This paper mainly considers the elderly life satisfaction in China. We find that influenced by the traditional concept and culture, the care of the elderly in China is mainly undertaken by relatives [18] . Since many elder live away from their children, the elderly always live together with their spouse and they need to take care of their spouse. The existing research focuses on the effect of taking care of your spouse and the companionship of spouse [14] . Previous research shows that, taking care of spouse always brings huge life burden and great mental pressure [19] . Moreover, with the decrease of social communication and the increase of loneliness experience, caregivers are prone to depression [20] . At the same time, since caregivers usually can’t get the desired thanks from their spouse, their emotional demands can’t be satisfied [21] . Therefore, some studies have pointed out that caregivers and their spouse need to maintain a certain emotional distance, which is beneficial to their own health [22] . In addition, in recent years, some studies have added individual characteristics into the discussion. Studies have shown that caregivers’ psychological states moderated the relationship between taking care of spouse and owning life satisfaction [23] . With positive self-psychological adjustment, their life satisfaction was less affected by their spouse relatively [24] . This paper aims to study how their spouse’s physical health influence their own life satisfaction. Considering previous study, we propose:

Hypothesis 1: Spousal health is positively related to elderly people’s life satisfaction.

Simultaneously, optimism is often viewed as a positive mindset in terms of individual characteristics [25] . At present, there exist mainly three definitions of optimism in the academic fields: temperament orientation, explanatory style orientation, and information processing orientation [26] . The study of optimism was primarily in the field of physical health, mental health, and personal achievement [27] . In the field of mental health, optimism is considered to be the most important predictor variables, the results show that people more optimistic tend to own higher levels of life satisfaction [28] . At the same time, further research indicates that there is a strong direct relationship between optimism and positive emotions or negative emotions [29] .

In recent years, many researchers became interested in the study of optimism in the field of intimate relations [30] . They have found that optimism is a stable personality trait, higher optimistic level leads to higher marital satisfaction [31] . So we wonder whether optimism has an effect on life satisfaction, and how the relationship be moderated by other variables. To sum up, we propose:

Hypothesis 2: Elderly people’s optimism moderates the relationship between spousal physical health and their life satisfaction such that this relationship is stronger when their optimism is low than when it is high.

In addition, the socioeconomic status (SES) plays an important role in the life satisfaction of the elderly [32] , there are mainly three aspects included in elderly SES: the level of social service, the level of own economic life, and the intergenerational support of children. In terms of social support, most studies have pointed out that the more perfect social basic services for the elderly, the higher life satisfaction they will own [33] . In the standard of their own SES, the higher income levels, the higher life satisfaction [34] . But some researches also pointed out that the SES of the elderly is not directly affect the life satisfaction. Life satisfaction also affected by the emotional factors [35] . For instance, in terms of intergenerational support, most of the study pointed out that higher economic support, higher life satisfaction [36] . But there also exist some of the opposite conclusions: since the elderly incapacitated, the high support of their children will bring sense of pressure; at the same time, anxiety declines life satisfaction [1] . Therefore, we are interested in whether the economic income will affect the life satisfaction of the elderly, and what’s the specific mechanism. According to the above statements, we have the following hypothesis:

Hypothesis 3: There is a three-way interaction between elderly people’s SES, optimism, and spousal health such that when optimism is low rather than high, the moderating effect of SES on the relationship between spousal physical health and life satisfaction will be stronger.

To sum up, the existing literature for the study between spouse’s health and their life satisfaction mainly focused on a direct impact. Although some studies have pointed out that the caregiver’s mentality has a moderate effect, but the detail in moderating process and effecting factors has no further research. At the same time, there are different views on the influence of SES for their life satisfaction. Since life satisfaction is positively related to self-perception, we use subjective perceptions of SES as a variable to further explore the relationship between SES and life satisfaction. Based on the existing research, this article mainly starts with the subjective perception of the elderly. We try to find out the influencing factors on the life satisfaction of older people, and select spouse’s health, optimism, and their socioeconomic status as three key factors for consideration. Data from the 2011-2012 Chinese Longitudinal Healthy Longevity Survey (CLHLS) are used to examine our hypotheses. We find that there is a three-way interaction effect between elderly people’s SES, their optimism, and their spouse’s health on their own life satisfaction. Additionally, the results show that when elderly people’s optimism is low rather than high, the moderating effect of SES on the relationship between spousal physical health and life satisfaction is stronger.

Data from the 2011-2012 Chinese Longitudinal Healthy Longevity Survey (CLHLS) are used to examine our hypotheses. This survey started with 1998 and included approximately two-thirds of the provinces in mainland China, accounting for 82% of the total population of China in 2010. Various researchers at Peking University, the Chinese Academy of Social Sciences, Duke University, the Max Planck Institute for Demographic Research, and the University of Southern Denmark coordinated the design of the study and the required fund-raising. The major aim of this survey was to investigate the life quality of elderly people in China. Thus, it is appropriate to use it to examine our framework. Because this study focused on the influence of elderly people’s spouses on their own quality of life, the suitable participants were selected by the item “who lived together with their spouse.” After excluding those who did not live with their spouse, we had a final sample of 3150 elderly adults (average age = 79). According to the descriptive statistical analysis results, the participants are mainly from two age groups (70 - 79 and 80 - 89), accounting for 43.9% and 27.9%, respectively. Regarding education level, 37.9% of the participants had no educational experience, 30.9% had 1 to 5 years of schooling, and 24.4% had spent 6 to 10 years in school. Regarding geographical location, the majority of the respondents were from eastern and central China. Table 1 provides the demographic distributions in the sample used for analyses (unweighted n’s, weighted percentages).

