Religious Affiliation and Marital Satisfaction: Commonalities Among Christians, Muslims, and Atheists

Scientists have long been interested in the relationship between religion and numerous aspects of people’s lives, such as marriage. This is because religion may differently influence one’s level of happiness. Some studies have suggested that Christians have greater marital satisfaction, while others have found evidence that Muslims are more satisfied. Additionally, less-religious people have shown the least marital satisfaction. In the present study, we examined marital satisfaction among both sexes, and among Muslims, Christians, and atheists, using a large, cross-cultural sample from the dataset in Sorokowski et al. (2017). Our results show that men have higher marital satisfaction ratings than women, and that levels of satisfaction do not differ notably among Muslims, Christians, and atheists. We discuss our findings in the context of previous research on the association between marriage and religion.


INTRODUCTION
Religion has been present nearly since the dawn of human history (Dickson, 1992;Clottes, 2006). Nowadays, it continues to play a key role in most societies (Tarakeshwar et al., 2003). Almost 82% of the world's people affiliate themselves with a religion. By country, only 5% of Americans, 4% of South Africans, 1% of Brazilians, and 3% of Indians claim to be atheists (Win-Gallup International Poll, 2012). It therefore seems viable that we should deepen our understanding on how religion influences our lives (Miller and Thoresen, 2003;McCleary and Barro, 2006). As religion is strongly connected with a wide range of relationship-related values and norms (Zarean and Barzegar, 2016), the link between religion and family life has been among the most widely discussed topics in the social sciences (Thomas and Cornwall, 1990;Ammerman and Roof, 1995;Christiano, 2000). The present study aimed to investigate one of those aspects: the association between religion and marital satisfaction.
There is even less evidence of the relationship between atheism and marital satisfaction. Some studies have shown a positive association between religiosity and marital satisfaction (Lichter and Carmalt, 2009;Wilcox and Wolfinger, 2008), or mental well-being (Galen and Kloet, 2011), which would suggest atheists (at the low end of the religiosity continuum) may have lower indicators of marital happiness than religious adherents. Nevertheless, to date, researchers have not directly addressed the issue of atheists in the marriage context, as existing studies have generally focused on religious married couples (Giblin, 1997;Fincham et al., 2011), thus excluding the relatively large number of atheists. These prevent drawing of certain conclusions about marital satisfaction among non-religious people.
In sum, no cross-cultural studies have compared marital satisfaction among people of various religious affiliations (or nonreligious: atheists). One can only hypothesize why scientists are not willing to tackle this issue. One reason might be that such comparisons are often perceived as politically incorrect (Raines, 1996). Nevertheless, comparisons within a single religion or culture do not permit generalization of the conclusions, as people of different religious affiliations might be subject to different, culture-specific pressures and situations (Tarakeshwar et al., 2003). To fill this gap in knowledge, the present study aimed to analyze the relationship between religious affiliation and marital satisfaction, in a large, cross-cultural sample.

Participants
We used data from the dataset published in Sorokowski et al. (2017), a study conducted between July 2012 and December 2013. Participants, after providing informed consent, completed a written questionnaire (except in two countries where data were collected online), and were not compensated for their participation (except in one country where participants received 50 Hong Kong dollars). See Sorokowski et al. (2017) for more details regarding the participants in the dataset.
The present study's main goal was to compare people from the world's most common religions (Grim et al., 2015). The Sorokowski et al. (2017) dataset included Protestants, Christians, Jews, Muslims, Buddhists, Atheists, Jehovah's Witnesses, Evangelicals, Spiritualists, Orthodox, Hindus, and others not of the aforementioned religious affiliations. Despite this wide representation, we decided to only analyze answers provided by Christians, Muslims, and atheists, as these were the most highly represented religious and non-religious samples deriving from the different countries in the dataset (Christians from 27 countries; Muslims from 23 countries, and atheists from 27 countries; see Tables 1, 2). Thus, in contrast with studies of people from a single country (e.g., Brown et al., 2008;Vaaler et al., 2009), our study aimed to compare religious affiliation and marital satisfaction among various nationalities.

