Nudging consumers towards sustainable packaging through the interplay of packaging material, surface varnishing and environmental claims

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Nudging consumers towards sustainable packaging through the interplay of packaging material, surface varnishing and

environmental claims

Final version Master Thesis

MSc in Business Administration – Consumer Marketing Track University of Amsterdam

2020/2021

Author: Marit Smithuis Student number: 12910759 Date of submission: 28 January 2021 EBEC approval number: 20201114031128

Supervisor: dr. Carina Thürridl

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2 STATEMENT OF ORIGINALITY

This document is written by Student Marit Smithuis 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.

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3 TABLE OF CONTENTS

ABSTRACT ... 5

1. INTRODUCTION ... 6

1.1 Problem Statement ... 6

1.2 Research gap ... 10

1.3 Contribution ... 11

1.4 Structure of the thesis ... 13

2. LITERATURE REVIEW ... 14

2.1 The role of packaging and its impact on consumer perceptions ... 14

2.2 Sustainable packaging and consumers’ sustainability perceptions of a package ... 15

2.2.1 Sustainability perceptions ... 16

2.3 Packaging design and its influence on consumers’ sustainability perceptions ... 17

2.3.1 Structural design elements ... 18

2.3.2 Informational design elements ... 21

2.3.3 Graphical design elements ... 25

2.4 Three-way interaction of packaging material, environmental claim and surface varnishing ... 28

2.5 Downstream consequences ... 30

3. CONCEPTUAL MODEL & HYPOTHESES ... 32

4. METHODS ... 34

4.1 Research design ... 34

4.2 Sample ... 34

4.3 Operationalization of variables ... 36

4.3.1 Manipulation of independent variables within the stimuli ... 36

4.3.2 Measurement of dependent variables, manipulation and attention checks ... 41

4.3.3 Measurement of control variables ... 42

4.4 Procedure ... 44

4.5 Data preparation ... 45

5. RESULTS ... 47

5.1 Preliminary analysis ... 47

5.1.1 Normality check ... 47

5.1.2 Outlier check ... 47

5.1.3 Reliability test ... 48

5.1.4 Manipulation check ... 49

5.1.5 Descriptive statistics ... 50

5.1.6 Correlations ... 53

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5.2 Hypothesis testing ... 55

5.2.1 Main effects of packaging material, surface varnishing and environmental claim 55 5.2.2 Interaction packaging material and environmental claim ... 56

5.2.3 Interaction effect packaging material and surface varnishing ... 57

5.2.4 Three-way interaction packaging material, environmental claim and surface varnishing ... 58

5.2.5 The effect of sustainability perceptions on downstream consequences ... 61

6. DISCUSSION ... 64

6.1 Theoretical Implications ... 68

6.2 Managerial Implications ... 70

6.3 Limitations & Future research ... 72

7. CONCLUSION ... 75

8. REFERENCES ... 76

9. APPENDICES ... 88

9.1 Appendix 1: Descriptive statistics entire sample ... 88

9.2 Appendix 2: Sample descriptive statistics per condition ... 89

9.3 Appendix 3: Stimuli ... 94

9.4 Appendix 4: Pre-test results ... 96

9.5 Appendix 5: Measurement scales ... 98

9.6 Appendix 6: Normality check results ... 100

9.7 Appendix 7: Reliability tests of multiple item measurement scales ... 101

9.8 Appendix 8: Manipulation checks main experiment ... 103

9.9 Appendix 9: Examining differences across conditions ... 105

9.10 Appendix 10: Hypothesis testing Three-way ANOVA overall results ... 107

9.11 Appendix 11: Main effects on sustainability perceptions ... 108

9.12 Appendix 12: Interaction effects on sustainability perceptions ... 109

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5 ABSTRACT

This study examines how sustainability perceptions of different packaging materials (paper versus plastic) can be altered by modifying specific packaging design elements: surface varnishing (matte versus glossy surface) and environmental claim (presence versus absence of an environmental claim). Quantitative research was conducted through an online experiment, in which 386 participants evaluated a soap package that varied on packaging material, surface varnishing and environmental claim. The findings revealed that, as expected, sustainability perceptions were generally higher for paper than plastic packaging. Both paper and plastic packaging were perceived as most sustainable when the package’s surface was matte, and an environmental claim was present. Interestingly, due to this matte surface and environmental claim, plastic packaging experienced a significantly higher increase in sustainability perceptions than paper packaging, such that sustainability perceptions of plastic and paper packaging became less distinct, possibly caused by a ceiling effect for paper packaging. Hence, the findings revealed that under the condition that an environmental claim was present, the effect of a matte surface supported the notion of a ceiling effect where sustainability perceptions increased more strongly for plastic packaging, whereas when an environmental claim was absent, the notion of congruence was supported where paper packaging experienced a higher increase. Overall, this study contributes to literature by enhancing understanding of consumer responses to sustainable packaging and provides valuable implications for marketers to develop effective packaging design strategies to nudge consumers towards sustainable packaging.

Keywords: sustainable packaging, packaging design elements, sustainability perceptions, packaging material, surface varnishing, environmental claims.

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6 1. INTRODUCTION

1.1 Problem Statement

Global warming and other environmental issues have augmented sustainability concerns and have caused consumers to become more aware of the consequences of their actions and consumption choices (Patel, Modi, & Paul, 2017; Steenis, van Herpen, van der Lans, Ligthart, & van Trijp, 2017). Hence, consumers increasingly care for the environment (Moser, 2015; Nordin & Selke 2010; Rokka & Uusitalo, 2008), which has led to changes in their consumption behaviour (Patel et al., 2017; Steenis et al., 2017). A central aspect of this change is the increased importance of product sustainability. Consumers are increasingly expecting and judging products on its sustainability to influence their choices (Lindh, Olsson, Williams, 2016a; Rokka & Uusitalo, 2008). Therefore, incorporating sustainable developments in products has become essential for businesses (Jermsittiparsert, Siam, Issa, Ahmed, & Pahi, 2019; Lee & Carroll, 2011; Lyon & Maxwell, 2004). Several studies have highlighted that packaging is playing a sizeable role in causing pollution. Consequently, packaging and its impact on the environment have become a primary subject, which has raised a growing need for more sustainable packaging (Herbes, Beuthner, & Ramme, 2020; Rokka & Uusitalo, 2008).

Multiple research studies have examined the impact of sustainable packaging on consumers’

perceptions, evaluations and consumption behaviour. Sustainable packaging appears to have a positive influence on consumers’ perceptions and preferences when compared to conventional packaging (Magnier & Schoormans, 2017; Magnier, Schoormans, & Mugge, 2016; Petersen

& Brockhaus, 2017; Prakash and Pathak, 2017; Rokka & Uusitalo, 2008). Even though consumers state sustainability of packaging to be influential for the choices they make (Lindh et al., 2016a; Magnier & Schoormans, 2015), it appears that there is a significant lack of knowledge when judging packaging sustainability (Ketelsen, Janssen, & Hamm, 2020; Lindh et al., 2016a; Young, 2008). Consumers have trouble evaluating the environmental friendliness

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7 of the package, which may lead to counteracting choices that threaten actual sustainable development, opposed to their sustainable intentions (Lindh et al., 2016a, Ketelsen et al., 2020).

