1 Introduction

1.1 Peace

Peace is universally valorised, as reflected in its selection as the very first word of the UN’s motto: “Peace, dignity, and equality on a healthy planet.” Similarly, it is celebrated in their Universal Declaration of Human Rights (United Nations General Assembly, 1948), drafted and agreed by representatives from all world regions: “Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world.” Much attention has accordingly been paid to it, giving rise to an entire field of scholarship known as Peace and Conflict Studies. Yet despite this interest, academic understanding of the concept is limited in a significant but underappreciated way. Although peace has two main meanings in common language, namely ‘outer’ and ‘inner’ varieties, the literature on this topic mostly focuses on the former, with relatively little consideration of the latter, for reasons we speculate about shortly. Outer peace is a collective phenomenon, referring to relations among people at myriad levels of scale, including relational/interpersonal (one-to-one) peace, intragroup peace, intergroup peace, and more broadly, community, national, and global peace (Cohrs et al., 2013; Niemiec, 2022). Inner peace (IP) by contrast is an individual phenomenon, pertaining to a person’s state of mind, understood through the lens of concepts like calmness, serenity, and equanimity. Here we focus on IP, aiming to redress its relative omission from scholarship on this topic. First though it is worth briefly considering the notion of peace more generally.

The term has a long history and – prefiguring the academic bias highlighted above – originally pertained more to outer societal conditions, at least in English. It entered the lexicon around the 12th Century, via Old French, from the Latin pax (agreement, treaty of peace, absence of war). As the caveat about English implies though, this etymological consideration does not necessarily apply to all cultures and languages. Elsewhere concepts roughly equivalent to IP had roots other than an adaptation from a term originally pertaining to outer phenomena. There is a particularly rich lexicon around IP in Eastern languages, where qualities like upekkha/upeksa (Pāli/Sanskrit), often rendered as equanimity, have for over two millennia been revered in Buddhism as one of the sublime meditative states one ideally seeks to cultivate (Weber, 2017). Similarly in the Hindu tradition, IP accompanies realisation of Brahman (absolute reality beyond the illusions of ego-centric experiences). Such states are not only an Eastern concern moreover, but have also been prized in Western arenas. Classical Greek philosophy features celebrations of qualities such as ataraxia (an equanimous freedom from distress particularly prized by the Epicureans) and apatheia (a level-headed balance between excessive emotion and indifference associated particularly with Stoicism) (Nguyen, 2018). IP was highly valued in such contexts as necessary for wisdom and enlightenment, as well as a precondition for contributing to harmony in the outer world (Xi & Lee, 2021). In reflecting on the origins of the English word peace therefore we must bear in mind this is only a partial history of this concept, just applying to English speaking cultures. Crucially though it is such cultures that have come to dominate fields like psychology, as discussed below, with English the hegemonic international language of academia. The linguistic and cultural biases inherent in English consequently have had an outsized impact on our understanding of this concept. With these points in mind we turn to IP specifically, which despite its importance has been rather overlooked.

1.2 Seeking Inner Peace

The main way IP has been approached in an academic psychological context is through the prism of low arousal positive states (LAPS). The context to this framing is Russell’s (1980) influential circumplex model, which holds that affective states can be primarily understood through the intersection of two parameters: valence (i.e., pleasant and approach-inducing versus unpleasant and withdrawal-inducing), and arousal (i.e., high versus low, or active versus passive). Various forms of affect are thereby understood as being generated – physiologically, mentally, experientially, etc. – by their interaction (Posner et al., 2005). By juxtaposing them Russell created a two-dimensional state space with four quadrants: (1) low arousal and negative valence (e.g., depression); (2) high arousal and negative valence (e.g., anxiety); (3) low arousal and positive valence (e.g., calmness); and (4) high arousal and positive valence (e.g., elation). Per this model IP is situated in third quadrant, broadly labelled as LAPS. One might note though that IP need not necessarily be construed through a LAPS lens, which may in fact reflect a Western-centric perspective. A gathering of Western cognitive scientists and Tibetan Buddhist scholars at MIT for example uncovered differences in what it means to categorise emotions as positive or negative (Goleman, 2003; Harrington & Zajonc, 2006). While the scientists regarded positively-valenced emotions as positive in a more general sense (i.e., desired and desirable), the Buddhists generally saw any movement away from a neutral state of observing the fleeting nature of emotions – even positively valenced ones – as an essentially ‘negative’ state. They therefore recommended people seek emotional stillness – which they characterized, most relevantly, as a state of IP – unperturbed by emotional swings in either direction. IP is thus still valued, but would not be considered a LAPS (at least insofar as ‘positive’ denoted emotional valence), but a state of emotional neutrality.

