Changing the vertical location of healthy products on supermarket shelves:
A VR supermarket study on healthiness of food choices.
M.G. Groot Beumer
(S2561891)
January 2019
MSc Marketing Management Faculty of Economics and Business University of Groningen
Table of content
Abstract P. 3
Introduction P. 5
Consequences of Overweight and Obesity P. 5
Causes of Overweight and Obesity P. 6
Current Research Objectives P. 7
Nudging Interventions in Stores P. 8
Shelf Position P. 9
Vertical Location of Healthy Products on Supermarket Shelves P. 10
Implementation Intentions P. 12
Personal Interest in General Health P. 13
Abstract
The percentage of overweight and obese people worldwide has been increasing over the past decades: there seems to be a global obesity epidemic, with all its negative consequences (e.g., Finer, 2015; Ng et al., 2014; WHO, 2003; WHO, 2014). One of the causes of obesity is overeating unhealthy food (WHO, 2018). Eating unhealthy food starts with buying unhealthy food. Therefore, it is important steer consumers into buying healthier products. This research focusses on the effect of the vertical location of healthy products (i.e., product is either places at eye level or at knee level) on the healthiness of the food choice made by the customer. It is expected that when the vertical location of the healthy product is at eye level, the consumer more likely is to choose the healthy product. Besides that, the potential moderator effects of
implementation intentions (i.e., if-then statements; Gollwitzer & Sheeran, 2009), and of
consumers’ interest in the healthiness of the food they consumer (measured with the GHI scale; Roininen, Lähteenmäki & Tuorila, 1999). The research makes use of Virtual Reality (VR) techniques to be able to test the effect of the vertical location of a product as close to nature as possible without going to an actual supermarket.
Because the effect of vertical location was so extreme, empirical tests could not be carried out in order to test the hypotheses. The Chi-Square Test that could be carried out found a significant association between whether a healthy or an unhealthy product is chosen (i.e., the healthiness of the product choice) and whether the healthy products are displayed at eye level or at knee level. The Chi-Square Test did not find a significant association between the healthiness of the product choice and whether the implementation intention was task related or task unrelated.
Changing the vertical location of healthy products on supermarket shelves: A VR supermarket study on healthiness of food choices.
The percentage of overweight Dutch citizens aged 20 years and over has increased from 33.4% (of which 5.3% was obese) in 1981 to 49.9% (of which 14.2% was obese) in 2017 (CBS, 2018). For adults, being overweight is defined as having a Body Mass Index (BMI, calculated in kg/m2) greater than or equal to 25. When one’s BMI is greater than or equal to 30, one is
considered to be obese (WHO, 2018). This drastic increase in the number of overweight citizens does not only occur in the Netherlands; there seems to be a global obesity epidemic (Ng et al., 2014; WHO, 2003; WHO, 2014). The goal of the present research is to gain insights in possible effective interventions that might be beneficial to altering one of the behaviours contributing to the obesity problem: unhealthy grocery shopping behaviour.
The intervention that will be studied in this research revolves around changes in the product layout on the shelves in supermarkets in order to make consumers more likely to choose the healthier food option. More specifically, I examine the effect of the vertical location of a healthy product (i.e., whether a healthy product is displayed on a shelf at eye level or at knee level) on the healthiness of the food choice (i.e., whether a consumer makes a healthier or unhealthier food choice). Furthermore, the potential moderating effects of implementation intention and of the consumers’ interest in the healthiness of the food they consume will be examined. Before discussing this in more depth, the background of the obesity problem will be reviewed.