Therefore, due to this lacking ability to correctly judge the sustainability of packaging, stimulating consumers to choose sustainable packaging is a great challenge for marketers (Steenis et al., 2017, Steenis, van der Lans, van Herpen, & van Trijp, 2018). Consumers’

perceptions of packaging sustainability impact multiple downstream consequences, such as product and brand evaluations (Magnier & Schoormans, 2015), perceived naturalness and quality of the product (Magnier et al., 2016), willingness to pay (Lindh et al., 2016a), and most importantly, sustainability perceptions have a direct effect on purchase intention (Ketelsen et al., 2020; Steenis et al., 2018). Therefore, matching sustainability perceptions to the actual sustainability of packaging is essential for businesses to aid in their challenge to stimulate sustainable packaging purchases.

Research shows that when assessing the sustainability of packaging, consumers tend to primarily focus on the visual design of the package (Ketelsen et al., 2020; Seo, Ahn, Jeong, &

Moon, 2016). Therefore, effectively designing sustainable packaging to actually signal sustainability is key to influence consumers sustainability perceptions (Petersen & Brockhaus, 2017). Packaging design can be divided into structural, graphical and informational elements (Magnier & Crié, 2015). The material of the package (as structural element) appears to be the most significant feature that influences consumers’ judgements of packaging sustainability, making packaging material the most important cue when selecting sustainable packaging (Ketelsen et al., 2020; Lindh et al., 2016a; Magnier & Crié, 2015; Nguyen, Parker, Brennan,

& Lockrey, 2020). Current research shows that certain packaging materials are generally perceived as more environmentally friendly than others. Apparently, consumers tend to perceive plastic as most detrimental for the environment, in contrast to paper, which is perceived as the most environmentally friendly material (Lindh et al., 2016a; Magnier &

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8 Schoormans, 2017; Nguyen et al., 2020). In a study as much as 99 percent of consumers stated to be at least somewhat concerned about the sustainability of plastic packaging (Gendell &

Pierce, 2018). This indicates that consumers seem to have a general aversion towards plastic, generally considering it as harmful for the environment. Whereas for paper packaging, consumers experience a halo effect, believing paper to be a sustainable choice. However, when assessing the objective environmental impact through the Life Cycle Assessment (LCA), plastic appears to be more environmentally friendly than paper on certain aspects, such as energy and water consumption, distribution, and required storage space (Nguyen et al., 2020).

For instance, few people know that paper bags weigh six to ten times more than plastic bags and thus require seven more trucks to transport the same number of bags (Cho, 2020). Hence, whether paper or plastic is more sustainable, depends on which aspects are assessed. This indicates that a discrepancy exists between consumers’ subjective sustainability perceptions and the actual objective impacts of certain packaging materials (Lindh et al., 2016a; Steenis et al, 2017; Tijssen, Zandstra, de Graaf, & Jager, 2017), which may lead to counteracting choices based on inaccurate beliefs (Steenis et al., 2017). Therefore, more guidance is needed to aid consumers to actually buy the most sustainable packaging (Ketelsen et al., 2020; Lindh et al., 2016a; Nguyen et al., 2020; Shao & Ünal, 2019), and hence further research is required on this discrepancy and how it can be reduced (Lindh et al., 2016a; Steenis et al, 2017; Tijssen et al., 2017). Since effective packaging design is crucial and material appears to be most influential (Ketelsen et al., 2020; Lindh et al., 2016a; Magnier & Crié, 2015; Nguyen et al., 2020), it is necessary to further examine consumers’ sustainability perceptions of different material types (paper and plastic as most opposites) and how these perceptions can be altered.

Besides packaging material, research shows that environmental claims also have a strong influence on consumers’ sustainability perceptions and can help to reduce the discrepancy between consumers’ sustainability perceptions and the actual packaging

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9 sustainability (Magnier & Schoormans, 2017; Ye, Morrin, & Kampfer, 2019). As informational elements, they can inform consumers of the sustainability of the package to influence their judgements (Magnier & Schoormans, 2017). Correspondingly, current research shows that verbal environmental claims can lead to higher sustainability perceptions, particularly when congruent with a sustainable visual appearance of the packaging (Magnier

& Schoormans, 2017). Hence, this indicates that a claim may vary in effectiveness for different materials. Research on whether environmental claims increase sustainability perceptions for all materials in the same way or differently for specific materials is lacking. Therefore, it is interesting to investigate how sustainability perceptions of different materials (paper versus plastic) can be altered by adding environmental claims. It may be expected that claims will increase sustainability perceptions more when congruent with paper, since less scepticism of the claim is expected as compared to plastic packaging (Ertz, François, & Durif, 2017; Magnier

& Schoormans, 2015).

Furthermore, next to structural and informational elements, research has shown that consumers’ sustainability perceptions and choices of packaging are also highly influenced by graphical elements of the package (e.g. shape, colour, size, surface varnishing and typography) (Ahmed, Parmar, & Amin, 2014; Chrysochou & Grunert, 2014; Ketelsen et al., 2020; Magnier

& Schoormans, 2017; Steenis et al., 2017). Current research has investigated the effects of various graphical design elements on consumers’ sustainability perceptions. Nevertheless, one type of graphical design element, surface varnishing, is scarcely researched and no research has examined any effects on sustainability perceptions yet. Surface varnishing refers to the glossiness of the package (matte versus glossy surface), which alters the visual appearance of the package and is therefore considered a graphical element (Kirwan, 2012). Current research shows that matte surfaces as opposed to glossy surfaces of packaging induced healthier evaluations (Ye et al., 2019) and higher perceived naturalness of the product (Marckhgott &

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10 Kamleitner, 2019). Further insights are required into how surface varnishing affects sustainability perceptions and to what extent the effect of a matte versus glossy surface potentially varies for different types of packaging material (Marckhgott & Kamleitner, 2019).

Therefore, it will be interesting to investigate how surface varnishing (matte vs glossy) influences sustainability perceptions for plastic versus paper packaging. Current research by Marckhgott and Kamleitner (2019) showed that the positive effect of a matte surface on naturalness perceptions disappeared when a stronger naturalness cue was present. As sustainability perceptions are correlated to naturalness and healthiness perceptions (Binninger, 2015; Magnier et al., 2016), it might be possible that the effect of surface varnishing on sustainability perceptions will be similar. Therefore, since paper is already perceived as very sustainable, it might be possible that a ceiling effect occurs (Everitt & Skrondal, 2010) and thus a matte surface may not increase sustainability perceptions as much for paper packaging as compared to plastic packaging, which is often perceived as not sustainable and may therefore benefit more from a matte surface. Moreover, when considering the findings of Marckhgott and Kamleitner (2019), it can be expected that when an environmental claim is present, the positive effect of a matte surface is eliminated. Therefore, it is relevant to examine how packaging material, surface varnishing and environmental claim interact to investigate how an environmental claim and surface varnishing can alter sustainability perceptions of paper versus plastic packaging and hence whether an environmental claim eliminating the effect of surface varnishing may differ for paper versus plastic packaging.

