Are we sustainable for ourselves or for the planet?
Author: Charlot Oudbier Student number: 12249149 EBEC number: 20220429060417 Program: MSc Business Administration Track: Entrepreneurship and innovation Supervisor: Dr. B. Szatmari
Second reader: C.D. Esposito Date: June 24, 2022
Statement of originality
This document is written by Student Charlot Oudbier who declares to take full responsibility for the contents of this document.
I declare that the text and the work presented in this document is original and that no sources other than those mentioned in the text and its references have been used in creating it.
The Faculty of Economics and Business is responsible solely for the supervision of completion of the work, not for the contents.
Table of contents
Abstract ... 4
1. Introduction ... 5
2. Theoretical framework ... 9
2.1 Effect of self-interest on sustainable purchasing behaviour ... 9
2.2 Moderating role of age ... 11
2.3 Moderating role of gender ... 12
2.4 Mediating role of status consumption ... 13
2.5 Moderating role of materialism ... 15
3. Method ... 19
3.1 Research design and data collection ... 19
3.2 Variables ... 20
3.3 Data preparation ... 21
3.4 Data analysis... 21
4. Results ... 23
4.1 Demographics ... 23
4.2 Data screening and preliminary analyses ... 24
4.3 Linear regression ... 26
4.4 Moderation analysis ... 27
4.5 Mediation analysis ... 29
4.6 Moderation analysis ... 31
4.7 Moderated mediation analysis ... 32
5. Discussion ... 34
5.1 Principal findings ... 34
5.2 Managerial implications ... 38
5.3 Limitations and suggestions for future research ... 39
6. Conclusion ... 41
Acknowledgement ... 44
Reference list ... 45
Appendix ... 50
Household purchases account for 40% of all ecological destruction, explaining why humans play an important role in tackling the code red for humanity the IPCC report announced. Due to this urgency, this study aims to explore different determinants of sustainable purchasing. A quantitative study was conducted by distributing an online survey among Dutch consumers above 16 years old. This resulted in a study population of 483 respondents, of which 85.2%
are female. To investigate the main relationship of this study, a positive relationship between self-interest and sustainable purchasing behaviour, a linear regression analysis was
conducted. In addition, age and gender were investigated as potential moderators on the main relationship through a moderation analysis. Moreover, to test for the moderated mediation effect, a mediation analysis was conducted to explore whether status consumption mediates the main relationship. Next, a moderation analysis was used to test whether materialism moderates the relationship between status consumption and sustainable purchasing behaviour.
The analyses showed a significant positive relationship between altruism and sustainable purchasing behaviour. Age and gender were not identified as moderators in this relationship.
However, the analysis did show a significant positive direct effect of age on sustainable purchasing behaviour. No support was found for the moderated mediation on the relationship between status consumption and sustainable purchasing behaviour. By outlining the
determinants of sustainable purchasing behaviour, social entrepreneurs can leverage the knowledge regarding the effect of age and altruism on sustainable purchasing behaviour by integrating it into product placement and marketing to promote sustainable consumption behaviour.
Keywords: sustainable purchasing behaviour, self-interest, altruism, social entrepreneurs
Code red for humanity. That was the main takeaway of the IPCC report of 2022, confronting us with disturbing facts regarding climate change (IPCC, 2022). It shows that the global temperature is rising, and even in the most positive scenario, it will result in an additional increase of 1.5 degrees Celsius by 2030. In addition, the report shows that climate change is the result of human activity, which resulted in increasing the temperature of the atmosphere, ocean and land. However, even though humans caused it, the report also shows that it is still possible for humans to decrease global warming by controlling the world’s emissions (IPCC, 2022). Research showed that 40% of all ecological destruction is a result of household purchases (Joshi & Rahman, 2019). This demonstrates the importance of buying sustainable products, since that would minimize the use of natural resources and preserve the ability of future generations to meet their needs as well. Thus, to control the world’s emissions, a change in our consumer behaviour is necessary and a shift towards sustainable consumer behaviour is inevitable.
Sustainable consumer behaviour can be defined as behaviour that satisfies the needs of the present, without compromising the ability of future generations to meet their needs (Trudel, 2018). It is important to make the shift towards sustainable behaviour since the current issues regarding climate change can, for a significant part, be traced back to consumers. Specifically, in order to be able to meet the needs of the consumers, tremendous amounts of resources are needed. However, the price at which consumers buy, for instance, a pair of jeans does not reflect the environmental and social costs associated. On average, the true price of a pair of jeans is 33 euros above the current market price (Impact Institute, 2019). This gap is also referred to as the true price gap, meaning that to reflect the real price of a product, the environmental and social costs should also be included. Sustainable brands try to reduce the true price gap, for instance, by reducing the air pollution or material use. Following the
presence of this true price gap, it is important to shift consumer behaviour from traditional products to more sustainable options. Shifting towards sustainable consumer behaviour helps minimize the burden that is our current consumption behaviour (Trudel, 2018).
Sustainable entrepreneurs play an important role in solving the challenges pointed out by the IPCC report. Sustainable entrepreneurship can be defined as “the discovery, creation, and exploitation of opportunities to create future goods and services that sustain the natural and/or communal environment and provide development gain for others” (Volkmann, Fichter, Klofsten, & Audretsch, 2021, p. 1048). Thus, the role of sustainable entrepreneurs is to create products and services that allow for sustainable purchasing behaviour.
Nonetheless, the adoption of the developed solutions is dependent on the willingness of consumers. Research by CBS among Dutch consumers shows that even though consumers advocate valuing sustainability and the climate, their behaviour is not always corresponding (CBS, 2018). According to Griskevicius, Cantú and van Vught (2012), the phenomenon that consumers claim to value sustainability and the climate, while this is not consistent with their behaviour, can be explained by evolutionary bases. They identified five evolutionary bases that are responsible for many environmental and social problems humankind is facing. The five bases are propensity for self-interest; motivation for relative rather than absolute status;
proclivity to unconsciously copy others; predisposition to be short-sighted; and proneness to disregard impalpable concerns. During this research, the focus will be on the self-interest base and how that influences sustainable purchasing behaviour.
