and attitudes of employers and job seekers.
5. Discussion
In this study, I reviewed the relationship between ERI and passion exploitation, and between passion exploitation and intrinsic motivation, and summarized three issues remaining in ERI research. To address these issues, I propose integrating ERI with passion exploitation theory. ERI has clarified the relationship between imbalance measured by a unified and objective evaluation scale and economic or health disadvantages, but it does not clarify the type of personality of people who suffer from imbalance. As a result, it is less wary of situations in which people who are enthusiastic about their work are exploited without realizing it, as dealt with in passion exploitation theory. On the other hand, passion exploitation theory has clarified the personality characteristics of people who are easily exploited mainly by experimental methods, but does not clarify the relationship between exploitation and economic or health disadvantages by not having a unified and objective evaluation scale. As a result, it has little interest in, for example, differences in imbalance by occupation, as revealed by some ERI studies. By incorporating the methods and perspectives of both, it may be possible to predict in advance who is likely to suffer health problems due to imbalance, and use this information for career selection.
ERI is usually measured with a scale consisting of 16 items, including 5 items to measure Effort and 11 items to measure Reward [
40], and later a shortened version consisting of 10 items was developed [
41]. Effort items include, for example, "I have constant time pressure due to a heavy work load." Reward items include, for example, "Considering all my efforts and achievements, my salary/income is adequate." The greater the Effort exceeds Reward, the greater the imbalance between the two is. However, it can be difficult to interpret such imbalances. This is because, in addition to cases where the imbalance occurs because of blatant exploitation by unscrupulous managers, such imbalances may also occur because of intrinsic motivation. In this case, intrinsic motivation is not only generated in an environment where such motivation is easily generated, but also increased by managers' attempts to exploit employees' passion. If this is the case, exploited employees may not perceive the occurrence of an imbalance as a negative thing. Employees who have been domesticated by their managers in this way may not feel sorry for themselves for devoting themselves to the organization at the expense of their physical and mental health, and may even feel proud of themselves. For such employees, even if they are in a state of imbalance, their performance may not decline in the short term. However, if it is harmful from a long-term perspective, organizations and employees need to recognize the exploitation of employees' motivation at an early stage. To do this, ERI alone is insufficient; a multifaceted evaluation using other measures at the same time is necessary.
The Psychological Empowerment Scale (PES) developed by Spreitzer [
42] is a scale consisting of four subscales: impact, competence, meaning and self-determination, and is based on the research of Thomas and Velthouse [
43], who argued that empowerment is related to intrinsic motivation for tasks. Therefore, it has been used as a determinant of intrinsic motivation in previous studies [
44]. The Job Diagnostic Survey (JDS), developed by Hackman & Oldham [
45] and later revised by Idaszak & Drasgow [
46], consists of five subscales: skill variety, task identity, task significance, autonomy and feedback, and is similarly considered to be a determinant of intrinsic motivation [
47]. However, even if these items are determinants of intrinsic motivation, they do not exclude passion exploitation. For example, Spreitzer's [
42] "meaning" includes the item "My job activities are personally meaningful to me." Managers may be skillfully manipulating loyal and obedient employees to have this kind of impression of their jobs.
Therefore, to determine whether passion exploitation has occurred, the ERI alone is insufficient, and even if it is used in conjunction with the PES or JDS, it is insufficient. This is because passion exploitation and intrinsic motivation are conceptually similar, as mentioned above. To determine whether passion exploitation has occurred, attention should be paid not to whether employees are intrinsically motivated, but to the conditions that determine the employees' consciousness. A manager who is good at passion exploitation will want to control the psychology of employees and make them believe that they are doing extra work of their own volition and choice. Further, an employee who is asked by his or her superior to do work that goes beyond his or her original role may try to gain a reputation as a "passionate employee" by accepting it. In this case, the employee may not think that he or she is being exploited. However, if one looks at the background personnel, it may not be impossible to notice such exploitation.
Let us think about it a little based on the discussion in this paper. For example, this situation may have come about because the roles of employees are ambiguous, which allows the boss to assign work arbitrarily, and loyal subordinates who are unlikely to refuse may be targeted (role ambiguity). Also, because it was a workplace where it was difficult to disagree with the boss, obedient subordinates may have become targets for exploitation (psychological safety). These are conditions that make it easy for passion exploitation to occur. On the other hand, workplace social capital may be useful in determining the extent of passion exploitation after it has occurred. In workplaces where exploitation is occurring, there may be a breakdown in solidarity among employees, as the "moralization" theory preaches. Furthermore, if employees lack support from each other, they will become more dependent on their bosses and will be more susceptible to further exploitation (social capital). Furthermore, exploitation may cause a disruption in the balance between life and work. If employees who sacrifice their lives and devote themselves to work are praised and seen as role models in the workplace, it will be easier for their bosses to exploit them (work-home interaction). Therefore, to measure whether passion exploitation is occurring in the workplace, it is recommended to use the items shown in
Table 1, for example. This study proposes that these items be used in conjunction with the ERI as reference information for determining whether the ERI is at an acceptable level.