Procedure
All questionnaires were translated into the participants' local language (with the exception of English-speaking countries, where questionnaires were administered in their original wording), using back-translation (Brislin, 1970). Participants were surveyed (inter alia) via two questionnaires that inquired on marital satisfaction. In the present study, one questionnaire, the Kansas Marital Satisfaction Scale (KMSS) (Nichols et al., 1983;Schumm et al., 1986), was included in the analysis. The KMSS is a well-established and commonly used tool for assessing satisfactory psychometric characteristics (Schumm et al., 1986;Crane et al., 2000), and was successfully used in studies involving non-Western samples (Shek and Tsang, 1993). Sorokowski et al. (2017) found the scale was culturally equivalent (Tucker's phi coefficient from 0.92 to 1), and reliable (Cronbach's alpha on the pooled data reached 0.94). Questions from the scale include: "How satisfied are you with your marriage?" and "How satisfied are you with your wife/husband as a spouse?" Participants answered each item on a seven-point scale ranging from 1 (extremely dissatisfied) to 7 (extremely satisfied). In all subsequent analysis, as a measure of marital satisfaction we used mean scores of each participant's KMSS answers.
Participants were asked directly about their religious affiliation. Certain variables that in previous studies have been shown to correlate with marital satisfaction-such as age, length of relationship, education, number of children, and material situation (Bradbury et al., 2000;Twenge et al., 2003;Sorokowski et al., 2017)-were also included in the analysis. Detailed information about the procedure for data collection can be found in Sorokowski et al. (2017).

RESULTS
We conducted an analysis of covariance to determine the relation between religious affiliation and marital satisfaction. There was a non-significant effect of the former on the latter, after controlling for sex, age, length of marriage, number of children, education, and material situation [F(2,5194) = 1.11, Overall, men (mean = 5.83, SD = 1.34) had higher marital satisfaction than women (mean = 5.59, SD = 1.48) (see Figure 1). Nevertheless, this effect was extremely weak (Eta < 0.01).

