1
What appeals on packaging are most effective
to increase willingness to pay in sustainable
consumption?
A Choice Based Conjoint Analysis to measure the impact of appeals on
packaging on WTP for sustainable consumption
2
What appeals on packaging are most effective to increase willingness to pay
in sustainable consumption?
Nina van der Have
Faculty of Economics and Businesses
MSc. Marketing Intelligence
January 11, 2016
Rijnstraat 14B
9725ET Groningen
(+31) 6 38382404
s1768611
s1768611@student.rug.nl
University of Groningen
First supervisor: dr. J. van Doorn
3
Abstract
This research aimed to get insight in consumer willingness to pay (WTP) for sustainable consumption, since future consumer consumption that will harm the environment should be minimized. The study tested the effects of price and different types of appeals (biospheric, normative or symbolic) on the packaging of a sustainable product on WTP. Furthermore, the study tested if the amount of effort (high versus low) to obtain the product led to differences in WTP. Findings show that biospheric appeals led to the highest WTP among consumers and that WTP increases when consumers have to put high effort into getting the product.
Key words: Willingness to Pay, sustainable consumption, biospheric appeals, normative
4
Summary
Since consumer spending is harming the environment and the fact that consumer spending will only increase in the future, insight in the topic of sustainable consumptions is needed in order to understand how to minimize environmental impact. Retailers are enlarging their assortment of sustainable products, but what is the best way for marketers to convince the consumer to buy their sustainable product? This research aims to get insight in consumers’ WTP for sustainable consumption, whereby it studies the effect of different types of appeal
on the packaging and price on WTP for sustainable shoes by means of a Choice Based
Conjoint Analysis (CBC). Both product attributes have different levels to be tested, price will be tested at 70€, 90€ and 110€ and the different types of appeals have a biospheric, normative or symbolic nature.
Results show that consumers attach most importance to the price of sustainable
products, i.e. they are considering the price of the product first. The other attribute, the type of appeal that is on the package, appeared to be less important to consumers. However, of all tested types of appeals the biospheric type will result in the highest WTP among consumer. Then, appeals stressing the symbolic function are following and lastly appeals that are stressing normative information are least preferred and have the lowest WTP.
Furthermore, amount of effort (5 vs. 25 minutes bike ride) that is needed to obtain the product, was included as a variable to see if it altered the relationships between the types of appeal and WTP. Results show that effort did not lead to a change in preferences for the types of appeal, but the price of the product becomes less important when participants have to put high effort.
5
Preface
This thesis is written to complete my study MSc. Marketing Intelligence at the university of Groningen. I couldn’t complete my thesis without the help and support of several parties, therefore I would like to thank them. In the first place I would like to thank my supervisors for their feedback and guidance throughout this period of writing my thesis. Furthermore, I need to thank all the participants that took the time to fill in my survey. Lastly, I want to thank my friends and family for their support during this process.
6
Table of contents
1. Introduction... 7 2. Theoretical framework... 10 2.1 Sustainable consumption 2.2 Biospheric appeals2.3 Appeals that stress normative information
2.4 The symbolic function and sustainable consumption 2.5 Barriers to sustainable consumption
2.6 Conceptual model 2.7 Hypotheses
3. Research design... 22 3.1 Research method
3.2 Data collection 3.3 Attributes and levels 3.4 Experimental design 3.5 Plan of analysis 4. Results...27 4.1 Descriptive statistics 4.2 Construct validity 4.3 Model specification 4.4 Model fit
4.5 Importance of attributes - Aggregated model 4.6 WTP per attribute – Aggregated model 4.7 Moderator effect
4.8 Hypotheses overview
7
What appeals on packaging are most effective to increase willingness to pay in
sustainable consumption?
1. Introduction
The worldwide population is expected to grow to 9 billion people in 2050, while a rise in global affluence (GDP) is expected as well (WBCSD, 2008). These trends are inherent to more consumer spending on goods and services and will cause more impact on the
environment in turn, whereas already 60% of the ecosystems (such as water regulations, air quality, aesthetic values) on earth are degraded in the last decades (WBCSD, 2008). The topic of sustainable consumption needs to be studied in order to get insight in ways to minimize the forecasted increase in environmental impact.
Based on the United Nations Commission on Sustainable Development (1994) sustainable consumption is defined as ‘the use of goods and services that respond to basic needs and bring a better quality of life, while minimizing the use of natural resources, toxic materials and emissions of waste and pollutants over the life cycle, so as not to jeopardize the needs of future generations’.
Over the past years research on sustainable consumption has been done already, but still there are some areas that need to be studied. One of those areas is the gap between attitudes and actual behavior, the so called attitude-behavior gap (Prothero et al., 2011). To illustrate this gap, several studies and surveys show that environmental concern among the consumer is high; a survey of Eurobarometer for the European Commission (2008) showed that 96% percent of European citizens say that protecting the environment is an important topic for them personally. Another survey (Eurobarometer, 2009) found that more than 8 out of 10 EU citizens sees a product’s impact on the environment as an important factor when they are deciding which product to buy. It seems that consumers are acknowledging that it is important to protect the environment and that they try to minimize the impact that their buying behavior is causing.
8
2005). How can we influence actual behavior in a way that promotes sustainable consumption? In order to limit the increasing consumption patterns and impact on the
environment it is important to know how to persuade the consumer to act pro-environmental. Research is necessary to move more towards a sustainable society.
In an attempt to investigate how actual behavior can be influenced, this paper will address the importance of appeals on the packaging of a product. Several studies showed that consumers are paying attention to package and label claims when they are deciding whether to buy a product or not; A Nielsen (2014) survey showed that 52 percent of respondents indicate that their purchase decision partly depends on the package of the product, before buying they are looking at the product label to make sure that the brand is committed to minimizing environmental impact. It seems that consumers use packaging and labels as an important factor to decide whether to buy a product or not. This paper will therefore look into the effect of different types of appeals on packaging on the willingness to pay for a
sustainable product;
What appeals on packaging are most effective to increase willingness to pay in sustainable consumption?
Research of Bolderdijk et al. (2012) compared the effectiveness of biospheric versus
economic appeals in environmental campaigning. They found that biospheric appeals led to more compliance than the economic appeals, which they explain by the idea that people want to maintain a positive self-concept.
Another study by Nolan, Schultz, Cialdini, Griskevicius and Goldstein (2008) provided consumers with different types of information regarding their willingness to
conserve energy. Although participants did not acknowledge that normative information was motivating them to conserve energy, the study revealed that participants’ willingness to conserve energy was higher when they were provided with normative information about the behavior of their neighbors compared to information about protecting the environment. These findings show that there is no consensus of which appeals perform better in promoting pro-environmental behavior. Hence, more research to the effectiveness of different types of appeal is needed.
9
sustainable products have a strong symbolic value (Griskevicius et al., 2010). It is worth to investigate whether appeals that address the symbolic function of a product can be effective in promoting pro-environmental behavior.
