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Options for labelling circular products: Icon design and consumer preferences
Accepted Manuscript Options for labelling circular products: Icon design and consumer preferences María D. Bovea, Pilar Quemades-Beltrán, Victoria Pérez-Belis, Pablo Juan, Marta Braulio-Gonzalo, Valeria Ibáñez-Forés PII:
S0959-6526(18)32523-X
DOI:
10.1016/j.jclepro.2018.08.180
Reference:
JCLP 13964
To appear in:
Journal of Cleaner Production
Received Date: 6 June 2018 Revised Date:
13 August 2018
Accepted Date: 17 August 2018
Please cite this article as: Bovea MaríD, Quemades-Beltrán P, Pérez-Belis V, Juan P, Braulio-Gonzalo M, Ibáñez-Forés V, Options for labelling circular products: Icon design and consumer preferences, Journal of Cleaner Production (2018), doi: 10.1016/j.jclepro.2018.08.180. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Options for labelling circular products: icon design and consumer preferences a,
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María D Bovea *, Pilar Quemades-Beltrán , Victoria Pérez-Belis , Pablo Juan , Marta Braulio-Gonzalo , a Valeria Ibáñez-Forés Department of Mechanical Engineering and Construction. Universitat Jaume I. Av. Sos Baynat s/n, 12071 Castellón, Spain b
Department of Mathematics, Universitat Jaume I, Av. Sos Baynat s/n, 12071 Castellón, Spain *[email protected]
Abstract
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The demand of products that incorporate circular requirements depend on consumer perceptions. So effective communication is necessary between the product and consumers through product labelling. The use of specific icons facilitates this communication. This study presents a methodology for identifying the icons that best associate and identify consumers with the different design requirements that a circular product should meet. To do this, a set of icons for each circular requirement (upgrade, disassembly, lifetime extension, repairability and reuse) is presented to a representative sample of consumers who select the preferred one by taking into account different icon characteristics (simplicity, familiarity, semantic distance and aesthetic appeal). To validate the comprehension of the selected icons, ISO 9186-3 was applied to test the association of the selected icons with their corresponding requirement. Multinomial regression models were applied to explore whether any significant differences appeared among the responses obtained (icon selection) by the different respondent profiles. The most significant socio-economic variables were gender and age, while the most significant icon characteristics were semantic distance and aesthetic appeal. The results of this study could be useful for the companies committed to integrate the principles of circular economy into their product design since the use of selected icons can help consumers to identify them. Consumers’ understanding is ensured due to the high percentages of correct answers obtained in the validation test (>85%).
EEE: Electrical and Electronic Equipment
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1. Introduction
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WEEE: Waste Electrical and Electronic Equipment
The principles of circular economy (The Ellen MacArthur Foundation, 2012) aim to ensure not only that the value of products, materials and resources are kept in economy for as long as possible, but also the reduction of generated waste. For this purpose, the European Commission promotes a transition to a more circular economy through a series of measures that cover the whole life cycle of products and materials (COM 614, 2015; COM 33, 2017). More specifically and directly related to eco-design, COM 33 (2017) points out that, to date, measures have focused on improving products’ energy efficiency (Directive 2009/125/EC). However, there is a current trend to promote the incorporation of circular economy-related design requirements. Specifically, the current "The Eco-design Working Plan 2016-2019" (COM 773, 2016) is committed to more systematically incorporate design requirements, specifically circular requirements, such as durability, possibility of repair, possibility of updating, possibility of disassembly, ease of reuse and recycling. 1
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However, the demand of products that incorporate these circular requirements depend, to a large extent, on consumer perceptions. As concluded by WBCSD (WBCSD, 2008), consumers are increasingly concerned about environmental and social features of products and services. According to Moser (2016) consumers care for the environment and mirror environmental attitudes in their purchasing behaviour. Thus, producers should know about what consumers are looking for (Maniatis, 2016).
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For consumers to be able to identify circular products and to recognise the specific requirements that they incorporate, effective communication is necessary between the product and consumers through product labelling. According to Silvennoinen et al. (2017), the use of icons facilitates this communication.
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Previous research into this field has focused on studying icon characteristics, such as simplicity/complexity (Forsythe et al., 2003, 2008), semantic distance (Isherwood, 2009; McDougall et al., 1999, 2016), familiarity (Wang et al., 1994), etc. of individual icons. However, when a set of icons represents aspects that are related to one another, such as the requirements that a circular product should meet, it is important that icons are able to be differentiated and to subtly transmit the aspect that they represent. Icons that are not always easily recognised by consumers run the risk of being under-used or even becoming superfluous (Böcker, 1996). In this sense, the Flash Eurobarometer (2009) revealed that there is difficult for consumers to understand the information that environmental labels try to convey.
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The literature on icon design has focused on analysing icon communication in different sectors. In the automotive sector, Chi et al. (2017) analysed the quality of in-vehicle auditory signals, Johann and Mahr (2011) introduced a procedure for the evaluation of icons of automotive sector by considering relevant criteria from current ISO standards, Kujala and Saariluoma (2011) studied the effects of alternative navigation device display features on drivers' visual sampling efficiency while searching for points of interest and Silvennoinen et al. (2017) analized semantic distances of icons to menu functions with preference rankings, verbal protocols, and the primed product comparisons method; etc.). In the software sector, Byrne (1993) outlined the factors involved in icon search and proposed a model for this process, while Huang et al. (2002) identified the main factors involved in the design of computer graphic user interfaces. In the mobile context, Gatsou et al. (2012) examined how far an icon for mobile devices represents the meaning of the function for which it has been designed, while Ghayas et al. (2013) determined the effects of icon characteristics on users’ perception. In the scholars sector, Chiu et al. (2012) suggested three icon design principles to better design icons for preschool users graphical user interface.
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Therefore, the icon design associated with the communication of circular economy-related requirements included in a product has not been yet analysed in the literature, despite of being a pending issue according to the regulatory framework regarding circular economy. Hence, a research gap in this field exists, thus it is addressed in this study. In this context, this study aimed to present a methodology to identify the icons that best fit with the different design requirements that a circular product should meet, according to consumers’ preferences. To do so, a set of icons for each circular requirement was presented to a representative sample of consumers who selected the best icon after taking into account different icon characteristics. To validate the comprehension of the selected icons, ISO 9186-3 (2014) was applied to test the association of the selected icons with their corresponding requirement. 2. Methodology
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With a view to selecting the icons that best identified consumers with the design requirements that a product should have from a circular economy perspective, the methodology shown in Figure 1 was proposed, whose stages are described below:
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Stage I: Selection of requirements for a circular product. The requirements that a product should meet from the circular economy perspective are identified by taking into account the current regulatory framework. Stage II: Icon definition (literature and own design). The existing icons from different bibliographic sources (internet, regulations, manuals, research and dissemination articles, databases, etc.) that may be related to the identified requirements are explored and collected. They are completed with the new icons designed by a design team. As a result, a collection of icons for each requirement that a circular product has to fulfil is obtained. Stage III: Selection of icon characteristics. A literature review was done to select the most common characteristics that make an icon easier to use and understand by consumers. Stage IV: Selection of icons. Each collection goes through a debugging process until the number of alternatives for each requirement is reached after taking into account different icon characteristics. These reduced sets of icons for each requirement had to be evaluated by consumers. So they could choose the icon that best represented each requirement by bearing in mind the icon characteristics. Stage V: Survey design. A survey needs to be designed considering all the aspects previously described. Stage VI: Sample definition. The survey is handed out to a representative sample. In order to calculate statistically the representative sample size needed for this study, the method proposed by Bartlett et al. (2001) was applied according to the following equation: () ∗()( ) ( )
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where n is sample size, t is the Z value for a specific confidence level, p is the proportion of respondents who selected a specific choice, and d is the confidence interval or margin of error.