Consequences of Overweight and Obesity
very likely to negatively affect the quality of life of the person concerned. Due to their condition, obese persons suffer from increased risks of getting diseases such as heart and vascular disease, type 2 diabetes, and several forms of cancer, among others, than their normal-weight
counterparts (Finer, 2015; Visscher & Seidell, 2001; WHO, 2018). In congruence to that, being overweight may result in a lower quality of life and even a lower life expectancy (Olshansky, 2005; Visscher & Seidell, 2001). Furthermore, obese persons are more likely to be discriminated in, for example, work settings, and they tend to complete fewer years of education (Finer, 2015). In addition to all these psychosocial and health related issues, being overweight has a negative impact on economic welfare, for example because of the health care costs associated with
overweight and obesity, and treatments thereof (Finer, 2015; Hammond & Levine, 2010). For all these reasons, it is important to gain knowledge on how to reduce the number of overweight people. Consequently, it is important to know which factors underlie overweight and obesity. Causes of Overweight and Obesity
The main cause of overweight and obesity is the disbalance between the amount of calories consumed and the amount of calories used (WHO, 2018). The consumption part of this disbalance consists of eating too much unhealthy food (i.e., food that includes fats, is low in fibre and vitamins, and/or high in salt; Medical Dictionary, n.d.; WHO, 2018). Eating unhealthy food starts with buying that unhealthy food. Therefore, grocery shopping behaviour needs to change.
Current Research Objectives
In the present study, the influence of the vertical location of a healthy product (i.e., healthy product is displayed on an eye level or on a knee level shelf) on the healthiness of customer’s product choice will be examined with the use of a Virtual Reality (VR) supermarket study. Advantages of this VR-approach is that it is more true to reality than an experiment on a computer (i.e., greater external validity), while at the same time it is more controllable and standardized than a field study in an actual supermarket (i.e., greater internal validity).
As mentioned, the purpose of the current research is to examine how food choices of consumers in supermarkets can be altered from an unhealthy to a healthier food choice in the same product category. The focus of this research is on how the vertical location of healthy products on supermarket shelves influences the healthiness of consumers’ food choice.
Furthermore, the potential moderator effects of implementation intentions and personal interest in general health will be examined. The literature will be discussed according to this conceptual model (see Figure 1 on the next page).
The current research contributes to the theories and interventions in the field of in-store decision making, influenced by environmental nudges. With this research, we gain relevant insights on how customers choose products, and how they can be steered towards, maybe subconsciously, making healthier choices. From a managerial point of view, it is relatively easy to use the gained insights, especially when all products involved are from the same brand. By simply placing the healthier options within a product category on the eye level shelves,
Figure 1 Conceptual model of the effect of the vertical location of the healthy product on
the healthiness of the food choice, moderated by implementation intentions and by general interest in healthy food.
Nudging Interventions in Stores
buying unhealthy food; Thaler & Sunstein, 2008). Nudging has been extensively studied in in-store settings, and has proven to have an effect on how customers behave in a in-store and on whether and what they buy (Kotler, 1974; Mohan, Sivakumaran, & Sharma, 2013; North, Hargreaves, & McKendrick, 1997; North, Hargreaves, & McKendrick, 1999). Previous research showed for example that customers are more likely to buy German (rather than French) wine when typical German music is played in the store and vice versa (North, Hargreaves, & McKendrick, 1997; North, Hargreaves, & McKendrick, 1999). Additionally, other research suggests that store environment aspects, such as music, the layout of the store and the presence and effectiveness of salespeople, may effect in-store customer behaviour such as unplanned buying (Mohan, Sivakumaran, & Sharma, 2013). The bulk of research on nudging effects in store settings does however not focus on steering people towards the more healthy food options in supermarkets (e.g., North, Hargreaves, & McKendrick, 1999). The current research aims to this knowledge gap, as it focusses on nudging effects on the healthiness of the product choice. Shelf Position
Besides the aforementioned nudging effects, there is another, less examined, way to nudge consumers: altering the location of the product on the supermarket shelf. Indeed, Drèze, Hoch and Purk (1994) suggest that “changes in space can affect consumer attention; altering the visibility of a product through changes in location (...) should influence the probability of
purchase” (p. 303). On top of that, research demonstrates that consumers generally have positive attitude towards nudges that steer towards making healthier choices (Van Gestel, Kroese, & De Ridder, 2018). Furthermore, a study on horizontal positioning suggests that the horizontal position of the healthy food option relative to the position of the unhealthy food option
