The meaning of colours in nutrition labelling in the context of expert and consumer criteria of evaluating food product healthfulness

Abstract

Qualitative and quantitative studies were conducted to explore the effect of front-of-pack nutrition labels on the perceived healthfulness of food products. Consumers were found to hold beliefs about colours and their fit to product categories that influence the assessment process. Consumers associate certain colours with product healthfulness. Yellow, blue, green and red were found to be evocative of health. Heather, pink and celadon suggested an artificial thus unhealthful product. The impact of labels on healthfulness assessment was observed only in the unhealthful category. The findings show the complexity of psychological processes in the perception of food healthfulness.

Keywords

beliefs food health promotion qualitative methods quantitative methods

Introduction

The growing extent of diet-dependent diseases (World Health Organization (WHO), 2007) has resulted in an increase in the number of practitioners and researchers seeking ways to help consumers choose healthful foods (Aschemann-Witzel et al., 2013). Health literacy is an important factor in the ability to make healthful choices (Estacio, 2013; Estacio and Comings, 2013). As it is perceived as an outcome of health promotion (Nutbeam, 2000), health literacy can be improved, among other things, by education and communication related to front-of-pack nutrition labels. Consumers perceive the idea of nutrition labelling positively (Grunert and Wills, 2007). However, inferences drawn from labels depend on prior experience (Lähteenmäki et al., 2010; Van Herpen et al., 2012). This constitutes a source of inspiration for further study on the complex psychological processes occurring at the cognitive and emotional levels and which are involved in the potential choice of healthful food (Cromby, 2012; Lyons and Chamberlain, 2012; Santiago-Delefosse, 2012). Describing and explaining these processes is crucial for understanding the determinants of label effectiveness.

Nutrition labels communicate objective information based on nutrition science (expert criteria of product healthfulness). Inferences drawn about product healthfulness from figures, nutrient names and symbolic elements (e.g. colours) can be biased by limited knowledge and prior beliefs and experience. Beliefs and experience can serve as subjective criteria for product healthfulness and can vary across product categories. Consumers may also find it difficult to process information concerning health, especially if the content of the label conflicts with their lay theories about food. Inferences drawn from labels are not limited to beliefs about the healthfulness of a product (Lähteenmäki et al., 2010).

Colours are important formal elements of nutrition labels. Proponents of various labelling systems assume that colours help attract consumers’ attention to a given label and the content it presents as well as help them draw proper conclusion about the healthfulness of the product in question. However, research on the importance of colours, particularly in the context of food and nutrition labels, is scarce (Garber and Hyatt, 2003; Labrecque et al., 2013) and is devoted to other cognitive processes than drawing inferences from colours (Aschemann-Witzel et al., 2013; Bialkova et al., 2014). The aim of our research was to investigate the meaning of colours in nutrition labelling in the context of assessing food product healthfulness according to the criteria of experts and consumers.

Role of colours in making inferences about food

Colours are an objective feature of stimuli and are the object of subjective perception and inferences (Harman, 2001; Hilbert, 1987). They are considered an important means of persuasive communication as they are salient, carry multiple meanings and can affect attention, emotions, beliefs and behaviours (Bellizzi and Hite, 1992; Garber and Hyatt, 2003; Labrecque et al., 2013).

The impact of colours is complex for several reasons. First, colours affect people at coexisting sensory/embodied levels as well as at cognitive/referential levels (Garber and Hyatt, 2003; Labrecque et al., 2013). Sensory impact is biologically based, and it induces automatic response mechanisms (such as hedonic or valenced feelings) because it is related to colour stimulation properties (e.g. aesthetics), which are independent from the context and semantic content. Cognitive impact is based on symbolic and content associations acquired through individual experience or cultural socialization. This experience makes colours the carriers of referential meaning (Labrecque et al., 2013) implying that

colour is a highly interactive, relative, and context-dependent phenomenon, reliant for its effects on the entire visual field in which it is perceived, the larger sensory environment in which it is encountered, and the circumstances, situation, disposition and cognition of the viewer. (Garber and Hyatt, 2003: 315)

From this dual perspective, the use of colours has one indisputable advantage: colours are recognized more easily and more quickly than, for example, text. In addition, individuals’ preferences for colours can affect their behaviour (Garber and Hyatt, 2003). For example, the colour red is believed to trigger avoidance (Mehta and Zhu, 2009), which may reduce the consumption of products labelled with a red colour (Genschow et al., 2012). However, there are also studies on the attractive power of red (Bellizzi and Hite, 1992).

Food-labelling systems differ in terms of form (shape, presence of colours) and content (claims, figures, nutrient names). From a consumer standpoint, one can distinguish directive, nondirective and semi-directive labels represented by the health logo (HL), guideline daily amount (GDA) and traffic light (TL) systems (Hodgkins et al., 2012), respectively. Colours are used in various ways in all of these systems. One of the HL systems uses blue and yellow (http://choicesprogramme.org/about/product-criteria). The GDA system appears in monochrome versions with a uniform blue background (http://www.eufic.org/article/pl/5/19/artid/Making_Sense_of_Guideline_Daily_Amounts/) as well as in multichrome versions (http://www.tesco.com/grocery/onlineshopping/). The TL system uses the symbolism of traffic lights (http://tna.europarchive.org/20100929190231 or http://www.eatwell.gov.uk/foodlabels/trafficlights/). Colours are juxtaposed with symbols (sun and tick in the CHOICES foundation logo), slogans (‘Healthy Choice’) and nutrient names as well as numbers reflecting the quantities of nutrients in a given product (expressed in grams and/or percentage of guideline daily amount).