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Stage VII: Analysis of responses. After conducting the survey, responses were analysed to identify the icons that consumers mostly related to each requirement that a circular product should meet. Stage VIII: Validation. Finally, the selected icons passed a validation process to assess their understanding. This step is essential to validate if an icon adequately communicates its message. To do so, it is advisable to follow the recommendations of ISO 9186-3 (2014).
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I. Selection of requirements for a Circular Product
II. Icon definition: Literature & Own designs
IV. Selection of icons
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III. Selection of icon characteristics
V. Survey design
VI. Sample definition
VIII. Validation
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Figure 1. Methodology
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VII. Analysis of responses
3. Results
I. Selecting requirements for a circular product
The promotion and application of the principles of circular economy (The Ellen MacArthur Foundation, 2012) to product design have been reflected in different legislation and regulatory frameworks in Europe, as shown in Table 1.
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The Waste Electrical and Electronic Equipment Directive (WEEE directive) (Directive 2012/19/EU) establishes that eco-design requirements that facilitate the re-use, dismantling and recovery of WEEE should be laid down in the framework of measures by implementing the Eco-design directive (Directive 2009/125/EC). Better design can make products more durable or easier to repair, be upgraded or remanufactured. It can help recyclers to disassemble products to recover valuable materials and components (COM 614, 2015; COM 33, 2017).
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Electrical and electronic equipment (EEE) is particularly significant in this context. This whole framework encourages the design and production of EEE that takes into full account and facilitates its repair, possible upgrading, re-use, disassembly and recycling. So product design is a key aspect in this respect as it can have significant impacts across the product’s life cycle; e.g. in making a product more durable, easier to repair, be reused or recycled. The current Eco-design working plan 2016-19 (COM 773, 2016) also promotes the incorporation of relevant aspects to circular economy, such as reparability, recyclability and durability, when revising the existing measures from the Eco-design directive.
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Reuse
Recycling
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Repairability
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Lifetime extension
Disassembly
WEEE directive (2012) Eco-design directive (2009)
Upgrade
Table 1. Selection of requirements to be met by a "circular product"
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COM 773 (2016) COM 614 (2015) COM 33 (2017)
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● Requirement considered in each bibliographic reference
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According to Table 1, the requirements that a circular product needs to fulfil are: reuse, disassembly, repair, upgrade, lifetime extension and recycling. Of those, only recycling has an icon that represents it clearly that is internationally recognised with the Mobius loop (ISO 14021, 2006). So this study focuses on the remaining five requirements. II. Defining icons
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Disassembly
Table 2. Collection of icons selected for each circular product requirement Icons
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Requirement Upgrade
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After identifying the requirements for which icons have to be defined, a search for icons/images that could be associated with each one was done according to the literature, icon databases, manuals/reports on circular economy, etc. New icons were designed by the designers who belonged to the research team as new ideas/concepts, or as a combination of existing icons. Finally, a collection of between 24 and 39 icons was obtained per requirement. The selected icons went through a process to unify fonts and sizes, and those reported in Table 2 were obtained.
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Lifetime extension
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Repairability
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Reuse
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III. Selecting icon characteristics
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Aesthetic appeal
Semantic distance
Reference (Böcker, 1996) (Bresciani and Del Pone, 2017)
Familiarity
Table 3. Literature review of icon characteristics
Simplicity
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Table 3 reports the characteristics that can be considered in a first step to select the icons with a better relationship with each requirement. Other characteristics found in the literature, such as colour (Ko, 2017; Forsythe et al., 2008; Byrne, 1993 or Hynes, 2009), font (Ko, 2017), size (Byrne, 1993), luminance contrast (Ko, 2017) or legibility (Ko, 2017), can be analysed in a second step as variations of the selected icons.
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(Byrne, 1993) (Chen et al., 2017) (Forsythe et al., 2003) (Forsythe et al., 2008) (Gatsou et al., 2012) (Henderson and Cote, 1998) (Isherwood et al., 2007) (Ko, 2017) (McDougall et al., 1999) (McDougall et al., 2016) (Mirzabeigi et al., 2017) (Pittard et al., 2007) (Silvennoinen and Jokinen, 2016) (Silvennoinen et al., 2017) (Sonderegger and Sauer, 2010) (Tung and Chen, 2017) (Wang et al., 1994) (Wang and Li, 2017) (Wang et al., 2018) (Zhang et al., 2016)
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● Icon characteristic included in each bibliographic reference
IV. Selecting icons
The collection of icons reported in Table 2 was submitted to a debugging process to select a set of five icons per requirement to be included in the survey. This process was divided into two stages:
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Unifying variations on the same idea to reduce the number of alternatives, and that these cover the largest spectrum of different ideas (14-15 icons per requirement). Selecting the five icons for each requirement to be included in the survey for consumers. This process was carried out using a survey with 20 designers who were external to this study. They were asked to select five icons for each requirement by taking into account the characteristics reported in Table 3 and bearing in mind that the selected icons should cover the broadest spectrum of alternative ideas. The five selected icons are those reported in Table 4, along with the definition of each requirement.
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Table 4. The selected icons to be included in the survey for each requirement Upgrade Product able to adapt to new versions of it Disassembly Product that can be easily disassembled into its components or parts Lifetime extension Product that can be used for longer than usual
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Repairability Product that can be easily fixed after failing
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Reuse Product which, after being discarded, can be used again with the same or different use as/from the initial one
V. Survey design
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The aim of the survey was for consumers to select the icon (from those shown in Table 4) which is best identified with the requirements that a circular product should meet. The type of chosen survey was a questionnaire directly administered to the respondents. The objective was to design a questionnaire that was easy to understand by different profiles of the respondents and quick to answer to obtain the maximum number of valid answers. The finally selected format after a feedback process, during which different pilot formats were tested, is shown in Figure 2 (for one of the requirements). The respondents had to mark the icon that they considered was more appropriate for each requirement (see the definitions in Figure 4), and according to the icon characteristics identified in Stage III: simplicity, aesthetic appeal, familiarity and semantic distance. Finally, they were asked to globally choose the icon that best identified the requirement. In this way, the order in which the icons were presented in the questionnaire did not influence the response, which was alternated from one questionnaire to another.