Being aware of what affects sustainable purchasing behaviour is important since an important element where progress could be made is the consumer’s sustainable purchasing behaviour. In addition, when it is known what influences consumer behaviour, sustainable entrepreneurs can leverage that knowledge to promote sustainable consumer behaviour.
However, personality characteristics such as altruism and self-interest are difficult to incorporate in, for instance, marketing campaigns. Therefore, this study will also investigate the role of status motivation and materialism on sustainable consumer behaviour, specifically on their purchase behaviour.
Status and materialism are elements that can incentivize consumers to choose for a more sustainable option. If a sustainable product demonstrates status, it might be a reason for a consumer to buy that product. For instance, Puska et al. (2018) found that when the reputational or status aspects were highlighted, consumers made more organic food choices. This strongly indicates that with regard to food, consumers go green to be seen (Puska et al., 2018).
Therefore, a way in which nudges can be applied to promote sustainable purchasing behaviour is through the encouragement of a social status competition (Schubert, 2017). Green nudges are “interventions that aim at altering people’s behaviour by either harnessing their cognitive biases or responding to them” with the aim of encouraging sustainable behaviour. Encouraging social status competition is a green nudge that allows consumers to signal their sustainable behaviour to other people. Research has shown that incorporating an element of rivalry can in fact be a successful green nudge (Schubert, 2017).
Therefore, investigating the effect of status motivation on sustainable purchasing behaviour is important since this would create possibilities for sustainable entrepreneurs and policy makers to incorporate green nudges to promote sustainable consumer behaviour.
Knowledge about which elements influence sustainable purchasing behaviour can help sustainable entrepreneurs in the implementation of its solutions for environmental or societal problems. Since status motivation has not yet been examined as a mediator in the relationship between the evolutionary bases and sustainable consumer behaviour, this study will provide valuable insight to sustainable entrepreneurs and policy makers in how to promote sustainable
behaviour, in the context of Dutch consumers. As a result, this will be one step in the right direction of moving away from code red for humanity, with the aim of getting to code green.
Thus, the research questions that will be investigated in this thesis are the following:
What is the relationship between self-interest and sustainable purchasing behaviour of Dutch consumers? What is the role of age and gender on this relationship? Is the relationship between self-interest and sustainable purchasing behaviour mediated by status consumption, and what is the role of materialism on this indirect effect?
In the next chapter, the theoretical framework, the relevant literature regarding the research questions mentioned above will be outlined. Based on the literature, the hypotheses that will be tested in this study are proposed. The chapter thereafter discusses the methods used in this study to test the hypotheses. Next, chapter 4 described the results of the statistical analyses. The discussion summarizes the main findings of this study, its limitations, and highlights several recommendations for future research. Finally, chapter 6 will present a conclusion on this study.
2. Theoretical framework
There is a gap between consumers’ attitude towards sustainability and their actual sustainable purchasing behaviour, also referred to as the ‘sustainable attitude-behaviour gap’
(CBS, 2018; Joshi & Rahman, 2017). According to Joshi and Rahman (2019), sustainable purchasing behaviour can be defined as “procuring sustainable products that possess social, economic, and environmentally friendly attributes” (p. 1). There has been a lot of research aiming to find what solves this gap and which factors influence this (ElHaffar et al., 2020; Joshi
& Rahman, 2017; Park & Lin, 2020). However, one of the factors possibly influencing the sustainable attitude-behaviour gap that has not been extensively studied is self-interest.
2.1 Effect of self-interest on sustainable purchasing behaviour
Griskevicius et al. (2012) investigated the behavioural side of this gap by studying the evolutionary bases for sustainable behaviour. One of these evolutionary bases is propensity for self-interest, which implies that humans are more likely to put their own interest over the interest of others (Griskevicius et al., 2012). From an evolutionary perspective, this can be explained due to the process of natural selection, which main purpose is the replication of genes ensuring the survival of the species. This relates to the current environmental problems since it explains through the tragedy of the commons why some consumers choose the non- sustainable option instead of the sustainable option. The tragedy of the commons refers to the opposing interests between the individual and the collective (Griskevicius et al., 2012). Since the individual consumer is such a small fraction of the world population, consumers lose a sense of responsibility for taking care of planet earth since their individual contribution seems futile. Therefore, consumers do not perceive the significant value in choosing, for instance, a sustainable pair of jeans that is more expensive to represent the true price as opposed to a regular pair of jeans where environmental and social costs are not included. The tragedy of commons translated to this scenario means that if their peer is not buying sustainable jeans, why should they do it? The individual impact seems insignificant and therefore, consumers
might prefer to choose the option that benefits them the most in the short term. While in reality, progress with regards to climate change can only be made through collective action, since supply for unsustainable products will continue to grow if demand will not decrease (Griskevicius et al., 2012). Thus, when consumers do not perceive a personal benefit, the propensity for self-interest can serve as an explanation as to why consumers are likely to choose for the unsustainable option instead of the sustainable option. This is also supported by De Dominicis et al. (2017) who show that when behaviour solely results in an environmental benefit, people will not engage in this behaviour. However, when pro-environmental behaviour results in a personal benefit as well, self-interested individuals will also behave in a pro- environmental manner (De Dominicis et al., 2017; Schradin, 2022).