1.2 Research gap

Overall, the topic of sustainable packaging is not extensively researched yet and much more insights are required (Ketelsen et al., 2020; Lindh et al., 2016a; Nordin & Selke, 2010;

Steenis et al., 2017). Multiple studies have investigated the impact of packaging design on

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11 consumers, however only a limited amount of research has looked into sustainability perceptions of packaging (Lindh et al., 2016a). Existing research has examined the direct effects of different types of packaging materials and various graphical and informational design elements on sustainability perceptions. However, no research has studied the effect of surface varnishing (glossy versus matte surface) on sustainability perceptions. Furthermore, even though the effectiveness of environmental claims and surface varnishing and their interaction in altering sustainability perceptions may vary for different materials, research is lacking.

Therefore, to address these gaps, the aim of this thesis is to investigate how consumers’

sustainability perceptions of specific types of packaging materials (paper versus plastic) can be altered by modifying surface varnishing and environmental claim, and how these sustainability perceptions eventually impact several downstream consequences, such as perceived quality of the product, attitude towards the product, willingness to pay, and purchase intention. Therefore, the study addresses the following research question:

“How can consumers’ sustainability perceptions of different packaging materials (paper versus plastic) be altered by modifying surface varnishing (matte versus glossy) and environmental claim (present or absent) to subsequently result in multiple downstream

consequences?”

1.3 Contribution

This research contributes to academic literature in the field of sustainable marketing, and more specifically the underresearched field of packaging sustainability (Lindh et al., 2016a; Nordin & Selke, 2010). The research provides further insights into the discrepancy between consumers’ subjective sustainability perceptions and the actual objective environmental impacts of packaging, for which further research is demanded (Lindh et al., 2016a; Steenis et al., 2017). Furthermore, the study provides requested insights on how different design elements can alter sustainability perceptions (Magnier & Crié, 2015). As

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12 supported by Ketelsen et al. (2020), additional insights are valuable on how the design of sustainable packaging can be optimized to increase consumers’ recognition, acceptance, and purchase intention of sustainable packaging. More specifically, this study greatly contributes to literature by addressing literature gaps by being the first to examine the impact of surface varnishing on sustainability perceptions and the three-way interaction of material type, surface varnishing and environmental claim. The results provide novel insights into how consumers’

sustainability perceptions of different materials can be altered, and therefore, enhance understanding of consumer judgements of packaging sustainability and specific packaging design solutions.

Regarding managerial relevance, consumers’ misjudgement of packaging sustainability and the lack of recognition of sustainable materials, except for paper, forms a significant barrier to stimulating sustainable purchases (Ketelsen et al., 2020). Hence, marketers struggle to stimulate sales of sustainable packaging (Steenis et al., 2017). Since sustainability perceptions positively impact multiple purchase-related downstream consequences and consumers’

perceptions are mostly influenced by the impression of the package and available cues (Steenis et al., 2017), effectively designing packaging is crucial for marketers (Petersen & Brockhaus, 2017). Therefore, to reduce misjudgements and nudge consumers towards sustainable packaging, it is necessary for marketers to understand the sustainability perceptions that consumers have of different material types (paper versus plastic) and how these perceptions can be altered (Lindh et al., 2016a; Steenis et al, 2017; Tijssen et al., 2017). As supported by Ketelsen et al. (2020), insights into consumer responses to various visual designs of sustainable packaging are key to marketers for effectively designing sustainable packaging. In conclusion, whether packaging surface and environmental claims and their interaction have equivalent or different impacts on sustainability perceptions of paper and plastic packaging are valuable insights for marketers to establish effective packaging design strategies to reduce discrepancies

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13 that form a threat to stimulating sustainable packaging purchases and nudge consumers towards making the right sustainable choice (Steenis et al., 2017).

1.4 Structure of the thesis

The following chapter provides an extensive literature review, resulting in the conceptual model and hypotheses. Hereafter, the research methods are discussed, followed by the results. Subsequently, in the discussion chapter, the results are thoroughly discussed in relation to current literature, and the theoretical and managerial implications, limitations, and suggestions for future research are elaborated on. Lastly, the thesis finalizes with an overall conclusion.

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14 2. LITERATURE REVIEW

2.1 The role of packaging and its impact on consumer perceptions

Due to high competition in the marketplace, packaging has become an imperative marketing tool that impacts the success of a product (Mutsikiwa, Marumbwa, & Mudondo, 2013). Packaging is an important and well-discussed topic in the marketing literature and can be defined as “the container for a product – encompassing the physical appearance of the container and including the design, color, shape, labeling and materials used” (Deliya, 2012).

In recent years, the role of packaging has experienced a significant shift (Ye et al., 2019).

Besides the functional role of packaging to protect the product and facilitate convenient distribution and usage of the product, a more emerging and increasingly important function for marketers is the communicative role to consumers (Lindh, Williams, Olsson, & Wikström, 2016b; Rundh, 2013; Silayoi & Speece, 2007; Ye et al., 2019). This communicative role aims to inform consumers of particular product or package attributes (Silayoi & Speece, 2007; Ye et al., 2019). Since packaging appears to be the most dominating impact driving consumers’

perceptions and buying decisions, this role has become more dominant (Ahmed et al., 2014;

Ampuero & Vila, 2006). Remarkably, as communication effectiveness is most optimal at the point-of-sale where at least 70 percent of product choices are made (Clement, 2007), packaging may even be more effective than other marketing communications (Rundh, 2013). Therefore, packaging can be considered the ‘silent salesman’ (Ye et al., 2019) and has developed to be a powerful, strategic marketing tool to influence consumers’ perceptions and choice directly during purchasing (Ahmed et al., 2014; Silayoi & Speece, 2007; Vilnai-Yavetz & Koren, 2013).

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15 2.2 Sustainable packaging and consumers’ sustainability perceptions of a package

One of the attributes that marketers aim to successfully communicate via the package is the packaging sustainability. Even though many people acknowledge the benefits of packaging, such as preservation, higher accessibility to information among consumers resulted in higher awareness of packaging pollution and therefore criticism on packaging due to its negative environmental impacts (Herbes et al., 2020; Sand, 2014). As a consequence, packaging sustainability has become a significant factor for consumers to assess products and base their choice on (Lindh et al 2016a; Rokka & Uusitalo, 2008). At least 80 percent of consumers state that sustainability of a package impacts their purchase decision (Lindh et al., 2016a). Therefore, to meet consumer demands and stay competitive, more sustainable packaging is produced (Nordin & Selke, 2010; Rundh, 2013). Sustainable packaging is complex to define due to the numerous dimensions it involves, nevertheless, the Sustainable Packaging Coalition (2011) stated: “sustainable packaging is beneficial, safe and healthy for individuals and communities throughout its life cycle; meets market criteria for performance and cost; is sourced, manufactured, transported, and recycled using renewable energy;

maximises the use of renewable or recycled source materials; is manufactured using clean production technologies and best practices; is made from materials healthy in all probable end of life scenarios; is physically designed to optimise materials and energy; and is effectively recovered and utilised in biological and/or industrial cradle-to-cradle cycles”. In addition, a more simplified and concise definition is: “packaging that has a comparatively low environmental impact as assessed by life-cycle assessment models” (Steenis et al., 2017).