Furthermore, previous research has been done to identify factors that are causing the attitude-behavior gap (Prothero et al., 2011). The majority of research on barriers to
sustainable consumption provided factors that relate to costs (in time, money, or effort) for the consumer. The availability of sustainable products was mentioned several times as an
important barrier to sustainable consumption (Bonti-Ankomah and Yiridoe, 2006; Robinson and Smith, 2002). In general, low availability of sustainable products predicts low sustainable consumption (Bezawada and Pauwels, 2013; Reibstein and Farris, 1995). In turn, lower availability of products implies that consumers have to put more effort into obtaining a product. If costs for the consumer become too high, it is expected that they are less likely to buy sustainable products (Robinson and Smith, 2002). This study will elaborate on the
amount of effort that is needed to obtain a product, since it can be seen as an important barrier to sustainable consumption.
Current study
10
2. Theoretical framework
First of all, the chapter starts with general background on sustainable consumption. Second, current findings of two types of appeals and their effectiveness on sustainable consumption will be presented. In addition, a new type of appeal that is based on the symbolic value of sustainable products will be discussed. Furthermore, the moderating role of effort will be addressed. Finally, the chapter concludes with the conceptual model and hypotheses.
2.1 Sustainable consumption
Prior research on the topic of sustainable consumption showed that consumers became increasingly aware of environmental issues and the importance of sustainable consumption. For instance, a survey of Eurobarometer for the European Commission (2009) found that more than 8 out of 10 EU citizens sees a product’s impact on the environment as an important factor when they are deciding which product to buy. Next, 96% percent of European citizens say that protecting the environment is an important topic for them personally (Eurobarometer, 2008). The environment became a mainstream issue and a strong increase in environmental awareness emerged (Goleman, 2009). The increased awareness among consumers encouraged them to take some responsibility and to adjust their consumption patterns, consumers are willing to pay for the ‘privilege of buying green’ (Mintu-Wimsatt and Bradford, 1995; Garcia-Gallego and Georgantzi’s, 2011).
Unfortunately, positive attitudes towards sustainable consumption do not necessarily translate into purchases (Thøgersen, 2000). This can be illustrated with findings of McKinsey Quarterly (2008) that revealed that 53 percent of their respondents were concerned about the environment, but were not willing to take action when they are shopping. In addition, findings of the UN Environmental Program (2005) showed that 40% percent of consumers were willing to buy green products, while only 4% of consumers were actually buying green. The discrepancy between attitudes and behavior is known as the so called attitude-behavior gap (Prothero et al., 2011), resulting in the fact that the consumption of sustainable products is lower than expected. The attitude-behavior gap makes it very hard for producers of sustainable alternatives to estimate the right amount of demand when relying on traditional market research methods (Prothero et al., 2011). This topic needs attention to move towards a more sustainable society.
11
availability, price, lack of time, lack of money, inconvenience and lack of information as barriers to their sustainable consumption (Blake, 1999; Robinson and Smith, 2002; Vermeir and Verbeke, 2006).
The lack of information on the labels or packaging of a product was found the be an important barrier. A Nielsen (2014) survey revealed that 52 percent of respondents indicate that their purchase decision partly depends on the package of the product, before buying they are looking at the product label to make sure that the brand is committed to minimizing environmental impact. In addition, one of the reasons that consumers gave in the survey of Mintel (2011) for not buying sustainable was the absence of relevant claims on the packaging of the product. It appears that consumers use packaging and labels as an important factor to decide whether to buy a product or not.
The presence of relevant sustainability claims on the packaging of a product was found to increase sustainable consumption. Nielsen (2014) looked at actual sales data and compared brands that have sustainability claims on their packaging or were actively promoting their sustainability with sustainable brands that did not have sustainability claims or promotion. After one year, sales data revealed that sustainability claims on packaging led to a sales increase of 2 percent, whereas sustainable products without sustainability claims led to an increase of only 1 percent. Actively promoting their sustainability even led to a sales increase of 5 percent.
Hence, absence of credible claims on sustainable products seems a misstep for sustainable marketing, since consumers pay attention to labels and sustainability claims in their decision process. In addition, sustainable product characteristics are difficult to observe and verify for the consumer, therefore they tend to rely on the information on product labels (Kirchhoff, 2000).
Hence, it is very important to communicate sustainability on the label or packaging of a product, but what type of appeals on packaging are most effective in increasing WTP for sustainable consumption? Since the assumed importance of claims on packaging this chapter will further elaborate on different types of appeals that can be used on the packaging of sustainable products.
2.2. Biospheric appeals and sustainable consumption
12
to persuade consumers to act pro-environmentally by referring to the intrinsic value of the nature and the environment. In the studies of Bolderdijk et al. (2012) consumers had to read either an economic appeal (‘Want to save money? Check your car’s tire pressure!’) or a biospheric appeal (‘Want to protect the environment? Check your car’s tire pressure!’). They found that consumers feel better about complying with biospheric appeals rather than
economic appeals, which they explain by the idea that people want to maintain a positive self-concept. According to the cognitive dissonance theory (Festinger, 1957) people strive for consistency between their behavior and self-concept, otherwise they will experience feelings of discomfort. Hence, when consumers attach importance to protecting the nature and
environment, they are likely to comply to biospheric appeals in order to be consistent and protect the nature and environment.
Other research states that protecting the environment is seen as morally right and appropriate (Lindenberg and Steg, 2007). Hence, consumers that attach less importance to protecting the nature and environment still might be motivated to comply to biospheric appeals in order to behave appropriate. Complying to biospheric appeals and thus doing what is appropriate makes consumers feel good about themselves, it will maintain a positive self-concept.
These studies have in common that biospheric appeals will increase the willingness to engage in pro-environmental behavior. If not resulting from strong biospheric values, then it might be the result of consumers that want to do what is right and maintain a positive self-concept.
Next, Evans et al. (2012) compared two types of motives in campaigns to promote pro-environmental behavior. They compared motives that stressed self-interest (for instance, economic interest) with motives that have a self-transcendent cause (i.e. protecting the environment). In two experiments they found that pro-environmental behavior was higher in the condition where participants received environmental information.
In contradiction with the previous studies, research of Nolan, Schultz, Cialdini,
Griskevicius and Goldstein (2008) that provided consumers with information about protecting the environment as a means to increase sustainable behavior appeared to perform worse compared to normative information in promoting pro-environmental behavior.
13
Some research has been done to the effectiveness of appeals that stress normative information on pro-environmental behavior.
A study by Nolan, Schultz, Cialdini, Griskevicius and Goldstein (2008) provided consumers with different types of information regarding their willingness to conserve energy. Among the different types of information the study provided were; information that stressed environmental protection, information that stressed social responsibility, information that stressed the opportunity to save money or lastly they provided information about the
conservation behavior of other households in the same neighborhood. The study revealed that participants’ willingness to conserve energy was higher when they were provided with the normative information about the behavior of their neighbors, although participants did not acknowledge that this information was motivating them to conserve energy.