Research sheds some light on the effect of the self-interest base of behaviour on sustainable purchasing behaviour. With regard to the definition of self-interest, or egoism, it can be approached as the opposite of altruism. Clark et al. namely state that egoism is considering an action with “awareness of consequences for oneself” (2003, p. 238). Whereas altruism can be defined as “the condition under which the consumer acts on another’s behalf without expecting any type of benefit” (Uddin & Khan, 2018, p. 272). Accordingly, in this study, self-interest will be treated as the opposite of altruism.
With regard to the target population of this study, Dutch consumers, there are reasons to assume that the relationship between self-interest and sustainable purchasing behaviour is positive. Since Dutch consumers are living in a Western society, there are a lot of developments and innovations to tackle climate change. With a relatively high income on average, rich consumers are able to buy, for instance, solar panels and electric cars to comply with society’s demands with regards to reducing climate change. In the Global Wealth Report of 2021, the Netherlands was ranked fourth place with a net worth of 128.557 euros per citizen (Allianz, 2021). This provides reason to assume that the average Dutch consumer has the ability to buy
sustainable products, even though they are often more expensive (Sun et al., 2021). However, the aforementioned sustainable behaviour, buying solar panels or an electric car, does not actually improve their individual carbon footprint (Schradin, 2022). According to Schradin (2022), the reason behind this is because Western people buy solar panels and electric cars as a way to show prestige. This complements the findings of De Dominicis et al. (2017), who found that self-interest indeed positively influences sustainable behaviour, due to the fact that this makes them look good. Buying sustainable products is then seen as a personal benefit, which makes buying them a self-interest. Therefore, it can be assumed that self-interest can increase sustainable purchasing behaviour among Dutch consumers. This results in the first hypothesis of this study which states that:
H1: There is a positive relationship between self-interest and sustainable purchasing behaviour, such that a higher level of self-interest results in a higher level of sustainable purchasing behaviour.
2.2 Moderating role of age
Research has shown that there is a difference between younger and older generations with regards to their attitude towards sustainability and their actual sustainable behaviour (Casalegno et al., 2022). Even though there is more concern among the younger generations regarding climate change and societal issues, this is not necessarily in line with their actual green purchasing behaviour. Casalegno et al. (2022) found that older people in fact buy more eco-friendly and sustainable products compared to younger generations. So, the older the buyer, the higher the sustainable purchasing behaviour.
One of the explanations for this gap between attitude and behaviour as proposed by the literature is that older consumers experience greater social pressure from others to buy sustainable products (Casalegno et al., 2022). In addition, it has been proven that sustainable products are in fact more expensive compared to conventional products in general (Witek &
Kuźniar, 2021). This implies that when a consumer is of higher age, they can afford the sustainable products that have a higher price compared to regular products. Thus, even though the younger generations are more concerned with climate change, the older generations are the ones who buy the actual products. These findings are complemented by a study of Wiernik et al. (2013), who found that “older individuals appear to be more likely to engage with nature, avoid environmental harm, and conserve raw materials and natural resources” (p. 826).
However, examining the relationship between self-interest and sustainable purchasing behaviour, it can be hypothesized that age moderates this relationship according to Eastman and Liu (2012). As explained in the theoretical framework regarding hypothesis 1, consumers are more likely to engage in sustainable behaviour when it benefits themselves. Investigating the effect of age on the desire for status, Eastman and Liu (2012) found that the level of status consumption was higher for Generation Y, consumers born between 1977 and 1987, than for Baby Boomers, born between 1946 and 1964 (Norum, 2003). This implies that younger consumers engage more in behaviour that benefits themselves, compared to older consumers.
Therefore, it can be expected that age strengthens the effect of self-interest on sustainable purchasing behaviour for younger consumers.
H2a: The positive relationship between self-interest and sustainable purchasing behaviour is moderated by age, such that this relationship is stronger for lower levels of age.
2.3 Moderating role of gender
Another factor that influences the relationship between self-interest and sustainable purchasing behaviour is gender. As Meinzen-Dick et al. mention (2014), most of the efforts aimed to promote sustainability are focused on men as a target group. Therefore, they refer to the concept of ecofeminism to raise awareness on the differences between men and women with regard to sustainability (Meinzen-Dick et al., 2014). This is in line with Bloodhart and Swim (2020), who emphasize the different effects of programs aiming to promote sustainable
consumption on the different genders. Another study among students reveals an gender gap between men and women, where women score higher for sustainability consciousness (Olsson
& Gericke, 2017). This shows that women have a sustainable attitude, and this gives a possibility to bridge the gap between attitude and behaviour by also including women in the marketing efforts. By investigating these differences, parties involved such as policymakers and sustainable entrepreneurs, are able to improve gender inequality (Bloodhart & Swim, 2020).
Regarding the moderating effect of gender on the relationship between self-interest and sustainable purchasing behaviour, Roux et al. (2017) explored the role of gender in the context of luxury brand consumption. Their findings indicate that the relationship between self-interest and sustainable purchasing behaviour is strengthened for men rather than for women (Roux et al., 2017). They found that men value elitism and exclusivity more compared to women. In addition, they found that there is a desire for uniqueness and status consumption, and that these factors positively influence exclusivity and elitism for men (Roux et al., 2017). In other words, the desire for prestige, a self-interested motive for sustainable purchasing behaviour, is strengthened for men rather than for women.
Thus, the hypothesis associated with the role of gender as a moderator is presented below, stating that the main relationship will be stronger for men and weaker for women.
H2b: The positive relationship between self-interest and sustainable purchasing behaviour is moderated by gender, such that this relationship is stronger for men and weaker for woman.
2.4 Mediating role of status consumption
According to Tascioglu et al. (2017), status consumption, or status motivation, is a factor influencing sustainable behaviour. Status consumption can be defined as “a motivational process, rather than a behaviour, by which individuals strive to improve their social standing
through the conspicuous consumption of consumer products that confer and symbolize status for both the individual and surrounding significant others” (Tascioglu et al., 2017, p. 294).