Numerous studies have dealt with the effectiveness of labels but none has focused on the impact of colours exclusively. These studies have tested labels regarding the presence and type of colour, resulting in differences in the measured reactions. Multichrome GDA labels are better at attracting attention than monochrome ones (Bialkova et al., 2014). Aschemann-Witzel et al. (2013) found weak evidence that colours promote more healthful choices depending on the cultural context. Koenigstorfer et al. (2014) provided evidence that a combination of the HL and TL systems helps consumers choose more healthful products, and the visual attractiveness and usefulness of the label in buying situations depend on the combinations of labels (Wąsowicz-Kiryło and Styśko-Kunkowska, 2011).

As Labrecque et al. (2013) suggest, the impact of colours can be explained through the classical network models of memory, according to which notions are stored in memory as nodes interconnected by paths. Activating one of these nodes leads to the activation of a subsequent node on the implicit level. Thus, one can expect that the activation of a single meaning associated with a particular colour can lead to the activation of other contents and to the formulation of certain expectations. This supposition is confirmed by study results showing that colours affect inferences about the quality of a product (Ndom et al., 2011), the image of a user (Labrecque and Milne, 2013) and the evaluation of the product and brand category (Garber and Hyatt, 2003). Moreover, colours modify inferences with regard to product taste, while the accuracy of the inference depends on the extent to which the base colours of a product are expected to provide a given taste and are associated with the product (Garber and Hyatt, 2003).

Conclusion about the properties and characteristics of a product go far beyond objective data, and the consumer inference process includes subjective logic (Kardes et al., 2008). Both conceptual coherence of incoming information and the knowledge already stored in memory play a significant role in the inference process. Due to the potential impact of nutrition label colours on inferences about the healthfulness of products, label colours should be consistent with the spontaneous – evaluative and content – reasoning connected with colours. Such consistency would help consumers in understanding the labels and making correct assessments about the healthfulness of products.

General objectives of the studies

To the best of our knowledge, no studies have been conducted on spontaneous inferences about colours used in labels. Therefore, we aimed to answer the following main questions: how are label colours interpreted in the context of consumers’ product healthfulness criteria across different product categories? Are nutrition labels the basis of assessment only of the products’ healthfulness or do they also influence the assessment of the other product attributes?

We present the results of two studies. A qualitative study served to identify the subjective, spontaneous understanding of colours placed in various contexts. The results of this study gave rise to hypotheses that were verified in a subsequent quantitative study. Data were collected in the context of two product categories that differed in terms of their objective healthfulness. Education as well as experience gained from learning about food labelling systems can modify inferences about colours used in labels (Lähteenmäki et al., 2010; Van Herpen et al., 2012). As we wished to identify spontaneous associations with colours, this study was conducted in Poland, a country in which health-related campaigns and nutrition labelling barely exist (Storcksdieck genannt Bonsmann et al., 2010). For the research presented in the article, ethical approvals were obtained from the Ethical Committee of Scientific Research of the Faculty of Psychology, University of Warsaw. The consent form was signed by all participants. Data are available from the corresponding author (G.W.).

Study 1

Aims

The main objective of the study was to explore consumers’ criteria when assessing the healthfulness of products and the processes of perception, evaluation and inference-making about product healthfulness based on colours used in selected food labelling systems. We formulated four research questions: (Q1) Which subjective criteria do consumers apply in the assessment of product healthfulness? (Q2) How do consumers perceive single colours in the context of health, healthful and unhealthful food products? (Q3) Does the formal context (the presence of other colours, words or figures) modify colour assessment and inferences about products’ healthfulness? (Q4) Do the assessment and the inferences derived from colours depend on product category, and if yes, how?

Method

The study was carried out by means of an extended focus group interview.

Participants

The study involved eight mothers, who had bought several times recently items from two food categories, yogurt and frozen pizza, and who declared full colour vision, aged 25–45 years.

Stimuli

We used elements of food labelling systems from three groups differing in degree of directiveness (the HL, GDA and TL labels). The stimuli – each presented on an A4 card – differed both in terms of form (colours, words and numbers) and in terms of content. The content included slogans (‘I know what I choose’ – Polish version of ‘Healthy Choice’), names of energy and nutrients (calories, fats, sugars, salt) and information (‘% of guideline daily amount’ and ‘based on international dietary guidelines’). Eight colours (Stimuli 1–8 in Appendix 1) and three sets of colours (S9–S11) and labels (S12–S14) were used as subjects of discussion.