Current research has investigated consumer responses to sustainable packaging. A few studies show that occasionally sustainable packaging may result in negative consumer perceptions, such as lower perceived quality when the removal of over-packaging is considered less hygienic, and less pleasure during consumption when the package is less aesthetically

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16 appealing (Magnier & Crié, 2015). Nevertheless, most studies have shown that predominantly sustainable packaging has a favourable influence on consumers’ perceptions and attitudes, when compared to conventional packaging (Ketelsen et al., 2020; Magnier & Schoormans, 2017; Magnier et al., 2016; Martinho, Pires, Portela, & Fonseca, 2015; Petersen & Brockhaus, 2017; Prakash and Pathak, 2017; Rokka & Uusitalo, 2008). Consumers stated to be more willing to pay and have higher purchase intentions when the package is stated to be environmentally friendly (Ketelsen et al., 2020). Hence, sustainable packaging can generate a significant competitive advantage (Rundh, 2013). However, to be successful, sustainable packaging also needs to be perceived by consumers as sustainable (Adeyeye, She, & Baïri, 2017; Magnier & Schoormans, 2017; Nordin & Selke, 2010). Therefore, generating the appropriate consumers’ sustainability perceptions that correspond with the actual packaging sustainability is essential.

2.2.1 Sustainability perceptions

Sustainability perceptions are defined as: “the subjective judgment of a product to enhance well-being, give satisfaction to the user and conserve resources in economically viable, safe and healthy ways for consumers” (Glavic & Lukman, 2007). Multiple research studies have shown that consumers are not able to correctly judge a package on its sustainability and thus consumers’ sustainability perceptions often mismatch the actual sustainability of a package (Ketelsen et al., 2020; Lindh et al., 2016a; Young, 2008). Therefore, it is essential to know how these sustainability perceptions are formed and how they can be altered.

Research shows that when assessing the sustainability of packaging, consumers tend to primarily focus on the visual design of the package (Ketelsen et al., 2020; Seo et al., 2016).

Therefore, it is necessary that the package clearly signals its sustainability to inform consumers and align their sustainability perceptions with the actual sustainability (Steenis et al, 2017;

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17 Magnier & Schoormans, 2015). To achieve this, marketers can use the communicative role of packaging and develop a successful packaging design strategy to effectively communicate sustainability to influence consumers’ sustainability perceptions and help them choose sustainable packaging (Lindh et al., 2016b; Togawa, Park, Ishii, Deng, 2019). This can be done not only through verbal claims, but also through other specific packaging design features that affect perceptions, such as colour and graphics (Ye et al., 2019).

2.3 Packaging design and its influence on consumers’ sustainability perceptions

Packaging design is defined as “the various elements chosen and blended into a holistic design to achieve a particular sensory effect” (Orth & Malkewitz, 2008). Packaging design significantly impacts consumer perceptions about a product and is thus extremely important in influencing consumers during the decision-making process (Ampuero & Vila, 2006; Creusen

& Schoormans, 2005; Steenis et al., 2018; Togawa et al., 2019). The appearance of a package determines consumers’ initial impression of a product, which in turn affects the inferences and perceptions about the product (Ampuero & Vila, 2006; Creusen & Schoormans, 2005; Steenis et al., 2018). Since most purchase decisions are made at the point-of-sale and are thus made rapidly (Clement, 2007; Vila, 2006), consumers primarily base their purchase decision on a package (Petersen & Brockhaus, 2017; Seo et al., 2016). Therefore, marketers can use packaging design as a competitive tool to communicate desired product features and hence alter consumer perceptions and evaluations of a product (Creusen & Schoormans, 2005; Silayoi

& Speece, 2007).

More specifically, as consumers’ sustainability perceptions of packaging are mostly determined by the visual design of a package, packaging design is particularly important for sustainable packages (Seo & Scammon, 2017). Therefore, effectively designing sustainable packaging to actually signal sustainability is key to assist consumers in choosing sustainable

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18 packaging (Ketelsen et al., 2020; Magnier & Schoormans, 2015; Petersen & Brockhaus, 2017).

Effective packaging design requires the right combination of packaging cues to evoke desired consumer perceptions, and hence create the desired positioning in consumers’ minds (Ampuera

& Vila, 2006). As described in the cue utilization theory, consumers’ perceptions are generated by processing available cues. Consumers cognitively process different packaging cues, and based on that, generate inferences about products and its packaging, which shape their perceptions and evaluations (Burnkrant, 1978; Karnal, Machiels, Orth, & Mai, 2016). Hence, various packaging cues can indicate the sustainable character of a package and can induce sustainability perceptions (Magnier & Crié, 2015). For marketers to be able to successfully achieve this, it is necessary to first identify how consumers respond to specific packaging cues to understand how to effectively design sustainable packaging (Ketelsen et al., 2020; Magnier

& Crié, 2015; Magnier et al., 2016; Silayoi & Speece, 2007).

Consumers’ sustainability perceptions can be influenced by cues from various packaging design elements. They have been categorized in literature in various ways, such as visual and informational elements (Silayoi & Speece, 2007) and graphic and structural elements (Underwood, 2003). However, Magnier and Crié (2015) and Magnier and Schoormans (2017) specifically classified ‘ecological’ packaging cues or design elements that can communicate packaging sustainability into structural, graphical and informational design elements (Magnier & Crié, 2015; Magnier & Schoormans, 2017). Therefore, this research follows this categorization to investigate how consumers’ sustainability perceptions can be influenced.

2.3.1 Structural design elements

Structural design elements refer to the structure of a package, and more specifically in relation to sustainable packaging design to “choice of materials, amount of packaging material

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19 used, and the re-usability of the package” (Magnier & Crié, 2015). Structural design elements have received the least attention in marketing literature compared to graphical and informational design elements. Nevertheless, regarding sustainability perceptions structural elements might be the most important, as prior research has demonstrated that when assessing packaging sustainability, consumers predominantly judge the packaging material and its environmental impact (Lindh et al., 2016a). Hence, packaging material, such as plastic, paper or glass, can be considered the most important cue for customers when choosing sustainable packaging, and therefore, also the most determining in influencing consumers’ sustainability perceptions of a package (Ketelsen et al., 2020; Lindh et al., 2016a; Magnier & Crié, 2015;

Nguyen et al., 2020; Steenis et al., 2017). Nevertheless, consumers appear to be often unable to correctly assess packaging sustainability based on structural elements, particularly since sustainable packaging materials frequently look the same as conventional materials (Ketelsen et al., 2020; Lindh et al., 2016a; Magnier & Schoormans, 2015).