Figure 2. Survey format for one of the requirements
VI. Sample definition The survey was conducted in the Spanish city of Castellón de la Plana (Spain), which has 169,498 inhabitants (INE, 2017). Equation 1 has been applied considering a 90% confidence level (t=1.65) 8
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and the maximum possible proportion of 50% (p=0.5), which gives the largest sample size, and a 5% margin of error (d=0.05). This results in a sample size of 272. Therefore, the survey was conducted in a representative population sample of 272 inhabitants aged over 18 years old, and represented the characteristics of the city's population in gender and age range terms according to Table 5 (INE, 2017).
VII. Analysing the responses The obtained answers were analysed for different purposes:
To choose an icon globally for each requirement To analyse which icon characteristics most influenced the respondents’ selection To analyse if there were differences between the respondents’ distinct profiles.
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Table 5. Characteristics of the sample (%) (INE, 2017) Age ranges 18-34 35-49 50-64 >65 Males 9.8% 16.2% 12.5% 10.4% 48.8% Females 9.4% 15.5% 12.9% 13.4% 51.2%
Table 6 shows the icon chosen as a higher percentage for each requirement. It shows the response obtained for each icon characteristic and that finally chosen after considering them all globally. The shaded cells are those in which there is a match between the globally selected icon and the icon selected for a specific icon characteristic. It can be observed that familiarity and aesthetic appeal are the icon characteristics that most influenced the final icon selection for each requirement. Simplicity is the icon characteristic that least influenced the final selection.
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Table 6. The icon selected for each requirement for each icon characteristic and globally Semantic Aesthetic Simplicity Familiarity Global distance appeal
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Upgrade
Disassembly
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Lifetime extension
Repairability
Reuse
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Figure 3a-e shows all the results in an aggregated form for each requirement and presents the percentage of respondents who chose each icon, for each icon characteristic and globally. It also denotes that the icon selected globally for each requirement was chosen by more than one third of the respondents (33.6 – 38.8%, depending on the requirement). 3b)
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Figure 3. Percentage of the respondents who chose each icon
Regarding the socio-economic variables of the respondents, it would also be interesting to analyse if there were differences in the choice made by the different respondent profiles. Supplementary Material 1 includes the detailed results obtained for the icon selection for each requirement and for each respondent profile. However, this fact is discussed in the next section as it is necessary to analyse if the differences obtained by the respondent profile are statistically significant or not. VIII. Validation: testing icon association with its corresponding referent The method applied to test the association of icons with their corresponding referent (requirement) is based on ISO 9186-3 (2014). This test is a fundamental step to validate that an icon adequately communicates its referent, in this case, its requirement. The selected format of 10
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the survey is shown in Figure 4, where each respondent had to relate the icon and the requirement that he/she considered the most appropriate.
Figure 4. Model of the validation questionnaire
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This survey was handed to a sample of 117 people, and differed from the respondents to the previous questionnaire in order to avoid any type of influence. This sample size was bigger than the 96 required according to Equation 1 for a 90%confidence interval, a 50% proportion and a 10% margin of error.
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The respondents were asked to join each icon with the most appropriate requirement. The answers for each pair of icon/requirement were classified as correct answer/wrong answer. According to ISO 7001 (2007), a 66%level of understanding is required, among others, so that a public information icon can be used with no supplementary text. The results are reported in Table 7 and show that between 85.5% and 91.5% of the respondents correctly associated each icon with its corresponding requirement. Repairability was the requirement with the best results, followed by upgrade, lifetime extension and disassembly. Reuse was the requirement with the lowest percentage of correct answers (85.5%), but it clearly exceeded the minimum considered to validate the results of this study.
No. answers
117
117
117
117
117
Correct answers
106
102
103
100
107
Wrong answers
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15
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90.60%
87.18%
88.03%
85.47%
91.45%
Table 7. Percentage of correct answers in the validation survey for each requirement Disassembly Upgrade Lifetime extension Reuse Repairability
% correct answers
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4. Discussion A statistical analysis was conducted to explore whether any significant differences appeared among the responses obtained (icon selection) by the different respondent profiles. Three different aspects were assessed:
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How the respondents’ socio-economic profile influenced the global icon selection for each requirement How icon characteristics influenced the global icon selection for each requirement How the respondents’ socio-economic profile influenced the icon characteristic selection, independently of each requirement.
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The statistical analysis was done by applying multinomial regression models. Multinomial regression coefficients are interpreted as the rate of change in the logarithm of the probability at level k (k = 2, …, n) against level 1, which is considered a reference level according to Equation 2: [Eq. 2]
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where X represents the design matrix whose entries are the values of the socio-economic variables, and β represents the regression coefficients. These regression coefficients measure the linear effect on the logarithm of the proportion of probabilities. The general model structure is shown in Equation 3: = + ∑
[Eq. 3]
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where Yi represents each response variable, Xi denotes each socio-economic profile/icon characteristic variable, β0 is a scalar that represents the intercept, and βi = (β1, …, βM) are the coefficients of the linear effects of each socio-economic profile/icon characteristic variable Xi. It is considered that socio-economic profile/icon characteristic variable Xi is significant if the pvalue is less than or equals 0.05. In addition, the positive sign of the corresponding βi implies that the response variable increases when the socio-economic variable increases. The higher the coefficient βi, the stronger the effect of this socio-economic variable.
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Tables 8 and 9 summarise the results obtained for the three assessed aspects. The multinomial regression models are included in Supplementary Material 2, where the coefficients (βi) and pvalue are reported for each model. The highlighted cells (●) in Tables 8 and 9 indicate that the variable (socio-economic profile or icon characteristic) is significant in the icon selection, either globally (Table 8) or independently (Table 9), as the p-value of the corresponding multinomial regression model is less than or equals 0.05.
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● Significant characteris^c
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Semantic distance
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(1 (<1000), 2 (1000-1999), 3 (2000-2999), 4 (≥3000)
Monthly family income (€)
(1 (primary), 2 (secondary), 3 (university))
Familiarity
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Aesthetic appeal
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Simplicity
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Level of education
(1 (female), 2 (male))
Gender
Age
Requirement Upgrade Disassembly Lifetime extension Repairability Reuse
(1 (18-34), 2 (35-49), 3 (50-64), 4 (≥65))
Table 8. Significance of the respondents’ socio-economic profile (left) and icon characteristics (right) on selecting each requirement globally Socio-economic profile Icon characteristic
Disassembly
Lifetime extension
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(1 (<1000), 2 (1000-1999), 3 (2000-2999), 4 (≥3000)
Monthly family income (€)
Level of education
(1 (primary), 2 (secondary), 3 (university))
(1 (female), 2 (male))
Gender
Icon characteristic Simplicity Aesthetic appeal Familiarity Semantic distance Simplicity Aesthetic appeal Familiarity Semantic distance Simplicity Aesthetic appeal Familiarity
(1 (18-34), 2 (35-49), 3 (50-64), 4 (≥65))
Requirement Upgrade
Age
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Table 9. Significance of the respondents’ socio-economic profile on selecting each icon characteristic independently of each requirement
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Reuse
Semantic distance Simplicity Aesthetic appeal Familiarity Semantic distance Simplicity Aesthetic appeal Familiarity Semantic distance
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Reparability
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Taking requirement disassembly in Table 8 as an example, Table 10 reports the multinomial regression model for the disassembly icon global selection vs. the respondents’ socio-economic profile (coefficient ; p-value). The differences obtained in the global selection of icons by age, gender and level of education are statistically significant (p-value lower than 0.05 in at least one of the cases). In addition, the gender profile becomes the most significant variable as it has higher coefficients ( ). The multinomial regression models for the remaining requirements are reported in Supplementary Material 2. Table 10. Example of the multinomial regression “coefficient ; p-value” calculations for the global icon selection of disassembly vs. the respondents’ socio-economic profile
2 3 4 5
Age
Gender
0.5024; 0.1248 -0.2502; 0.4289 0.1587; 0.3879 -0.6980; 0.0064
0.0909; 0.8853 0.9902; 0.0778 1.3159; 0.0001 0.7062; 0.1033
Level of education !