Whether IP is best characterized as a LAPS or instead emotionally neutral is an open question. But whatever the framing, participants in the gathering noted above would agree that IP matters. In Buddhism it is valorized as a desirable mental state, and perhaps even an optimal one, constituting a zenith of psychospiritual development. And even though IP has been understudied in Western psychology, research on related concepts similarly indicates the relevance of IP to mental health. The best way to appreciate this literature is to consider the antonyms of peace. Merriam Webster (www.merriam-webster.com/thesaurus/peace) for instance differentiates peace into outer forms (“as in peacefulness”) and inner forms (“as in tranquillity”), with antonyms for the latter including anxiety, anguish, agitation, concern, care, apprehension, uneasiness, worry, alarm, stress, tension, vexation, and many more. One might therefore reasonably draw on scholarship on any of these topics to illustrate the value of IP. The vast clinical psychology literature on anxiety and stress, for example, could from this perspective be construed as being concerned with a relative lack of IP, while conversely one could construe IP as a relative lack of anxiety and stress. This is not to imply that IP is necessarily a polar opposite of these concepts. Anxiety and stress are not identical states, and so treating IP as an antonym of both implies there are different forms of IP, depending on the negative state of which IP constitutes a lack. Drawing on the aforementioned Buddhist perspective though, all these negative states might constitute forms of mental perturbation, of which IP does indeed simply constitute the relative absence, whatever the degree and type of perturbation. By analogy, ocean waves can vary in all manner of ways – size, force, shape, etc. – but calm water is simply the absence of waves.

Whatever the precise dynamics of IP though, we would argue that its relevance and importance can be grounded in the literature around states like anxiety and stress, of which IP could be construed as a relative lack. But as our cautious language here indicates (“… could be construed…”), this assertion is more by inference, based on consideration of the linguistic properties of peace and its antonyms. Our speculations in the paragraph above around the dynamics of IP are exactly that – speculative ideas that need to be explored empirically. Yet as foregrounded above there has been a distinct lack of research focusing on IP, even among disciplines where one might expect to find such work. Since positive psychology emerged in the late 1990s, for instance, it has generated a great wealth of scholarship into topics such as subjective wellbeing (Diener et al., 1999). This is generally conceptualized as comprising: a cognitive component, usually understood using constructs like life satisfaction or evaluation; and an affective component, viewed through the prism of high positive and low negative affect (Watson et al., 1988). LAPS are therefore an integral part of the latter component. Most research on subjective wellbeing however has focused on high arousal states (McManus et al., 2019). Perhaps the dominant explanation for these trends are, (a) the Western-centric nature of psychology, and (b) greater importance being placed on high rather than low arousal states in Western cultures, and hence psychology. Let’s briefly consider these in turn.

2 Overlooking Inner Peace

The Western centricity of psychology is increasingly acknowledged. Long a concern in some quarters, it was influentially brought to attention by Henrich et al. (2010), who argued most research is conducted by and on people in societies deemed “WEIRD” (Western, Educated, Industrialised, Rich, and Democratic). Although one cannot simplistically classify places in a binary way as WEIRD versus non-WEIRD – as each element of the acronym is a spectrum upon which countries may be variously situated (Ghai, 2021) – most of the world is not as WEIRD as the USA, from where most research in top journals originates. This cultural bias has numerous issues and implications, including calling into question the generalizability of the findings. Some scholars would counter they are generalizable, on the basis that humans are relatively similar across cultures and share a common nature. However, a wealth of research shows people do have meaningful differences across myriad aspects of life related to their cultural location (as discussed next). Consequently, one cannot simplistically draw conclusions based on participants mainly from WEIRD contexts.

This Western-centricity has been linked to the relative inattention in the literature to LAPS such as IP. Cross-cultural scholars, notably Tsai (2007), suggest that preference for, and emphasis of, high arousal states may be a relatively Western-centric concern, whereas Eastern cultures place greater value and weight on LAPS. Tsai described such preferences as “ideal affect” – “the affective states that people strive for or ideally want to feel” (p. 243) – and has observed these across an extensive series of studies (Tsai et al., 2000; Tsai, Knutson et al., 2006a, b; Tsai et al., 2007a, b; Tsai et al., 2007b, 2016), with similar patterns found by others (Leu et al., 2011; Lee et al., 2013; Kuppens et al., 2017; Xi & Lee, 2021). That said, new research on LAPS in the Gallup World Poll – discussed below – indicates that both peace (Lomas et al., n.d.) and calmness (Lomas et al., 2023) may be more universally valued than is frequently appreciated, and indeed, in their data, had no particular association with Eastern countries. Even so, the work of scholars like Tsai nevertheless suggests there is a relatively robust connection between LAPS and Eastern cultures.