Procedure

Following the topic guide, participants were first asked to state their associations with ‘health’, ‘healthful’ and ‘unhealthful food’ and with the two product categories yogurt and frozen pizza (Q1). In the second part of the discussion (Q2, Q3), participants were first stimulated to reveal the words, symbols, images and colours they associated with the three above-mentioned terms, and then to provide their associations with the presented stimuli (single elements of labels and combinations of elements). The participants were asked to provide general evaluations (how they liked, for example, the colours) and to answer questions such as the following: how is a particular colour associated with health; if a colour would be placed on a product’s label, what would it convey; what ingredients does a colour connote; does the colour match the food category and yogurt/frozen pizza category.

Results

The analysis included two main dimensions: evaluation and content. The subject of the evaluation was colour and how it matched the category of food and each of the analysed product categories. The content analysis included associations with health and healthfulness and other product attributes.

Product healthfulness – consumer and expert criteria

The notion of ‘health’ triggered an association with an active lifestyle and healthful diet. The latter was understood as avoiding the consumption of unhealthful products, consuming healthful products, paying attention to lack of information that signals unnaturalness of products (‘E’ additives), preparing meals ‘from scratch’ and shopping in trusted places.

Respondents perceive healthful products to be natural, free from preservatives and to contain vegetables and fruit. In contrast, products considered unhealthful contain a lot of calories, fat and artificial colours. Healthful yogurt is of high quality, is natural, contains little or no sugar, calories or fat and contains fruit, whereas unhealthful yogurt contains artificial colours and fruit syrups instead of fruit. In contrast, a healthful pizza contains many colourful vegetables, and an unhealthful pizza is made of unknown ingredients, is fatty and has a long shelf life. The respondents clearly recognized yogurt as representative of a healthful food category, recommended for children (quote of respondent’s statement), while, in the case of pizza, the evaluation was less positive because it is not freshly prepared and contains a lot of calories. In their spontaneous statements, the respondents mentioned only three types of information consistent with expert criteria: kilocalories, fat and sugar.

Reactions to single colours in the context of health, healthful and unhealthful products

The participants associated the terms ‘health’, ‘healthful products’ and ‘unhealthful products’ with different colours. In the context of health and healthful products, the colours evoked positive emotions and were connected with nature, naturalness, fruit and vegetables. The respondents mentioned green (like grass, leaves, spring, colours of nature), blue (like the sky and water), red (like tomatoes, peppers, strawberries, raspberries), yellow (like the sun, happiness, summer) and white (like milk). Colours described as being artificial, not occurring naturally, bringing up thoughts of chemistry and artificial additives, such as turquoise, reminded the respondents of unhealthful products.

These associations are consistent with reactions to the tested stimuli of single colours (Table 1). Each colour evoked different responses in terms of the criteria analysed. For example, a comparison of the colours yellow (S1 in Appendix 1) and blue (S2) shows that although both were considered evocative of health and befitting the category of food, there were differences in the overall evaluation and the evaluation of fit to the categories. The colour yellow was perceived as being unequivocally positive and fitting to the pizza category (like the yellow ingredients found in pizza), but not fitting to the yogurt category and suggesting a peculiar taste. The colour blue was given an ambivalent evaluation and was considered to fit the yogurt category (like something from a freezer), but less fitting the frozen pizza category (it contradicts the ‘warm’ colours of pizza ingredients). The colours light heather (S3), light pink (S4) and celadon (S5) were associated with unhealthful products and were generally evaluated negatively as the colours mismatched the food category in general, in particular yogurt and pizza.

Table 1.

Short summary of reactions to the stimuli tested in the qualitative study.

Type of inferences	Single colours
Type of inferences	Yellow (S1)	Blue (S2)	Heather (S3), pink (S4), celadon (S5)	Amber (S6)	Red (S7)	Green (S8)
Evocative of health	Yes	Yes	No	Ambivalent	Ambivalent	Ambivalent
Evaluation	Positive	Ambivalent	Negative	Positive	Positive	Positive
Fit to …
Food	Yes	Yes	No	Yes	Yes	Yes
Pizza	Yes	Less	No	No	Yes	Yes
Yogurt	No	Yes	No	No	No	No
	Colours in the context of other colours
	Yellow + blue (S9)		Yellow + heather, pink, celadon, green (S10)	Green, amber, red (S11)
Evocative of health	Yes		Ambivalent	Ambivalent
Evaluation	Positive		Negative	Ambivalent
	Colours in the context of the entire label
	HL (S12)		Monochrome GDA (S13)	Multichrome GDA (S14)
Evaluation	Positive		Positive	Negative
Inferences
Healthful	Yes		Yes	No
Other attributes	Yes		Yes	Yes

TL: traffic light; HL: health logo; GDA: guideline daily amount.

(S1)–(S14) – numbers of stimuli in Appendix 1.

The colours amber (S6) and red (S7) suggested the presence of vegetables and fruit, and the colour green (S8) the presence of vegetables only; both vegetables and fruit were associated with naturalness and considered as symbols of health. However, reactions depended on the product category. With respect to yogurt, the colours suggested a rather unhealthful product because of association with artificial colouring, and they were considered as inappropriate to the yogurt category because of the association with vegetables. In the context of frozen pizza, a variety of vibrant colours was associated with vegetables and – through this – with healthful products. Also, two of the colours – green and red – were considered as befitting the pizza category.

Reactions to single colours in the context of other colours, words and numbers

In this section, we refer to evaluations and inferences with regard to the associations with colours evaluated in a set of colours and the associations with colours in the context of an entire nutrition label (which is composed of a set of colours and text/numeric information).