Level of family income "
0.3215; 0.4991 0.0065; 0.9896 0.6531; 0.0276 -0.2153; 0.5785
-0.1713; 0.5611 -0.1505; 0.5910 -0.0455; 0.7796 0.0941; 0.6425
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Note. The significant variables of each model per covariate are highlighted in grey
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As to how the respondents’ socio-economic profile influenced the global icon selection for each requirement (Table 8 left), several findings were drawn. For disassembly, the differences obtained in the choice of icons were statistically significant by gender, level of education and age, and in decreasing order of importance. For reuse, it resulted significant age and gender, which was more significant the age. Concerning repairability, the level of education is found the most significant. Regarding upgrade and lifetime extension, no significant differences were found for any of the analysed socio-economic variables. Besides, it should be noted that the level of income was not significant for any of the requirements. In contrast, icon characteristics consistently affected the global icon choice (Table 8, right), except for lifetime extension, which was not affected by any of them. Semantic distance was the most significant characteristic for the upgrade, disassembly, reparability and reuse requirements. When analysing the influence of the respondents’ socio-economic profile on the icon characteristic selection independently of each requirement (Table 9), we can generally state that aesthetical appeal and semantic distance were statistically significant for selecting the icon that globally represented a requirement, while simplicity and familiarity were less significant.
5. Conclusions This study proposed a methodology to identify the icons which best represent the requirements that a product should fulfil from a circular economy perspective (update, disassembly, extension 14
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of useful life, repair and reuse), by taking into account different icon characteristics (simplicity, familiarity, semantic distance and aesthetic appeal). The globally chosen icons are those shown in Table 11. Table 11. Globally selected icons Disassembly
Lifetime extension
Repairability
Reuse
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This result was validated because between 85.5% and 91.5% of the respondents, depending on the requirement, correctly linked the icon with the requirement in a second validation survey.
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In addition, taking into account the aim of the study, the icon characteristics statistically influenced the global requirement selection more than the respondents’ socio-economic profile. However, this profile became more significant when selecting each icon characteristic independently of each requirement. The most significant icon characteristics were semantic distance and aesthetic appeal, while the most significant respondents’ socio-economic variables were gender and age, and in this order. This is partially in line with Isherwood et al. (2007) whose findings showed that semantic distance and familiarity were of primary importance when selecting icons. According to Chen et al. (2017), when semantic distance is not properly considered during the icon design process, it can affect to the user's cognition. Although results obtained in this study showed that familiarity is not the icon characteristic that most determine the consumers’ choice, it can help to reduce the amount of information required to communicate a message (Forsythe et al., 2008). In reference to aesthetic appeal, our results are in line with Wang and Li (2017), whose study showed that aesthetic design of icons plays an important role in the choice of consumers. In addition, Sonderegger and Sauer (2010) determined that aesthetic appeal influence usability. Therefore, in our case, the icons selected could be considered those with higher usability.
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The results of this study could be useful for the companies committed to integrate the principles of circular economy into their product design process. The use of the selected icons in the labelling helps consumers to identify the designed products by taking into account the requirements demanded from the circular economy perspective. Consumers’ understanding is ensured due to the high percentages of correct answers obtained in the validation test. The proposed methodology and findings can serve as a reference for designing and selecting icons for other circular economy requirements defined in the future. It could be also helpful in formulating research methodology for conducting other icon studies, and when facilitating graphic designers to create more effective ones. As a future research to continue this study, it is proposed to explore the relationships between the different visual features of the selected icons (for example, colour contrast, contrast and sharpness, colour combinations, figure/background area ratio, etc.) and users’ attention. For that, an eye tracker can be employed in order to retrieve and measure data from experimental studies with consumers combining their subjective evaluation of attention. Acknowledgments
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The authors are grateful to the Ministerio de Ciencia, Innovación y Universidades, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad for funding for this study (Project DPI2017-89451-R).
Supplementary material
Supplementary material 2: Multinomial regression models
References
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Supplementary Material 1: Icon selection for each requirement and for each profile of respondents
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Chen, X., Xue, C., Wang, H., Zhang, Q., 2017. Design method of icon based on semantic research of universal symbols. Adv. Transdiscipl. Eng. 5, 498–505. Chi, C.F., Dewi, R.S., Surbakti, Y.Y., Hsieh, D.Y., 2017. The perceived quality of in-vehicle auditory signals: a structural equation modelling approach. Ergonomics 60, 1471–1484. doi:10.1080/00140139.2017.1323121
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Flash Eurobarometer, 2009. Europeans’ Attitudes Towards the Issue of Sustainable Consumption and Production. Analytical Report. European Commission. Forsythe, A., Mulhern, G., Sawey, M., 2008. Confounds in pictorial sets: The role of complexity and familiarity in basic-level picture processing. Behav. Res. Methods 40, 116–129. doi:10.3758/BRM.40.1.116
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Forsythe, A., Sheehy, N., Sawey, M., 2003. Measuring icon complexity: an automated analysis. Behav. Res. Methods, Instruments, Comput. 35, 334–342. Gatsou, C., Politis, A., Zevgolis, D., 2012. The importance of mobile interface icons on user interaction. Int. J. Comput. Sci. Appl. 9, 92–107.
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Isherwood, S., 2009. Graphics and semantics: The relationship between what is seen and what is meant in icon design, in: Lecture Notes in Computer Science. pp. 197–205. doi:10.1007/9783-642-02728-4_21
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Isherwood, S.J., McDougall, S.J.P., Curry, M.B., 2007. Icon Identification in Context: The Changing Role of Icon Characteristics With User Experience. Hum. Factors J. Hum. Factors Ergon. Soc. 49, 465–476. doi:10.1518/001872007X200102 ISO 14021, 2006. Environmental Labels and Declarations. Self-declared Environmental Claims (Type II Environmental Labelling).