A common interpretation of this link invokes another pattern often noted in relation to East-West differences: the distinction between individualism and collectivism. The East is widely viewed as leaning towards a collectivist orientation, which Markus and Kitayama (1991) describe as involving “distinct conceptions of individuality that insist on the fundamental relatedness of individuals… [where the] emphasis is on attending to others, fitting in, and harmonious interdependence with them” (p. 224). This distinction has since been explored in hundreds of studies, with numerous meta-analyses, not only of the distinction per se, but specific facets, such as its link to subjective wellbeing (Yu et al., 2018). Most relevantly here, high arousal states are seemingly liable to be interpreted in the East as self-aggrandizing and therefore disruptive of social harmony, whereas LAPS are more conducive to such harmony (Leu et al., 2011; Uchida & Kitayama, 2009). Then, besides individualism and collectivism, scholars have pointed towards other cultural trends, such as the rich history of contemplative practices in Eastern cultures, that perhaps also contribute to a greater valorisation of LAPS (Joshanloo, 2014). Whatever the explanation, there has been a relative inattention to LAPS in the literature, with research tending to focus on high arousal states (McManus et al., 2019). The situation may now be changing though within a broader concern with redressing the Western-centricity of psychology: a bibliometric analysis by Hendriks et al. (2019) of positive psychology interventions found that although 78.2% were from Western countries, there was “a strong and steady increase in publications from non-Western countries since 2012,” indicating an encouraging “trend towards globalization” of happiness research (p. 89).

These dynamics have also meant LAPS are beginning to receive more attention: a good example is the Global Wellbeing Initiative (GWI), whose remit is to develop a module of items for the Gallup World Poll (GWP) that reflect ideas relating to flourishing associated with Eastern cultures. Since debuting in the 2020 GWP, the module has been through two substantive iterations (Lomas et al., 2022), and by 2022 was focused entirely on balance and harmony, together with the closely linked phenomenon of LAPS, described collectively as “harmonic principles of wellbeing” (Gallup & Wellbeing for Planet Earth, 2023). Each year it has featured an item on IP: “Did you feel at peace most of the day yesterday, or not?” (2020); “In general, how often do you feel you are at peace with your thoughts and feelings?” (2021); and “In general, how often can you find inner peace during difficult times?” (2022, 2023, 2024). While work is underway to explore these items, such as an assessment of their relationship with forms of outer peace (Lomas et al., n.d.), much more research is needed to better understand this topic more broadly, especially the various factors that shape this valued outcome.

To that end, this paper reports on an assessment of IP in the Global Flourishing Study (GFS), an unprecedently ambitious intended five-year (minimum) longitudinal panel study investigating the predictors of human flourishing across over 200,000 participants from 22 geographically and culturally diverse countries. This includes an item on IP, adapted from the 2021 GWI item: “In general, how often do you feel you are at peace with your thoughts and feelings?” (always, often, rarely, never). The analysis is guided by three research questions: (1) What are the distributions and descriptive statistics of key demographic factors in our international sample; (2) how do mean levels of IP order across countries; and (3) how do levels of IP in life vary across demographic categories? In relation to these questions, we have three hypotheses: (1) the distributions and descriptive statistics of key demographic features will reveal diverse patterns across our international sample; (2) mean levels of IP will vary meaningfully across different countries; and (3) IP will exhibit variations across different demographic categories, and these differences across categories will themselves vary by country. The study design was pre-registered with the Open Science Framework on November 18th, 2023 (https://osf.io/yf6s3).

3 Methods

The description of the methods below has been adapted from VanderWeele et al. (2024). Further methodological detail is available elsewhere (Crabtree et al., 2021; Lomas et al., 2024; Padgett et al., 2024a; Ritter et al., 2024; Johnson et al., 2024).

3.1 Data

The GFS involves 202,898 participants (in this first year) from 22 geographically and culturally diverse countries, with nationally representative sampling within each country, concerning the distribution of determinants of well-being. Wave 1 of the data included the following countries and territories: Argentina, Australia, Brazil, Egypt, Germany, Hong Kong, India, Indonesia, Israel, Japan, Kenya, Mexico, Nigeria, the Philippines, Poland, South Africa, Spain, Sweden, Tanzania, Turkey, UK, and US. Countries were selected to (a) maximize coverage of the world’s population, (b) ensure geographic, cultural, and religious diversity, and (c) prioritize feasibility and existing data collection infrastructure. Data collection was carried out by Gallup. Data for Wave 1 were collected principally during 2023, with some countries beginning data collection in 2022 and exact dates varying by country (Ritter et al., 2024). Four additional waves of panel data on the participants will be collected annually from 2024 to 2027. The precise sampling design to ensure nationally representative samples varied by country and further details are available in Ritter et al. (2024). Survey items included aspects of well-being such as happiness, health, meaning, character, relationships, and financial stability (VanderWeele, 2017), along with other demographic, social, economic, political, religious, personality, childhood, community, health, and well-being variables. The data are publicly available through the Center for Open Science (https://www.cos.io/gfs). During the translation process, Gallup adhered to TRAPD model (translation, review, adjudication, pretesting, and documentation) for cross-cultural survey research (ccsg.isr.umich.edu/chapters/translation/overview).