An analysis of the statements about the colour yellow shows differences in evaluation and inferences depending on the formal context. When evaluated individually, yellow evoked a clearly positive response and an association with health. The combination of yellow and blue (S9) was also evaluated positively and was associated with health. Thus, the addition of blue did not change the interpretation of the colour yellow. In contrast, the assessment of a colour set in which the colours green, heather, pink and celadon were found along with yellow (S10) was negative, and the association with health was ambivalent. Reactions to colours evaluated negatively, as unnatural, dominated this set of colours.

Associations with the colour blue were also analysed in the context of the entire HL and the monochrome GDA labels. Blue (tick) and yellow (sun) are presented with verbal information ‘I know what I choose’ and ‘based on international dietary guidelines’ in the HL label (S12). This label received the most positive response out of all discussed. The participants appreciated the fact that the symbols and colours were associated with naturalness, and thus, the label undoubtedly conveyed that the product was healthful. Moreover, they inferred high quality and price of the labelled product, which in turn led them to the conclusion that the product was healthful.

The monochrome GDA label (S13) also received positive reactions. The respondents appreciated that it presented a lot of information clearly, and that this label let them evaluate the product from the information provided in kilocalories/grams and percentages. In terms of colour, the label fitted both the yogurt and frozen pizza category, yet both the values given in grams as well as the percentages of guided daily intake made it difficult for the consumers to properly evaluate the amount of nutrients. The participants avoided interpreting the numerical values or interpreted them in unintended ways. For example, in the case of sugar (5.6 g/10% GDA per serving), the product was believed to contain a lot of sugar, which suggested that it was abnormally sweetened. Moreover, consumers spontaneously inferred that the percentages referred to the percentage content of the nutrient in the product. This led to certain beliefs about the product’s naturalness and taste. The 30 per cent of the guideline daily amount for salt meant that the pizza was perceived as being composed of 30 per cent salt, which led to the conclusion that the pizza was terribly salty and distasteful. The respondents found the information about salt completely incomprehensible in the yogurt context as they did not expect to find this nutrient in this product. It should also be noted that similarly to the HL label, the label suggested high price and high quality.

The GDA label was also tested in a multichrome version using the colours yellow, green, light heather, light pink and celadon (S14) perceived by the respondents as unnatural, artificial and more appropriate to clothes than food. This label was evaluated negatively. Consumers pointed out that the colours were mismatched in terms of aesthetics as well as in terms of colour juxtaposition with the nutrient (why is salt yellow and fat green?), and that the colours suggested an artificial and thus unhealthful product. The respondents claimed that the colours diverted attention from the numerical figures and percentages blurring the information.

The importance of formal context is further illustrated by the analyses of the colours amber (S6), red (S7) and green (S8). When the respondents discussed them one by one, they evaluated each of them positively. In contrast, the evaluation of a set of these colours (S11) proved ambiguous. The consumers considered the amber and red colours to be well associated with health; however, their perception of green was ambivalent. On one hand, green was associated with vegetables, and on the other hand, with something not naturally occurring due to its intensity. Based on the entire set, these precise interpretations of the colour green could translate into ambivalent associations with health.

Discussion

In evaluating a product’s healthfulness, participants tended to refer to their own subjective criteria (naturalness, high quality of the product, the presence of vegetables and fruit, recommendation for children, the lack of artificial additives and preservatives and expiry date). Only three criteria commonly advocated by experts (kilocalories, fat and sugar) were mentioned spontaneously, although we observed a lack of knowledge about the desired nutrient levels in a healthful product and a misinterpretation of the numeric information presented on the labels. Colours discussed in the context of food products evoked associations with other objects (fruits, vegetables, chemicals, clothing) and phenomena (sky, sun), which triggered varied evaluations (positive, negative and ambivalent), varied beliefs related to health and inferences about the product’s attributes (healthfulness, quality and taste). The sign and the content of the spontaneous associations with colours depended on the formal context in which the colour was presented and on the product category that the inference was related to.

The study revealed that certain colours have a greater potential to arouse associations with a healthful product, while others evoke quite the opposite associations. Therefore, colours can strengthen, complement or undermine expert messages.

Study 2

Aims

The quantitative study consisted of a survey and an experiment the objective being to quantitatively verify some of the results obtained in the qualitative study. Five research questions were posed: (Q1) Does the colour symbolism of the TL system allow correct inference about the amount of nutrients and the recommended consumption level regardless of product category, nutrients and their corresponding colours? (Q2) Does a nutrition label overall (including colours) influence and differentiate the assessment of a product’s healthfulness? (Q3) Does the assessment of labelled product healthfulness differ as compared to the assessment of product category healthfulness? (Q4) Does a nutrition label overall (including colours) influence and differentiate the assessment of other product attributes? (Q5) Does the assessment of labelled product attributes differ as compared to the assessment of product category attributes?