2.3.1.1 Packaging material

Prior research has shown that many consumers are not capable of assessing packaging sustainability and recognizing sustainable materials. Multiple studies revealed that consumers often misjudge a package’s sustainability (Ketelsen et al., 2020; Lindh et al., 2016a; Steenis et al., 2017), which is mainly caused by consumers’ predetermined judgements regarding the sustainability of specific packaging materials (Steenis et al., 2017). Current research shows that consumers commonly perceive certain materials as more sustainable than others. For instance, glass is perceived as more sustainable than metal (Lindh et al., 2016a). Moreover, consumers tend to perceive plastic as the most detrimental, in contrast to paper which is perceived as the most sustainable material (Lindh et al., 2016a; Magnier & Schoormans, 2017; Nguyen et al., 2020), for instance due to the perceived ease in decomposability (Nguyen et al., 2020).

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20 Therefore, to compare sustainability perceptions of different packaging materials, this study focuses on paper and plastic packaging materials as most extremes. In a study by Gendell and Pierce (2018), as much as 99 percent of consumers stated to be at least somewhat concerned about the sustainable potential of plastic packaging. Accordingly, several other studies showed that consumers are particularly negative about the use of plastic (Dilkes-Hoffman, Pratt, Laycock, Ashworth, & Lant, 2019) and consumers judged packaging to be more environmentally beneficial simply when plastic was absent (Herbes et al., 2020). From these findings, it can be inferred that consumers seem to have a general aversion towards plastic when considering sustainability and experience a halo effect when it comes to paper. However, when assessing the actual environmental impact through the Life Cycle Assessment (LCA), it appears that plastic is not always the most harmful. Remarkably, plastic is less detrimental than paper on multiple aspects, such as energy and water consumption, required amount of material, distribution, and required storage space (Nguyen et al., 2020). For instance, few people know that paper bags weigh six to ten times more than plastic bags and thus require seven more trucks to transport the same number of bags (Cho, 2020). This indicates a discrepancy between consumers’ subjective sustainability perceptions and the actual objective impacts of certain packaging materials (Lindh et al., 2016a; Steenis et al, 2017; Tijssen et al., 2017). This is caused by the fact that when consumers assess packaging sustainability, consumers tend to rely on lay beliefs and simple inferential cue utilization processes, which determine their sustainability perceptions of a package (Boz, Korhonen, Sand, 2020; Magnier & Schoormans, 2015; Steenis et al., 2017). Their lay beliefs are informal and created based upon learned associations with specific materials, which are partly a result of repeated exposure to media that portray plastic as a great harm for the environment (Trivedi, Patel, & Acharya, 2018). This is illustrated by a study which demonstrated that ‘plastics in the ocean’ was considered the most significant environmental problem (Dilkes-Hoffman et al., 2019).

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21 Therefore, based on multiple studies demonstrating that paper is often perceived as most environmentally friendly compared to plastic as least environmentally friendly (Magnier

& Schoormans, 2015, 2017; Nguyen et al., 2020; Steenis et al., 2017), the following hypothesis is created:

H1: Paper packaging will lead to higher sustainability perceptions as compared to plastic packaging.

2.3.2 Informational design elements

As discussed, consumers often appear unable to recognize the sustainability of a package through structural elements (Ketelsen et al., 2020; Lindh et al., 2016a). As supported by the cue utilization theory (Karnal et al., 2016), the sustainability perceptions of paper and plastic packaging materials can be altered by adding cues from informational and graphical design elements. Since informational and graphical cues can help in signalling sustainability and hence influence consumers’ sustainability perceptions of a package, they can guide consumers in recognizing sustainable packaging and sustainable materials (Magnier &

Schoormans, 2017; Steenis et al., 2017).

Informational design elements, also known as verbal elements, refer to “the information displayed on the packaging” (Magnier & Crié, 2015). When looking for sustainable packaging, consumers commonly look for concrete information that communicates the sustainability of a package to simply identify them, which underlines the cue utilization theory but can also be considered related to heuristics in decision-making (Chan & Lau, 2004; Herbes et al., 2020).

Hence, informational elements can influence consumers’ sustainability perceptions of a package and help them recognize sustainable packaging (Mutsikiwa et al., 2013).

Consequently, information elements cannot only aid in changing biased perceptions about the sustainability of plastic versus paper packaging but can also help consumers to generally infer

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22 the sustainability of a package, which is essential as sustainable materials are often hard to distinguish from conventional materials (Ketelsen et al., 2020; Lindh et al., 2016a; Magnier &

Schoormans, 2015). In relation to sustainability, multiple variations of informational packaging elements exist (Allison & Carter, 2000; Ertz et al., 2017; Magnier & Crié, 2015; Gruère, 2013).

First of all, ecolabels, which are claims certified by third parties when complying with criteria on a product’s life cycle environmental impact, such as the EU Eco-label. Secondly, environmental claims, which are self-declared by retailers or manufacturers and uncertified but expected to be valid, such as ‘100% recycled material’. Thirdly, environmental declarations, which elaborate on objective and quantitative environmental performance, such as the actual carbon dioxide emissions per product (Allison & Carter, 2000; Gruère, 2013).

The advantage of informational packaging elements is that they are concrete and explicitly communicate the packaging sustainability, in contrast to structural and graphical packaging elements (Magnier & Schoormans, 2015). They present reasons to buy a product and can therefore have strong effects in influencing consumers’ purchase decisions (Mutsikiwa et al., 2013). Nonetheless, verbal elements also require more intentional cognitive processing from consumers, when compared to visual elements (Magnier & Schoormans, 2015). As a consequence, verbal elements may be observed after visual elements (Silayoi & Speece, 2007).

However, even though verbal may not attract as much immediate attention (Clement, Kristensen, & Grønhaug, 2013), the findings of a study by Mutsikiwa et al. (2013) show that they can be very powerful in influencing perceptions and preferences of products, which stresses the relevance of informational elements for this thesis since they can significantly alter sustainability perceptions.

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23 2.3.2.1 Environmental claims

The use of self-declared environmental claims, such as ‘environmentally friendly’ or

‘sustainable’, is growing and has become more common (Chan & Lau, 2004; OECD, 2016).