3.2 Measures

3.2.1 Demographics Variables

Continuous age was classified as 18–24, 25–29, 30–39, 40–49, 50–59, 60–69, 70–79, and 80 or older. Gender was assessed as male, female, or other. Marital status was assessed as single/never married, married, separated, divorced, widowed, and domestic partner. Employment was assessed as employed, self-employed, retired, student, homemaker, unemployed and searching, and other. Service attendance was assessed as more than once/week, once/week, one-to-three times/month, a few times/year, or never. Immigration status was dichotomously assessed with: “Were you born in this country, or not?” Religious tradition/affiliation with categories of Christianity, Islam, Hinduism, Buddhism, Judaism, Sikhism, Baha’i, Jainism, Shinto, Taoism, Confucianism, Primal/Animist/Folk religion, Spiritism, African-Derived, some other religion, or no religion/atheist/agnostic; precise response categories varied by country (Johnson et al., 2023). Racial/ethnic identity was assessed in some, but not all, countries, with response categories varying by country. Income was assessed using country-specific income brackets to align with local currency. For additional details on the assessments see the COS GFS codebook or Crabtree et al. (2024)

3.2.2 Outcome Variable

IP is assessed with one question: In general, how often do you feel you are at peace with your thoughts and feelings? The response categories are: always, often, rarely, never. In our analyses, we dichotomized IP as always/often [1] vs. rarely/never [0]. Also, as a post-hoc sensitivity analysis we provide the equivalent results of Table 1 in the Supplemental Tables with a different dichotomization point (see Tables S24a and S24b).

Table 1 Ordered proportions of inner peace
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3.3 Analysis

Descriptive statistics for the full sample, weighted to be nationally representative within each country, were estimated for each of the demographic variables. Nationally representative proportions for IP were estimated separately for each country and ordered from highest to lowest along with 95% confidence intervals, and robust standard errors. Variation in proportions in IP across demographic categories were estimated, with all analyses initially conducted by country (online supplement). Primary results consisted of a random effects meta-analyses of country-specific proportions of IP in each specific demographic category (Borenstein et al., 2010; Hunter & Schmidt, 2000), along with 95% confidence intervals, standard errors, lower and upper limits of a 95% prediction interval across countries, heterogeneity (τ), and for evidence concerning variation within a particular demographic variable across countries (Mathur & VanderWeele, 2020). Forest plots of estimates are available in the online supplement. All meta-analyses were conducted in R (R Core Team, 2024) using the metafor package (Viechtbauer, 2010). Within each country, a global test of variation of outcome across levels of each particular demographic variable was conducted, and a pooled p-value (Wilson, 2019) across countries reported concerning evidence for variation within any country. Bonferroni corrected p-value thresholds are provided based on the number of demographic variables (Abdi, 2007; VanderWeele & Mathur, 2019). Religious affiliation/tradition and race/ethnicity were used, when available, as control variables within country, but were not included in the meta-analyses since the availability of these response categories varied by country. As a supplementary analysis, population weighted meta-analyses were also conducted. All analyses were pre-registered with COS prior to data access (https://doi.org/10.17605/OSF.IO/YF6S3); all code to reproduce analyses are openly available in an online repository (Padgett et al., 2024c).

3.4 Missing Data

Missing data on all variables was imputed using multiple imputation by chained equations, and five imputed datasets were used (Sterne et al., 2009; van Buuren, 2023). To account for variation in the assessment of certain variables across countries (e.g., religious affiliation/tradition and race/ethnicity), the imputation process was conducted separately in each country. This within-country imputation approach ensured that the imputation models accurately reflected country-specific contexts and assessment methods. Sampling weights were included in the imputation model to account for missingness related to probability of study inclusion.

3.5 Accounting for Complex Sampling Design

The GFS used different sampling schemes across countries based on availability of existing panels and recruitment needs (Ritter et al., 2024; Padgett et al., 2024a). All analyses accounted for the complex survey design components by including weights, primary sampling units, and strata. Additional methodological detail, including accounting for the complex sampling design, is provided elsewhere (Padgett et al., 2024b).

4 Results

4.1 Descriptive Analyses

In the total sample, there were similar proportions of different age groups, except fewer participants were older than 70 + years (Table 2). The sample had a balanced representation of female (51%) and male (48%), and a small proportion of ‘other’ gender (< 1%). Most participants were married (52%), employed for an employer (39%), with 9–15 years of education (57%), never attended religious services (37%), and were native-born (94%). Sample sizes in each country ranged from 1,473 (Turkey) to 38,312 (United States). Participant characteristics for each country were shown in Supplementary Table S1A to S22A.

Table 2 Nationally representative descriptive statistics of the observed sample
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4.2 Ordered Proportions of Inner Peace by Country

The population percentage of IP was highest in Hong Kong (89 [95% CI = 87,91]) and Israel (87[85,88]). The estimated percentage of IP was lowest in the Philippines (50[48,52]) and Turkey (49[46,52]). The median (rank 11 & rank 12) estimated percentage of IP was in the UK (72[70,74]) and Indonesia (71[69,73]).

