Materialistic cues make us miserable: A meta‐analysis of the experimental evidence for the effects of materialism on individual and societal well‐being

Funding information The British Academy, Grant/Award Number: SRG1819\190659 Abstract Consumer‐oriented societies are awash with materialistic messages that link happiness and success to wealth and consumption. However, despite extensive research evidence that dispositional materialistic orientations are correlated with lower well‐ being, the effects of materialistic cues on the well‐being of individuals and social groups have not been examined. The present research meta‐analytically reviews the experimental evidence for the causal effects of materialism on two dimensions of well‐being: (a) individual and (b) societal. We included 27 independent studies that met the inclusion criteria of priming materialism and measuring well‐being (N = 3,649), containing a total of 62 effect sizes. Multilevel modeling revealed that materialism has an effect on both individual (δ = −0.39) and societal well‐being (δ = −0.41), suggesting that materialistic cues cause lower well‐being. Moderation effects suggested that materialistic cues might have a higher effect on interpersonal well‐being than on self‐evaluation indicators. We discuss the limitations of the current evidence, highlight the research gaps and underdeveloped areas, and provide recommendations such as minimum sample size for future experimental work, since the advancement of this area will help us to gain a better understanding of the impact of consumer‐oriented societies on the well‐being of individuals and social groups.

implicitly link money and consumption to positive affective states, high self-esteem, and social recognition. This may be because the promotion of materialistic narratives through popular culture is beneficial for the development of consumer-oriented economies 1 , as the more money individuals spend on products and services, the higher the economic growth of a society. However, classic philosophers (e.g., Diogenes, Pythagoras, and Socrates), modern economists (e.g., Kuznets, 1934), and contemporary psychologists (e.g., Diener & Biswas-Diener, 2002;Kasser & Ryan, 1993;Maslow, 1954) have warned that wealth, material possessions, and economic growth indexes do not reflect the welfare of individuals or social groups. In fact, an extensive body of empirical studies has found that a desire for wealth, possessions, and consumption is negatively related to personal well-being in different societies with diverse cultural and political backgrounds . However, the bulk of the research looking at the materialism-well-being paradigm has been correlational in nature and has also largely left unexplored the implications that materialism might have for the wellbeing of society. Nevertheless, in recent years, a number of experimental studies have examined the causal relationship between materialism and well-being. This expanding body of research looks at the effects of inducing a materialistic focus, not only on personal well-being indicators such as self-esteem (Liang et al., 2016) or positive and negative affect (Nagpaul & Pang, 2016), but also on attitudes and behaviors that have direct implications for the well-being of society, such as helping behaviors (Lamy, Guéguen, Fischer-Lokou, & Guegan, 2016) or proenvironmental donations (Ku & Zaroff, 2014). Given that members of consumer-oriented societies are constantly being badgered by advertisements promoting consumption and media narratives portraying ragsto-riches stories and displaying upscale living, there is a need to scrutinise the effects that materialistic cues have on the well-being of individuals and social groups. Therefore, by systematically reviewing the experimental evidence on the causal relationship between materialism and well-being-not previously examined in past meta-analytic research Wright & Larsen, 1993)-we aim to gain a deeper understanding of the impact that consumer-oriented economies have on the well-being of society and its individual members. Furthermore, by examining this literature, we aim to identify research gaps and best practices to encourage the development of further experimental work in this area, since this study serves not only to identify causality between materialism and different well-being outcomes, but also help us to further explore the human motivation system (Kasser, 2016).

| Materialism: From theoretical conceptualizations to experimental manipulations
Since the mid-1980s, extensive research has been conducted into the relationship between materialism and well-being. The construct of materialism has been conceptualized and measured in the literature as: (a) a tendency to believe that wealth and possessions define success, provide happiness, and play a central role in one's life (e.g., Richins, 2004;Richins & Dawson, 1992); (b) a set of personality traits and behaviors related to nongenerosity, envy, possessiveness, and/or the accumulation of material things (e.g., Belk, 1984;Ger & Belk, 1996); (c) beliefs related to love for money and social status, such as achievement, power, prestige, and/or reputation (e.g., Mitchell & Mickel, 1999;Tang, 1992); and (d) the importance of money and possessions, often in relation to other life goals and values (e.g., Kasser & Ryan, 1993, 1996Srivastava, Locke, & Bartol, 2001). However, it is only in recent years that researchers have started to use experimental methodologies in this area.
Experimental research on materialism has adopted different methodologies to induce a materialistic focus. For example, some authors have primed materialism by exposing participants to visual stimuli (VS) such as advertisements or fashion magazines (e.g., Ashikali & Dittmar, 2012;Bauer, Wilkie, Kim, & Bodenhausen, 2012), while others asked participants to read a text from a magazine or newspaper highlighting the importance of money and consumption (e.g., Ku & Zaroff, 2014;Leyva, 2018). Some have induced a materialistic focus through subtle environmental cues such as shop window displays (e.g., Lamy et al., 2016; or screensavers running luxury fashion images in the background (e.g., Jiang, Gao, Huang, DeWall, & Zhou, 2014). This diversity of materialistic inductions will help us to gain an overall picture of the effects of materialistic cues on individual and societal well-being, since it mirrors the variety of stimuli and situations that individuals might encounter in their everyday life as members of a consumer-oriented society. We acknowledge that different methods of priming materialism might generate distinct effects. However, there is currently little comparison of different manipulations within the literature. The present meta-analytic research will, therefore, also aim to provide an initial exploration of the effects of the different types of materialistic inductions by performing moderation analyses.