They state that status is at the core of people’s opinions about others, and the same goes for their personal social identity. This is based on the products they consume. This results in status products, which can serve two purposes, “expressing social standing, wealth and status as part of illustrating group membership and as self-expressive symbols to represent one’s unique qualities” (Tascioglu et al., 2017, p. 294).
With regard to the relationship between self-interest and status motivation, Schradin (2022) proposes that the egoistic drivers of sustainable behaviour are to obtain status. As mentioned before, sustainable products are oftentimes more expensive compared to conventional products (Witek & Kuźniar, 2021). Nonetheless, consumers are still willing to spend money on these products, and according to Schradin (2022) the reason is that it is perceived as a way to gain status. When someone is self-interested, they will engage in behaviour that benefits them, which could be gaining status (Clark et al., 2003; Tascioglu et al., 2017).
With regard to the relationship between status consumption and sustainable purchasing behaviour, research has shown that consumers sometimes use sustainable shopping as a way to demonstrate their status towards others (Eastman & Iyer, 2021). In other words, they are motivated by status to engage in sustainable purchasing behaviour. An example could be when a consumer purchases a Tesla, an electric car which can be seen as a sustainable mode of transportation. Tesla is the perfect example when discussing status-motivated sustainability, it was namely described as: “it was not about doing good for the environment, it was about acquiring status. The environment was a bonus” (Eastman & Iyer, 2021, p. 566). In the case of Tesla, it can be categorized as a status product since it expresses the consumer’s wealth, social standing and status, one of the purposes of status products as mentioned above (Tascioglu et
al., 2017). By owning a Tesla, the consumer is able to show off that they are doing their part in tackling climate change and that they have the means, money, to do so.
This case is supported by the findings of Tascioglu et al. (2017), who found a positive relationship between status motivation and sustainability. Moreover, this is also in line with the findings of Eastman and Iyer (2012), who found that status motivation can positively impact ecologically conscious consumer behaviour. They suggest that ecologically conscious consumer behaviour is, therefore, a way for a consumer to meet their status needs. Thus, it is hypothesized that the positive relationship between self-interest and sustainable purchasing behaviour is mediated by status consumption. Self-interested people engage in behaviour that will benefit them and gaining status is part of that. The example of Tesla shows that status positively influences sustainable purchasing behaviour since it is a way of showcasing their wealth, uniqueness and efforts to be sustainable (Eastman & Iyer, 2021).
H3a: The positive relationship between self-interest and sustainable purchasing behaviour is mediated by status consumption.
2.5 Moderating role of materialism
Another factor that plays a role in sustainability is materialism. This can be defined as
“the importance a consumer attaches to possessions, with the idea that possessions play a central role in one’s life” (Tascioglu et al., 2017, p. 295). This implies that when someone is materialistic, they use possessions to define their identity. Sirgy et al. (2012) conceptualize materialism in three dimensions, namely happiness, social recognition and uniqueness. Firstly, happiness refers to the idea that possessions contribute to the person’s happiness in life.
Secondly, social recognition implies that possessions are a way of showing other people their success in life and showcasing their status and prestige. Finally, uniqueness means that possessions are a way of demonstrating their uniqueness to other people, highlighting their differences compared to other people (Sirgy et al., 2012).
Materialism is two-sided in the context of sustainability. On the one hand, it could be expected that materialistic consumers are not sustainable since they value possessions and could possibly consume in an excessive way. While sustainability is more focused on consuming less, with elements such as zero waste, materialism is pro-consumption (Lee &
Ahn, 2016, Markauskaitė & Rūtelionė, 2022). On the other hand, it could be the case that materialistic consumers value the possessions that they have, due to the fact that they signal their social identity. In that case, when sustainable products are seen as status products, materialistic consumers might prefer those. Tascioglu et al. (2017) found indeed that materialism can act as a moderator between status consumption and social sustainability, especially in the uniqueness dimension. Suggesting that demonstrating uniqueness is the main motivator. They propose that this implies that the status motivation of more materialistic consumers is driven by their willingness to be unique, also known as a snob effect (Tascioglu et al., 2017).
This complements the literature highlighting the fact that materialism strengthens status consumption. In fact, Goldsmith and Clark (2012) found that materialism is positively related to buying products that demonstrate status. An explanation for this is associated with the definition of materialism, since they argue that materialistic reasons for buying products are associated with a desire for status and prestige (Goldsmith & Clark, 2012). Furthermore, specifically related to sustainable purchasing behaviour, Talukdar and Yu (2020) investigated whether materialistic consumers care about sustainable luxury. They state that expensive sustainable luxury products can be used to signal status. This study found that materialistic consumers perceive a higher functional value of sustainable luxury products compared to conventional products. They argue that, therefore, activating status motives related to materialism drive sustainable purchasing behaviour. Kaur et al. (2022) conducted a similar study, which complemented the findings of Talukdar and Yu (2020). They also found that high
materialism strengthens the purchase intention of sustainable luxury products. As a reason, they argue that this is due to the status attained when buying such a product.
Based on the findings of the aforementioned studies, it can therefore be argued that hat the relationship between status consumption and sustainable purchasing behaviour is moderated by materialism, indicating a stronger effect for higher levels of materialism.
H3b: The positive relationship between status consumption and sustainable purchasing behaviour is moderated by materialism, such that this relationship is stronger for higher values of materialism.
The gap to be addressed in this paper is the impact of one of the evolutionary bases, of self-interest, on sustainable consumer behaviour. Griskevicius et al. (2012) discussed the evolutionary bases and possible solutions, but no research has been conducted to confirm the effect of these bases on sustainable consumer behaviour. Since these bases might play an important role in the explanation of the aversion towards sustainability, it is important to investigate this relationship. In addition, there is no consensus in the literature on what the determinants of sustainable consumer behaviour are and what their effect is on sustainable purchasing behaviour. By investigating the role of status consumption, materialism, gender and age, this study sheds light on several factors that might play an important role in sustainable purchasing behaviour. This can have significant implications for practitioners such as social entrepreneurs and policy makers with regards to promoting sustainable behaviour among consumers.