To answer question (Q1) about the influence of product category, nutrients and their colours on the correctness of inferences and recommended level of consumption in the case of the TL system, two contradictory hypotheses were posed. The assumption underlying the TL system is that it allows for inferences about the amount of nutrients marked with green, amber or red (low, medium and high amount of a nutrient, respectively). Furthermore, it allows for inferences about the recommended implications for consumer choice, namely, that this product is a healthful option (green), that this product is a good choice most of the time (amber), and that this product should be consumed only occasionally as a treat (red – although, by association with traffic lights, consumers can interpret the red colour as ‘should be avoided’). For the system to perform well, these inferences should be independent from the nutrient and colour juxtaposition and from product category (H1). On the other hand, when taking into account the results of the qualitative study (associations with ingredients based on colours and subjective evaluation of the green and red TL colours’ fit to pizza only), one can expect that inferences are more likely to occur in the case of pizza than yogurt and can be dependent on nutrient and colour juxtaposition (H2).

With regard to the assessment of product healthfulness (Q2), the objective characteristics of the applied stimuli (as further described) should lead to products with the HL label being assessed as healthful and products with the TL labels being assessed as having various degrees of healthfulness depending on the nutrient information and colours in the label (H3). Considering the results of the qualitative study, an alternative hypothesis can be stated. Aaker and Lee (2001) and Kardes et al. (2008) state that when memory-based knowledge is congruent with the stimulus message, the stimulus message is processed more thoroughly. As shown in the qualitative study, the HL label undoubtedly indicated that the product was healthful, but the TL label colours were perceived as appropriate for the pizza category and not the yogurt category. Therefore, one can expect that processing of the TL labels is more likely in the case of pizza, which can lead to differences in the assessment of healthfulness based on these two types of labels only in this product category (H4).

The label effects on the healthfulness assessment (Q3) should occur regardless of whether the evaluated product belongs to a category perceived as healthful or unhealthful. As shown in the qualitative study, depending on the product category, the same colours evoke different associations with ingredients (related to or unrelated to health) and different evaluations of label fit. Therefore, one can expect differences in the assessments of labelled product healthfulness depending on the type of label (H5) and the perceived healthfulness of the product category (H6).

Nutrition labels should only influence the assessment of product healthfulness and should not influence the assessment of other product attributes (Q4 and Q5). Considering the results of the qualitative study on the product attributes inferred from colours, it can be expected that the impact of labels is not restricted to healthfulness but can extend to other product attributes (H7) depending on product category (H8), on the assessment of category attributes as a reference point (H9) and on the attribute assessed (H10).

Method

Participants

The study included 90 mothers with full colour vision, aged 25–45 years, who were buyers of yogurt or frozen pizza in their households. They differed in terms of socio-demographic characteristics.

Stimuli

The study used a multichrome HL label (S12) and a multichrome TL label, presented in Appendix 1. We applied three versions of the TL label (S15–S17) in order to verify H1.

The information presented on the labels corresponded to the characteristic of the products differing in the level of objective healthfulness: the HL label signified the most healthful product, which was more healthful than the product labelled with the TL-A label; less healthful products were marked with the TL-B label and the least healthful with the TL-C label. This assessment is based on the SSAg/1 system. Roughly estimated, the values obtained for labels TL-A, TL-B, TL-C are 4, 5 and 8, respectively, and the product with the HL label − 0.

Procedure

The study was conducted by means of a face-to-face questionnaire interview with participants belonging either to the group of yogurt or frozen pizza buyers; thus, the product category was a between-participants factor. In the first part, the participants answered statements about the general assessment of the healthfulness and taste of a product category (yogurt or frozen pizza) and statements related to expert and consumer criteria for product (yogurt or frozen pizza) healthfulness (attributes) following the instruction: ‘Please assess to what extent the following statements match yogurt (frozen pizza), for example, “it gives energy”’.

The next task was to respond to the statements referring to the inferences from the TL colours. The researcher showed the participant one TL card at the time (S15–S17 in Appendix 1) with the instruction ‘Please look at the green (amber/red) colour next to the information about sugars (S16 – fats/S17 – salt). What do you think that this colour means?’ and asked three times for each colour juxtaposed with the information about the nutrient (given in grams) with the following possible answers: ‘the colour means there is a low/medium/high level of the nutrient in the product (yogurt or pizza)’ and ‘the colour means the product (yogurt or pizza) can be eaten without limits/only occasionally/should be avoided’. Thus, the TL labels (TL-A, TL-B, TL-C) were a between-participants factor and colours (juxtaposed with nutrients) on the TL labels were a within-participant factor.

Finally, the participants evaluated the attributes of yogurt or pizza marked with the HL (S12 in the Appendix 1) and TL labels (S15–S17) with the instruction ‘In your opinion, which of the following statements concerning yogurt (frozen pizza) shown on the label are false and which are true’, for example, ‘the product is tasty’. The type of label (HL vs TL) was a within-participant factor.

For all but one set of questions, responses were measured on a nominal scale (No, Yes). Assessments of the attributes of product categories were given on a 5-point scale and recoded into dichotomous values. In order to enable comparison, the same stimuli were applied in both the yogurt and the pizza group.