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| 1397 different elements that lead to good health, comfort, and prosperity-is thought to comprise not only hedonic aspects, but also eudemonic elements, such as self-realization (Ryan & Deci, 2001), as well as other social and relational components, such as healthy interpersonal relationships (Keyes, 1998). Therefore, to obtain an overall picture of the effect of materialism on personal well-being, we have widened the scope of previous meta-analytic work to include studies that measure selfdevelopment (e.g., achievement, in Ku, Dittmar, & Banerjee, 2014) as well as relational and social aspects that affect personal well-being (e.g., social integration, in Jiang et al., 2014). Our inclusive approach to well-being is aligned with prior conceptualizations that have broadly defined well-being as the state of "being well" (e.g., Kitayama & Markus, 2000, p. 114;Oishi, 2012, p. 2).

| Materialism and societal well-being
Materialism is a socially grounded value that is related to attitudes and behaviors that can have implications for the well-being of a social group and future generations. For example, recent longitudinal works have shown that materialistic values are positively correlated with social dominance and racial and ethnic prejudice (Duriez, Vansteenkiste, Soenens, & De Witte, 2007), but negatively associated with pro-environmental attitudes and behaviors (Hurst, Dittmar, Bond, & Kasser, 2013). Therefore, materialism has broader sociopolitical implications that could jeopardize the well-being of a society by encouraging self-enhancing attitudes and behaviors, and discouraging prosocial, altruistic, or pro-environmental ones.
In addition, conceptualizations of materialism include elements such as achieving higher social power and status through the acquisition of money and luxury possessions (e.g., Mitchell & Mickel, 1999;Tang, 1992), and linking individual and social success with economic resources (e.g., Richins, 2004;Richins & Dawson, 1992). These conceptualizations imply that materialists are more likely to endorse economic inequality, because only when there are different levels of wealth and economic power in society can one achieve a higher status than one's peers. Indeed, correlational evidence collected at society level has suggested that higher social inequalities-as reflected in steeper social pyramids and bigger material differences-have negative consequences not only for individual health (e.g., lower life expectancy and higher risk of mental health problems), but also for the well-being of the social group (e.g., higher levels of violence and crime; Wilkinson & Pickett, 2010). Therefore, the present article aims to expand the examination of the effects of materialism by reviewing the current experimental research into the wider consequences of materialism on the well-being of society. We consider that a materialistic focus affects not only one's private sphere, but also one's coexistence with other members of society, since the individual's interaction with their social group affects the well-being of the group and other individual members.
For the purposes of this study, we conceptualize societal wellbeing as factors that contribute to the good functioning of a group and that will directly or indirectly affect the current and future welfare of the group and other members. Consequently, we classify "societal well-being" as any measure of individual attitudes and behaviors that directly or indirectly affect the welfare of the group or the personal well-being of other members (e.g., volunteering or helping behaviors). Moreover, we also incorporate sustainability indicators to capture attitudes and behaviors towards the environment and other common resources, since the long-term well-being of a society will depend on the legacy left for future generations (e.g., proenvironmental behaviors or attitudes towards the misuse of public funds). It is worth noting that we make a distinction between social well-being and societal well-being. Social well-being has been described in Keyes (1998) as an indicator of one's social health, measured using items that consider an individual's perceptions of the social group and the place and value that they have within society (such as perception of social integration or evaluations of one's social value).
Moreover, social well-being also integrates measures that provide an indication on the quality and closeness of one's social relationships (e.g., interpersonal conflict or perception of proximity and/or intimacy with others). Consequently, social well-being falls under personal well-being because aims to capture the social and interpersonal elements of an individual's life that are directly influencing their wellbeing (i.e., the effect that others and the group has on an individual's well-being). On the other hand, societal well-being looks at indicators of the positive or negative impact that a person has on society and other people (i.e., the effect of the individual on the group's wellbeing), and therefore covers individual attitudes and behaviors towards common resources (such as the environment or collective funds) and other people within society (including both in-group and out-group members). As a result, the construct of societal well-being includes measures on prosocial, pro-environmental, and (un)ethical attitudes and behaviors. Nevertheless, we acknowledge that both constructs, individual and societal well-being, can be mutually dependent and, that there might not be a clear-cut between them, particularly when collecting measures on interpersonal or relational elements because a well-being indicator might capture elements that could have an effect on both (e.g., social engagement). As a result, when classifying the outcome measures included in the present metaanalysis, we have looked at who will be most affected by alterations in the outcome measure, the individual or the group. For a detailed classification of the well-being measures, see Table B in Supplementary Materials.