A visual representation of the model as depicted in this study is presented in Figure 1.
Schematic representation of the hypothetical models for sustainable purchasing behaviour
Self-interest Sustainable purchasing
Status (age, gender)
3. Method 3.1 Research design and data collection
The design of this study is correlational since it investigates the relationships between the variables examined in this study. This study is based on primary data collected by conducting a survey among Dutch consumers, see Table A1 in the appendix for the survey. As a consequence, this resulted in quantitative data that was examined using SPSS (IBM, n.d.).
Respondents were gathered using convenience sampling, since the survey was distributed via the personal social media network and via the social enterprise hetkanWEL, where a request was posted on social media and in its newsletter. The time span of data collection was during the end of April and beginning of May. The minimum sample size established beforehand was 200 (Qualtrics, n.d.).
Since it was an online survey conducted using the online survey tool Qualtrics, available in both English and Dutch, there was a low threshold to participate in this study. In addition, it was a short survey that only took on average three to five minutes to complete. Moreover, the questions measuring the different variables were asked before inquiring about their demographics in case respondents are unwilling to answer personal questions. At the beginning of the questionnaire, respondents were asked for their consent prior to starting the questionnaire. Regarding the ethics of this study, it was approved by the Economics & Business Ethics Committee of the University of Amsterdam.
The population of this study was the Dutch consumer. This implied two inclusion criteria:
1. The consumer should be a resident in the Netherlands 2. The consumer should be 16 years or older
Finally, the questionnaire was based on studies where English sources were used. Since this study investigates the Dutch consumer, this survey was available in both English and Dutch. To ensure consistency among the constructs measured and to avoid confusion, the items
were translated to Dutch and afterwards, translated back to English by a third person. The revealed inconsistencies in the Dutch questionnaire were then solved.
The scales used in the questionnaires all had a Cronbach’s Alpha of 0.7 or higher, indicating sufficient internal consistency. In addition, the variables are measured using a 7-point Likert scale, ranging from strongly disagree to strongly agree, unless indicated otherwise. Firstly, the independent variable in this study, self-interest, is measured as the opposite construct of altruism. Altruism is measured using four items of the BFI facet scales with a Cronbach’s Alpha of 0.74 (Soto & John, 2009). An example item of this scale is I see myself as someone who is helpful and unselfish with others. The statements are evaluated using a 5-point Likert scale (1 = strongly disagree, 5 = strongly agree). Of the four items, one needs to be recoded before data analysis to reflect altruism, namely I see myself as someone who can be cold and aloof. Secondly, the dependent variable of sustainable purchasing behaviour is measured (Cronbach’s Alpha = 0.86), e.g. when shopping, I deliberately choose products with environmentally friendly packaging (Joshi & Rahman, 2019). The mediator status consumption is measured as status motivation, using a 4 item scale with a Cronbach’s Alpha of 0.91 (Tascioglu et al., 2017). An example item of this scale is I would pay more for a product if it had status. Next, materialism is measured using a three-dimension scale from Tascioglu et al.
(2017), consisting of items measuring happiness, social recognition and uniqueness (Cronbach’s Alpha = 0.88). Firstly, happiness consists of a four-item scale, e.g. material possessions are important because they contribute a lot to my happiness (Cronbach’s alpha = 0.91). Secondly, social recognition is questioned using three items, such as I love to buy new products that reflect status and prestige (Cronbach’s Alpha = 0.91). Finally, uniqueness is measured using three items, for instance, I enjoy owning expensive things that make people think of me as unique and different (Cronbach’s Alpha = 0.93). Finally, the control variables
in this study are education and income. Education is measured using seven categories, ranging from PhD to Post-secondary vocational education. Income is also measured in categories, namely six categories ranging from Less than €9.999 to €100.000 or more.
3.3 Data preparation
In this study, 533 Dutch consumers participated by filling in the survey. However, it became clear that not everyone completed the survey. Therefore, 50 respondents had to be excluded since they did not answer any questions apart from giving their consent. Thus, 483 respondents were included in this study in the end.
The data was analysed using the 27th version of SPSS (IBM, n.d.). Before executing the statistical analyses to test the hypotheses of this study, the data was checked for outliers, using the z-score. The threshold was three standard deviations, which means a case was not included when it differed more than three standard deviations from the mean. This threshold was decided since these cases can be considered as extreme outliers (Field, 2013). This was the case for fifty-five cases, which resulted in 428 respondents that were included in the analyses that did not take the outliers into account. The statistical analyses were run both with and without outliers to check for differences. In addition, the variables were constructed by calculating the mean score of the different items measuring the variables used in this study. Afterwards, a correlation matrix was created to investigate the correlations between the different variables.
3.4 Data analysis
To test for the main relationship between self-interest and sustainable purchasing behaviour, a linear regression was conducted after ensuring the assumptions were met. This statistical analysis was most appropriate since both variables are continuous variables. In addition, to test for the moderation effect of age and gender on the relationship between self- interest and sustainable purchasing behaviour, model 1 of PROCESS macro by Hayes was used (Hayes, 2018). Furthermore, model 14 of PROCESS macro by Hayes investigated a moderated
mediation effect. This included a mediation analysis exploring the mediating role of status consumption on the relationship between self-interest and sustainable purchasing behaviour using model 4 of PROCESS macro by Hayes (2018). In addition, a moderation analysis was conducted using model 1 to test for the moderating effect of materialism on the relationship between status consumption and sustainable purchasing behaviour (Hayes, 2018).