4.3 Inner Peace Within Sociodemographic Groups

The random effect meta-analyses pooled country-specific analyses of the proportion of the population within sociodemographic characteristics endorsing IP (see Table 3, all global p-values were below the Bonferroni corrected significance level of p < .007). The global p-value was significant (< 0.001) for IP across demographic characteristics, which provides evidence that in at least one country every demographic characteristic had significantly different proportions of IP across categories, even though the meta-analysis average proportions for groups may be similar. For instance, regarding gender, IP was similar on average among men (74[69,78]), women (72[67,77]), and other (81[43,96]), but within some countries gender differences in IP could be large (see Supplementary Tables for details). In Brazil, for instance, the percentage for males was 77 (75,78) while it was 66 (65,68) for women; conversely, in Japan, IP was higher among women (71[70,72]) than men (64[63,65]). The results in Table 3 also point to how older populations tend to report higher levels of IP, where 70–79 years olds report, on average, IP of 79 (73,75), while younger populations 18–24 report, on average, lower IP of 68(63,73). Married individuals also report higher IP on average than other marital statuses. And those attending religious services more often report higher IP (> 1/week; 80[73,85]) than those never attending (68[62,73]).

Table 3 Random effects meta-analysis of inner peace proportions by demographic category
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However, all demographic characteristics exhibited significant variability across countries. As illustrated above with gender, demographic groups may, on average, have similar levels of reported IP, but within different countries, these differences can be quite large. The bounds of the prediction intervals provide a better sense of how disparate across countries the percentage of individuals within a category can be. For example, the percentage of individuals within the 18–24 age group reporting IP is on average 68, and a randomly selected country in the GFS could have a percentage of the 18–24 population endorsing IP ranging from 44 to 86 with approximately 95% confidence. Estimates of heterogeneity (tau/) provide an estimate of how varied the proportions are on average across countries (i.e., the standard deviation of the percentage across countries). Further quantitative details on variation across countries are provided in the Online Supplement and additional comment on these results is provided in the Discussion below.

5 Discussion

The analysis sheds unique light on the demographic predictors of IP, a topic which has been relatively understudied and underappreciated in research on flourishing. In summary, all three of our hypotheses were supported, namely: (1) distributions and descriptive statistics of key demographic features reveal diverse patterns across our international sample; (2) mean IP varies meaningfully across different countries; and (3) IP exhibits variations across different demographic categories, and these differences across categories themselves vary by country.

Before delving into the predictors, let’s emphasize the striking confirmation of (2), with considerable differences in IP across countries. Dichotomizing people into those who either have IP (��often” or “always”) or do not (“rarely” or “never”), the percentage reporting IP ranged from just 49(95% CI = 46,52) in Turkey and 50(48,52) in the Philippines to 87(85,88) in Israel and 89(87,90) in Hong Kong. As valuable as is our analysis of the demographic predictors of IP, arguably an even more notable contribution of this study is its cross-national coverage. Above we noted the Western-centricity of fields like psychology, which is an issue for many reasons, including the common attempt to extrapolate from populations in heavily-studied places like the US to the rest of the world. Our findings show the folly of that kind of generalization. Here the percentage with IP in the US was 79(78,80), meaning nearly four out of five adults often or always experience it. Based on that figure we would conclude IP is fairly common. But that would occlude the fact that 15 of the 22 countries had lower levels, yet also that some countries managed yet higher levels. We should acknowledge though that some caution is needed in interpreting cross-national differences as these may be influenced by matters of translation, cultural norms, interpretation of items and response scales, and seasonal effects arising from data being collected in different countries at different times of year.

As to why this national variation is observed, we are unable to determine that from our analysis. Even so, there are some speculative lines of enquiry on which such research can draw. One resource is a new Global Comparison Framework, which ranks nations on 100 “psychologically salient ways of conceptualizing and evaluating the world” (Lomas, 2023). It is intriguing to compare the top (Hong Kong) and bottom (Turkey) ranked countries for IP on measures that might plausibly be related to this outcome. Significantly, Hong Kong does better across the board, including the following (with Hong Kong’s rank always listed first, and with high or low rankings variously better or worse depending on the measure, but with Hong Kong always doing better, and with the total number of countries in the ranking noted after a forward slash): (1) economic factors, such as GDP per capita (2 vs. 93 / 217) and unemployment rate (126 vs. 39 / 203); (2) health factors, such as life expectancy at birth (2 vs. 82 / 217) and maternal mortality rate (191 vs. 137 / 191); environmental factors, such as air pollution (119 vs. 98 / 169); educational factors, such as mean years of schooling (37 vs. 113 / 191) and primary completion rate (17 vs. 146 / 207); crime factors, such as incarceration rate (136 vs. 17 / 208) and homicide rate (194 vs. 120 / 200); institutional factors, as represented by indices for democracy (85 vs. 101 / 165), civil liberties (26 vs. 143 / 165), strength of legal rights (50 vs. 70 / 190), and corruption perception (12 vs. 108 / 179); and general societal functioning, such as the Human Development Index (4 vs. 46 / 189). Based on these factors one might conclude life in Hong Kong is more conducive to IP than in Turkey. Over recent years however both places have seen considerable upheaval amidst a general era of global instability. Hong Kong for example saw an eruption of anti-government protests in 2019–2020, the ramifications of which are still playing out, such as stringent new security laws which critics fear will erode civil liberties (BBC Chinese & Ng, 2024). Thus even if recent conditions there have conceivably been relatively favourable to IP – such that it ranks first among nations in the GFS on data collected in 2023 – it is a dynamic picture, hence the value of the GFS collecting such data longitudinally.