| Research aims and hypotheses
The aim of this study is to examine the effects that materialistic cues have on individual and societal well-being, by meta-analyzing experimental research that primes materialism and measures wellbeing. For the purposes of this task, we have, therefore, included experimental studies that induce a temporary materialistic focus in a randomly selected group of individuals and subsequently measure individual or societal well-being in the manipulated group as well as in a control group. The present research also aims to test possible moderators of the causal relationship between materialism and wellbeing, such as type of materialistic induction, type of well-being measure, gender, and population type. In addition, by carrying out a systematic review of the literature on experimental research into materialism and well-being, we aim to identify gaps and best practices to develop recommendations for future experimental work in this area.

| Materialistic cues as a cause of lower individual well-being
Within the extended literature that has found a negative association between the constructs of materialism and well-being, three main theoretical explanations have been proposed (see Dittmar et al., 2014 for an extended review): 1) Self-determination theory, which postulates that individuals focused on seeking materialistic goals-also referred to as extrinsic goals (such as wealth, appearance, and social popularity)-might be distracted from pursuing intrinsic ones (such as self-development, intimate relationships, or group belonging) that better satisfy the basic psychological needs of competence, autonomy, and relatedness Kasser & Ryan, 1993).
3) Negative self-appraisals, based on previous psychological theoretical accounts of self-discrepancy theory (Higgins, 1987) and social comparison (Collins, 1996), which suggests that consumer-oriented media portraying unattainable ideals leads to lower well-being, because individuals use these unreachable standards when making self-evaluations (e.g., Ashikali & Dittmar, 2012;Richins, 1995). The first theoretical explanation, self-determination theory, is limited when it comes to explaining experimental research results involving materialistic manipulation and subsequent measures of well-being, given that pursuing certain goals (vs. others) requires an extended period of time. This explanation would, therefore, be more relevant to longitudinal research designs (e.g., Sheldon, Ryan, Deci, & Kasser, 2004). The second theoretical explanation, psychological insecurities, is a fitting way to test the opposite causal direction in experimental research that manipulates well-being and measures the endorsement of materialistic values (e.g., Chang & Arkin, 2002;Lambert, Fincham, Stillman, & Dean, 2009), but is not suitable for testing the causality of materialism on well-being. Finally, the third theoretical explanation, negative self-appraisals, does predict that a materialistic induction would cause a decrease in individual wellbeing, because materialistic cues will make unattainable consumer culture ideals salient when making subsequent self-evaluations. Therefore, this theory suggests that the gap between the self and the perceived social standards portrayed by media and advertising will generate emotional discomfort, since individuals will make upward social comparisons and/or self-assessments against an unattainable ideal self. As a result, we will expect that individuals randomly exposed to a materialistic prime will report lower individual well-being than participants allocated to a control group.
1.6 | Materialistic cues as a cause of lower societal well-being While theoretical accounts based on self-evaluations might provide an explanation for lower individual well-being, through cognitive psychological processes that link perceptions of the self with affective states, they are limited when it comes to predicting prosocial and pro-environmental attitudes and behaviors following exposure to materialistic cues. We, therefore, turn to prior research on value priming (Maio, Pakizeh, Cheung, & Rees, 2009) based on previous work on priming (Bargh & Chartrand, 2000) and values structure (Schwartz, 1992). This study proposes that the induction of a specific value will cause an increase on the importance of those and similar values and decrease on the relevance of opposing values and, it will lead to behaviors consistent with the primed value, while at the same time it will inhibiting behaviors that are opposite to that value in Schwartz's (1992) circular value model (Maio et al., 2009). For example, empirical studies supporting this model found that priming ambition versus helpfulness lead participants to exhibit behaviors that were consistent to those values while diminished behaviors that support opposing values such as pursuing personal achievement versus volunteering for an unpaid research study (Maio et al., 2009).
Materialism has been conceptualized in previous literature as a construct involving a desire to acquire wealth, social status, and power (e.g., Mitchell & Mickel, 1999;Richins & Dawson, 1992;Tang, 1992), and has been found to be in opposition to community and affiliation values (Grouzet et al., 2005). Therefore, we predict that priming materialism will lead to lower societal well-being, because it will bring to the forefront self-enhancement goals and consistent behaviors with these goals (such as seeking power or wealth) and will diminish the importance of self-transcendent ones and inhibit supporting behaviors (such as prosocial and pro-environmental attitudes and behaviors, like social cooperation or protecting the environment). As a result, we will expect that individuals randomly exposed to materialistic cues will score lower on societal well-being measures than participants allocated to a control group.