Another research that studied the effect of social norms in the context of
pro-environmental behavior is of Goldstein, Cialdini and Griskevicius (2008). In two experiments they studied the effect of social norms on towel reuse among hotel guests. In the first
experiment they provided guests with information, either a message that stressed social norms or a message that focused on the importance of protection of the environment. The message that stressed social norms stated that the majority of hotel guests participated in the reuse of their towel at least once during their stay at the hotel. Results showed that the message providing social norms led to significantly more towel reuse than the message that stressed environmental protection. In the second experiment they made the social norms more specific and changed the reference group in the message, it was now saying that the majority of hotel guests that stayed in the same room participated in the reuse of their towel. This is explained by the fact that people often evaluate themselves by comparing themselves to others that are similar or have similar characteristics (Festinger, 1954).
The studies have in common that they found that providing normative information is more effective than information about protecting the environment in increasing
pro-environmental behavior.
14
2.4 The symbolic function and sustainable consumption
Previous sections focused on biospheric appeals and appeals that provide normative information in order to promote pro-environmental behavior. Next to these type of appeals that can drive consumers to buy sustainable products, this section will elaborate on the idea that sustainable consumption can be driven by the symbolic value of sustainable products. Research of Noppers, Bolderdijk and Steg (2014) showed that adoption of sustainable innovations is partly driven by symbolic motives of the consumer. Adoption does not solely depend on instrumental attributes, but consumers may be motivated to adopt because of the positive environmental- and symbolic attributes that can be used to signal positive
characteristics to others. Although this study found that consumers may not acknowledge or recognize the importance of symbolic motives for adoption of sustainable innovations. Furthermore, Griskevicius et al. (2010) found that buying sustainable products is often associated with status, because you are showing that you are able and willing to pay more to protect the environment. As a result of a more costly production process, sustainable products are often more expensive than conventional products (Conrad, 2005).
That sustainable products have a strong symbolic function is shown as well by an article of Maynard (2007). He published about the hybrid Toyota Prius which had very successful sales figures, although the car is small, has a slow engine and is also very expensive. The article reported that more than half of Toyota Prius owners state that they bought the car because ‘it made a statement about him or her’ as main reason, rather than pro-environmental reasons. This suggest that the car does not only serve an instrumental function, but also a strong symbolic one.
All studies have in common that sustainable products are used to show one’s identity to others and to make a statement. It seems that the strong symbolic value of sustainable products can motivate consumers to buy sustainable. It is unclear if consumers are willing to acknowledge that their buying behavior is driven by symbolic motives. In the study of
Noppers, Bolderdijk and Steg (2014) consumers did not recognize the importance of symbolic motives, while Maynard (2007) found that owners of a sustainable car overtly stated that they bought the car because it made a statement about him or her.
2.5 Barriers to sustainable consumption – Availability
15
Previous research found factors such as lack of time, lack of money and lack of information as barriers to sustainable consumption (Blake, 1999); Other research found that consumers perceive lack of availability, inconvenience and price as barriers (Robinson and Smith, 2002). Vermeir and Verbeke (2006) found that consumers have more negative attitudes towards the price, appearance, convenience and conservation attributes of a sustainable product. In addition, they found that low perceived availability of sustainable products led to low buying intentions.
Bonti-Ankomah and Yiridoe (2006) mention low-availability/distribution, price premiums and consumer lack of knowledge as factors that are inhibiting consumers to buy organic products.
Following from the factors in aforementioned studies, it seems that the availability of sustainable products plays an important role. Previous research on availability of products has been done, but there is no consensus in literature. On the one hand, Bezawada and Pauwels (2013) found that higher availability of organic products led to more organic consumption. Likewise, higher distribution of products will increase sales (Reibstein and Farris, 1995). If a product or brand is more available it will increase the opportunities for consumers to buy that product or brand (Aertsens, Mondelaers, and Huylenbroeck,2009; Leone and Schultz, 1980; Reibstein and Farris, 1995).
On the other hand, Ngobo (2011) found, for organic products, that a wide distribution of products made consumers less likely to buy them. Consumers preferred to buy this type of products in specialty stores instead of widespread and conventional stores.
The majority of research on barriers to sustainable consumption provides factors that relate to costs (in time, money, or effort) for the consumer. Furthermore, there is no consensus on the role of availability of products and sustainable consumption. Part of the studies based their results on organic products, it is unclear if these results also hold for sustainable
products. Research is needed to investigate the role of availability for sustainable products.
2.6 Conceptual model
16
promote sustainable behavior. From past studies it is known that biospheric and normative appeals on packaging are known to be effective tools to promote pro-environmental behavior. (Bolderdijk et al., 2012; Evans et al., 2012; Nolan, Schultz, Cialdini, Griskevicius and
Goldstein, 2008). Since sustainable consumption has a strong symbolic value and consumers can use sustainable products to show their identity (Noppers, Bolderdijk and Steg, 2014; Griskevicius et al., 2010; Maynard, 2007), appeals that address the symbolic function of products are proposed as a new type of appeal. This results in three different types of appeals that are included in the conceptual model.
Whereas complying with biospheric appeals enables consumers to maintain a positive self-concept (Bolderdijk et al., 2012) and the fact that maintaining a positive self-concept is such a strong driver of various human behaviors (Pyszczynski, 2004), it is expected that biospheric appeals are most effective as a means to increase WTP. Normative appeals are expected to have the second highest WTP and symbolic appeals lowest WTP. This is expected based on the hierarchy of needs that is driving human behavior (Maslow, 1943).
Furthermore, the majority of barriers to sustainable consumption that were mentioned in past research have in common that they are related to costs for the consumer. Since the availability of sustainable products was mentioned several times (Bonti-Ankomah and Yiridoe, 2006; Robinson and Smith, 2002; Vermeir and Verbeke, 2006), it is assumed as an important barrier to sustainable consumption. In this study the availability barrier is framed as the amount of effort (5 minutes or 25 minutes bicycle ride) that is needed to obtain a product, since lower availability of products implies that more effort is needed to obtain those
products. This variable will be included in the conceptual model as a moderator. In general, based on literature it is expected that the amount of effort to obtain a product will lower the willingness to pay for sustainable products. If costs for the consumer become too high, they are less likely to buy sustainable products (Robinson and Smith, 2002). In addition, low availability of sustainable products predicts low sustainable consumption (Bezawada and Pauwels, 2013; Reibstein and Farris, 1995).
However, the amount of effort that is needed to obtain a product can possibly have a positive effect on WTP for sustainable consumption, since Ngobo (2011) found that a wide distribution of products made consumers less likely to buy them.