Results

Inferences about the level of nutrients and the recommended level of consumption based on the TL labels (H1 and H2)

Different patterns of results were observed for the inferences made about yogurt and pizza (Table 2). In the case of yogurt, the McNemar’s test showed significant differences only with regard to the inferences about nutrient level, marked with colours green (sugar), amber (salt) and red (sugar). For the colours green and amber, the majority of participants correctly inferred that the level of a nutrient was low and medium, respectively. The colour red was more confusing. The difference was found for the comparison of the answers ‘low’ and ‘high’ levels of nutrient, although the majority of the participants incorrectly interpreted the colour as showing a medium level of sugar. The interpretation of the colours in the context of pizza showed more significant differences for both the inferences about nutrient levels and the recommended level of consumption. For the former inferences, the number of valid answers was different in the case of the colour green (salt), amber (fat and salt) and red (salt and sugar). For the latter inferences, the differences were observed for the colour green (sugar, fat and salt), amber (fat and salt) and red (sugar, fat and salt). The analyses show that the inferences depend on product category and on the nutrient and colour juxtaposition. These results provide a basis for rejection of H1 and confirmation of H2.

Table 2.

Inferences about the level of nutrient and the recommended level of consumption as a function of product category and colour–nutrient juxtaposition.

Type of meaning	Percentage of valid answers ‘True’ for green colour		Percentage of valid answers ‘True’ for amber colour		Percentage of valid answers ‘True’ for red colour
	Yogurt	Pizza	Yogurt	Pizza	Yogurt	Pizza
	TL-A (n = 30)
	Green – Sugars (3, 0 g)		Amber – Fat (7, 0 g)		Red – Salt (1, 6 g)
Inferences about the level of the nutrient in the product
Low	75_a	57_a	64_a	50_a,b	53_a	7_a
Medium	73_a,b	43_a	79_a	92_a	62_a	0_a
High	43_b	29_a	31_a	14_b	43_a	93_b
Inferences about the recommended level of consumption
Without limits	67_a	100_a	36_a	15_a	36_a	8_a
Only occasionally	31_a	0¹_b	64_a	79_b	71_a	46_a,b
Should be avoided	36_a	0¹	20_a	39_a,b	62_a	73_b
	TL-B (n = 30)
	Green – Fat (3, 0 g)		Amber – Salt (1, 0 g)		Red – Sugars (20, 0 g)
Inferences about the level of the nutrient in the product
Low	54_a	70_a	50_a,b	43_a,b	27_a	7_a
Medium	73_a	46_a	73_a	86_a	80_a,b	0_a
High	47_a	14_a	27_b	8_b	43_b	93_b
Inferences about the recommended level of consumption
Without limits	57_a	86_a	79_a	36_a,b	60_a	8_a
Only occasionally	43_a	0¹_b	60_a	64_a	46_a	71_b
Should be avoided	15_a	0¹_b	60_a	21_b	47_a	92_b
	TL-C (n = 30)
	Green – Salt (0, 2 g)		Amber – Sugars (7, 0 g)		Red – Fat (20, 0 g)
Inferences about the level of the nutrient in the product
Low	73_a	93_a	43_a	33_a	53_a	0¹_b
Medium	60_a	40_b	73_a	77_a	53_a	0¹_b
High	43_a	0_b	36_a	15_a	71_a	93_b
Inferences about the recommended level of consumption
Without limits	50_a	100_a	64_a	29_a	31_a	0_a
Only occasionally	53_a	14_b	82_a	64_a	71_a	46_a,b
Should be avoided	33_a	0_b	36_a	50_a	62_a	73_b

TL: traffic light.

a, b – percentages within a given product category (yogurt or pizza) presented in the same subcolumn that do not share subscripts differ statistically at the level p < .05 in the non-parametric between dependent samples McNemar’s comparison test for pairs: low–medium, low–high, medium–high and for pairs: without limits–only occasionally, without limits–should be avoided, only occasionally–should be avoided.

Neither variable is dichotomous with the same values.

Assessment of product healthfulness based on labels (H3 and H4)

According to Table 3, no significant differences were found in the healthfulness assessments performed on the basis of the HL and the TL labels in the yogurt group. Differences were however observed for pizza, correctly assessed as less healthful when marked with two TL labels. These results legitimize the rejection of H3 and confirmation of H4.

Table 3.

Assessment of product attributes as a function of product category and label type: percentage of answers showing that the category or labelled product has the given attribute.

Type of product attribute	Yogurt					Frozen pizza
	Type of label
	Category	Logo	TL-A	TL-B	TL-C	Category	Logo	TL-A	TL-B	TL-C
	n = 45	n = 45	n = 15	n = 15	n = 15	n = 45	n = 45	n = 15	n = 15	n = 15
Healthful	82_a	82_a	67_a	60_a	47_a	31_a	86_b	13_a	27_a	47_a,b
Consumer criteria of healthfulness
Natural	87_a	84_a	80_a	73_a	80_a	73_a	88_a	40_a	60_a	53_a
A high quality	82_a	82_a	80_a	73_a	73_a	73_a	93_b	53_a,b	47_a	73_a,b
Recommended for children	71_a	80_a	87_a	87_a	47_a	22_a	57_b	27_a,b	13_a,b	40_a,b
Content of vegetables	–	52_a	53_a	53_a	27_a	–	30_a	0_a	20_a	33_a
Content of fruit	–	61_a	47_a	53_a	60_a	–	6_a	0_a	0_a	0_a
Artificial food colouring added	–	24_a	40_a	27_a	40_a	–	12_a	20_a	7_a	13_a
Content of preservatives	–	31_a	40_a	40_a	7_a	–	7_a	7_a	0_a	13_a
Expert criteria of healthfulness
Gives energy (c)/a lot of energy (l)	76_a	84	80_a	73_a	67_a	89_a	95_a	87_a	93_a	93_a
Content of a lot of fat (c)/fatty (l)	33_a	36_a	47_a	40_a	67_a	69_a	32_b	60_a	60_a	67_a
Content of little sugar (c) – reversed)/sweet (l)	8,9_a	58_b	53_b	67_b	80_b	18_a	21_a	33_a	47_a	40_a
Content of a lot of salt (c)/salty (l)	22_a	25_a	33_a	40_a	40_a	60_a,c	34_b,c	67_a	40_a,b	33_a,b
Others
Tasty	84_a	80_a	80_a	93_a	93_a	98_a	95_a	73_a	80_a	93_a