| Moderators of the causal relationship between materialism and well-being
There are several factors that could affect the strength of the effects on the causal link between materialism and well-being. Prior metaanalytic work on correlational studies found stronger effects for the well-being measures of risky health and compulsive-buying behaviors MOLDES AND KU | 1399 and for self-evaluations . This study also found weaker effects for general subjective well-being indicators, such as life satisfaction and positive affect. Furthermore, this study showed that the greater the proportion of women in the sample, the higher the effects that were found. No differences between university students and general population samples were found, but there was a stronger effect for individuals over 18 years old than for participants under that age. However, none of these moderation effects have been tested on experimental research. Furthermore, there is currently little comparison of manipulation types in the literature. As a result, the present research will explore different possible moderators, such as type of manipulation, type of well-being measure, gender, age, type of population, and country to identify possible factors that might reduce or facilitate the effects of priming materialism on well-being.

| Literature search
A literature search was carried out by the first author on Web of Science, Scopus, and PsycInfo in September 2018. It was then updated in February 2020, using keywords relevant to the project (see Table A in Supplementary Materials for a detailed account of the search terms used). The search was refined further to improve its focus (e.g., excluding papers in physics, maths, or pharmacy; limiting studies based on their methodology to ensure that only experimental studies were included). A total of 711 articles were identified after removing duplicates. Ascending and descending searches using key papers in the area of materialistic values and well-being were carried out on Google Scholar and identified another 24 articles that used experimental methods. Prominent authors in the area were contacted for unpublished data and/or further literature suggestions.
As a result, eight further texts (including one unpublished data set) were suggested by the experts contacted by email. Finally, a total of 769 articles were screened (see Figure 1).

| Inclusion criteria
The present research included experimental studies that primed materialism to a randomly selected subset of their participants and subsequently collected at least one measure of individual or societal well-being for both the manipulated and the control groups.

| Manipulation inclusion
We included experimental studies that induced materialism by (a) exposing participants to VS in the form of either advertisements of luxury products (e.g., Ashikali & Dittmar, 2012;Bauer et al., 2012;Jiang et al., 2014;Ku & Zaroff, 2014), visual descriptions of desirable material items and gadgets by peers , or TV advertisements for toys (Goldberg & Gorn, 1978); (b) having participants complete a scrambled-sentence task with materialistic concepts F I G U R E 1 Flow diagram of the literature search and selection procedure of the studies. This diagram was constructed according to the American Psychological Association Meta-Analysis Reporting Standards (MARS) embedded within it (e.g., Bauer et al., 2012;Liang et al., 2016); asking participants to write about unfulfilled material desires (e.g., Maggaß, Hamm, & Ozimek, 2018), to describe a situation in which economic resources, social popularity, and appearance had a positive impact on their life (e.g., Moldes, 2018) or to write about the benefits of having money and possessing the trendiest toys (e.g., ; (d) framing a situation from a consumer perspective (e.g., Bauer et al., 2012); (e) having participants read materials from a fashion magazine (e.g., Ku & Zaroff, 2014) or a rags-to-riches story from a newspaper (e.g., Leyva, 2018); or, (f) using environmental cues such as luxury shop window displays or screensavers presented in the background (e.g., Lamy et al., 2016;. Most articles were excluded because they lacked an experimental manipulation or were outside the scope of the present research (e.g., there were several entries on the philosophical concept of materialism and beliefs relating to how physical laws might answer most questions, and on materialism as a property of a substance or element from engineering or physics research). We excluded experimental manipulations that only aimed to prime the concept of "money" (e.g., Gąsiorowska, Zaleśkiewicz, & Kesebir, 2018), as prior research has determined that materialism goes beyond a simple desire for money (Burroughs & Rindfleisch, 2002;Dittmar et al., 2014). Mere exposure to money on its own does not imply a materialistic focus. Along the same lines, we excluded studies that used windfall scenarios in which participants in the treatment condition were informed of receiving a sum of money (e.g., Li, Lu, Xia, & Guo, 2018;Ozimek & Förster, 2017;Wang & Krumhuber, 2017). A hypothetical scenario portraying an increase in disposable income might make salient the construct of money or manipulate the perceived social class, but it does not necessarily induce a temporary materialistic outlook. In fact, it has been found that priming money to low-social-class students can help to decrease materialistic desires (as shown in Li et al., 2018). We excluded all studies that asked participants to describe a material purchase (against participants describing an experiential one), because participants in both conditions were reminded about spending behaviors, and recent research has found that experiential consumer products fulfill conspicuous consumption desires as much as material ones (Moldes, Banerjee, Easterbrook, Harris, & Dittmar, 2019). We excluded manipulations that framed a specific task (such as recycling or exercise) by highlighting the intrinsic or self-transcendent goals against extrinsic or selfenhancement motives for performing the task (e.g., Evans et al., 2013;Vansteenkiste, Matos, Lens, & Soenens, 2007), as these manipulations might have changed the participants' orientations when carrying out the task (learning or exercise), but do not necessarily make salient a materialistic focus or consumer culture ideals.