With this cross-cultural perspective in mind, let’s proceed through the factors. The greatest variation overall was regarding age. The older the participant, the more likely they are to have IP, with the percentage rising accordingly: 18–24 = 68(63,73); 25–29 = 69(63,74); 30–39 = 70(65,75); 40–49 = 71(65,75); 50–59 = 74(69,79); 60–69 = 77(70,82); 70–79 = 79(73,85); 80 + = 86(73,94). Despite a lack of much relevant work on IP, there are understandable reasons why this effect may be observed. Although aging brings challenges, such as deteriorating physical health, and related issues such as loneliness, among the most consistent demographic findings in the literature around flourishing is that aging actually tends to be associated with “better psychological health and well-being” (Jeste & Oswald, 2014, p. 317). In some past analyses, life satisfaction, for example, appears relatively ‘U-shaped’ across the lifespan, declining into middle-age, before rising in people’s 50s and 60s, although it tends to tail off after 75 (Blanchflower, 2021). Following such trends, one can understand how aging could engender beneficial qualities that could be conducive to IP, such as psychological maturity (Sheldon & Kasser, 2001) and wisdom (Lim & Yu, 2015). Compared to the relative energy and activity of youth, the generally slower pace of life in later years might also contribute (Droit-Volet, 2019).

While demonstrating a link between age and IP is notable, of even greater value here is the way this study reveals national variation, showing the relationship differs considerably based on location. The general linear pattern was not observed in all countries: rather than the lowest IP always being in the youngest category, this was also found among those 25–29 (in Argentina, Australia, India, US), 30–39 (Tanzania), 40–49 (Japan, Kenya, Spain, Tanzania), 50–59 (Nigeria, Tanzania, Turkey), 60–69 (Philippines, South Africa, Tanzania), 70–79 (Indonesia, Israel), and 80+ (Hong Kong, Poland). Conversely the highest IP was not always in the oldest 80 + category, and was instead found among those 18–24 (Kenya, Poland), 50–59 (Indonesia), 60–69 (Brazil, Egypt, Hong Kong, Israel), and 70–79 (Argentina, Australia, Hong Kong, Nigeria, Tanzania). Other variation concerned the range between the highest and lowest categories in a given country; this ranged from just 6 in Israel and Nigeria, implying that age there has relatively little bearing on IP, to 33 in US (spanning 61 for those 18–24 to 94 for those 80+), suggesting much greater association with age. One possible explanation for this cultural variation is the treatment of, and provisions available for, people at different life stages in the respective countries. It might be easier for an older person to find IP if they are widely treated with respect in their culture, say, or benefit from generous retirement provisions. Another source of variation may lie in the periods in which people were born and experienced critical stages of childhood development, which may have affected their IP. Differences across countries might be influenced by, (1) significant events in each country (such as peace-war, economic growth-stagnation-depression, food poverty-abundance, droughts-plentiful crops), (2) predominant social-cultural structures at that time, and (3) how cultures in that country responded to those events. Future research might explore these significant events and how each culture’s response either strengthened or weakened the IP of people in that generation.

The next most impactful factor was employment status: the percentage with IP ranged from 63(57,68) for those unemployed and looking for a job, 70 for students (65,75) and homemakers (65,75), 73(69,78) for those employed for an employer, 74(69,79) for the self-employed, peaking at 78(72,83) for retirees. This accords with a now vast literature showing the relation of working patterns across myriad aspects of flourishing, with numerous reviews showing that employment (versus unemployment) generally has a positive impact on mental health (Modini et al., 2016). There are of course caveats, since work can be detrimental to health if overly taxing or stressful (Nixon et al., 2011). Most research though finds at least some benefit to work, to which we can now add greater IP. While we could not find any relevant previous studies on IP per se, it is not hard to imagine how these dynamics might operate; employment often leads to greater stability and security, for example, which in turn might be conducive to IP. This claim can be observed in the popular literature in this area, like Seeking Inner Peace and Financial Freedom: Stepping Stones in a Chaotic World (Lewis, 2008). It is also fascinating though to see the greatest IP among retirees, who are also technically ‘out of work.’ Although there is an age dimension to IP, as we saw above, this employment-related finding suggests it may not necessarily be lacking employment per se that is detrimental to IP, but rather needing and seeking work yet not being able to find it. This aligns with research on outcomes such as happiness, where although generally hindered by unemployment, that is not necessarily so if people are materially secure and not wanting or needing to work (Von Scheve et al., 2017; Luo, 2019).