TL: traffic light.

(c), (l) – content of the attribute presented in the case of inference-making about (c) category and (l) label.

a, b, c – percentages within a given product category (yogurt or pizza) that are presented in the same row and that do not share subscripts differ statistically at p < .05 in the non-parametric between dependent samples McNemar’s test. Different subscripts reflect significant differences between percentages for category (without labels) and for each label type and between percentages for each label type (with exception of comparisons between TL labels).

In order to verify H5 and H6, category healthfulness assessment (that differs significantly for yogurt and pizza, χ²(1, N = 90) = 23.94, p = .0001) was compared with the healthfulness assessment of labelled products. The evaluation of yogurt with the HL label was the same as the assessment of the category: the vast majority of respondents in both cases considered yogurt as healthful. The HL label placed on the pizza increased three times the number of positive healthfulness responses as compared to the category assessment. There were insignificant differences between the assessments based on the TL labels (both in the yogurt and pizza groups). Thus, the impact of the HL and TL labels depends on the type of label and the product category, which confirms H5 and H6.

Assessment of attributes of labelled products (H7–H10)

The distributions of the assessments of product attributes marked with different labels were compared (Table 3). Comparison of the HL labelling and the TL labels resulted in more participants assessing pizza as of high quality (HL vs TL-B), less fatty (HL vs all TL labels) and less salty (HL vs TL-A). The differences in the yogurt group were insignificant.

With regard to the category assessment, a labelled yogurt was assessed as sweeter (with the HL and TL labels). Marking pizza with the HL label resulted in less subjects stating that it was fatty, yet more people agreed that the pizza was of high quality and was suitable for children. The overall results legitimize the confirmation of H7–H10.

Discussion

The product category and the nutrient the colour is juxtaposed with, influence the inferences based on the TL labels. This can result from the spontaneous colour associations that are triggered in the context of food, as described in the qualitative study, as well as from the beliefs about the appropriate colour scheme to the given product category and its typical ingredients.

The impact of the HL and TL labels on the assessment of the healthfulness of products was observed only in the case of the pizza category. This may indicate that the TL label colours, perceived as appropriate for this category, were processed more thoroughly (Aaker and Lee, 2001; Kardes et al., 2008).

The impact of labels on product assessment extends to other product attributes, although it depends on the label, product category and assessment of category attributes as reference points as well as on the attribute in focus. The HL label, which is perceived as suggesting a healthful and high quality product, influences the assessment of attributes related to consumer criteria of product healthfulness, spontaneously mentioned in the qualitative study (sugar content in yogurt, quality recommendation for children and fat content in pizza). These results show that consumers’ beliefs and their coherence with communication are important factors in consumers’ inference-making (Kardes et al., 2008).

Conclusion

The set of results from the two studies improve the understanding of the meaning of colours applied in nutrition labels. Consumers were found to hold beliefs about colours and their appropriateness to product categories and to have their own criteria of food healthfulness. The HL label showing blue and yellow colours evoked positive emotions and associations with health and naturalness, the latter one corresponding to the consumers’ criterion of food product healthfulness. The TL label colours green, amber and red were positively received as associated with healthful fruit and vegetables, but their set was evaluated as ambivalent and appropriate for an unhealthful product category and not a healthful one. The impact of the tested labels on healthfulness assessments differed consistently proving better performance of labels and their colours in the assessment of unhealthful product category in the context of which the tested colours were perceived as appropriate for this category.

In future studies, it is important to explore the process of product attribute inference-making based on labels in the context of entire product packages including other colourful elements (e.g. background, product picture) and in the broader context of real-life buying situations.

The conclusion from the studies must be limited to countries in which health-related campaigns and nutrition labelling are barely present; nevertheless, the findings indicate how important it is to select colours that are unequivocally and positively related to health in order to communicate that a product is healthful. Further investigation is necessary to determine the colours that would help to warn consumers.

Footnotes

Appendix

Acknowledgements

The authors acknowledge that the 7th EU Framework Programme Small Collaborative Project FLABEL (contract no. 211905) has been the major source of information for this paper. The content of the paper reflects only the views of the authors. The European Commission is not liable for any use that may be made of the information contained in this paper. G.W., M.S.K. and K.G.G. contributed to the overall design of the study. M.S.K. completed (designed, conducted and analysed) the qualitative study. G.W. and M.S.K. conducted the statistical analysis and wrote the manuscript. All authors reviewed, edited and approved the final manuscript.