Research shows that environmental claims may be very successful. In particular textual information is shown to have a stronger effect on sustainability perceptions than numerical information (Gleim, Smith, Andrews, & Cronin, 2013). Multiple studies have shown that environmental claims do certainly influence sustainability perceptions of a package (Herbes et al., 2020). Research by Söderlund and Mattsson (2020) shows that many consumers believe in claims, even though no objective evidence is present. They show that unsubstantiated, simple ecological claims, stating a product is ‘ecological’, can increase subjective perceptions of the product being ecological. Research by Chan and Lau (2004) has demonstrated that consumers seem to desire packages that provide more and specific information when aiming to buy green products. Hence, substantive environmental claims, which elaborate on specific and detailed information of the sustainable contribution of a product or production process such as “the package is recyclable”, are relied upon more by consumers than associative claims, which are intangible and thus not concrete regarding its environmental contribution, such as “we care about the environment”. Moreover, Gleim et al. (2013) found that more elaborated text elements did not significantly increase purchase intentions compared to simple text elements.

Generally, the studies by Magnier and Schoormans (2015; 2017) revealed that putting environmental claims on packaging can be important in enhancing sustainability perceptions, for both conventional looking and ecological looking packages.

Nevertheless, besides its potential effectiveness, it is important to consider that informational elements are vulnerable to scepticism (Ertz et al., 2017; Magnier & Schoormans, 2015). Due to the augmenting number and diversity of environmental claims and labels that have been used on packaging over the last years, more complexity is present, which has led to

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24 confusion among customers who question the effectiveness of informational elements (OECD, 2016). Consumers deem many environmental claims as false and misleading, do not know which ones to trust, and suspect them of contributing to greenwashing. This may influence how consumers perceive these claims and how they influence their sustainability perceptions of a package (Magnier & Crié, 2015).

Current research shows that verbal environmental claims can lead to higher sustainability perceptions, particularly when congruent with a sustainable visual appearance of the packaging (Magnier & Schoormans, 2015; 2017). Magnier and Schoormans (2015) showed that an environmental claim was perceived most credible and sustainability perceptions were higher when accompanied by an ecological graphical design, and thus when the claim was congruent with the visual appearance. Additionally, Magnier and Schoormans (2017) found that an environmental claim was perceived as more credible and persuasive when being present on a fibre-based package than on a plastic package. Accordingly, for paper packaging, adding an environmental claim can be expected to increase sustainability perceptions rigorously as the claim is congruent with a sustainably perceived material. On the other hand, for plastic packaging, an environmental claim would contradict with consumers’ initial beliefs of plastic being not sustainable, which may lead to scepticism, and thus a weaker increase in sustainability perceptions can be expected (Ertz et al., 2017; Magnier & Schoormans, 2015).

Therefore, the following hypothesis is created:

H2: There is a significant interaction effect between packaging material and environmental claim, such that the presence of an environmental claim, as compared to absence of a claim, will lead to a stronger increase in sustainability perceptions for paper than for plastic packaging.

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25 2.3.3 Graphical design elements

Besides structural and informational design elements, graphical elements can play a vital role in influencing consumer perceptions and evaluations of products (Ahmed et al., 2014;

Chrysochou & Grunert, 2014; Ketelsen et al., 2020; Magnier & Schoormans, 2017; Steenis et al., 2017). Graphical design elements refer to “the graphics or icons displayed on the packaging” (Magnier & Crié, 2015). Graphical design elements comprise for instance photographs, colour, typography, images, shape, transparency of the package, and surface varnishing (Magnier & Crié, 2015; Magnier & Schoormans, 2017). Graphical cues are most often perceived by consumers prior to verbal elements (Silayoi & Speece, 2007; Townsend &

Kahn, 2014). They are processed more rapidly, less deliberate and thus more unconsciously when compared to words (Townsend & Kahn, 2014), and hence highly impact the first impression of a package (Magnier & Schoormans, 2015). Therefore, according to Clement (2007), visual or graphical elements might even be more powerful than verbal cues to impact perceptions and purchase intention. Graphical elements express certain implicit, symbolic meanings that elicit certain inferences and perceptions of the product in consumers’ minds (Karnal et al., 2016). Consequently, graphical design elements are stated to be crucial to signal the sustainability of a package to consumers (Magnier & Schoormans, 2017). Correspondingly, Steenis et al. (2018) stresses the importance of packaging’s graphical design to increase visual sustainability of packaging in order to stimulate sustainable purchases. Multiple research studies have investigated the effects of various graphical elements on consumers’ sustainability perceptions. For instance, research has shown that a white coloured package provokes higher perceptions of sustainability than a red package (Magnier & Schoormans, 2017). Furthermore, green is shown to be often associated in consumers’ minds with sustainability (Parcer, McShane, Noseworthy, 2017). Other research shows that sustainably looking graphics on a package made consumers judge a package as more sustainable (Steenis et al., 2017). These are

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26 merely examples of the large academic literature that exists regarding the effects of various graphical elements, where many graphical elements have received quite some attention in relation to sustainability perceptions. However, one graphical element, surface varnishing, is relatively new in packaging design and is thus very limitedly researched (Marckhgott &

Kamleitner, 2019). Nevertheless, surface varnishing may be highly relevant to consumers’

sustainability perceptions, since its effects on other perceptions that are correlated to sustainability perceptions have already been proven, such as naturalness and healthiness perceptions (Marckhgott & Kamleitner, 2019; Ye et al., 2019).

2.3.3.1 Surface varnishing

Surface varnishing refers to the glossiness of the surface which has impact on the way the packaging reflects light (Keskin & Atar, 2008), which comprises matte and glossy surfaces as contraries. Matte surfaces are dull, rough and feature diffuse light reflections, whereas glossy surfaces are rather smooth and shiny due to specular light reflections, which provides a rather mirror-like reflection (Nayar & Oren, 1995). Hence, surface varnishing impacts the appearance of the packaging material (Kirwan, 2012) and may thus influence consumers’ perceptions by conveying a symbolic message of being sustainable (Tijssen et al., 2017). Current research has demonstrated that surface varnishing has a significant impact on consumers’ perceptions regarding the healthiness (Ye et al., 2019) and naturalness of products (Marckhgott &

Kamleitner, 2019). A study by Ye et al. (2019) showed that matte packages were perceived as healthier. They argued that consumers’ perceptions are opinionated due to learned associations through frequent exposure in the marketplace to glossy packages being connected to unhealthy foods and matte packages to more healthier foods. Furthermore, the study by Marckhgott and Kamleitner (2019) showed that consumers perceived food products in matte packaging as more natural, which in turn increased purchase intention. Since in general, natural materials, such as

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27 soil, generate diffuse reflections, matte packaging may be associated to nature in consumers’

minds (Nayar & Oren, as cited in Marckhgott & Kamleitner, 2019). Remarkably, even though the effectiveness of graphical elements is stressed (Clement, 2007), their effectiveness may be different than informational elements. In contrast to the notion of congruence as expected for environmental claims, Marckhgott and Kamleitner’s (2019) findings indicate that surface varnishing may only impact artificial products, since a matte surface does not increase naturalness perceptions when the product is already perceived as natural. Hence, other stronger cues of product naturalness, such as informational claims, can eliminate the positive effect of matte surface varnishing. Interestingly, packaging material can also be expected to be a stronger sustainability cue than surface varnishing (Ketelsen et al., 2020; Lindh et al., 2016a;