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Johann, V., Mahr, A., 2011. A new icon selection test for the automotive domain based on relevant ISO usability criteria, in: 3rd International Conference on Automotive User Interfaces and Interactive Vehicular Applications. Ko, Y.H., 2017. The effects of luminance contrast, colour combinations, font, and search time on brand icon legibility. Appl. Ergon. 65, 33–40. doi:10.1016/j.apergo.2017.05.015 Kujala, T., Saariluoma, P., 2011. Effects of menu structure and touch screen scrolling style on the variability of glance durations during in-vehicle visual search tasks. Ergonomics 54, 716–732. doi:10.1080/00140139.2011.592601 McDougall, S., Reppa, I., Kulik, J., Taylor, A., 2016. What makes icons appealing? The role of processing fluency in predicting icon appeal in different task contexts. Appl. Ergon. 55, 156– 172. doi:10.1016/j.apergo.2016.02.006 17
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McDougall, S.J.P., Curry, M.B., De Bruijn, O., 1999. Measuring symbol and icon characteristics: Norms for concreteness, complexity, meaningfulness, familiarity, and semantic distance for 239 symbols. Behav. Res. Methods, Instruments, Comput. 31, 487–519. doi:10.3758/BF03200730
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Sonderegger, A., Sauer, J., 2010. The influence of design aesthetics in usability testing: Effects on user performance and perceived usability. Appl. Ergon. 41, 403–410. doi:10.1016/j.apergo.2009.09.002 The Ellen MacArthur Foundation, 2012. Towards a Circular Economy. Economic and Business Rationale for an Accelerated Transition.
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Tung, T.C., Chen, H.Y., 2017. Integrating conjoint analysis with TOPSIS algorithm to the visual effect of icon design based on multiple users’ image perceptions. Eurasia J. Math. Sci. Technol. Educ. 13, 1025–1040.
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Wang, M., Li, X., 2017. Effects of the aesthetic design of icons on app downloads: evidence from an android market. Electron. Commer. Res. 17, 83–102. Wang, Q., Cavanagh, P., Green, M., 1994. Familiarity and pop-out in visual search. Percept. Psychophys. 56, 495–500. doi:10.3758/BF03206946 Wang, Z., Duff, B.R.L., Clayton, R.B., 2018. Establishing a Factor Model for Aesthetic Preference for Visual Complexity of Brand Logo. J. Curr. Issues Res. Advert. 39, 83–100. doi:10.1080/10641734.2017.1372325 WBCSD, 2008. Sustainable Consumption Facts and Trends, from a Business Perspective. World Business Council of Sustainable Development: Geneva, Switzerland Zhang, J., Xue, C., Shen, Z., Chen, X., Shao, J., Zhou, L., Zhou, X., 2016. Study on the effects of semantic memory on icon complexity in cognitive domain. Lect. Notes Comput. Sci. 9736, 147–157. 18
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Highlights
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A methodology for identifying the icons related to a circular product is proposed. Icons for reuse, disassembly, repair, upgrade, lifetime extension and recycling are analysed. The simplicity, familiarity, semantic distance and aesthetic appeal of icons are analised. A survey is designed to choose the set of icons for circular products. The most significant socio-economic variables were gender and age The most significant icon characteristics were semantic distance and aesthetic appeal
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S0959-6526(18)32523-X
DOI:
10.1016/j.jclepro.2018.08.180
Reference:
JCLP 13964
To appear in:
Journal of Cleaner Production
Received Date: 6 June 2018 Revised Date:
13 August 2018
Accepted Date: 17 August 2018
Please cite this article as: Bovea MaríD, Quemades-Beltrán P, Pérez-Belis V, Juan P, Braulio-Gonzalo M, Ibáñez-Forés V, Options for labelling circular products: Icon design and consumer preferences, Journal of Cleaner Production (2018), doi: 10.1016/j.jclepro.2018.08.180. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Options for labelling circular products: icon design and consumer preferences a,
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María D Bovea *, Pilar Quemades-Beltrán , Victoria Pérez-Belis , Pablo Juan , Marta Braulio-Gonzalo , a Valeria Ibáñez-Forés Department of Mechanical Engineering and Construction. Universitat Jaume I. Av. Sos Baynat s/n, 12071 Castellón, Spain b
Department of Mathematics, Universitat Jaume I, Av. Sos Baynat s/n, 12071 Castellón, Spain *[email protected]
Abstract
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The demand of products that incorporate circular requirements depend on consumer perceptions. So effective communication is necessary between the product and consumers through product labelling. The use of specific icons facilitates this communication. This study presents a methodology for identifying the icons that best associate and identify consumers with the different design requirements that a circular product should meet. To do this, a set of icons for each circular requirement (upgrade, disassembly, lifetime extension, repairability and reuse) is presented to a representative sample of consumers who select the preferred one by taking into account different icon characteristics (simplicity, familiarity, semantic distance and aesthetic appeal). To validate the comprehension of the selected icons, ISO 9186-3 was applied to test the association of the selected icons with their corresponding requirement. Multinomial regression models were applied to explore whether any significant differences appeared among the responses obtained (icon selection) by the different respondent profiles. The most significant socio-economic variables were gender and age, while the most significant icon characteristics were semantic distance and aesthetic appeal. The results of this study could be useful for the companies committed to integrate the principles of circular economy into their product design since the use of selected icons can help consumers to identify them. Consumers’ understanding is ensured due to the high percentages of correct answers obtained in the validation test (>85%).
EEE: Electrical and Electronic Equipment
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1. Introduction
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WEEE: Waste Electrical and Electronic Equipment
The principles of circular economy (The Ellen MacArthur Foundation, 2012) aim to ensure not only that the value of products, materials and resources are kept in economy for as long as possible, but also the reduction of generated waste. For this purpose, the European Commission promotes a transition to a more circular economy through a series of measures that cover the whole life cycle of products and materials (COM 614, 2015; COM 33, 2017). More specifically and directly related to eco-design, COM 33 (2017) points out that, to date, measures have focused on improving products’ energy efficiency (Directive 2009/125/EC). However, there is a current trend to promote the incorporation of circular economy-related design requirements. Specifically, the current "The Eco-design Working Plan 2016-2019" (COM 773, 2016) is committed to more systematically incorporate design requirements, specifically circular requirements, such as durability, possibility of repair, possibility of updating, possibility of disassembly, ease of reuse and recycling. 1
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However, the demand of products that incorporate these circular requirements depend, to a large extent, on consumer perceptions. As concluded by WBCSD (WBCSD, 2008), consumers are increasingly concerned about environmental and social features of products and services. According to Moser (2016) consumers care for the environment and mirror environmental attitudes in their purchasing behaviour. Thus, producers should know about what consumers are looking for (Maniatis, 2016).
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For consumers to be able to identify circular products and to recognise the specific requirements that they incorporate, effective communication is necessary between the product and consumers through product labelling. According to Silvennoinen et al. (2017), the use of icons facilitates this communication.
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Previous research into this field has focused on studying icon characteristics, such as simplicity/complexity (Forsythe et al., 2003, 2008), semantic distance (Isherwood, 2009; McDougall et al., 1999, 2016), familiarity (Wang et al., 1994), etc. of individual icons. However, when a set of icons represents aspects that are related to one another, such as the requirements that a circular product should meet, it is important that icons are able to be differentiated and to subtly transmit the aspect that they represent. Icons that are not always easily recognised by consumers run the risk of being under-used or even becoming superfluous (Böcker, 1996). In this sense, the Flash Eurobarometer (2009) revealed that there is difficult for consumers to understand the information that environmental labels try to convey.