left side of the unhealthy product, the preference for the healthy option is higher than when the healthy product would be on the right side of the unhealthy product (Romero & Biswas, 2016). It is proposed that this effect is due to the fact that in Western societies people tend to read from left to right, which makes the products on the left easier to process (Romero & Biswas, 2016; Chae & Hoegg, 2013). In other words, it costs less effort to choose the healthy product when it is placed on the left hand side of the unhealthy product. Based on this study, it seems that placing the healthier food to the left of the less healthy products is an effective way to nudge consumers towards the healthier food options. However, in the aforementioned study, the choices were between different food categories (e.g., broccoli salad versus grilled cheese sandwich; Romero & Biswas, 2016). For canteens, this might be a valuable insight, but for supermarkets, it would not be feasible to implement this insight in the whole store, due to fixed locations of for example products that need to be refrigerated. Moreover, in supermarkets, products are placed on the shelves in product category groups (e.g., all types of gingerbread cake (ontbijtkoek in Dutch) are placed on the shelves next to and/or above each other. Because it is easier to achieve a small behaviour change (e.g., change the type of gingerbread cake) rather than a larger behaviour change (e.g., broccoli salad instead of grilled cheese sandwich; Romero & Biswas, 2016), it might be more effective to nudge consumers into buying the healthier option of the same product category (e.g., the type of gingerbread cake with the lowest amount of kcal).
Vertical Location of Healthy Products on Supermarket Shelves
products placed at eye level are more likely to be sold than products that are on a lower shelf (Drèze et al., 1994). This might be due to the fact that middle and top shelves generally receive more attention than products on the bottom shelves (Chandon, Hutchinson, Bradlow, & Young, 2009), as the natural resting position of the eye is on the upper shelves (Drèze et al., 1994). Nonetheless, there is a knowledge gap in this line of research as the effect of vertical location of healthy versus unhealthy products has yet to be researched. Firstly, the studies of Chandon and colleagues (2009) and of Drèze and colleagues (1994), non-food products were used (i.e., soap and pain relievers, and oral care and laundry care products, respectively). Secondly, the eye-movement tracking study by Chandon and colleagues (2009) was executed with the participants seated in front of on a screen. By doing research on vertical location of products in supermarket shelves, it is more realistic to do the experiment while standing instead of sitting down.
Therefore, in the present research I use Virtual Reality (VR). Participants are asked to stand up during the VR part and have to move their head in order to look down (as opposed to only move their eyes as in Chandon et al., 2009). This enables the experiment to be as true to nature as possible without having to execute the study in an actual supermarket.
Considering all of the above, the assumption that consumers are more likely to choose the product that is at eye level (i.e., these products easier to see and to process, and generally are paid more attention to), whether or not it is the healthier option, will be tested in this VR study in the following hypothesis:
Implementation Intentions
As aforementioned, the effect of the vertical location of healthy products on the supermarket shelves (i.e., eye or knee level) on the healthiness of the food choice might be moderated by whether or not a task related implementation intention is introduced (Figure 1). As extensive research on the Theory of Planned Behaviour shows, the intention to change one’s behaviour is the best predictor of actually changing that behaviour (Ajzen, 1991; Sheppard, Hartwick, & Warshaw, 1988). However, there is a discrepancy between the intention and the actual behaviour: the intention behaviour gap. This phenomenon implies that the mere intention to change one’s behaviour (in this case the intention to buy healthier food) does not necessarily lead to behavioural change (here: actually buying healthier food). This might be due to, for example, a lack of motivation to perform the intended behaviour, or due to a lack of resources (here: the healthier food option might be out of stock).
One form of reducing the gap between intention and actual behaviour is to introduce an implementation intention (Gollwitzer & Sheeran, 2009). Implementation intentions are so-called if-then statements that specify what a person ought to do in a certain situation: “If I am grocery shopping, then I will buy the healthier food option.”. The more precise and specific the
effect of vertical location on the healthiness of the choice made (Figure 1) has not been studied yet. Taken all the above discussed into account, the following hypothesis is proposed:
H2: The effect of vertical product location on healthiness of food choice will weaken when a task related implementation intention is introduced.