17
framework the following conceptual model is presented to study consumer WTP for sustainable consumption:
2.7 Hypotheses
Biospheric appeals
Based on the theoretical framework there seems to be a clear relationship between biospheric appeals and pro-environmental behavior. It is suggested that biospheric appeals will be effective in promoting pro-environmental behavior for several reasons. In the first place biospheric appeals will be effective because people that are highly valuing nature and the environment strive for consistency between their behavior and self-concept, otherwise they will experience feelings of discomfort (Festinger, 1957). Second, protecting the environment and nature is seen as morally right and appropriate (Lindenberg and Steg, 2007). This implies that even consumers that have a low biospheric value orientation may engage in
18
environment or not, in both cases complying to biospheric appeals enables the consumer to maintain or build a positive self-concept.
Humans are strongly motivated to maintain a positive self-concept and this motive drives the majority of human behavior. Diverse behaviors (such as altruism, aggression, love and hatred) are found to be rooted in the human need to see ourselves in a positive way (Pyszczynski, 2004). It seems that maintaining a positive self-concept is such a strong driver of various human behaviors, based on this idea it is expected that biospheric appeals are most effective as a means to increase WTP for sustainable consumption compared to normative- or symbolic type of appeals whereas complying with biospheric appeals enables consumers to maintain a positive self-concept (Bolderdijk et al., 2012). The following is hypothesized; [H1] Biospheric appeals on packaging will lead to a higher willingness to pay for a
sustainable product compared to appeals that stress normative information or the symbolic function.
Appeals that stress normative information compared to appeals stressing the symbolic function
A strong relationship between appeals stressing normative information and willingness to engage in pro-environmental behavior may exist. Several studies showed that normative information can be a powerful instrument to change behavior (Nolan, Schultz, Cialdini, Griskevicius and Goldstein, 2008; Goldstein, Cialdini and Griskevicius, 2008; Vermeir and Verbeke (2006). The effectiveness of normative information can be explained by the fact that people have the tendency to conform to norms, because it is associated with social
acceptance. They want to gain social approval and want to avoid social disapproval (Deutsch and Gerard, 1955). Looking for social approval is driven by the need to belong, i.e. to be an accepted member of a group or family (Baumeister and Leary, 1995). Hence, conforming to norms can be explained by the idea that human behavior is driven by their strong desire to belong to groups. The need for belonging is seen as one of the basic human needs, according to the hierarchy of human needs as suggested by Maslow (1943).
19
symbolic function (Maynard, 2007; Noppers, Bolderdijk and Steg, 2014). Research showed that products have an instrumental and symbolic function and that consumers use the latter as a mean to express themselves (Dittmar, 2008). Material possessions function as an extension to the self and are used to show ones identity to others (Elliot, 1998; Belk, 1988).
This tendency to express yourself and to show others your identity with buying expensive products can be linked to the costly signaling theory (Miller, 2009; Griskevicius, Tybur, Sundie, Cialdini, Miller and Kenrick, 2007). The theory states that people often engage in costly behavior to show their identity. Since sustainable products are often more expensive than conventional products (Conrad, 2005), it is suggested that the symbolic function of sustainable products can be used to show your identity to others. The need to show your identity to others can be linked to the idea of Maslow (1943) that human behavior is
motivated by the need to increase esteem. Individuals want to feel respected by others, they want to gain status and recognition. Hence, complying to appeals stressing the symbolic function of sustainable products can be explained by the human need to increase esteem. Human behavior is driven by the motivation to feel respected by others and to gain status in order to increase esteem (Maslow, 1943).
On the one hand is expected that appeals that stress normative information will increase WTP for sustainable consumption, since conforming to norms is driven by the need to belong to groups. On the other hand is expected that appeals that stress the symbolic function will increase WTP for sustainable consumption, since the symbolic function of sustainable products enable consumers to show their identity to others as a result of their need to increase esteem.
Based on the hierarchy of needs of Maslow (1943) is supposed that the need for belongingness is a more fundamental need than the need for esteem. Therefore it is expected that appeals that are stressing normative information are more effective in promoting
sustainable consumption compared to appeals that are stressing the symbolic function. The following is hypothesized;
[H2] Appeals that stress normative information on packaging will increase the willingness to pay for a sustainable product compared to appeals that stress the symbolic function.
Amount of effort to obtain product
20
be altered when consumers have to put effort into getting the product. On the one hand
consumers mentioned several barriers to sustainable consumption that all were related to costs for the consumer, such as time, lack of availability, inconvenience, money or (cognitive) effort (Blake, 1999; Robinson and Smith, 2002; Vermeir and Verbeke, 2006). The costs for the consumer should not be too high in order to increase sustainable consumption (Robinson and Smith, 2002). Therefore, in general it is expected that high amount of effort that is needed to obtain a product will lower the WTP.
For biospheric appeals and appeals stressing normative information it is expected that WTP will decrease when more effort is needed. Complying with biospheric appeals was related to the need for a positive self-concept (Bolderdijk et al., 2012), while complying with appeals stressing normative information was related to the need for belongingness (Maslow, 1943). For both types of appeals, it is expected that simply complying with the appeal is sufficient to fulfill the underlying need. A higher amount of effort that is needed to obtain a product will not stronger reinforce the underlying needs for these types of appeal.
However, the opposite is expected for appeals that are stressing the symbolic function of sustainable products. Sustainable products have a strong symbolic function (Maynard, 2007; Noppers, Bolderdijk and Steg, 2014) which consumers can use to express themselves (Dittmar, 2008). Likewise, costly signaling theory argued that consumers can make a
statement and show their identity to others when they engage in costly behavior (Miller, 2009; Griskevicius, Tybur, Sundie, Cialdini, Miller and Kenrick, 2007). However, this statement will be stronger when the required behavior is costlier (Miller, 2009; Noppers, Bolderdijk and Steg 2014). This gives rise to the expectation that for consumers that are motivated to show their identity to others, it could be that a higher amount of effort to obtain a product can increase their willingness to engage in pro-environmental behavior compared to a lower amount of effort. If consumers that are buying sustainable products are driven by the need to increase esteem and gain status, they can gain more status when they have to put more effort into getting the product, i.e. their need to increase esteem will be fulfilled stronger.
Hence, for appeals that are stressing the symbolic function of a sustainable product it is expected that WTP will increase when high amount of effort is needed to obtain the product compared to low effort. The following hypotheses are stated;
21
[H3b] Higher amount of effort will lead to lower willingness to pay for a sustainable product with appeals that stress normative information.
22
3. Research Design
This chapter will discuss the chosen research methods, data collection and the plan of analysis.
3.1 Research method
The method that is used in this research is a Choice Based Conjoint (CBC) analysis. This is an experimental method to study consumer preferences for products. Products are seen as
attribute bundles, whereby each product attribute can have several levels. Consumers’ preferences are decomposed statistically from the overall evaluation of the product.