| Well-being inclusion
In the present research, we included studies that had a dependent variable measuring: (a) subjective well-being (SWB), (b) self-evaluations (SE), (c) mental health indicators (MHI), (d) self-development indicators (SDI), and (e) interpersonal well-being (IWB). We included studies that measured prosocial and environmental attitudes and behaviors, as we used these measures as indicators of societal well-being (see Table B in Supplementary Materials for a detailed account of the measures included in each category).
We excluded reports that looked at social judgments of and attitudes towards individuals wearing symbols of consumer culture (e.g., by exposing participants to images of people wearing logos of high-end brands in the manipulation condition and no symbols or logos in the control condition), as these reports examined judgments of people endorsing consumer culture, not the effect of endorsing consumer culture on social judgments (e.g., Lee, Ko, & Megehee, 2015).  Table B in Supplementary Materials for a detailed account of the measures included in each category).

| Reliability checks
All studies were coded by the first author. The second author also coded 20% of the sample selected at random to ensure the interrater reliability of the coding scheme, and reviewed 20% of the excluded sample to review the application of the inclusion-exclusion criteria. The second author agreed on 100% on the excluded studies and the coding scheme (inter-rater reliability of Cohen's kappa = 1).  (Borenstein, Hedges, Higgins, & Rothstein, 2011). The correction factor Hedges' g (noted as J) was calculated for each study from the reported mean (M), SD, and sample size (n) of each group (1 = materialistic manipulation; 2 = control) applying the following formulas: Correction factor: For studies that collected categorical data (Goldberg & Gorn, 1978) 3 ; Lamy et al., 2016;Moldes, 2019) and presented a frequency table or reported a χ 2 statistic from a 2 × 2 contingency table, we computed d from the data reported by using an effect size calculator (Wilson, 2001) to obtain d and V d and then transformed it into Hedges' g (using the formulas reported above). Finally, we created a valence variable and assigned the value of 1 to measures in which higher scores reflected higher levels of well-being (e.g., life satisfaction scale) and −1 to measures in which lower scores meant higher well-being (e.g., self-discrepancy index). The final effect size used in the meta-analysis was obtained by multiplying the valence variable by the effect size initially obtained to correct and align the direction of the effect on the subsequent analyses.

| Descriptive statistics
The sample contained 17 reports that included 27 independent samples with a total of 3,649 participants (see Table 1 and 2 for a detailed account of the studies). The proportional mean age was 18.62. Of the total sample, 66% were female, 30% of the data were collected in the UK (n = 1,095), 30% in China (n = 1,089), 12% in France (n = 432), 12% in Canada (n = 428), 9% in Germany (n = 330), 5% in the USA (n = 193), and 2% in Singapore (n = 82). Forty-four percent of the sample belonged to the general population, 43% were university students, and 13% were children.

| Data analysis
The final data set consisted of 17 reports, containing 27 unique studies, contributing to a total of 62 effect sizes. We used random effect models, because data collected in social science is likely to have variable population parameters (Field & Gillett, 2010). As several studies provided multiple effect sizes, we performed multilevel meta-analyses with two levels (effect sizes at Level 1 and clustered within studies at Level 2) to overcome the violation of the effect size independence assumption and to avoid having a single study contributing several times to the overall effect size calculation (Field, 2015). The software used for the analyses was R with the package metafor and the function rma.mv() with restricted maximum-likelihood, because this estimation method has been recommended by several authors for performing multilevel meta-analyses (Assink & Wibbelink, 2016;Hox, 2010;Viechtbauer, 2010).