Personal Interest in General Health
Besides the introduction of implementation intentions, the general interest a person has in his or her own health could also influence the effect the vertical location of a healthy product has on the healthiness of the food choice. Previous research provides evidence that attitude
influences the intention to perform certain behaviour (Honkanen, Verplanken, & Olsen, 2006). Therefore, it could be the case that people with a positive attitude towards healthy food (i.e., with a high interest in their health) are in such a way concerned about their health, that they will pay more attention to healthier alternatives than people with a low(er) interest in their health.
Roininen, Lähteenmäki and Tuorila (1999) developed a scale that measures someone’s attitude towards General Health Interest (GHI). In accordance with the aforementioned, people with a high GHI score have been found to have an increased attention for health labels (e.g., the traffic light indication on packages), whereas people with a low GHI score do not (Fenko, Nicolaas, & Galetzka, 2018). Therefore, I suspect that when someone scores high on the GHI scale, the effect of the location of the healthy product has a less strong (or maybe even no) effect on the healthiness of the food choice, as these people will search for the healthy product. This results in the following hypothesis:
Methods Participants
92 persons participated and were randomly assigned to one of the four conditions. Due to an error, the product choice of 11 participants was not saved. Therefore, these 11 participants are removed from the dataset and only the responses of the remaining 81 participants are used in the analyses (M = 26.58 years old, SD = 11.10 years; 51.85% female). 54 participants (66.67%) are Dutch, 8 (9.88%) are German, 7 (8.64%) are Italian, and 12 participants (14.81%) have another nationality. The educational level of the participants is distributed as follows: 76.54% university education, 13.58% higher vocational education, 7.41% secondary vocational education, and 2.46% secondary education. The Body Mass Index of the participants ranges from 16.98 to 31.05 (M = 22.44, SD = 2.96). According to the World Health Organization, a healthy BMI lies
between 18.50 and 24.99 (WHO, 2019). Having a BMI between 25.00 and 29.99 would mean one is overweight, while a person with a BMI above 30.00 is considered obese (WHO, 2019. This means that in the current sample, 4.94% (4 participants) is underweight, 76.54% (62 participants) has a healthy weight for their height, 17.28% (14 participants) is overweight, and 1.23% (1 participant) is obese. Lastly, as reward for participating, participants can enter a lottery in which one in every 10 participants wins a prize based on the choice they made during the VR part of the study (i.e., the type of Peijnenburg gingerbread cake the participant chose in the VR supermarket).
Research Design
intention, 19 to the condition healthy product at knee level*task unrelated implementation intention, 21 to the condition healthy product at eye level*task related implementation intention, and 21 participants are assigned to the condition healthy product at knee level*task related implementation intention.
The dependent variable is the healthiness of the food choice participants make. Participants choose one of six Peijnenburg gingerbread cakes, of which three are healthier options (Figure 2) and three are unhealthier options (Figure 3). The independent variable is the vertical location of the healthy products on the supermarket shelves. The three healthy products are placed either at knee level or at eye level on the shelves. When the three healthy products are placed at knee level, the three unhealthy products are placed at eye level and vice versa (see Figure 4 and Figure 5, respectively). One of the moderators is implementation intention. Participants get the instruction to read, familiarize themselves, and write down an
implementation intention that is either task related (“If I am grocery shopping, then I will buy the healthier food option.”) or task unrelated (“If I am finished with working/studying on …day (fill
in a day of the week), then I will go for a walk”). The other moderator is the level of interest one
has in the healthiness of the food they consume. This level of interest is based on the average score of the participant on the GHI scale by Roininen and colleagues (1999) and is not manipulated by the researcher (Appendix A).