DISCUSSION
The present study's primary goal was to examine the association between religious affiliation and marital satisfaction, and the results showed that there was no relationship between the former and level of the latter-Christians and Muslims were found to be similarly satisfied with their marriages, as were atheists. Nevertheless, the present analysis provided support for a link between marital satisfaction and age (younger people showed higher marital happiness), material status (higher material status, higher marital satisfaction), or sex (men were happier in their marriages than women). Previous findings have indicated Abrahamic religions (e.g., Christianity, Islam) share many similarities (Agius and Chircop, 1998;Zarean and Barzegar, 2016) and promote formation of traditional family ties, such as marriage rather than cohabitation, and marital rather than non-marital births (Dollahite and Lambert, 2007;Zarean and Barzegar, 2016). However, these religions have some substantive differences in beliefs and practices. For example, polygyny is not accepted in Christianity, whereas it is widely accepted in Islam, and such a family model may negatively influence marital life (Al-Krenawi and Graham, 2006). Despite the discrepancies between those two religions, the present study found no differences between them as far as marital satisfaction, and this included people from different parts of the world.
Moreover, since the New York City terrorist attacks on September 11, 2001, Islam has been central in many debates, discussions, and publications (Alghafli et al., 2014). Discussion on Islam frequently concerns familial issues, perceived by the Western media mostly in a negative light. Problematic issues include, for instance, gender roles and the treatment of women (McDonald, 2006;Ridouani, 2011;Ennaji, 2016). Studies, however, do not support this unfavorable view of females' situations: religious Muslims show increased marital satisfaction (Abdel-Khalek, 2006Asamarai et al., 2008;Ahmadi and Hossein-Abadi, 2009;Zaheri et al., 2016, but see also Abu-Rayya, 2007).
The present study's results provide evidence that Christians and Muslims do not differ in their level of marital satisfaction. People from various countries identifying themselves as belonging to one of these two religions had similar level of marital happiness, which is consistent with previous findings. For instance, Dabone (2012) compared marital satisfaction among Muslim and Christian spouses, and found relative dissatisfaction, while the religious affiliation did not affect the satisfaction.
As scarce data exist on marital satisfaction among atheists, the present study's second aim was to investigate whether atheists have similar marital satisfaction to marriages as do religious adherents. Considering positive correlations found between religiosity and marital satisfaction (Marks, 2005), atheists may be expected to have significantly lower levels of both variables. A major drawback of previous related research is its predominant focus on comparisons between more-religious and less-religious people (Fincham et al., 2011), excluding the relatively large group that atheists represent. Additionally, most studies have been conducted in the United States, where atheists are often negatively stereotyped (Zuckerman, 2009). The present study results provide evidence that atheists are neither more nor less satisfied with their marriages than religious adherents, which suggests religion may not influence marital satisfaction.
There are a few possible explanations for observed similar marital satisfaction ratings across people of different religions. Overall, married couples constitute a lower percentage of people in a relationship (Nock, 1995). Those who decide to get married may be particularly committed or well-suited to partnership, regardless of their religious affiliation. Entering a serious relationship, such as marriage, requires strong enthusiasm toward the partner (Wang and Chang, 2002) and, thus, results in higher ratings of subjectively perceived relationship satisfaction. Another possible explanation may be that people generally consider marriage a long-lasting relationship (Silliman and Schumm, 2004;Willoughby and Dworkin, 2009), and when they decide to get married, they rationalize and "cognitively close" their choice (Webster and Kruglanski, 1994). Participants in the study population may have felt they had to be satisfied with their relationship, as they had invested so much energy into its development. Had they reported being unsatisfied, feeling an internal conflict may have surfaced (e.g., "Why am I even with him/her if it makes me unhappy?"). The need to explain the dissonance of staying in an unsuccessful relationship would be negatively perceived, and could yield unpleasant emotions, especially in Western, individualistic cultures, which value the pursuit of personal happiness at all costs (Gilovich et al., 2015). Such emotion could also occur in Eastern, collectivistic cultures, which emphasize the importance of being unselfish, grateful, and appreciative of one's partner (Kagawa-Fox, 2010).
In general, participants were relatively satisfied with their marriages. Nonetheless, men's marital satisfaction differed from women's (independent of religious affiliation). Over 40 years ago, Bernard (1975) presented a provocative and controversial thesis asserting marriage is better for men than for women, and his statement has raised heated discussions. Most of the research has provided evidence for to support Bernard's (1975) that thesis (Fowers, 1991;Schumm et al., 1998), and this is also true in non-Western cultures (Shek and Tsang, 1993;Asamarai et al., 2008). However, there was also one study which yielded unclear findings (McNulty et al., 2008). Results of the present study -which is based on the analysis of a large, cross-cultural sample, confirm the differences among men's and women's marital satisfaction: husbands did indeed have higher marital satisfaction than wives. Nevertheless, the size effect of these sex differences was extremely small (Eta < 0.01).
In conclusion, despite a large body of research on marital satisfaction (Bradbury et al., 2000;Twenge et al., 2003;Hilpert et al., 2016), most studies have rarely controlled for participants' religion. Even when they have done so, they have not explored the differences between people of various religious affiliations (Sullivan, 2001;Williams and Lawler, 2003;Olson et al., 2016). Future research should therefore focus on people of different (1) religions (especially lessprevalent ones); and (2) cultures (as most studies up to date have been conducted on Western, educated, industrialized, rich, and democratic populations (Henrich et al., 2010), and should take into consideration other factors that may influence marital satisfaction among people of different religious affiliations (e.g., number of children, education, country's development), as this would provide further understanding on the interaction between religion and marital happiness, as well as culture.

DATA AVAILABILITY STATEMENT
Publicly available datasets were analyzed in this study. This data can be found here: https://figshare.com/s/ d2bd33a9605a3a204881.

ETHICS STATEMENT
The studies involving human participants were reviewed and approved by the Institutional Review Board of the Institute of Psychology, University of Wrocław. The patients/participants provided their written informed consent to participate in this study.