Once again though there are notable country-level nuances. Some countries buck the overall trends, with retirees faring worse than people who are employed in Israel and Tanzania, and even worse than people who are unemployed in Nigeria, Philippines, and South Africa. The benefit of retirement to peace is thus not universal, and most likely is affected by factors such as the nature of the retirement and healthcare systems in different countries. Strikingly, unemployed participants in South Africa had the highest IP of any group, which also deserves further attention. Some trends nevertheless remained robust: those unemployed fared worse than people who are employed in nearly all countries (apart from South Africa, as noted, as well as Philippines and Tanzania, where people who were self-employed fared worse, and Nigeria, where the unemployed and self-employed were tied). The unemployed however were only the lowest category in seven countries, with last place taken instead by students in the US, homemakers in Kenya, Philippines, and Tanzania, and “other / none of the above” in Argentina, Australia, Germany, Hong Kong, Mexico, Nigeria, Poland, Spain, Sweden, Tanzania, and UK. Other variation concerns the range of values, where some countries had only a narrow difference between the main categories (just 6% in Kenya and Spain), implying employment status has a relatively small impact; conversely others have a much larger range (the biggest being 34% in Japan), suggesting greater impact. These nuances merit further study to help us better understand the complexities of the overall trend linking employment status to IP.

The factor exhibiting the next most variation is religious attendance. The percentage with IP increased with frequency, rising from 68(62,73) for non-attendees, 72(66,77) for a few times a year, 74(69,79) for 1–3 times a month, 77(72,82) for once a week, to 80(73,85) for more than once weekly. This aligns with an extensive literature on the benefits of religious attendance to flourishing (Koenig, 2009), and with scholarship showing the centrality of peace to many religious traditions (Xi & Lee, 2021). Again though there was striking regional variation, most revealingly in terms of the range of IP within countries; comparing those who attended the least (never) versus the most, the gap was just 1% in India versus 22% in the US, suggesting the impact of religious attendance is much greater in the latter. Four countries – Egypt, India, Nigeria, and South Africa – also subverted the overall trend, with no significant relationship between attendance and IP. Intriguingly Egypt and Nigeria actually had marginally higher IP among those who never attended compared to those attending more than once a week. All these dynamics merit further investigation to better understand the nuances of this factor. Is it relevant for instance that Nigeria, unlike many countries, is divided between two main religions – Islam (53.5% of the population) and Christianity (45.9%) (CIA, 2022) – which moreover are often in tension in the country (Ojo & Lateju, 2010)? It seems plausible that religious involvement in Nigeria is more complicated than elsewhere, bringing a level of friction that can potentially hinder IP. Yet this explanation cannot be the whole story, given that the other three countries with non-significant relationships are dominated by one major religion (with Egypt estimated at 90% Muslim, India 80% Hindu, and South Africa 78% Christian).

The next most variable factor was marital status: the percentage with IP ranged from 68 for people with a domestic partner (62,74) and those single and never married (64,73), to 69 for those separated (61,76) or divorced (63,74), to 74(67,79) for those widowed, and 76(70,81) for those married. It is perhaps unsurprising to see the highest levels among those married. Across myriad aspects of flourishing, married people consistently fare better than all other groups (Manzoli et al., 2007), though the quality of the marriage also matters (Robles et al., 2014). One might wonder whether flourishing people are more likely to marry, for which there is support (Lucas et al., 2004). However, there is also longitudinal evidence for the positive impact of marriage (Grover & Helliwell, 2019). Perhaps more unexpected though is the lowest IP being for those with a domestic partner (as well as the never married), while those widowed fared second best. Research does suggest cohabitation is less conducive to flourishing than marriage, due to factors such as being a less stable arrangement (Foran et al., 2022). But it is striking that it seems even more detrimental to peace than separation and divorce; might the latter, while usually unpleasant to go through, nevertheless result in a degree of stability that is more conducive to such peace? Perhaps for similar reasons being widowed is associated with higher peace than separation and divorce, since the relationship may have been resolved with a degree of closure that could often be missing in cases of divorce/separation, in which the other partner may still have a role in the person’s life (e.g., co-parenting children), which might likewise hinder IP. Again though we must acknowledge the regional variation, such as in the range within countries, from just 6 in Indonesia (between separation at 66[52,80] to marriage at 72[70,74]), to 28 in Australia (between never married at 64[60,69] to widowhood at 91[86,95]), and even 48 in Nigeria (albeit with a very wide CI for having a domestic partner, at 33[0,79], up to single and never married, at 81[79,83]) suggesting marital status has a much bigger impact in some countries.

Education levels also manifest notable variation in the percentage with IP, ranging from 71(65,77) for up to eight years education, to 72(67,77) for 9–15 years, to 78(74,82) for 15+ years. These findings accord with a burgeoning literature on the impact of education, both directly and indirectly, on different aspects of flourishing (though the causal influence might also go in the other direction, with people who are flourishing pursuing greater education or having greater access). Education may directly help by providing people with skills and qualities associated with flourishing, such as mastery or meaning in life (Michalos, 2008), while can also indirectly impact flourishing, for instance by enhancing people’s socio-economic prospects (Ilies et al., 2019). To reiterate the point about uncertainty around causal dynamics though, while education may well engender IP, people with greater IP may also be more likely to progress to greater levels of education, while a third factor (e.g., socioeconomic status) might also affect both outcomes. It is curious though to see the association only manifest among those with 15+ years of education, with minimal difference between the other groups. Whatever positive impact education may have for IP, this would appear to not be acquired easily or quickly, but instead seems to need extensive educational involvement. Again though the regional dynamics are fascinating. Not all places share the overall pattern of IP increasing with education: in five countries (Australia, Hong Kong, South Africa, Sweden, and the US), those with the least education had the greater IP (with respective percentages in Australia, for instance, of 92[80,100], 76[73,78], and 81[79,83]). There was also again variation in the range within countries, from just 1% in South Africa (implying education there has barely any impact) to 21% in Japan (suggesting a considerable effect).