Since this study aims to study WTP for sustainable products, a CBC is an appropriate method to use. Consumers have to indicate repeatedly their most preferred product from a set of alternatives that are specified with different combinations of attribute levels. In case of this paper, the CBC will study which attributes (‘type of appeal on package’ or ‘price’) consumers prefer and how much they are willing to pay for sustainable shoes. Shoes are selected as product, since it is common for participants of all age groups (18 – 65 years) and both genders to buy this type of product. WTP is chosen as dependent variable.
Since it is expected that the amount of effort that is needed to obtain the sustainable shoes will moderate the relationship between the different types of appeals and willingness to pay for a sustainable product, participants will read a short text before the conjoint part. One half of the participants will read that little effort is needed to obtain the product while the other half will read that a lot of effort is needed to obtain the product. Participants will be randomly assigned to one of these conditions.
3.2 Data collection
23
measuring the symbolic value of the product, the second scale based on De Groot and Steg (2008) measured to what extent consumers have biospheric values and the third one measured the social comparison orientation (SCO) (Gibbons and Buunk, 1999). Finally, a few questions asked for demographic information.
3.3 Attributes and Levels
The attributes that are used in the Choice Based Conjoint for this study are shown in table 1. Attributes and levels are independent from each other, with a concrete and unambiguous meaning of the levels.
Attribute Level 1 Level 2 Level 3
Type of Appeal on Package
Biospheric ‘Help saving the environment and buy these
sustainable shoes’
Symbolic ‘Show others that you care and buy these sustainable shoes’
Social Norms ‘Join the majority of your peers and buy these sustainable shoes’
Price €70,- €90,- €110,-
Table 1. Overview of attributes and levels in the CBC
3.4 Experimental Design
The CBC Analysis had a 3x3 experimental design, manipulating the attributes ‘type of appeal on package’ (biospheric-, symbolic- or social norm type) and ‘price’ (€70,-, €90,- or €110,-). With a 3x3 design, there were 9 possible combinations of stimuli. To avoid fatigue among consumers, 5 choice sets with 2 alternatives were shown to participants, i.e. a full factorial design. The choice design should be efficient and balanced, which implies that each attribute level should be displayed an equal number of times. Furthermore, the conjoint design should be orthogonal, meaning that each combination of attribute levels is displayed an equal number of times. Lastly, the design had minimal overlap, which means that the same level didn’t appear twice.
24
the no-choice option. In this case information will be lost, therefore it was decided not to include a no-choice option. Instead, after choosing one of the alternatives a question was added asking respondents if they ‘would actually buy their chosen product if it was available’. See figure 1 for an example of a choice set in the CBC of this research.
Figure 1. Example of choice set.
3.5 Plan of Analysis
3.5.1 Construct Validity
25
3.5.2 Model Specification
The model parameters are estimated based on the random utility model, which assumes that goods and services are combinations of attributes to which consumers attach utilities. In turn, the choices of the consumers depend on the overall utilities of alternatives. The systematic utility of consumer n for each product i is the sum of part-worth utilities:
𝑉𝑖 = 𝛽1Ap𝑖 + 𝛽2𝑃𝑖
with,
V = Utility
Ap = Type of Appeal on package P = Price
Furthermore, the willingness to pay (WTP) will be measured for the attribute ´type of appeal on package´ by dividing the estimated parameter of this attribute by the estimated parameter of the price attribute.
𝑊𝑇𝑃𝑖 =β1
𝛽2
3.5.3 Model estimation
The parameters of this study are estimated in Latent Gold with the Maximum Likelihood method. This method aims to find the parameters that maximizes the likelihood of observing the actual sample, i.e. maximizing the (log) likelihood function. This function is defined as:
26
3.5.4 Model fit
To assess how well the estimated models fit the data in this research, several tests can be conducted. The Likelihood Ratio test will be carried out, by comparing the estimated models with the null model. The likelihood function will be at its maximum when the parameters fit the data perfectly, and will be minimum when the parameters are zero. The latter is called the null model:
𝐿𝐿 (0) = 𝑛 ∗ 𝑐 ∗ 𝑙𝑛 (1/𝑚) with,
m = number of alternatives per choice set J n = number of consumers
c = number of choice sets per consumer
In the first model that will be compared with the null model, all attributes are assumed to have a nominal function. Then the parameters will be plotted to assess whether the attribute
functions need to be specified, they may have a linear, nominal or quadratic function. If necessary, the specification of the attribute functions may be changed and new models will be estimated. Their fit will be assessed as well with a Likelihood Ratio test, Pseudo R2 and Pseudo R2 adjusted. Information criteria such as BIC and AIC will be used to compare models with each other. Since models with more parameters always result in a higher LogLikelihood, these information criteria penalize models with more parameters. Next, to see which attribute has the most influence on consumer choices, the relative
27
4. Results
The next chapter will discuss the outcomes of the conducted choice based conjoint. First of all, some descriptive statistics of the sample will be given. Next, different models are defined and evaluated with respect to their validity. The selected model will be used to calculate the WTP. After that, the effect of the moderator will be tested. The chapter will conclude with the results of the tested hypotheses.
4.1 Descriptives
The online survey in this study was opened 339 times, but only 123 respondents completed the survey. 64 participants were in the low effort condition (5 minute bike ride to obtain the product), the other 59 participants were in the high effort condition (25 minute bike ride to obtain the product). The majority of respondents are females, namely 72 (58,5%) against 51 males (41,5 %). The most frequent observed age category is between 25-29 years (51 respondents, 41,5 %), closely followed by the age category between 18-25 years (40 respondents, 32,5 %). The sample consists mainly of Dutch participants (102 respondents, 82,9 %), 9 Russian respondents (7,3%), 3 Italian respondents (2,4%), 3 German respondents (2,4 %) and the remaining respondents are from respectively Belgium, Bulgaria, Finland, Portugal, Swiss and Indonesia.
Table 2. Descriptive statistics of sample
28 Nationality (N=123) Frequency % Dutch 102 82,9 Russia 9 7,3 Italy 3 2,4 Germany 3 2,4
Other European countries 6 4,8
4.2 Construct validity
4.2.1 Biospheric value orientation
Three scales were included in the online survey to function as control variables. The first scale was included to measure the extent to which participants have a biospheric value orientation. The scale is based on research of De Groot and Steg (2008) that used value orientations to explain pro-environmental behavior, participants had to rate the following items on a 9-point Likert scale ranging from ‘opposed to my values’ to extremely important:
1)Preventing pollution: protecting natural resources 2)Respecting the earth: harmony with other species 3)Unity with nature: fitting into nature
4)Protecting the environment: preserving nature
A Cronbach´s Alpha of 0.86 was computed in SPSS for these items (N=4), which is good according to Nunnally (1978) who recommended reliabilities of 0.70 or higher. Hence, the scale is a reliable instrument to measure the extent to which participants have a biospheric value orientation. Looking at the overall sample shows that on average respondents score high on the extent to which they have a biospheric value orientation (M=6.17, SD= 1.53).
29
for a sustainable product.