In the 2011-2012 CLHLS, the demographic items included gender, age, education, and geographic location. Several variables concerning this study were used, such as elderly people’s optimism, quality of life, SES, and their spouse’s physical health. The statistical package SPSS 21 for Windows was employed to examine our hypotheses.

Elderly people’s life satisfaction. Self-reported life satisfaction was measured by the item “How do you rate your life at present?” This item was rated on a 5-point Likert scale ranging from 1 (very good) to 5 (very bad). Table 2 provides the percentages for the different levels of participants’ life satisfaction used for analyses. According to the results, most of the participants perceived their life to be good or so-so, and only 4.9% reported negative attitudes as an aspect of their life quality.

Spousal health. It was measured by the item “How do you rate your spouse’s health at present?” The options for this item included 1 (very good), 2 (good), 3 (so-so), 4 (bad), and 5 (very bad). Table 3 provides the percentages for spousal health in the sample used for analyses. This result showed that most of the participants’ spouse’s physical health was good or so-so.

Optimism. It was measured by the item “Do you always look on the bright side of things?” The item included five options, which were scored as follows: 1 = always, 2 = often, 3 = sometimes, 4 = seldom, 5 = never, 8 = unable to answer, 9 = missing. Every option reflected an attitude towards life, with lower scores indicating more optimistic. Table 4 provides the percentages for the different degrees of optimism in the sample used for analyses.

Socioeconomic status. It was assessed by the item “How do you rate your economic status compared with others in your local area?” The item was rated on a 5-point scale: 1 = very rich, 2 = rich, 3 = so-so, 4 = poor, 5 = very poor. Every option reflected the SES, with lower scores indicating higher SES. Table 5 provides the percentages of degree of SES in the sample used for analyses.

Control variables. To exclude the effects of other exogenous variables, we controlled the participants’ demographic information in our analyses, including their age, and gender.

This article contributes to the literature in several ways. First, this article further examines the association between elderly life satisfaction and their spouse physical health. The existing literature focuses on the negative effect of caring their spouse, however, this paper indicates that the optimism has an impact on their spouse health and their life satisfaction. The more optimistic, people are less affected by their spousal health. At the same time, this article calls for Carnelley & Janoff-Bulman’s (1992) research about how optimism effect the intimate relationship [40] . Furthermore, the SES as a factor of life satisfaction, some studies have shown that higher levels of social economic status lead to higher life satisfaction. We further find that the optimistic people are less affected by the SES, and the pessimistic people are easier to be affected by the economic status. We further examine how optimism plays an important role in elderly people’s life satisfaction. People with a low level of optimism are more likely to be influenced by external factors. The reason may be that optimistic people have more positive attitudes toward their lives and own higher life satisfaction. The prior literature has suggested that good physical and mental health, problem-free financial status, good family support, and an active social life are major contributors to elderly people’s life satisfaction [41] . Our results indicate that the effect of optimism is stronger than that of SES. Self-regulation is more important for individuals than material conditions. Therefore, we propose that good mental health makes elderly people happier.

The findings also make practical contributions. Firstly, we further demonstrate that in intimate relationships, their spousal health has an impact on their own health. Therefore, keeping healthy is not only important to themselves, but also important to their spouse. Secondly, we confirm the moderating effect of optimism on life satisfaction. We propose that it is important for elderly people to remain optimistic. So how to keep the elderly positive and optimistic is the key to improving the life satisfaction of the elderly. Thirdly, if the elderly is pessimistic, their life satisfaction is more easily to be influenced by SES. And pessimistic elder prefer to be more negative, so the life satisfaction will be lower when the SES is relatively lower. All in all, our results show that spousal physical health affects their own quality of life, and optimism and SES moderate the relationship between elderly people’s spousal physical health and their own quality of life.

As mentioned above, maintaining optimism among the elderly is the key to improving their life satisfaction. So we offer the following suggestions on how to promote optimism among the elderly. Firstly, the elderly could cultivate healthy hobbies and interests. They can actively participate in recreational and sports activities, and cultivate a variety of hobbies. Secondly, they could expand social exchanges and seek comfort and support, so that bad emotions can be eliminated, achieving the goal of easing ideological contradictions and psychological conflicts. Thirdly, children should spend more time with the elderly to ease their loneliness.

It is important to note several limitations of this study. First, the criteria to evaluate SES may vary across different regions. Our study attempts to address this flaw by controlling for variables that could possibly affect the participants’ feelings about life quality. Second, each variable was measured by only one item, which made our measurements unreliable. However, the relatively large sample size mitigates the negative effect of this issue. Third, we conducted this research in China, an emerging country. We should expand our research to other countries to generalize the results. Finally, George and Bearon (1980) indicated that elderly people’s life quality included many dimensions, such as their health status, self-esteem, life satisfaction, and absence of financial stress [42] . To better understand elderly people’s life quality, each dimension must be studied in depth in the future [43] .