Finally two factors had comparatively minimal variation in IP: sex and immigration status. Men had slightly higher IP than women (74[69,78] versus 72[67,77]), though the tiny minority who described their gender as “other” had even higher levels (81[43,96]), albeit with a very wide CI due to the very small size of this category. In terms of men faring slightly better than women, this finding is intriguing; however the literature on sex differences in flourishing is complex and contested, so it is difficult to judge how our finding fits into this picture. Analysing Gallup World Poll data, for instance, Kahneman and Deaton (2010) found that women report greater happiness than men (life satisfaction and positive affect), but also greater stress and negative affect. In any case it is intriguing to see men faring better on IP. But perhaps even more notable is the even higher score of those self-categorised as “other.” There is an extensive literature showing that people who identify as LGBTQ + tend to have lower levels of mental health across the lifespan, from youth (Russell & Fish, 2016) to older adults (Yarns et al., 2016). In that respect it is encouraging and surprising to note the higher IP in this group. The category is very small though, and the confidence interval very wide, so caution is needed interpreting such data. Once again we can also consider the regional variation for men and women (excluding “other” here, since numerous countries did not include figures pertaining to this group). Although men had greater peace in 14 countries (Argentina, Brazil, Germany, Hong Kong, Israel, Kenya, Mexico, Philippines, Poland, Spain, Sweden, Tanzania, UK, and US – by as much as 11% in Brazil), women had higher levels in five (Egypt, India, Japan, Nigeria, and Turkey – by as much as 7% in Japan), and were equal in three (Australia, Indonesia, South Africa). It is beyond the scope of this paper to delve into the gender dynamics in these countries, but these results highlight the point that any apparent sex-differences in relation to flourishing are not necessarily universal but are contingent on the cultural context.

Finally the factor with the least variation in IP was immigration status: people born in the country in which they live had a marginally higher percentage with IP (73[68,77]) than those born elsewhere (72[67,77]). This finding is nevertheless notable, given that being an immigrant is frequently perceived as presenting challenges that can be detrimental to mental health (Rodriguez et al., 2021). However research often finds immigrant mental health is “better than expected” (Alegría et al., 2017), and may even be surpass that of native people, a phenomenon remarked on often enough to have a label – the “healthy immigrant effect” – which “suggests that immigrants have a health advantage over the domestic-born,” though this usually “vanishes with increased length of residency” (Elshahat et al., 2022, p. 1564). While we didn’t observe this effect, neither were immigrants disadvantaged. Again though there were also significant regional disparities. Although non-immigrants had greater IP in 11 countries (Egypt, Germany, Hong Kong, India, Israel, Japan, Kenya, Poland, South Africa, Spain, and Sweden, and by as much as 8% in India), immigrants had higher levels in nine (Argentina, Australia, Brazil, Nigeria, Philippines, Tanzania, Türkiye, the UK and US, including by 12% in Nigeria), and were equal in two (Indonesia and Mexico). Here the same point applies as made in relation to sex: while we cannot explore the immigration dynamics in these countries, clearly immigrants face different situations in various countries, with some striking resultant variation in their IP respective to non-immigrants. Likewise, immigrants themselves are not a monolith – having immigrated from a wide range of countries, each with unique adversities and challenges – and the background and nature of the immigrants in the 22 nations studied here may well differ in meaningful ways.

6 Conclusion

IP has received relatively little attention amidst the proliferation of research into flourishing over the past few decades. Our paper is one of the first to explore its demographic predictors, especially in a cross-national way, covering 22 diverse countries. Strikingly, all factors here showed associations with IP, with the most impactful overall being age and employment status, with the old and retirees faring best of all, and the young and unemployed job-seekers with the lowest IP. To the extent IP is a desirable quality society should want to facilitate, such patterns suggest some practical implications. Ideally attention could be focused on those with the lowest IP, namely the young and the unemployed, and especially those who fall into both camps (i.e., unemployed youth). Part of the issue is structural, and while policy-makers cannot change a person’s age (and nor, one imagines, would young people want them to!), efforts to reduce unemployment would arguably improve overall levels of IP. Additionally though, to the extent that IP is also attainable through personal activities such as meditation, these could also be offered in systematic ways to these vulnerable categories, as indeed is already happening in some quarters, such as initiatives to teach mindfulness in educational settings (Dunning et al., 2019). Perhaps even more striking though than the demographic trends was the significant national variation across all factors, which suggests the overall demographic patterns associated with IP here are not necessarily universal but are contingent on the socio-cultural context. We hope future research will help to explain the reasons why we found divergent patterns across countries, and more generally that researchers will pay closer attention to IP as an important constituent of human flourishing.