Steenis et al., 2017). Since research has proven that naturalness perceptions are directly correlated with sustainability perceptions (Binninger, 2015; Tobler, Visschers, & Siegrist, 2011), it can be expected that surface varnishing will most likely also affect sustainability perceptions in a similar way. This suggests that paper, as already sustainable perceived material, would not experience as high increases in sustainability perceptions due to a matte surface when compared to plastic, which can be considered an artificial material. This view is explained by Everitt and Skrondal (2010) who states that a ceiling effect may happen when

“an independent variable reaches extremely high values it no longer generates any effect on the dependent variable”. Since paper is already perceived as quite sustainable, it might be that adding a matte surface may not significantly enhance sustainability perceptions. Whereas for plastic, initial sustainability perceptions are low, which may signify that perceptions can still be boosted by adding matte packaging. Therefore, it is assumed that:

H3: There is a significant interaction effect between packaging material and surface varnishing, such that a matte surface, as compared to a glossy surface, will lead to a stronger increase in sustainability perceptions for plastic than for paper packaging.

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28 2.4 Three-way interaction of packaging material, environmental claim and surface varnishing

This research examines whether modifying environmental claim and surface varnishing can be used to alter consumers’ existing sustainability perceptions of certain package materials, paper versus plastic. Currently, no research study has examined the three-way interaction of packaging material, environmental claim and surface varnishing on sustainability perceptions of the package. However, this would be a relevant insight for marketers to increase understanding on how to optimally design their most sustainable packages to produce the highest sustainability perceptions of the package among consumers (Coucke, Vermeir, Slabbinck, & Kerckhove, 2019; Ketelsen et al., 2020; Magnier & Schoormans, 2017).

Furthermore, further research is requested on how the effectiveness of certain packaging cues may vary for different materials to the extent it communicates sustainability (Tijssen et al., 2017) and whether the effects of matte packaging versus glossy packaging generalizes to different materials (Marckhgott & Kamleitner, 2019).

Existing research has shown that a matte surface, as compared to a glossy surface, does not increase naturalness perceptions when the product is already perceived as natural (Marckhgott & Kamleitner, 2019). Hence, the positive effect of matte surface varnishing on naturalness perceptions of the package was eliminated when a naturalness claim was present.

Due to the direct correlation of naturalness perceptions and sustainability perceptions (Binninger, 2015; Tobler et al., 2011), this is also expected to happen for sustainability perceptions, such that an environmental claim eliminates the positive effect of a matte surface, and hence there is no significant difference in sustainability perceptions between glossy or matte surfaces when an environmental claim is present, for both paper and plastic packaging.

Additionally, packaging material is considered a stronger cue than surface varnishing, since packaging material was considered most influential for consumers when judging packaging

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29 sustainability (Ketelsen et al., 2020; Lindh et al., 2016a; Magnier & Crié, 2015; Nguyen et al., 2020; Steenis et al., 2017). Since it was shown that any other stronger cue of naturalness can override the effect of surface varnishing and that a matte surface only increases naturalness perceptions for artificial products (Marckhgott & Kamleitner, 2019), it is expected that when an environmental claim is absent, paper packaging as already sustainable perceived material will make the package already look sustainable and will thus not experience any positive effects due to a matte surface. Conversely, a package made of plastic material, which is most likely perceived as not sustainable, will experience an increase in sustainability perceptions as result of a matte surface. Hence, it is expected that either when a claim is present, the material is paper, or both, a matte surface will not increase sustainability perceptions. Solely when the package is plastic and no claim is present, and thus no stronger cue of sustainability is present, a matte surface will increase sustainability perceptions. This also supports the ceiling effect as stated by Everitt and Skrondal (2010), which suggests that sustainability perceptions can only be boosted when the package is not perceived as sustainable already. Therefore, it is expected that:

H4a: As for paper packaging, when an environmental claim is present, a matte surface will not lead to a significant increase in sustainability perceptions compared to a glossy surface.

H4b: As for paper packaging, when an environmental claim is absent, a matte surface will not lead to a significant increase in sustainability perceptions compared to a glossy surface.

H4c: As for plastic packaging, when an environmental claim is present, a matte surface will not lead to a significant increase in sustainability perceptions compared to a glossy surface.

H4d: As for plastic packaging, when an environmental claim is absent, a matte surface will lead to a significant increase in sustainability perceptions compared to a glossy surface.

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30 2.5 Downstream consequences

Modifying the package design to steer consumers’ sustainability perceptions into the right direction is crucial for businesses since sustainability perceptions may lead to various positive purchase-related downstream consequences. Hence, an effective design that clearly signals the package sustainability helps in selling the product (Silayoi & Speece, 2007).

Multiple research studies have examined downstream consequences when the product itself was perceived as sustainable. However, scarce amount of research has studied what sustainability perceptions of a package lead to. Moreover, downstream consequences have been mostly tested as result of changes in graphical and verbal features of packaging, but only rarely as a result of material differences.

Current research has shown that, in general, consumers react positively to sustainable packaging (Magnier & Schoormans, 2015) and have a more favourable attitude towards the product (Prakash & Pathak, 2017). In addition, research has shown that sustainability perceptions directly influence purchase intention (Ketelsen et al., 2020; Magnier et al., 2016;

Steenis et al., 2018), and that a positive correlation exists between sustainable packaging and willingness to pay (Lindh et al., 2016a; Steenis et al., 2017). Nevertheless, this is contradicted by Nordin and Selke (2010), who found that consumers were not willing to pay a higher price for sustainable packages. Furthermore, sustainability perceptions seem to influence overall evaluations of the brand (Magnier & Schoormans, 2015).

Notably, current research has shown that perceptions of a package can also cause spillover effects to perceptions of the product inside (Becker, Van Rompay, Schifferstein, &

Galetzka, 2011; Silayoi & Speece, 2007; Steenis et al., 2017). It appears that, implicitly, consumers tend to draw inferences about the product based on the visual look of the package, particularly when concrete information about the product attributes are lacking (Steenis et al., 2017). Hence, the packaging is used as a symbol that signals features of the product itself

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31 (Silayoi & Speece, 2007). Accordingly, it has been shown that sustainability perceptions of the packaging material influence overall product evaluations (Petersen & Brockhaus, 2017).

Furthermore, sustainability perceptions influence perceived naturalness (Binninger, 2015;

Magnier et al., 2016; Steenis et al., 2017; Tobler et al., 2011), healthiness (Magnier et al., 2016;

Ye et al., 2019), and quality of the product (Lindh et al., 2016a; Magnier et al., 2016; Steenis et al., 2017). For instance, Magnier et al. (2016) showed that sustainable packaging makes consumers perceive the product as more natural, and hence as being of higher quality.