| Materialistic priming: Is it successful?
Out of the 17 reports included in the final sample, 10 included a manipulation check (either from the main study/ies or a preliminary pilot study) and reported the means, the SDs and number of participants of the materialistic measure split by condition. Therefore, we were able to calculate 11 effect sizes to perform a two-level meta-analysis (effect size at Level 1 clustered within reports at Level 2) on the effect of the manipulation on a dependent variable measuring materialism (see Figure A and Table B in Supplementary Materials for a detailed account of all the studies included). The overall effect between the control group and the materialistic-manipulated group on materialistic values was δ = 0.69, SE = 0.28, 95% confidence interval (CI) [0.14, 1.24], p < .05. However, studies within the sample were significantly heterogeneous, Q(12) = 35.17, p < .001, indicating that the studies included did not share a common effect size. Further moderation tests revealed that there was no significant difference between the studies that used visual stimuli priming versus other types of primes, F(1, 11) = 1.82, p = .176. However, there were significant differences between the studies that collected data in western nations (US, UK, and Germany) and samples from eastern countries (China and Singapore), F(1, 11) = 7.79, p = .005, suggesting that materialistic manipulations were more effective at inducing a materialistic focus in eastern populations than in western ones.

| Materialism and well-being: Testing causation
Out of the 62 effect sizes included in the sample, we classified 42 as individual well-being and 20 as societal well-being (see Tables 1 and 2).
We coded a dummy variable (1 = individual and 0 = societal) and carried 72 −0.10 The treatment group was exposed to materialistic advertisement with thin models The control group was exposed to nonmaterialistic advertisement The treatment group was exposed to materialistic advertisement without models The control group was exposed to nonmaterialistic advertisement without models ASI (Cash & Labarge, 1996)

63
−0.84 Participants were exposed to print advertisement of luxury products (e.g., a luxury car, a luxury watch, or a luxury house) Participants were exposed to print advertisement of lower budget consumer products (e.g., an economical car, a cheap watch, or a budget apartment)  (Cash & Labarge, 1996); PALS, Patterns of Adaptive Learning Scale (Midgley et al., 2000); PANAS, Positive and Negative Affect Schedule (Watson et al., 1988); SDI, self-discrepancy index (Dittmar, 2009 (2015) 54 −0.82 Participants were exposed to images of luxury products and were asked to describe their key features and rate them Participants were exposed to images of nonluxury products and were asked to describe their key features and rate them −0.32 Participants were exposed to images of luxury products and were asked to describe their key features and rate them Participants were exposed to images of nonluxury products and were asked to describe their key features and rate them Sustainability and cooperation orientations: Individual restrain measure from the −0.32 Participants were exposed to images of luxury products and were asked to describe their key features and rate them Participants were exposed to images of nonluxury products and were asked to describe their key features and rate them Attitude towards greed (Yamagishi & Sato, 1986 127 −0.53 Participants were asked to complete a scrambling sentence task in which 67% of the words were related with materialistic concepts (e.g., expensive) Participants were asked to complete a scrambling sentence task replacing materialistic terms with mundane ones (e.g., instead of expensive, the word accurate was presented) Conference paper out two meta-analyses after splitting the data into individual and societal subsets, due to the conceptual differences between the constructs.

| Effects of priming materialism on individual well-being
A meta-analysis carried out on the individual well-being subset revealed that there was a significant overall difference in individual well-being between the control group and the group primed with materialism The results showed a small-to-medium effect (Cohen, 1992) of materialism on individual well-being, indicating that participants in the materialistic groups reported significantly lower individual well-being than participants in the control groups (see Figure 2).

Outliers and influential observations
A preliminary examination of the distribution of the effect sizes revealed no noticeable potential outliers or extreme cases (see Figure B in Supplementary

Outliers and influential observations
An examination of effect size distribution revealed one extreme case influencing the overall results and, therefore, the results without them are more robust (see Figure 3). The overall effect of δ = −0.41 suggests a small-to-medium effect (Cohen, 1992) of materialism on societal wellbeing, indicating that participants in the materialistic groups reported significantly lower scores on the societal well-being indicators than participants in the control groups.