4. Results 4.1 Demographics
The baseline characteristics of the study population are outlined in Table 1. This showed that the majority of this population is female (85.2%). The mean age was 50 years old, ranging from 18 to 81 years. With regard to the highest level of education obtained, the largest category of 25.3 percent obtained a bachelor’s diploma, after that the biggest group was post-secondary vocational education with 15.5 percent. For the annual household income, it became clear that almost one third of the respondents (29.1%) has a household income between €25.000 and
€49.999. Finally, referring to the work sector of the respondents, there were two main categories apparent. Firstly, healthcare, where 25.1 percent of the respondents were employed.
Secondly, teacher training and education with 15.0 percent of the respondents.
Baseline characteristics of the study population
Total (n = 483) Demographics Gender, n (%)
Female 386 (85.2)
Male 63 (13.9)
Non-binary / third gender 1 (0.2)
Prefer not to say 3 (0.7)
Age, n [SD] 50 [15.5]
Education, n (%)
PhD 15 (3.3)
Master’s degree 114 (25.3)
Bachelor’s degree 41 (9.1)
High school 22 (4.9)
Post-secondary vocational 70 (15.5) Annual household income, n (%)
Less than €9.999 22 (4.9)
Between €10.000 & €24.999 67 (14.8)
Between €25.000 & €49.999 132 (29.1) Between €50.000 & €74.999 91 (20.1) Between €75.000 & €99.999 35 (7.7)
€100.000 or more 32 (7.1)
Prefer not to say 74 (16.3)
Work sector, n (%)
Accounting, banking & finance, 8 (2.3) Marketing, media, advertising &
PR, 21 (5.9) Business, consulting & management, 17
Public services, justice &
administration, 14 (4.0) Creative arts & design, 18 (5.1) Recruitment & HR, 4 (1.1) Engineering, manufacturing &
construction, 11 (3.1)
Retail & sales, 21 (5.9)
Environment & agriculture, 8 (2.3) Science & pharmaceuticals, 13 (3.7)
Healthcare, 89 (25.1) Teacher training & education, 53 (15.0)
Tourism, recreation & hospitality, 6 (1.7)
Transport & logistics, 3 (0.8)
Information technology (IT), 14 (4.0) Other, 54 (15.3)
4.2 Data screening and preliminary analyses
Before the statistical analyses could be performed, one item had to be recoded. This was part of the scale measuring altruism, namely: I see myself as someone who can be cold and aloof. Afterwards, a reliability analysis was conducted for every scale, which can be seen in Table 2 below. For the altruism scale, it has been decided to remove item three, which is the beforementioned item that was recoded. The Cronbach’s alpha was 0.653 before the exclusion, which signals a questionable internal consistency. After removing this item, Cronbach’s alpha increased to 0.736, which is acceptable. Therefore, it has been decided to remove this item from the scale measuring altruism. This ensured all the scales have a Cronbach’s alpha of above 0.7 which indicates acceptable internal consistency.
The results of the reliability analyses for the pre-validated scales
Variable n Cronbach’s alpha
1. Altruism (Soto & John, 2009) 483 0.736
2. Sustainable purchasing behaviour (Joshi &
3. Status consumption (Tascioglu et al., 2017) 483 0.800
4. Materialism (Tascioglu et al., 2017) 483 0.882
5. Materialism – happiness (Tascioglu et al., 2017) 483 0.831 6. Materialism – social recognition (Tascioglu et
7. Materialism – uniqueness (Tascioglu et al., 2017) 483 0.853
Next, the scale means were computed to create the variables. Using these variables, a correlation matrix was created which can be seen in Table 3 below. This also displays the means and standard deviations of the variables along with Cronbach’s alpha on the diagonal.
The correlation matrix showed several insightful correlations, namely that there is a small effect between altruism and sustainable purchasing behaviour, the main relationship investigated in this study (r = 0.10, p < 0.05). In addition, the happiness section of materialism has a small effect on sustainable purchasing behaviour (r = -0.21, p < 0.01) and a medium effect on status consumption (r = 0.35, p < 0.01). The social recognition dimension of materialism has a small effect on sustainable purchasing behaviour as well (r = -0.19, p < 0.01) and a strong positive correlation with status consumption (r = 0.50, p < 0.01). Materialism uniqueness also has a small negative correlation with sustainable purchasing behaviour (r = -0.12, p < 0.05).
and a medium to strong positive correlation with status consumption (r = 0.45, p < 0.01).
Furthermore, gender has a small negative correlation with materialism happiness (r = -0.10, p
< 0.05). Finally, age has a small effect on sustainable purchasing behaviour (r = 0.26, p < 0.01) as well as on the elements of materialism.
Correlations among variables, means and standard deviations
Variable M SD 1 2 3 4 5 6 7 8 9 10 11
1. Altruism 4.17 0.73 (.74)
2. Sustainable purchasing behaviour
5.21 1.22 .10* (.87)
consumption 1.91 0.86 .02 .00 (.80)
happiness 1.73 0.79 -.05 -.21** .35** (.83)
5. Materialism social recognition
1.22 0.49 -.04 -.19** .50** .54** (.79)
uniqueness 1.35 0.68 -.02 -.12* .45** .51** .69** (.85)
7. Materialism 1.43 0.55 -.05 -.21** .50** .85** .83** .86** (.88)
8. Gender 1.88 0.39 -.02 .09 -.02 -.10* -.04 -.04 -.08 -
9. Age 50.36 15.46 -.03 .26** -.22** -.28** -.22** -.27** -.31** -.06 -
10. Education 3.62 1.83 -.08 -.03 .11* .01 .04 -.03 .01 .02 -.02 -
11. Income 3.98 1.78 -.01 -.06 -.04 .12* .00 -.02 .05 -.02 .11* -.16** -
*. Correlation is significant at the 0.05 level (2-tailed).