Figure 2 Healthy products: Peijnenburg Zero% Sugar with plastic storage package,
Figure 3 Unhealthy products: Peijnenburg Natural with plastic storage package,
Peijnenburg Natural, and Peijnenburg Volkoren (whole grain).
Materials
The materials used in this study are VR goggles (Bobo Z4), smartphones (Nexus 5X), VRdeck (i.e., a program with which one can create a VR experiment), 360 degree pictures taken at the Peijnenburg gingerbread shelves at supermarket Jumbo in Haren (the Netherlands), a brief text about obesity, an implementation intention, instructions for the VR part of the study, and a pen-and-paper survey. This survey consists of the 8-item GHI-scale, some manipulation checks, and demographics. Please see Appendix B, Appendix C and Appendix D for all documents used for the execution of this research, and Appendix E for the screens of the VR part.
some products were at eye level and others at knee level, as the shelves in between those were filled with similar products. Another reason to choose only Peijenburg products is that this cancelled out that brand differences might be a third variable.
Procedure
Participants are randomly assigned to one of the four conditions (healthy product at eye or knee level*task related or task unrelated implementation intention). Before starting,
participants reive and sign an informed consent. Thereafter, they read a brief text of the WHO about obesity (Appendix B). Next, the participants in the task related implementation intention condition get the following instruction:
“We want you to plan to eat healthy during the next two weeks. Please read and familiarize yourself with the following statement:
If I am grocery shopping, then I will buy the healthier food option.
Please write this statement on the front page of the survey booklet before reading the instructions for the VR part.”
while participants in the task unrelated implementation intention condition receive this instruction:
“We want you to plan to exercise frequently during the next two weeks. Please read and familiarize yourself with the following statement:
If I am finished with working/studying on …day (fill in a day of the week), then I will go for a walk.
After writing down the statement, participants read the VR instruction (this instruction is for all participants the same, see Appendix C). When they have finished reading the instructions for the VR part, participants are asked whether they have any questions regarding this part. Once everything is clear to the participant, he/she is asked to stand up and to put on the VR goggles. During the whole VR part of the study the participant must remain standing.
In the VR part, the participant first sees three start screens which show the instructions once more and enables the participant to practise a little with selecting choices in the VR
program (Figures E1, E2, and E3, Appendix E). When they are in the supermarket environment, participants have to choose one of the large sized Peijnenburg gingerbread cakes (Figures E4, E5, E6, and E7, Appendix E). In the VR supermarket, half of the participants will see the healthy product at knee level (Figure 4), while the other half will see the healthy product at eye level (Figure 5). Participants are told that there are multiple large sized Peijnenburg gingerbread cakes to choose from, but they are not told how many options there are. The reason for this is the assumption that if participants know there are six options to choose from, it might influence how thoroughly they search in the shelves, which in turn might interfere with the potential effects of the implementation intention and the scores on the GHI scale.
After making a product choice and confirming this choice (Figures E8 and E9, Appendix E), participants are directed to the final screen in which participants are instructed to take of the VR goggles (Figure E10, Appendix E). Then, they fill out the pen-and-paper survey, in which they can also indicate whether they want to join the lottery (Appendix D). Lastly, the participants are debriefed if they want to know more about the research, the research question and the
Figure 4 Healthy products at knee level. N.B. In this image, the ‘point of view’ is moved
a down little in order for the three healthy as well as the three unhealthy products to be visible in the same image. Figure E4 (Appendix E) shows the default position participants see when they enter the VR supermarket.
Figure 5 Healthy products at eye level. N.B. In this image, the ‘point of view’ is moved a
the same image. Figure E5 (Appendix E) shows the default position participants see when they enter the VR supermarket.
Results
Preliminary Analyses
Participants in the conditions with the task related implementation intention seem to score higher on the manipulation check question “To what extent did you keep the statement you wrote on the front page of this booklet in mind during the VR part of the study?” than
participants in the conditions with the task unrelated implementation intention (M = 5.42, SD = 1.58, compared to M = 2.46, SD = 1.67, respectively, both on a Likert scale from 1 = “Not at all” to 7 = “Very much”).