4.2.2 Symbolic value of product
The second scale was included to assess the symbolic value of the used product and is based on research about the signaling strength of sustainable products (Noppers, Keizer, Bolderdijk and Steg (2014). The scale contains the following items, which had to be answered on a 5-point Likert scale from strongly disagree to strongly agree:
1) Having this product says something about the kind of person I am 2) Having this product gives me information about my personality. 3) Having this product gives me status.
4) Having this product gives me a positive feeling about myself. 5) Having this product gives me a sense of accomplishment. 6) Having this product fits with how I see myself.
7) I can impress others with this product
8) Having this product shows to others who I am.
A Cronbach´s Alpha of 0.83 was computed in SPSS for these items (N=8), this is good according to Nunnally (1978) who recommended reliabilities of 0.70 or higher. The scale is a reliable instrument to assess the symbolic function of the sustainable shoes. The overall sample evaluated the sustainable shoes with a 2.58, which is barely above scale average (5-point Likert scale). Participants that have to ride their bicycle for 25 minutes (compared to 5 minutes) perceive the sustainable shoes as having a higher symbolic value. The average symbolic value in the high effort condition is 2.76, against 2.40 in the low effort condition, whereby the difference is significant with F (1, 1228)= 54.26, p <0.01. This is in line with the theoretical framework that suggested that the more effort that is required to obtain a product can enhance the symbolic value of that product, however the overall perceived symbolic value of the sustainable shoes is barely above scale average.
30
of the sustainable shoes
4.2.3 Social Comparison Orientation (SCO)
The third scale based on Gibbons and Buunk (1999) was included to measure the extent to which respondents have a social comparison orientation (SCO). Respondents that have a strong tendency to compare his- or herself with others might faster comply with appeals that stress normative information, the SCO scale functions as a control variable for this.
Participants had to rate the following items on a 5 point Likert-scale from 1= Strongly Disagree to 5= Strongly Agree.
1) I often compare myself with others with respect to what I have accomplished in life 2) I always pay a lot of attention to how I do things compared with how others do things 3) I often compare how my loved ones (boy or girlfriend, family members, etc.) are doing with how others are doing
4) I am not the type of person who compares often with others (R)
5) If I want to find out how well I have done something, I compare what I have done with how others have done
6) I often compare how I am doing socially (e.g., social skills, popularity) with other people
A Cronbach’s Alpha of 0.5 was computed in SPSS for these items (N=6), which is low according to Nunnally (1978). Deleting item 4, which is a reversed item, improves the
reliability of the scale to an alpha of 0.74. This is sufficient according to Nunnally (1978). The overall sample showed a SCO of 2.58, with SD= 0.54. This is more or less the scale average and hence the sample does not say to have a strong tendency to compare oneself with others. Again, to see whether participants have different preferences as a result of a varying SCO scores, SCO was included in the model as a covariate. However, for none of the attributes were found significant differences between the classes (high or low SCO score). Hence, participants do not differ in their preferences as a result of differences in SCO.
4.3 Model specification
31
Package Help saving the environment and buy these sustainable shoes, Show others that you care and buy these sustainable shoes, Join the majority of your peers and
buy these sustainable shoes.
Price 70, 90, 110
In this part of the analysis process the model needs to be specified, since the used product attributes may have a linear, nominal or quadratic function. As a starting point for aggregate model 1, all attributes are assumed to have a nominal function. Figure 2a and 2b show the type of part-worth relationship of this model when all attributes are assumed to be nominal. However, attributes may have another type of function. Looking at figure 2b suggests that the price attribute could have a linear function. When testing model 1 with a Likelihood Ratio test, it turns out to be significantly different from the null model with a Chi-square
distribution of 282.62, 4 degrees of freedom and p-value < 0.05, see table 3.
Figure 2a and 2b. Type of relationships for the attributes (price and the type of appeal on package) in model 1.
4.4 Model fit
Since the plotted line in figure 2b indicates a linear relationship of the price attribute, another model is specified whereby price now is assumed to be linear.
Model 1: All attributes assumed nominal Model 2: Package nominal, Price numeric
0,4998 -0,1437 -0,3524 -1,5 -1 -0,5 0 0,5 1 1,5
Biospheric Symbolic Normative
Pa
ra
m
eter
Attribute level
Type of Appeal on Package
1,0989 -0,1398 -0,9591 -1,5 -1 -0,5 0 0,5 1 1,5
70 Euro 90 Euro 110 Euro
32
When testing model 2 with a Likelihood Ratio test, it turns out to be significantly different from the null model as well with a Chi-square distribution of 279.34, 3 degrees of freedom and p-value < 0.05, see table 3. The models seem to perform similar on the criteria in table 3, for example the Pseudo R2 and Pseudo R2adj are similar to each other. When comparing the models with each other, a test confirms that the models are not significantly different at α 5% level, with a Likelihood Ratio test of 3.28, with 1 degree of freedom and a p-value of 0.07. Based on the criteria in table 3 and since the models are not significantly different, model 2 will be chosen to use in the upcoming analysis. The selected criteria do not differ much, but model 2 has the lowest BIC value. Above all, model 2 has the advantage that is has the least number of parameters and that one of them is linear. Numeric variables allow for calculations between the values of the tested levels
Table 3. Assessing the model fit
Model 1 Model 2 LL model -284,98 -286,62 LL null1 -426,29 -426,29 Parameters (npar) 4 3 N 123 123 LR test 282,62 279,34 P (Chisq) LR test <0.01 <0.01 Pseudo R22 0,331488 0,3276 Pseudo R2 adj3 0,322105 0,320 AIC4 577,96 579,24 BIC5 589,21 587,67
4.5 Relative importance of attributes – Aggregated model
Based on the selected model 2, table 4 shows the estimated parameters for this model. Both attributes appear to have a significant influence on consumer preferences. The package
1LL[null] = respondents*choice sets*ln(1/nr alternatives) = 123*5*ln(1/2)= -426,29 2Pseudo R2 = 1 - (LL[model]/LL[null])
3Pseudo R2 adj = 1-((LL[model]-npar)/LL[null]) 4AIC = -2*LL[model] + 2*npar
33
attribute has a Wald statistic of 31.65 with p-value <0.01, the price attribute has a Wald statistic of 145.36 with p-value <0.01.
Table 4. Estimated parameters of model 2.
Attribute Parameter Wald P-value
Biospheric Appeal 0,4998 31,65 <0,01*
Symbolic Appeal -0,1437 Social Norms Appeal -0,3524
Price −0,0513 145,36 <0,01*
Based on the estimated parameters in table 4, the relative importance of the attributes can be calculated. In order to do so, first the range between the highest and lowest utilities of
attribute levels is calculated. For the type of appeal on package attribute this means (0,4998 – (-0,3524))= 0.8522. In case of the linear price variable the range is ((70*-0,0513)-(110*-0,0513))= 2.053. Summing up results in a total range of 0.8522+2.053 = 2.9052. Table 5 gives an overview of the relative importance per attribute that can be calculated in turn, dividing the absolute importance of an attribute by the total range. It can be seen that the price attribute is far more important with 70.66%. Interpreting this result implies that consumers consider price first when they are buying sustainable shoes. The type of appeal that is on the package seems to be less important, with a relative importance of 29.34%.