| Moderation analyses
Several potential methodological and theoretical moderators were coded in the sample, including type of manipulation performed, type of individual well-being measure collected, type of population tested, percentage of female participants in the sample, and country in which the data were collected. We performed a series of moderation analyses aiming to identify different factors that might create discrepancies on the strength of the effects of priming materialism on well-being. These analyses were carried out to compare our results with prior meta-analytic work looking at correlational studies that found several moderation effects such as type of well-being measure, gender, or age . Also, we performed moderation analyses due to the dif- F I G U R E 2 Forest plot displaying the standardized mean differences (Hedges' g) on individual well-being between treatment (exposed to materialistic cues) and control groups. Two-level meta-analytic random effect model ( personal well-being (k = 13). We selected self-evaluations as a reference F I G U R E 3 Forest plot displaying the standardized mean differences (Hedges' g) on societal well-being between treatment (exposed to materialistic cues) and control groups. Two-level meta-analytic random effect model (effect size at Level 1 clustered within studies at Level 2) conducted with a restricted maximum-likelihood estimation method. category to compare against the other categories because-drawing on the negative self-appraisal theoretical framework-we would expect that if the effects of materialistic primes on well-being were driven by individuals' lower self-assessments, self-evaluations might present stronger effects than other individual well-being measures. Moreover, selfevaluations were found by previous meta-analytic work on correlational research to produce higher effect sizes than other measures . The omnibus test for moderation effects concluded that there were nonsignificant moderation effects linked to the type of individual well-being measure, taking self-evaluations as a reference category, F(4, 37) = 5.59, p = .231. However, the regression coefficient of the dummy variable coded for interpersonal well-being showed a significant effect, t(37) = −2.04, p = .041, indicating that the effect sizes in the interpersonal well-being group were significantly higher than the effect sizes in the reference category of self-evaluations.

| Gender
The results of testing the percentage of females in the sample as a moderator on the full sample (excluding outliers and extreme cases) suggested that there were nonsignificant effects F(1, 54)= 1.94, p = .164.

| Type of population
We identified three categories within the sample: studies that collected a general population sample (k = 4), studies that recruited university students (k = 19) and studies that collected data from children (k = 3). Therefore, we created two dummy variables (one coding 1 = university students and 0 = nonuniversity students; and another coding 1 = children, 0 = nonchildren). We used the category "general population" as a reference in the moderation analysis and introduced the dummy coded variables as moderators. The results indicated nonsignificant differences between the effects observed in the general population samples and the other samples, F(2, 57) = 1.67, p = .433.

| Country
Given the diversity of population samples and the moderation found on the previous section, we decided to test the moderator "origin of the sample" by creating a variable that indicated whether the data were collected in a western country (UK, France, Germany, Canada, and USA; accounting for 68% of the sample) or eastern one (China and Singapore). The results from the moderation test suggested no differences between the effect sizes collected from eastern and western countries, F(1, 58) = 0.01, p = .936.

| Publication bias
The funnel plot of the studies included in the final sample used for the individual and societal meta-analyses (see Figure 4) displays a roughly symmetric distribution of the effect sizes, ordered in a funnel-like shape, suggesting the absence of publication bias and heterogeneity in the sample.