Table 1 Overview of the frequencies of healthy and unhealthy product choices for each of the four conditions for all 81 participants.
Vertical location of healthy product
Implementation intention
Chose healthy product? Total
Yes No
Eye level Yes 21 0 21
No 17 3 20
Knee level Yes 0 21 21
No 0 19 19
Total 38 43 81
Figure 6 Bar graph of the interaction between vertical location of the healthy product and
the healthiness of the product choice.
Testing Hypotheses
consisting of the data of the conditions in which the healthy product is at eye level and another subset consisting of the data of the condition in which the healthy product is at knee level, one could carry out a Logistic Regression for implementation intention on the former subset (the latter subset still does not meet the requirements). This Logistic Regression did not show a significant effect of implementation intention on healthiness of the product choice (p = .998).
The original dataset does meet the Chi-Square Test assumption of expected frequency (Kent State University, n.d.). Therefore, it is allowed to perform Chi-Square Tests. However, Chi-Square only gives correlational relations. Consequently, none of the three hypotheses can be confirmed by this dataset, as they all hypothesized causal relations. Nonetheless, Chi-Square Tests will be performed, as they may give more insight in the collected data.
Firstly, a Chi-Square Test of the healthiness of the food choice and the independent variable (vertical location of the healthy product) was carried out. A significant relation between these two variables was found (Χ2(1) = 69.84, p < .001). Secondly, a Chi-Square Test of the
healthiness of the food choice and task related/unrelated implementation intention was carried out. The relation between these two variables was not significant (Χ2(1) = .334, p = .564). Lastly,
the correlation of the dependent variable and general health interest (GHI) could not be analysed due to the aforementioned issues.
Explorative Analysis: Unhealthy Products at Eye Level
Because so many participants indicated they had not seen the products that were placed at knee level, I decided to examine whether the expected effect of implementation intention can be found when looking at a subset of the data. But first, the perceived healthiness of all types of
Peijnenburg gingerbread cakes needs to be calculated.
For each of type of Peijnenburg gingerbread cake, participants had to indicate to what extent they thought that type was healthy (1 = “Very unhealthy”; 7 = “Very healthy”). The perceived healthiness of Peijnenburg Natural was lowest (M = 3.10, SD = 1.14), followed by Pijnenburg whole grain (M = 4.11, SD = 1.19), Peijnenburg LowerCal (M = 4.69, SD = 1.30), and Peijnenburg Zero% Sugar (M = 4.71, SD = 1.44).
Based on this one could argue that some participants might think Peijnenburg whole grain is the healthiest option in the VR supermarket (especially if they fail to see Peijnenburg Zero% Sugar and LowerCal). Therefore, the subset used in this analysis consists of the data of the participants in the unhealthy-products-on-eye-level condition that chose one of the unhealthy products. In this analysis, Peijnenburg whole grain is labelled as the healthier choice, whereas Peijnenburg Natural is labelled as the unhealthier option (see previous paragraph). The effect of implementation intention on product choice in this subset was not significant in this Logistic Regression (p = .80).
Discussion
than expected. In fact, 78 of 81 participants chose a product that was at eye level for them (Figure 6). This large effect might relate to the fact that many people indicated to not have seen the products that were displayed at knee level. Because the effect of the vertical position of products is so large, it is impossible to empirically examine the effect of task related and unrelated implementation intention and the effect of the GHI-score on the healthiness of the product choice. Nonetheless, in the following sections I will discuss noteworthy results.
Vertical Product Location
Even though, when looking at Figure 6, one might think hypothesis 1 (H1: Customers are
more likely to choose a healthy product when the healthy products are displayed at eye level rather than when they are displayed at knee level.) is confirmed, it is not permitted to confirm
this hypothesis with the current dataset. The effect of the vertical location of the healthy product on product choice was so strong, it caused violation of one of the assumptions of Logistic Regression. Consequential, Chi-Square Tests were carried out to analyse the data. Therefore, conclusions about causality are unfortunately not possible with the collected data. The Chi-Square Test did show a significant correlation between the vertical location of the healthy product and the healthiness of product choice (Χ2(1) = 69.84, p < .001). To be able to test
whether a causal relation between vertical location of a healthy product and the healthiness of the product choice exists, further research is necessary.