Table 5. Relative importance per attribute.
Attribute Absolute Importance Relative Importance
Appeal on Package 0.8522 29.34%
34
4.6 WTP per type of appeal
Looking at the estimated utilities for the type of appeal that is on the package, a higher coefficient for a biospheric appeal indicates that consumers prefer to pay more for a product with this attribute level. Higher utilities will result in higher willingness to pay. The WTP can be calculated per attribute level by dividing the utility by the price parameter. Table 6 gives an overview of the WTP per attribute level. It shows that consumers are willing to pay more for sustainable shoes with a biospheric appeal on its package compared to symbolic- or normative appeals When biospheric appeals are on the package, the WTP is 12,54€ higher compared to symbolic appeals and 16,61€ higher compared to normative appeals. This confirms hypothesis 1 that ‘Biospheric appeals on packaging will lead to a higher willingness to pay for a
sustainable product compared to appeals stressing normative information or the symbolic function’. With respect to appeals that are stressing social norms on its packaging, consumers are willing to pay -4,07€ less compared to appeals stressing the symbolic function. This does not support hypothesis 2 that stated that ‘Appeals that stress social norms on its packaging will lead to a higher willingness to pay for a sustainable product compared to appeals stressing the symbolic function’.
Table 6. WTP per type of appeal
Parameter WTP
Biospheric Appeal 0,4998 9,74€
Symbolic Appeal -0,1437 -2,80€
Social Norms Appeal -0,3524 -6,87€
4.7 Moderator effect
35
significantly different from each other, with Wald (=) = 1.48 and p-value 0.48. For the price attribute there is a significant difference between the two groups, Wald (=)= 7.6431 and p-value of 0.005. Table 7 shows that the price attribute has a less negative utility when consumers have to ride their bicycle for 25 minutes to obtain the product compared to 5 minutes, this will result in higher WTP when consumers have to put high effort into getting a product. Since the amount of effort does not cause a significant difference in preferences for the type of appeal attribute, more results cannot be interpreted. The moderating role of the amount of effort that is needed to obtain the product cannot be confirmed statistically and hypotheses 3a, 3b and 3c cannot be supported.
Table 7. Parameter estimates for the two conditions of the moderator Attribute Parameter for 5
minutes bicycle ride Parameter for 25 minutes bicycle ride Wald (=) P-value Package Biospheric Appeal 0,3760 0,5860 1,4848 0,48 Symbolic Appeal -0,0580 -0,2199 Social Norms Appeal -0,3180 -0,3661 Price -0,0642 −0,0401 7,6431 0,0057* 4.8 Hypotheses overview
An overview of the aforementioned results can be seen in table 8 below, to show which of the hypotheses are accepted and which are rejected.
Table 8. Overview of hypotheses testing
Hypothesis
H1: Biospheric appeals on packaging will lead to a higher willingness to pay for a sustainable product compared to appeals that stress normative information or the symbolic function.
36
H2: Appeals that stress normative information on packaging will increase the willingness to pay for a sustainable product compared to appeals that stress the symbolic function
Rejected
H3a: Higher amount of effort will lead to lower willingness to pay for a sustainable product with biospheric appeals.
Rejected
H3b: Higher amount of effort will lead to lower
willingness to pay for a sustainable product with appeals that stress normative information.
Rejected
H3c: Higher amount of effort will lead to higher
willingness to pay for a sustainable product with appeals that stress the symbolic function.
37
5. Discussion and Recommendations
This research aimed to get insight in WTP for sustainable consumption. In this study
sustainable shoes were used as product in the choice based conjoint analysis, whereby WTP was measured based on two main product attributes, namely price and the type of appeal that is on the package of the product. Previous research showed that biospheric appeals and appeals that provide normative information are effective in promoting pro-environmental behavior, while little was known about appeals stressing the symbolic function of products. The latter type of appeal was included since sustainable products appear to have a strong symbolic value. This chapter will relate the results to the theoretical framework of this study. Furthermore, limitations and directions for future research will be discussed.
5.1 The role of appeals on packaging
Considering the importance of the product attributes (type of appeal and price), the findings of the conjoint analysis show that participants attached the highest importance to the price
attribute (70.66%). This implies that participants look at the price first when buying
sustainable shoes. The type of appeal that is on the package is by far less important (29.34%). Although the type of appeal appears to be less important, a closer look will be taken at the differences in WTP between the types of appeal.
Figure 3. WTP per type of appeal on packaging
9,74 € -2,80 € -6,87 € -8,00 € -6,00 € -4,00 € -2,00 € 0,00 € 2,00 € 4,00 € 6,00 € 8,00 € 10,00 € 12,00 €
Biospheric Symbolic Normative
W TP IN E URO 'S
TYPE OF APPEAL ON PACKAGE
38
The results of the conjoint analysis can be seen in figure 3 and showed that consumers rated the biospheric type of appeal as having the highest utility, followed by the symbolic type of appeals and lastly the normative type of appeals. It should be noted that WTP was positive only for the biospheric type of appeal, and negative for the other two type of appeals.
As expected, biospheric appeals perform best in promoting sustainable consumption. Figure 3 shows that for the biospheric type of appeal consumers are willing to pay 12,54€ extra compared to symbolic appeals and 16,61€ extra compared to normative appeals. These findings supported hypothesis 1 and are in line with the notion that human behavior is strongly driven by the need to see ourselves in a positive way (Pyszczynski et al., 2004) and the idea that consumers build a positive self-concept and feel good about themselves when complying with biospheric appeals (Bolderdijk et al., 2012; Evans et al., 2012). Another explanation might be that complying with one of the other types of appeals may be experienced as less socially desirable.
In order to explain any heterogeneity in WTP for the different types of appeal, a scale that measured the extent to which respondents have a biospheric value orientation was included as a control variable. It turned out that consumer differences in biospheric value orientation did not cause significant differences in preference for the type of appeal that is on packaging. The fact that respondents have the highest WTP for the biospheric type of appeal might be explained rather by the idea that individuals prefer to see themselves as green and to maintain a positive self-concept instead as having a strong biospheric value orientation. For the price attribute was found a significant difference between consumers with a high or low biospheric value orientation. The utility of the price attribute is less negative for participants that have a stronger biospheric value orientation (-0,05 compared to -0,03), this might be explained by the idea that participants that have a strong tendency to protect the environment care less about the price they have to pay for a sustainable product.
39
Furthermore, the Social Comparison Orientation (SCO) scale was included as a control variable to explain any heterogeneity in consumer WTP. It was expected that a strong tendency to compare oneself with others (a high SCO) might lead to more compliance with a normative type of appeal. However, no significant differences between consumers with a high or low SCO score were found. Hence, participants do not differ in their preferences as a result of differences in SCO.