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The literature on icon design has focused on analysing icon communication in different sectors. In the automotive sector, Chi et al. (2017) analysed the quality of in-vehicle auditory signals, Johann and Mahr (2011) introduced a procedure for the evaluation of icons of automotive sector by considering relevant criteria from current ISO standards, Kujala and Saariluoma (2011) studied the effects of alternative navigation device display features on drivers' visual sampling efficiency while searching for points of interest and Silvennoinen et al. (2017) analized semantic distances of icons to menu functions with preference rankings, verbal protocols, and the primed product comparisons method; etc.). In the software sector, Byrne (1993) outlined the factors involved in icon search and proposed a model for this process, while Huang et al. (2002) identified the main factors involved in the design of computer graphic user interfaces. In the mobile context, Gatsou et al. (2012) examined how far an icon for mobile devices represents the meaning of the function for which it has been designed, while Ghayas et al. (2013) determined the effects of icon characteristics on users’ perception. In the scholars sector, Chiu et al. (2012) suggested three icon design principles to better design icons for preschool users graphical user interface.
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Therefore, the icon design associated with the communication of circular economy-related requirements included in a product has not been yet analysed in the literature, despite of being a pending issue according to the regulatory framework regarding circular economy. Hence, a research gap in this field exists, thus it is addressed in this study. In this context, this study aimed to present a methodology to identify the icons that best fit with the different design requirements that a circular product should meet, according to consumers’ preferences. To do so, a set of icons for each circular requirement was presented to a representative sample of consumers who selected the best icon after taking into account different icon characteristics. To validate the comprehension of the selected icons, ISO 9186-3 (2014) was applied to test the association of the selected icons with their corresponding requirement. 2. Methodology
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With a view to selecting the icons that best identified consumers with the design requirements that a product should have from a circular economy perspective, the methodology shown in Figure 1 was proposed, whose stages are described below:
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Stage I: Selection of requirements for a circular product. The requirements that a product should meet from the circular economy perspective are identified by taking into account the current regulatory framework. Stage II: Icon definition (literature and own design). The existing icons from different bibliographic sources (internet, regulations, manuals, research and dissemination articles, databases, etc.) that may be related to the identified requirements are explored and collected. They are completed with the new icons designed by a design team. As a result, a collection of icons for each requirement that a circular product has to fulfil is obtained. Stage III: Selection of icon characteristics. A literature review was done to select the most common characteristics that make an icon easier to use and understand by consumers. Stage IV: Selection of icons. Each collection goes through a debugging process until the number of alternatives for each requirement is reached after taking into account different icon characteristics. These reduced sets of icons for each requirement had to be evaluated by consumers. So they could choose the icon that best represented each requirement by bearing in mind the icon characteristics. Stage V: Survey design. A survey needs to be designed considering all the aspects previously described. Stage VI: Sample definition. The survey is handed out to a representative sample. In order to calculate statistically the representative sample size needed for this study, the method proposed by Bartlett et al. (2001) was applied according to the following equation: () ∗()( ) ( )
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where n is sample size, t is the Z value for a specific confidence level, p is the proportion of respondents who selected a specific choice, and d is the confidence interval or margin of error.
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Stage VII: Analysis of responses. After conducting the survey, responses were analysed to identify the icons that consumers mostly related to each requirement that a circular product should meet. Stage VIII: Validation. Finally, the selected icons passed a validation process to assess their understanding. This step is essential to validate if an icon adequately communicates its message. To do so, it is advisable to follow the recommendations of ISO 9186-3 (2014).
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I. Selection of requirements for a Circular Product
II. Icon definition: Literature & Own designs
IV. Selection of icons
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III. Selection of icon characteristics
V. Survey design
VI. Sample definition
VIII. Validation
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Figure 1. Methodology
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VII. Analysis of responses
3. Results
I. Selecting requirements for a circular product
The promotion and application of the principles of circular economy (The Ellen MacArthur Foundation, 2012) to product design have been reflected in different legislation and regulatory frameworks in Europe, as shown in Table 1.
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The Waste Electrical and Electronic Equipment Directive (WEEE directive) (Directive 2012/19/EU) establishes that eco-design requirements that facilitate the re-use, dismantling and recovery of WEEE should be laid down in the framework of measures by implementing the Eco-design directive (Directive 2009/125/EC). Better design can make products more durable or easier to repair, be upgraded or remanufactured. It can help recyclers to disassemble products to recover valuable materials and components (COM 614, 2015; COM 33, 2017).
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Electrical and electronic equipment (EEE) is particularly significant in this context. This whole framework encourages the design and production of EEE that takes into full account and facilitates its repair, possible upgrading, re-use, disassembly and recycling. So product design is a key aspect in this respect as it can have significant impacts across the product’s life cycle; e.g. in making a product more durable, easier to repair, be reused or recycled. The current Eco-design working plan 2016-19 (COM 773, 2016) also promotes the incorporation of relevant aspects to circular economy, such as reparability, recyclability and durability, when revising the existing measures from the Eco-design directive.
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Recycling
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Disassembly
WEEE directive (2012) Eco-design directive (2009)
Upgrade
Table 1. Selection of requirements to be met by a "circular product"
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COM 773 (2016) COM 614 (2015) COM 33 (2017)
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According to Table 1, the requirements that a circular product needs to fulfil are: reuse, disassembly, repair, upgrade, lifetime extension and recycling. Of those, only recycling has an icon that represents it clearly that is internationally recognised with the Mobius loop (ISO 14021, 2006). So this study focuses on the remaining five requirements. II. Defining icons
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Table 2. Collection of icons selected for each circular product requirement Icons
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Requirement Upgrade
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After identifying the requirements for which icons have to be defined, a search for icons/images that could be associated with each one was done according to the literature, icon databases, manuals/reports on circular economy, etc. New icons were designed by the designers who belonged to the research team as new ideas/concepts, or as a combination of existing icons. Finally, a collection of between 24 and 39 icons was obtained per requirement. The selected icons went through a process to unify fonts and sizes, and those reported in Table 2 were obtained.
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III. Selecting icon characteristics
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Reference (Böcker, 1996) (Bresciani and Del Pone, 2017)
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Table 3. Literature review of icon characteristics
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Table 3 reports the characteristics that can be considered in a first step to select the icons with a better relationship with each requirement. Other characteristics found in the literature, such as colour (Ko, 2017; Forsythe et al., 2008; Byrne, 1993 or Hynes, 2009), font (Ko, 2017), size (Byrne, 1993), luminance contrast (Ko, 2017) or legibility (Ko, 2017), can be analysed in a second step as variations of the selected icons.