Since downstream consequences of packaging sustainability perceptions have been limitedly researched and several existing findings are contradicting, this thesis examines how sustainability perceptions of a package as a consequence of altering packaging material, environmental claim and surface varnishing exactly affect various consumption-related downstream consequences. Therefore, the following hypothesis will be tested:

H5: Sustainability perceptions lead to a number of purchase-related downstream consequences, such as higher perceived quality of the product (a), more positive attitude towards the product (b), higher willingness to pay (c), and higher purchase intention (d).

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32 3. CONCEPTUAL MODEL & HYPOTHESES

The conceptual model as illustrated in Figure 1 provides a clear overview of the study and the hypothesized relationships that resulted from the literature review, including the main effect of packaging material on sustainability perceptions (H1), the two-way interaction of packaging material and environmental claim (H2), the two-way interaction of packaging material and surface varnishing (H3), and the three-way interaction of packaging material, environmental claim and surface varnishing (H4). Finally, the relation of sustainability perceptions on various downstream consequences is shown (H5).

Figure 1

Conceptual model

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33 Hypotheses

H1: Paper packaging will lead to higher sustainability perceptions as compared to plastic packaging.

H2: There is a significant interaction effect between packaging material and environmental claim, such that the presence of an environmental claim, as compared to absence of a claim, will lead to a stronger increase in sustainability perceptions for paper than for plastic packaging.

H3: There is a significant interaction effect between packaging material and surface varnishing, such that a matte surface, as compared to a glossy surface, will lead to a stronger increase in sustainability perceptions for plastic than for paper packaging.

H4a: As for paper packaging, when an environmental claim is present, a matte surface will not lead to a significant increase in sustainability perceptions compared to a glossy surface.

H4b: As for paper packaging, when an environmental claim is absent, a matte surface will not lead to a significant increase in sustainability perceptions compared to a glossy surface.

H4c: As for plastic packaging, when an environmental claim is present, a matte surface will not lead to a significant increase in sustainability perceptions compared to a glossy surface.

H4d: As for plastic packaging, when an environmental claim is absent, a matte surface will lead to a significant increase in sustainability perceptions compared to a glossy surface.

H5: Sustainability perceptions lead to a number of purchase-related downstream consequences, such as higher perceived quality of the product (a), more positive attitude towards the product (b), higher willingness to pay (c), and higher purchase intention (d).

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34 4. METHODS

4.1 Research design

To investigate the effects of packaging material, surface varnishing and environmental claims on the sustainability perceptions of a package, and their consequent effects on downstream consequences, the study performed quantitative research through an experimental design as this method enables to manipulate variables and hence establish cause-effect relations (Shadish, Cook, & Campbell, 2002). The study was conducted through an online experiment with a 2 (packaging material: paper vs. plastic) x 2 (environmental claim: present vs. absent) x 2 (surface varnishing: matte vs. glossy) between-subjects design. The online experiment was performed via Qualtrics, an online survey tool that allows to randomly assign participants to different conditions. Participants received one of the eight stimuli, which was a soap package, each adjusted on its material, surface varnishing and environmental claim. Hereafter, participants were to answer multiple questions regarding the particular package in a questionnaire format to examine the sustainability perceptions, subsequent downstream consequences and control variables.

4.2 Sample

To obtain a heterogenous sample (Fricker, 2017), the sample was collected via Prolific, a professional online panel that allows for high-quality research participants by inviting people from their database to participate and automatically redirecting them to the experiment in Qualtrics. Hence, a probability sampling method was used, where participants were able to participate after receiving an invitation, which was based upon certain screening criteria. Both men and women were sampled between the age of 18 and 100, currently living in Western Europe. Western Europe was found to have the most eco-conscious consumers that are particularly seeking sustainably packaged FMCG products (Kantar, 2019). Therefore, this

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35 study focuses on Western Europe and samples the same countries as the related study by Kantar (2019): Netherlands, Belgium, Germany, Denmark, Sweden, France, UK, Spain, Austria. To ensure that all participants would fully understand all elements within the experiment, the sample was screened on having English as fluent language, as the entire experiment was in English. Furthermore, to obtain high-quality participants, a minimum approval rate of 95 percent within Prolific was used as screening criterium.

The sample consisted of 394 participants in total, of which 8 participants did not completed the experiment, and therefore 386 participants remained for data analysis. This number represents a reliable sample size, since it greatly exceeds the rule of thumb of minimum 30 participants per condition (Pallant, 2010), and thus 240 participants in total. Within the sample of 386 participants, 42.2 percent (N=163) were male, 57 percent (N=220) were female, and 0.8 percent (N=3) responded ‘other’. Participants’ age ranged from 18 to 80 and was on average 32.89 years (SD=12.18). Hence, the sample represented a fair distribution of gender and age. Regarding location of residence, all 9 countries were represented in the sample, whereas most participants lived in the UK (72 percent), followed by Spain (13.7 percent) and the Netherlands (6 percent). Furthermore, all types of employment status were represented, yet most participants were full-time employed (36.5 percent), followed by students (24.9 percent) and part-time employments (16.8 percent). Participants’ highest completed education ranged from less than a high school diploma to a Doctorate’s degree, nevertheless the greatest part of the sample at least completed high school, a bachelor’s or a master’s degree; 37 percent, 39.9 percent and 15.8 percent respectively. The detailed sample descriptives can be found in Appendix 1.

Participants were randomly assigned to one condition. The group sizes for the different conditions were nearly equal, fluctuating from N=46 to N=50. A randomization check was done to examine whether the randomization had succeeded and hence whether all conditions

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36 were equal in terms of demographics. To test whether there were any differences between the different conditions, Chi-Square tests were performed for categorical variables (Gender, Location of residence, Employment status, and Education), and a One-way ANOVA was conducted for the numerical variable Age, for which the homogeneity of variances assumption was met. The results showed that all condition groups did not significantly differ in terms of age, gender, location of residence, employment status, and education (p>.05). Therefore, it can be concluded that the randomization was successful and thus the group samples were similar.

Hence, the group samples are very unlikely to influence the results, and therefore causation can be established. For the detailed sample descriptives per condition, see Appendix 2.

4.3 Operationalization of variables

4.3.1 Manipulation of independent variables within the stimuli

To test the effect of the independent variables, eight different stimuli were created, as shown in Table 1. Since real, existing products differ greatly on multiple design elements, it was decided to design the product stimuli from scratch with a fictional product such that all design elements, next to the manipulations, could be kept constant for internal validity (Trochim, Donnelly, & Arora, 2015). The product used in the stimuli was from the personal care industry, since research showed that particularly in highly competitive markets where consumers have plentiful choice, effectively designing packaging to signal desired attributes, such as sustainability, is crucial (Hellström & Saghir, 2007; Rundh, 2005; Vila, 2006), specifically since many purchase decisions are made at the point of sale (Clement, 2007; Vila, 2006). This is predominantly the case for fast-moving consumer goods (FMCG) markets, such as the food and personal care industry. Within both these industries, an increasing number of packaging alternatives are offered, including an increasing number of sustainable packages (Adetayo, Opele, & Olasehinde, 2019). For instance, grapes are offered in both plastic and

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References

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