Previous research showed that normative information can be a powerful instrument to influence behavior, but within the context of this study design should be concluded that appeals stressing normative information are not an effective way to increase WTP. Possibly the implementation of the normative appeal (‘Join the majority of your peers and buy this sustainable product’) was not concrete enough for consumers. Furthermore, it is likely that consumers don’t want to admit that they are influenced by others, future research could be effective when normative information is used within a different study design.
Next, it is remarkable that the symbolic type of appeals perform better than normative type of appeals, since little was known about the effectiveness of symbolic type of appeals and the fact that normative appeals are proven to be effective in promoting pro-environmental behavior (Nolan, Schultz, Cialdini, Griskevicius and Goldstein, 2008; Goldstein, Cialdini and Griskevicius, 2008). If complying with a normative- or symbolic appeal is indeed driven by respectively the need for belongingness and the need for esteem, these findings do not support the expectation that the need for belongingness is a more fundamental human need than the need for esteem as suggested by Maslow (1943). It could be that participants in this study are driven by other factors than the need for belongingness or the need for esteem and that the setting of the conjoint analysis was not realistic.
Furthermore, it is unclear if the performance of the symbolic appeals is the result of the assumed symbolic value of the sustainable shoes that are used in the survey since the scale that measured the symbolic value of the products showed that consumers did not attach a lot of symbolic value to the sustainable shoes (M=2.56 on a 5-point scale). Using a product with a higher symbolic value might have been better to use.
5.4 The role of the amount of effort to obtain a product
40
products (Blake, 1999; Robinson and Smith, 2002; Vermeir and Verbeke, 2006). Except for the symbolic type of appeal, it was expected that high amount of effort that is needed will lower the WTP, since costs for the consumer should not be too high in order to increase sustainable consumption (Robinson and Smith, 2002).
However, for the type of appeal attribute there was no significant difference in
preferences between the two conditions (5 or 25 minutes bicycle ride). The moderating role of the amount of effort that is needed to obtain a product couldn’t be confirmed statistically and hypotheses 3a, 3b and 3c cannot be supported.
It might be that manipulation of the amount of effort is not implemented well and that consumers do not perceive a big difference between a 5 or 25 minutes bicycle ride. Another explanation for the fact that the two conditions did not differ from each other in their preferences for the appeals might be the fact that consumers are strongly price driven and hence consumers do not care much about the type of appeal. The relative importance of the price attribute was 70.66% compared to 29.34% for the type of appeal attribute.
For the price attribute was found a significant difference between the two conditions, price has a less negative utility when consumers have to ride their bicycle for 25 minutes to obtain the product compared to 5 minutes. This will result in a higher WTP for sustainable consumption when consumers have to put high effort. It may be that consumers become less price driven and attach more importance to other product characteristics, when they have to put a lot of effort to obtain a product.
5.5 Managerial implications
41
sustainable consumption can even be increased if managers make sure that consumers have to put moderate effort into getting their products. This can imply that management should decide to sell their products only at selected retailers so that it does not become too easy to obtain their products.
5.6 Limitations
This research aimed to get insight in WTP for sustainable consumption, whereby it studied the effect of different types of appeal. Some limitations might apply to this research, which could be addressed to improve future research.
The results showed that people place the highest utility and WTP to sustainable shoes with a biospheric appeal on its package. However, it could not be concluded that preference for the biospheric type of appeal is a result of a strong biospheric value orientation. It is likely that respondents would like to have a positive self-concept and prefer to see themselves as green. A limitation of this study might be that the design of the conjoint shows two
alternatives at the same time and it is easy for respondents to choose the one that is seen as socially desirable or makes them feel good about themselves. In general, people are not likely to admit that they are influenced by other people. This might be a reason why the appeal that stressed normative information is not preferred when participants have to make such explicit choices. To solve this limitation, future research should use a different study design that should prevent socially desirable answers.
Another limitation of this study might be shoes as chosen product in the conjoint. It was chosen because participants of both genders and all ages should be able to imagine that they are buying shoes. Literature suggested that the more costly behavior (i.e. putting more effort to obtain a product), the stronger the symbolic value of the product. However, the scale that measured the symbolic value of the sustainable shoes showed that people do not perceive the shoes as having high symbolic value (barely above scale average). Therefore symbolic appeals on the package might not have worked well in combination with the chosen product in this study. In future research it is recommended to use a product that is perceived as having high symbolic value.
Next, this study builds on the idea that complying with each type of appeal can be driven by a specific human need (i.e., the need for a positive self-concept, need for
42
43
6. References
Aertsens, J., Mondelaers, K. and Huylenbroeck, G. van (2009). Differences in Retail Strategies on the Emerging Organic Market. British Food Journal, 111 (2), 138– 54 Agriculture and Agri-Food Canada (2012). Socially Conscious Consumer Trends:
Sustainability
Baumeister, R. F., & Leary, M. R. (1995). The need to belong: Desire for interpersonal attachments as a fundamental human motivation. Psychological Bulletin, 117(3), 497-
529.
Belk, R.W. (1988) Possessions and the Extended Self. Journal of Consumer Research, 2, 139
-68.
Berger, J., Heath, C. & Ho, B. (2007). Divergence in cultural practices: Tastes as signals of identity. Working paper.
Bezawada, R. and Pauwels, K.H. (2013). What Is Special about Marketing Organic Products? How Organic Assortment, Price and Performance Driver Retailer Performance.
Journal of Marketing, 77 (1) (2013), pp. 31–51
Bolderdijk, J. W., Steg, L., Geller, E. S., Lehman, P. K., & Postmes, T. (2013). Comparing the effectiveness of monetary versus moral motives in environmental campaigning. Nature climate change, 3(4), 413-416.
Bonti-Ankomah, S. and Yiridoe, E.K. (2006). Organic and Conventional Food: A Literature Review of the Economics of Consumer Perceptions and Preferences. Organic
Agriculture Centre of Canada Nova Scotia Agricultural College, Truro, Nova Scotia,
Canada.
Cialdini, R. B. and Trost, M. R. (1998). Social influence: Social norms, conformity and compliance. In D. T. Gilbert, S. T. Fiske, et al. (Eds.), The handbook of social psychology, Vol. 2 (4th ed., pp. 151-192). New York: McGraw-Hill.
Conrad, K. (2005). Price competition and product differentiation when consumers care for the environment. Environment and Resource Economics 31, 1–19.
De Groot, J., & Steg, L. (2008). Value orientations to explain beliefs related to environmental significant behavior: How to measure egoistic, altruistic, and biospheric value
orientations. Environment and Behavior, 40(3), 330-354.
Deutsch, M., & Gerard, H. B. (1955). A study of normative and informational social
influences upon individual judgment. Journal of Abnormal and Social Psychology, 51,