**. Correlation is significant at the 0.01 level (2-tailed).
Note. On the diagonal Cronbach’s alpha of each variable is represented.
4.3 Linear regression
In order to test the main relationship of this study, as depicted in hypothesis 1, a linear regression was conducted. This statistical analysis was chosen since this revolves around two continuous variables, the mean of altruism and sustainable purchasing behaviour. Education and annual household income were considered as control variables. Before conducting the linear regression, it was ensured that there was independence of residuals, since the Durbin- Watson statistic was 1.722. There was a linear relationship visible on the scatterplot and no extreme outliers were found. In addition, the plot of standardized residuals versus standardized predicted values showed that there was homoscedasticity. Finally, the normal probability plot and histogram show that the residuals are normally distributed.
Table 4 presents a visual representation of the outcomes of the regression analysis.
Altruism accounts for 1.1% of the variation in sustainable purchasing behaviour with adjusted
R2 = 0.9%, which is a small size effect. The regression model showed that altruism significantly predicted sustainable purchasing behaviour, F(1, 475) = 5.28, p < .05. In addition, it showed that moving up one point in the Likert scale measuring altruism, resulted in an increase in sustainable purchasing behaviour by 0.175 points, 96% CI [0.025, 0.324].
These results indicated that no support has been found for hypothesis 1, which states that there is a positive relationship between self-interest and sustainable purchasing behaviour, such that a higher level of self-interest, results in a higher level of sustainable purchasing behaviour. Since altruism is the opposite of self-interest, a negative relationship was expected.
However, it has been found that altruism significantly predicts sustainable purchasing behaviour, in a positive manner.
Regression analysis summary for predicting Sustainable Purchasing Behaviour
Model Variable B 95% CI β t p
Model 1 (Intercept) 4.49 [3.85, 5.12] 13.91 0.000
R2 = .009 Altruism 0.18 [0.03, 0.32] 0.11 2.30 0.022
Model 2 (Intercept) 5.31 [4.53, 6.09] 13.34 0.000
R2 = .001 Altruism 0.05 [-0.11, 0.21] 0.03 0.66 0.511
Income -0.05 [-0.11, 0.01] -0.07 -1.54 0.126
Education -0.03 [-0.09, 0.03] -0.04 -0.91 0.362
Note. CI = confidence interval for B.
4.4 Moderation analysis
After establishing a significant effect of altruism on sustainable purchasing behaviour, model 1 of PROCESS Macro was used to investigate whether the size of this effect interacts with gender and age as moderators. The results of the moderator analyses are summarized in Table 5 below. Firstly, hypothesis 2a discussed the moderating effect of age. The results indicated no significant interaction effect for model 2 (b = -.007, se = .005, t = -1.351, p = .178, 95% CI = -
.016, .003). A notable finding in this analysis was nonetheless a significant relationship between age and sustainable purchasing behaviour. An unstandardized B coefficient of 0.048 indicates that when a Dutch consumer increases one year in age, sustainable purchasing behaviour increases by 0.048 on a 7-point Likert scale (p < 0.05). Regarding the role of gender as a moderator in the beforementioned relationship, the results showed no significant interaction effect for model 1 (b = .261, se = .205, t = 1.273, p = .204, 95% CI = -.142, .664).
Therefore, no support has been found for both hypotheses 2a and 2b and can thus both be rejected.
Moderator Analysis: Altruism and Sustainable Purchasing Behaviour Dependent variable: Sustainable purchasing behaviour
Model Variable Unstandardized
B coefficient SE t p
Model 1 Constant 6.425 1.610 3.991 .0001 3.261 9.590
R2 = .013 Altruism -.424 .388 -1.093 .275 -1.187 .339
Gender -.783 .849 -.922 .357 -2.451 .885
Altruism x Gender .261 .205 1.273 .204 -.142 .664
Model 2 Constant 6.818 1.637 4.165 .000 3.601 10.035
R2 = .019 Altruism -.443 .390 -1.136 .257 -1.210 .324
Gender -.819 .852 -.961 .337 -2.494 .856
Altruism x Gender .269 .206 1.304 .193 -.136 .673
Education 0.033 .032 -1.054 .292 -.095 .029
Income -.047 .032 -1.462 .145 -.111 .016
Model 3 Constant 2.491 1.136 2.194 0.029 .259 4.723
R2 = .072 Altruism .416 .268 1.550 .122 -.111 .943
Age .048 .021 2.299 0.022 .007 .088
Altruism x Age -.007 .005 -1.351 .178 -.016 .003
Model 4 Constant 2.631 1.135 2.319 .021 .401 4.861
R2 = .082 Altruism .468 .269 1.741 .083 -.061 .997
Age .053 .021 2.531 .012 .012 .094
Altruism x Age -.008 .005 -1.565 .118 -.017 .002
Education -.036 .031 -1.170 .243 -.096 .024
Income -.067 .032 -2.085 .038 -.129 -.004
4.5 Mediation analysis
Model 4 of PROCESS Macro investigated hypothesis 3a, which stated that the positive relationship between self-interest and sustainable purchasing behaviour is mediated by status consumption. The results of the analysis are summarized in Table 6 and 7 below. The indirect effect results showed that the 95% confidence interval is not statistically different from zero, indicating no significant mediating effect (b = -.001, Boot se = .005, 95% CI = -.013, .010).
Therefore, no support has been found for hypothesis 3a and can thus be rejected.