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(Byrne, 1993) (Chen et al., 2017) (Forsythe et al., 2003) (Forsythe et al., 2008) (Gatsou et al., 2012) (Henderson and Cote, 1998) (Isherwood et al., 2007) (Ko, 2017) (McDougall et al., 1999) (McDougall et al., 2016) (Mirzabeigi et al., 2017) (Pittard et al., 2007) (Silvennoinen and Jokinen, 2016) (Silvennoinen et al., 2017) (Sonderegger and Sauer, 2010) (Tung and Chen, 2017) (Wang et al., 1994) (Wang and Li, 2017) (Wang et al., 2018) (Zhang et al., 2016)
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IV. Selecting icons
The collection of icons reported in Table 2 was submitted to a debugging process to select a set of five icons per requirement to be included in the survey. This process was divided into two stages:
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Unifying variations on the same idea to reduce the number of alternatives, and that these cover the largest spectrum of different ideas (14-15 icons per requirement). Selecting the five icons for each requirement to be included in the survey for consumers. This process was carried out using a survey with 20 designers who were external to this study. They were asked to select five icons for each requirement by taking into account the characteristics reported in Table 3 and bearing in mind that the selected icons should cover the broadest spectrum of alternative ideas. The five selected icons are those reported in Table 4, along with the definition of each requirement.
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Table 4. The selected icons to be included in the survey for each requirement Upgrade Product able to adapt to new versions of it Disassembly Product that can be easily disassembled into its components or parts Lifetime extension Product that can be used for longer than usual
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Repairability Product that can be easily fixed after failing
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Reuse Product which, after being discarded, can be used again with the same or different use as/from the initial one
V. Survey design
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The aim of the survey was for consumers to select the icon (from those shown in Table 4) which is best identified with the requirements that a circular product should meet. The type of chosen survey was a questionnaire directly administered to the respondents. The objective was to design a questionnaire that was easy to understand by different profiles of the respondents and quick to answer to obtain the maximum number of valid answers. The finally selected format after a feedback process, during which different pilot formats were tested, is shown in Figure 2 (for one of the requirements). The respondents had to mark the icon that they considered was more appropriate for each requirement (see the definitions in Figure 4), and according to the icon characteristics identified in Stage III: simplicity, aesthetic appeal, familiarity and semantic distance. Finally, they were asked to globally choose the icon that best identified the requirement. In this way, the order in which the icons were presented in the questionnaire did not influence the response, which was alternated from one questionnaire to another.
Figure 2. Survey format for one of the requirements
VI. Sample definition The survey was conducted in the Spanish city of Castellón de la Plana (Spain), which has 169,498 inhabitants (INE, 2017). Equation 1 has been applied considering a 90% confidence level (t=1.65) 8
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and the maximum possible proportion of 50% (p=0.5), which gives the largest sample size, and a 5% margin of error (d=0.05). This results in a sample size of 272. Therefore, the survey was conducted in a representative population sample of 272 inhabitants aged over 18 years old, and represented the characteristics of the city's population in gender and age range terms according to Table 5 (INE, 2017).
VII. Analysing the responses The obtained answers were analysed for different purposes:
To choose an icon globally for each requirement To analyse which icon characteristics most influenced the respondents’ selection To analyse if there were differences between the respondents’ distinct profiles.
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Table 5. Characteristics of the sample (%) (INE, 2017) Age ranges 18-34 35-49 50-64 >65 Males 9.8% 16.2% 12.5% 10.4% 48.8% Females 9.4% 15.5% 12.9% 13.4% 51.2%
Table 6 shows the icon chosen as a higher percentage for each requirement. It shows the response obtained for each icon characteristic and that finally chosen after considering them all globally. The shaded cells are those in which there is a match between the globally selected icon and the icon selected for a specific icon characteristic. It can be observed that familiarity and aesthetic appeal are the icon characteristics that most influenced the final icon selection for each requirement. Simplicity is the icon characteristic that least influenced the final selection.
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Table 6. The icon selected for each requirement for each icon characteristic and globally Semantic Aesthetic Simplicity Familiarity Global distance appeal
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Disassembly
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Figure 3a-e shows all the results in an aggregated form for each requirement and presents the percentage of respondents who chose each icon, for each icon characteristic and globally. It also denotes that the icon selected globally for each requirement was chosen by more than one third of the respondents (33.6 – 38.8%, depending on the requirement). 3b)
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Figure 3. Percentage of the respondents who chose each icon
Regarding the socio-economic variables of the respondents, it would also be interesting to analyse if there were differences in the choice made by the different respondent profiles. Supplementary Material 1 includes the detailed results obtained for the icon selection for each requirement and for each respondent profile. However, this fact is discussed in the next section as it is necessary to analyse if the differences obtained by the respondent profile are statistically significant or not. VIII. Validation: testing icon association with its corresponding referent The method applied to test the association of icons with their corresponding referent (requirement) is based on ISO 9186-3 (2014). This test is a fundamental step to validate that an icon adequately communicates its referent, in this case, its requirement. The selected format of 10
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the survey is shown in Figure 4, where each respondent had to relate the icon and the requirement that he/she considered the most appropriate.
Figure 4. Model of the validation questionnaire
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This survey was handed to a sample of 117 people, and differed from the respondents to the previous questionnaire in order to avoid any type of influence. This sample size was bigger than the 96 required according to Equation 1 for a 90%confidence interval, a 50% proportion and a 10% margin of error.
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The respondents were asked to join each icon with the most appropriate requirement. The answers for each pair of icon/requirement were classified as correct answer/wrong answer. According to ISO 7001 (2007), a 66%level of understanding is required, among others, so that a public information icon can be used with no supplementary text. The results are reported in Table 7 and show that between 85.5% and 91.5% of the respondents correctly associated each icon with its corresponding requirement. Repairability was the requirement with the best results, followed by upgrade, lifetime extension and disassembly. Reuse was the requirement with the lowest percentage of correct answers (85.5%), but it clearly exceeded the minimum considered to validate the results of this study.
No. answers
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Wrong answers
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Table 7. Percentage of correct answers in the validation survey for each requirement Disassembly Upgrade Lifetime extension Reuse Repairability
% correct answers
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4. Discussion A statistical analysis was conducted to explore whether any significant differences appeared among the responses obtained (icon selection) by the different respondent profiles. Three different aspects were assessed:
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How the respondents’ socio-economic profile influenced the global icon selection for each requirement How icon characteristics influenced the global icon selection for each requirement How the respondents’ socio-economic profile influenced the icon characteristic selection, independently of each requirement.
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The statistical analysis was done by applying multinomial regression models. Multinomial regression coefficients are interpreted as the rate of change in the logarithm of the probability at level k (k = 2, …, n) against level 1, which is considered a reference level according to Equation 2: [Eq. 2]
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[Eq. 3]
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where Yi represents each response variable, Xi denotes each socio-economic profile/icon characteristic variable, β0 is a scalar that represents the intercept, and βi = (β1, …, βM) are the coefficients of the linear effects of each socio-economic profile/icon characteristic variable Xi. It is considered that socio-economic profile/icon characteristic variable Xi is significant if the pvalue is less than or equals 0.05. In addition, the positive sign of the corresponding βi implies that the response variable increases when the socio-economic variable increases. The higher the coefficient βi, the stronger the effect of this socio-economic variable.
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Tables 8 and 9 summarise the results obtained for the three assessed aspects. The multinomial regression models are included in Supplementary Material 2, where the coefficients (βi) and pvalue are reported for each model. The highlighted cells (●) in Tables 8 and 9 indicate that the variable (socio-economic profile or icon characteristic) is significant in the icon selection, either globally (Table 8) or independently (Table 9), as the p-value of the corresponding multinomial regression model is less than or equals 0.05.