| DISCUSSION
The present research is the first systematic review of experimental research that has looked at the causal effects of materialism on individual and societal well-being. The results from the analyses provide empirical evidence indicating that materialistic cues cause lower individual and societal well-being. These findings suggest that the promotion of materialistic messages through media and advertising not only has negative consequences for the personal well-being of individuals, but also for the welfare of society as a whole. This study constitutes an important step forward in the examination of the effects of consumer-oriented economies on the well-being of individuals and social groups, as most empirical evidence presented by prior work has been based on correlational studies. In fact, the use of experimental methodologies when studying well-being is rare, F I G U R E 4 Funnel plot displaying the observed effect sizes on the x-axis against the standard error for the meta-analysis combining individual and societal well-being. The vertical line in the middle indicates the model estimate, δ = −0.40, SE = 0.06, and 95% CI [−0.51, −0.21], p < .001. The white space within the diagonal lines show the expected 95% confidence intervals around the summary estimate. One extreme score and one outlier have been removed meaning the causal mechanisms in well-being are currently unknown (Oishi, 2012). Therefore, further research in this area will help deepen our knowledge of the impact that environmental factors such as materialistic cues have on individual and societal well-being.
The results of the moderation analyses provide some preliminary signs suggesting that materialistic cues might have a stronger negative impact on certain well-being domains. Materialistic cues were found to have higher effects on interpersonal well-being measures than on self-evaluation indicators. This finding suggest that materialistic environments might have higher detrimental effects on establishing and developing relationships with others than on one's individual self-esteem. However, given the limited number of studies in each category, this finding should be interpreted with caution.
Overall, the results of the moderation analyses provide limited insight into the specific mechanisms or individual characteristics enabling or inhibiting the causal effects of materialistic cues on wellbeing. That said, the sample size may have lacked the statistical power to detect significant moderation effects. Therefore, further research should examine the mechanisms that enable or inhibit the negative effects of materialistic cues on individual and societal wellbeing for developing strategies and/or interventions aiming to reduce the adverse effects of environmentally induced materialism. Furthermore, it is worth noting that 37% of the studies included in this meta-analysis were underpowered. As a result, given that the typical effect size was δ = −0.39 for individual and δ = −0.41 for societal wellbeing, we recommend future researchers to recruit at least 82 participants per condition for individual well-being and 75 for societal well-being to achieve the suggested power of 80%. 7 The moderation effect of socioeconomic status on the relationship between materialism and well-being has been left unexplored in the current report, because there was limited information regarding the participants' background in the literature. Therefore, we would encourage researchers to collect and publish further demographic data and background information on their participants, including socioeconomic status, education level, and information on different cultural backgrounds included in the samples. This data would not only enable researchers to perform moderation analyses to understand the self and the perceived social norm gap but would also help to track the diversity of the samples collected in the literature.
Furthermore, our research corroborates a direct link between exposure to a materialistic cue and an increase in situational materialistic focus that, subsequently, and after continuous and frequent exposure, could lead to a chronic materialistic disposition. These findings expand prior research on materialism, which suggested that frequent and prolonged exposure to materialistic messages increases dispositional materialistic orientations (e.g., Chan et al., 2006) as the short-term effects of exposure to a materialistic message on a materialistic focus had not been previously established by past correlational and longitudinal research. Interestingly, moderation analyses looking at the effectiveness of materialistic primes suggest that eastern populations experience stronger effects than western populations. However, this finding-along with the results of other moderation analyses performed on the materialistic prime-should be interpreted with caution, given the limited number of studies that reported a manipulation check. Nevertheless, it could suggest crosscultural differences perhaps due to distinct levels of exposure or adaptation effects.
Overall, our systematic review suggests that there is a need for further behavioral studies and more research on younger populations (children and adolescents), as well as research looking at the effects of materialism on the social and interpersonal aspects of well-being.
Moreover, the current research on societal well-being is scarce and the development of this study area could provide experimental support to prior correlational work at the society level that links economic and material inequality with lower societal well-being (Wilkinson & Pickett, 2010). Also, the effect of materialistic cues on ethical and unethical decision making has been identified as an underdeveloped area in the literature. In addition, further research should investigate the causal link between well-being and materialism, as there are a number of studies that have hinted at a possible bidirectional relationship between the two variables (Chang & Arkin, 2002;Chaplin & John, 2007;Lambert et al., 2009;Liu, Zhao, & Liu, 2018). Furthermore, given that the use of experimental methodologies in the materialism-well-being literature is relatively new, the data does not go back far enough to test for generational effects that could help us deepen our understanding of the effect of societal changes on well-being.
Finally, given the need to make research more replicable and transparent, we would encourage authors to share their manipulation materials. This practice would help future researchers to effectively select or design their own materials and would enable and encourage replication studies. Moreover, this would facilitate comparisons between different manipulations (and control materials) in terms of message(s) displayed, medium used (e.g., images, text, and audio), length of the stimuli, presentation order and so on, for further examination of theoretical and methodological questions around priming effects. Along the same lines, we would also invite researchers to include and publish manipulation checks in their articles, because this data would facilitate further effect size comparisons across stimuli and samples. Nevertheless, we acknowledge that certain research designs (e.g., experiments conducted in a public setting as in Lamy et al., 2016) do not enable the collection of a manipulation check, and that explicit self-reported scales on materialism (e.g., Richins, 2004) might not be able to capture implicit changes that occur at a subconscious level after an exposure to a subtle materialistic prime (Gawronski & LeBel, 2008).

| CONCLUSION
Materialistic cues cause lower individual and societal well-being.
However, there is a need for further research to determine the mechanisms that enable or inhibit the negative effects of materialism on the different aspects of individual and societal well-being as this will help in the development of strategies that could minimize its effects. Overall, these findings call for a reflection on the social discourses around consumption and wealth-promoted through media and advertising-that contain an implicit association with positive affective states, high self-esteem, and social recognition, or portray unattainable ideals, since environmental materialistic cues do in fact have negative effects on the well-being of both society and its individual members.

ACKNOWLEDGMENT
This publication was partially supported by the Department for Business, Energy and Industrial Strategy: British Academy: SRG1819\19065.

DATA AVAILABILITY STATEMENT
The data and supplementary materials for this report are available on its Open Science Framework page (https://osf.io/kcs5d/).