Funding

The project has been funded by the 7th EU Framework Programme Small Collaborative Project FLABEL (contract no. 211905).

References

Aaker

Lee

(2001) ‘I’ seek pleasures and ‘We’ avoid pains: The role of self-regulatory goals in information processing and persuasion. Journal of Consumer Research 28: 33–49.

Aschemann-Witzel

Grunert

Van Trijp

HCM

. (2013) Effects of nutrition label format and product assortment on the healthfulness of food choice. Appetite 71(0): 63–74.

Bellizzi

Hite

(1992) Environmental color, consumer feelings, and purchase likelihood. Psychology & Marketing 9(5): 347–364.

Bialkova

Grunert

Juhl

. (2014) Attention mediates the effect of nutrition label information on consumers’ choice. Evidence from a choice experiment involving eye-tracking. Appetite 76: 66–75.

Cromby

(2012) Beyond belief. Journal of Health Psychology 17(7): 943–957.

Estacio

(2013) Health literacy and community empowerment: It is more than just reading, writing and counting. Journal of Health Psychology 18(8): 1056–1068.

Estacio

Comings

(2013) Health literacy: Exploring future directions and potential contributions from health psychology. Journal of Health Psychology 18(8): 997–1003.

Garber

Hyatt

(2003) Color as a tool for visual persuasion. In: Scott

Batra

(eds) Persuasive Imagery: A Consumer Response Perspective. Mahwah, NJ: Lawrence Erlbaum Associates, pp. 313–336.

Genschow

Reutner

Wänke

(2012) The color red reduces snack food and soft drink intake. Appetite 58(2): 699–702.

10.

Grunert

Wills

(2007) A review of European research on consumer response to nutrition information on food labels. Journal of Public Health 15(5): 491–503.

11.

Harman

(2001) Explaining objective color in terms of subjective reactions. In: Byrne

Hilbert

(eds) Readings on Color: The Philosophy of Color. Cambridge, MA: Massachusetts Institute of Technology, pp. 247–261.

12.

Hilbert

(1987) Color and Color Perception: A Study in Anthropocentric Realism. Palo Alto, CA: Center for the Study of Language and Information.

13.

Hodgkins

Barnett

Wąsowicz-Kiryło

. (2012) Understanding how consumers categorise nutritional labels: A consumer derived typology for front-of-pack nutrition labelling. Appetite 59(3): 806–817.

14.

Kardes

Posavac

Cornley

(2008) Consumer inference. In: Haugvedt

Herr

Kardes

(eds) Handbook of Consumer Psychology. New York: Psychology Press, pp. 165–191.

15.

Koenigstorfer

Wąsowicz-Kiryło

Styśko-Kunkowska

. (2014) Behavioural effects of directive cues on front-of-package nutrition information: The combination matters! Public Health Nutrition 17(9): 2115–2121.

16.

Labrecque

Milne

(2013) To be or not to be different: Exploration of norms and benefits of color differentiation in the marketplace. Marketing Letters 24(2): 165–176.

17.

Labrecque

Patrick

Milne

(2013) The marketers’ prismatic palette: A review of color research and future directions. Psychology & Marketing 30(2): 187–202.

18.

Lähteenmäki

Lampila

Grunert

. (2010) Impact of health-related claims on the perception of other product attributes. Food Policy 35(3): 230–239.

19.

Lyons

Chamberlain

(2012) Challenges for health psychology: Theorizing belief and beyond. Journal of Health Psychology 17(7): 965–968.

20.

Mehta

Zhu

(2009) Blue or red? Exploring the effect of color on cognitive task performances. Science 323(5918): 1226–1229.

21.

Ndom

RJE

Elegbeleye

Ademoroti

(2011) The effect of colour on the perception of taste, quality and preference of fruit flavoured drinks. IFE PsychologIA 19(2): 167–189.

22.

Nutbeam

(2000) Health literacy as a public health goal: A challenge for contemporary health education and communication strategies into the 21st century. Health Promotion International 15(3): 259–267.

23.

Santiago-Delefosse

(2012) Deconstructing the notion of ‘belief’ in psychology: Commentary on ‘beyond belief’. Journal of Health Psychology 17(7): 974–976.

24.

Storcksdieck genannt Bonsmann

Celemin

Larranaga

. (2010) Penetration of nutrition information on food labels across the EU-27 plus Turkey. European Journal of Clinical Nutrition 64(12): 1379–1385.

25.

Van Herpen

Seiss

Van Trijp

HCM

(2012) The role of familiarity in front-of-pack label evaluation and use: A comparison between the United Kingdom and The Netherlands. Food Quality and Preference 26(1): 22–34.

26.

Wąsowicz-Kiryło

Styśko-Kunkowska

(2011) Attributes of nutritional information labelling that determine attractiveness of labels and correctness of inferences made about food healthfulness. Procedia – Social and Behavioral Sciences 30: 722–728.

27.

World Health Organization (WHO) (2007) World Health Report 2007: A Safer World. Geneva: WHO.