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● Significant characteris^c
●
●
● ●
● ●
● ●
●
● ●
● ●
● ●
● ●
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Semantic distance
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(1 (<1000), 2 (1000-1999), 3 (2000-2999), 4 (≥3000)
Monthly family income (€)
(1 (primary), 2 (secondary), 3 (university))
Familiarity
●
Aesthetic appeal
●
Simplicity
●
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Level of education
(1 (female), 2 (male))
Gender
Age
Requirement Upgrade Disassembly Lifetime extension Repairability Reuse
(1 (18-34), 2 (35-49), 3 (50-64), 4 (≥65))
Table 8. Significance of the respondents’ socio-economic profile (left) and icon characteristics (right) on selecting each requirement globally Socio-economic profile Icon characteristic
Disassembly
Lifetime extension
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●
●
●
●
●
● ● ● ● ●
●
●
●
(1 (<1000), 2 (1000-1999), 3 (2000-2999), 4 (≥3000)
Monthly family income (€)
Level of education
(1 (primary), 2 (secondary), 3 (university))
(1 (female), 2 (male))
Gender
Icon characteristic Simplicity Aesthetic appeal Familiarity Semantic distance Simplicity Aesthetic appeal Familiarity Semantic distance Simplicity Aesthetic appeal Familiarity
(1 (18-34), 2 (35-49), 3 (50-64), 4 (≥65))
Requirement Upgrade
Age
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Table 9. Significance of the respondents’ socio-economic profile on selecting each icon characteristic independently of each requirement
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Reuse
Semantic distance Simplicity Aesthetic appeal Familiarity Semantic distance Simplicity Aesthetic appeal Familiarity Semantic distance
● ●
● ● ●
● ● ● ●
● ● ●
● Significant characteris^c
● ●
● ●
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Reparability
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Taking requirement disassembly in Table 8 as an example, Table 10 reports the multinomial regression model for the disassembly icon global selection vs. the respondents’ socio-economic profile (coefficient ; p-value). The differences obtained in the global selection of icons by age, gender and level of education are statistically significant (p-value lower than 0.05 in at least one of the cases). In addition, the gender profile becomes the most significant variable as it has higher coefficients ( ). The multinomial regression models for the remaining requirements are reported in Supplementary Material 2. Table 10. Example of the multinomial regression “coefficient ; p-value” calculations for the global icon selection of disassembly vs. the respondents’ socio-economic profile
2 3 4 5
Age
Gender
0.5024; 0.1248 -0.2502; 0.4289 0.1587; 0.3879 -0.6980; 0.0064
0.0909; 0.8853 0.9902; 0.0778 1.3159; 0.0001 0.7062; 0.1033
Level of education !
Level of family income "
0.3215; 0.4991 0.0065; 0.9896 0.6531; 0.0276 -0.2153; 0.5785
-0.1713; 0.5611 -0.1505; 0.5910 -0.0455; 0.7796 0.0941; 0.6425
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Note. The significant variables of each model per covariate are highlighted in grey
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As to how the respondents’ socio-economic profile influenced the global icon selection for each requirement (Table 8 left), several findings were drawn. For disassembly, the differences obtained in the choice of icons were statistically significant by gender, level of education and age, and in decreasing order of importance. For reuse, it resulted significant age and gender, which was more significant the age. Concerning repairability, the level of education is found the most significant. Regarding upgrade and lifetime extension, no significant differences were found for any of the analysed socio-economic variables. Besides, it should be noted that the level of income was not significant for any of the requirements. In contrast, icon characteristics consistently affected the global icon choice (Table 8, right), except for lifetime extension, which was not affected by any of them. Semantic distance was the most significant characteristic for the upgrade, disassembly, reparability and reuse requirements. When analysing the influence of the respondents’ socio-economic profile on the icon characteristic selection independently of each requirement (Table 9), we can generally state that aesthetical appeal and semantic distance were statistically significant for selecting the icon that globally represented a requirement, while simplicity and familiarity were less significant.
5. Conclusions This study proposed a methodology to identify the icons which best represent the requirements that a product should fulfil from a circular economy perspective (update, disassembly, extension 14
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of useful life, repair and reuse), by taking into account different icon characteristics (simplicity, familiarity, semantic distance and aesthetic appeal). The globally chosen icons are those shown in Table 11. Table 11. Globally selected icons Disassembly
Lifetime extension
Repairability
Reuse
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Upgrade
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This result was validated because between 85.5% and 91.5% of the respondents, depending on the requirement, correctly linked the icon with the requirement in a second validation survey.
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In addition, taking into account the aim of the study, the icon characteristics statistically influenced the global requirement selection more than the respondents’ socio-economic profile. However, this profile became more significant when selecting each icon characteristic independently of each requirement. The most significant icon characteristics were semantic distance and aesthetic appeal, while the most significant respondents’ socio-economic variables were gender and age, and in this order. This is partially in line with Isherwood et al. (2007) whose findings showed that semantic distance and familiarity were of primary importance when selecting icons. According to Chen et al. (2017), when semantic distance is not properly considered during the icon design process, it can affect to the user's cognition. Although results obtained in this study showed that familiarity is not the icon characteristic that most determine the consumers’ choice, it can help to reduce the amount of information required to communicate a message (Forsythe et al., 2008). In reference to aesthetic appeal, our results are in line with Wang and Li (2017), whose study showed that aesthetic design of icons plays an important role in the choice of consumers. In addition, Sonderegger and Sauer (2010) determined that aesthetic appeal influence usability. Therefore, in our case, the icons selected could be considered those with higher usability.
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The results of this study could be useful for the companies committed to integrate the principles of circular economy into their product design process. The use of the selected icons in the labelling helps consumers to identify the designed products by taking into account the requirements demanded from the circular economy perspective. Consumers’ understanding is ensured due to the high percentages of correct answers obtained in the validation test. The proposed methodology and findings can serve as a reference for designing and selecting icons for other circular economy requirements defined in the future. It could be also helpful in formulating research methodology for conducting other icon studies, and when facilitating graphic designers to create more effective ones. As a future research to continue this study, it is proposed to explore the relationships between the different visual features of the selected icons (for example, colour contrast, contrast and sharpness, colour combinations, figure/background area ratio, etc.) and users’ attention. For that, an eye tracker can be employed in order to retrieve and measure data from experimental studies with consumers combining their subjective evaluation of attention. Acknowledgments
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The authors are grateful to the Ministerio de Ciencia, Innovación y Universidades, Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad for funding for this study (Project DPI2017-89451-R).
Supplementary material
Supplementary material 2: Multinomial regression models
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Highlights
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A methodology for identifying the icons related to a circular product is proposed. Icons for reuse, disassembly, repair, upgrade, lifetime extension and recycling are analysed. The simplicity, familiarity, semantic distance and aesthetic appeal of icons are analised. A survey is designed to choose the set of icons for circular products. The most significant socio-economic variables were gender and age The most significant icon characteristics were semantic distance and aesthetic appeal
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