Mediation analysis: Role of status consumption
Status consumption Sus. Purchasing behaviour
Model Antecedent Coeff. SE p Coeff. SE p
Model 1 Constant 1.801 .228 .000 4.491 .345 .000
Altruism .025 .054 .637 .177 .077 .021
Status consumption - - - -.005 .066 .937
R2 = .001 F (1,470) = .224
R2 = .011 F (2,469) = 2.665
Model 2 Constant 1.691 .278 .000 5.385 .398 .000
Altruism .019 .056 .730 .054 .080 .504
Status consumption - - - -.046 .068 .406
Education .051 .022 .021 -.026 .032 .406
Income -.014 .023 .528 -.051 .033 .121
R2 = 0.014
F (3,447) = 2.129, p = .096
R2 = .009
F (4,446) = .957, p = .431
Mediation analysis: effect of status consumption Dependent variable: Sustainable purchasing behaviour
Effect SE p LLCI ULCI
Model 1 Direct effect .177 .077 .021 .026 .327
Total effect .177 .077 .021 .026 .327
Effect Boot SE Boot LLCI Boot ULCI
Indirect effect -.000 .004 -.009 .010
Effect SE p LLCI ULCI
Model 2 Direct effect .054 .080 .504 -.104 .212
Total effect .053 .080 .511 -.105 .211
Effect Boot SE Boot LLCI Boot ULCI
Indirect effect -.001 .005 -.013 .010
4.6 Moderation analysis
Model 1 of PROCESS Macro was used to investigate the moderation effect of materialism on the relationship between status consumption and sustainable purchasing behaviour. This encompasses hypothesis 3b, which stated that the relationship between status consumption and sustainable purchasing behaviour is stronger for higher levels of materialism. The results of the analysis are summarized in Table 8 below. The results indicated no significant interaction effect, means materialism does not play a moderating role in the relationship between status consumption and sustainable purchasing behaviour (b = .040, se = .124, t = .327, p = .744, 95%
CI = -.203, .283). Thus, no support has been found for hypothesis 3b and this hypothesis can be rejected.
Moderation analysis: Effect of materialism Dependent variable: Sustainable purchasing behaviour Model Variable Unstandardized
B coefficient SE t p 95% CI
Model 1 Constant 5.858 .464 12.623 .000 4.946 6.770
R2 = .051 Status consumption .110 .189 .585 .559 -.261 .481
Materialism -.648 .346 -1.872 .062 -1.328 .032
Status x Mat. .029 .123 .233 .816 -.212 .270
Model 2 Constant 6.180 .486 12.712 .000 5.225 7.136
R2 = .056 Status consumption .082 .190 .431 .667 -.292 .456
Materialism -.667 .350 -1.908 .057 -1.354 .020
Status x Mat. .040 .124 .327 .744 -.203 .283
Education -.035 .031 -1.128 .260 -.096 .026
Income -.038 .032 -1.165 .245 -.101 .026
4.7 Moderated mediation analysis
Model 14 of PROCESS Macro was used to investigate the moderated mediation as depicted in hypotheses 4. The results of the analysis are summarized in Table 9 below and a schematic representation can be found in Figure 2. The results indicated no significant interaction effect, which investigated whether the relationship between altruism and sustainable purchasing behaviour was mediated by status consumption and whether this mediation was moderated by materialism (b = .031, se = .123, t = .253, p = .801, 95% CI = - .210, .272). Therefore, no support has been found for hypothesis 4 and can thus be rejected.
Moderated mediation analysis: Altruism and Sustainable Purchasing Behaviour Dependent variable: Sustainable purchasing behaviour
Model Variable Unstandardized
B coefficient SE t p 95% CI
Model 1 Constant 5.419 .562 9.635 .000 4.314 6.524
R2 = .055 Altruism .106 .077 1.379 .169 -.045 .256
Status consumption .103 .189 .548 .584 -.267 .474
Materialism -.645 .346 -1.864 .063 -1.324 .035
Status x Mat. .031 .123 .253 .801 -.210 .272
Model 2 Constant 6.046 .595 10.158 .000 4.876 7.216
R2 = .057 Altruism .031 .079 .393 .695 -.124 .186
Status consumption .080 .191 .422 .674 -.292 .455
Materialism -.664 .350 -1.899 .058 -1.352 .023
Status x Mat. .041 .124 .328 .743 -.203 .284
Education -.034 .031 -1.088 .277 -.095 .027
Income -.037 .032 -1.160 .247 -.101 .026
Schematic representation of the moderated mediation model
Note. All path coefficients are unstandardized B coefficients.
Altruism Sustainable purchasing
5. Discussion 5.1 Principal findings
The aim of this study was to investigate the determinants of sustainable purchasing behaviour and to generate valuable insights for social entrepreneurs and policy makers to enhance their ability to promote sustainable consumer behaviour. The research questions associated with this aim were: What is the relationship between self-interest and sustainable purchasing behaviour of Dutch consumers? What is the role of age and gender on this relationship? Is the relationship between self-interest and sustainable purchasing behaviour mediated by status consumption, and what is the role of materialism on this indirect effect?
Firstly, the main hypothesis stated that there is a positive relationship between self- interest and sustainable purchasing behaviour, such that a higher level of self-interest, results in a higher level of sustainable purchasing behaviour. In this study, self-interest was measured as the inverted value of altruism, as it was assumed that these concepts are opposites of each other. The correlation matrix showed a small positive correlation between altruism and sustainable purchasing behaviour (r = 0.10, p < 0.05). This relationship was further investigated by conducting a regression analysis.
The regression analysis showed that altruism predicts sustainable purchasing behaviour in a positive way (F(1, 475) = 5.28, p < .05), specifically that if altruism increases by one point on a 5-point Likert scale, it results in an increase in sustainable purchasing behaviour by 0.175 points. This suggests a negative relationship between self-interest and sustainable purchasing behaviour. However, since hypothesis one indicated a positive relationship between self- interest and sustainable purchasing behaviour, this hypothesis was rejected. This finding contradicts the current literature, where it was found that self-interest positively influences sustainable purchasing behaviour since caring for the environment benefits egoistic consumers (De Dominicis et al., 2017; Schradin, 2022). This was suggested since this increases their