Implementation Intention
choice will weaken when a task related implementation intention is introduced.) cannot be tested.
Besides not being able to do a causal analysis for the effect of implementation intention, the correlation between implementation intention and product choice was found to be not significant (Χ2(1) = .334, p = .564).
In the conditions with the unhealthy products at eye level, participants might be inclined to think that the Peijnenburg whole grain gingerbread cake is the most healthy option in the VR supermarket when they does not see any other large sized Peijnenburg gingerbread cake products besides Peijnenburg Natural (with and without storage package). Analyses on a subset,
consisting of only the data of the participants that were assigned to the condition with the unhealthy products at eye level, however, did unfortunately not result in a significant effect of implementation intention on product choice.
There are three possible causes for not finding an effect in either the original dataset or de subset. Firstly, the absence of significant effects might be due to the large influence of the
vertical location of the product.
Secondly, the implementation intention that was used in this research not have been effective. This, in turn, could be because the participants did not generated the implementation intention themselves. Previous research has found that there is no difference in effectiveness for experimenter-provided and self-set implementation intentions (Armitage, 2009). However, in this research the implementation intention was about reducing alcohol consumption. Although the study by Armitage (2009) and the present are both health related, there might be different factors involved in both studies. Therefore, in future studies on the effectiveness of
implementation intentions should be examined in the same study to find out whether one is more effective than the other is.
Thirdly, in a study about the promotion of eating healthy, no effects of implementation intention were found (Peach & Martin, 2017). This might be the case in the present research as well: a possible reason for not finding an effect for implementation intention is that there simply is no effect to be found.
Noteworthy is the fact that only three participants choose a product that was not at eye level (Table 1 and Figure 6). These participants were all three assigned to the same condition in which the healthy products were at eye level and they had to write down the task unrelated implementation intention, and all three of them chose an unhealthy product. Although the effect of this finding is not significant, it is interesting to see that this atypical finding of choosing an unhealthy product displayed on knee level did not happen in the task related implementation intention condition. This potential directional effect of not introducing a relevant implementation intention leading to the undesired rather than the desired behaviour (i.e., buying the unhealthy food option rather than the healthier option) should be examined in future research.
General Health Interest
As discussed before, due to the strong effect of the vertical location of the healthy products on the healthiness of product choice, it is not possible to test hypothesis 3 (H3: The
effect of vertical product location on healthiness of food choice is weaker when one scores high on the GHI scale compared to when one scores low on the GHI scale.). Additional research
should be carried out to examine whether and how the level of consumers’ interest in how healthy the food they consume is, is related to healthy grocery shopping behaviour.
Besides what is briefly mentioned in the previous sections, additional research is necessary to fill some other important knowledge gaps. Firstly, future research should examine to what extent the food choice in the present study is subconscious due to the vertical location nudge. Studies show that when a consumer has chosen a healthier food product, he/she is more likely to subsequently choose an unhealthier product (Hui, Bradlow, & Fader, 2009; van der Heide, van Ittersum, & van Doorn, 2016). In other words, these researchers found that a product choice might have an effect on the rest of the shopping trip. It is interesting to find out to what extent this effect holds when the decision to choose a healthy product is made without the consumer being fully conscious aware they made a healthier choice, due to the vertical location nudge.
Another suggestion for future research is to replicate this study in a real supermarket, rather than a VR supermarket. The reason for this suggestion is that, as there seems to be an effect of vertical location on healthiness of food choice, it might be worth the investment.
Furthermore, the results of the current research showed that less than 30% of the participants saw the products at knee level. This might be due to the fact that the products are placed at knee level and thus less visible anyway, but it could also be caused by the fact that it is not possible to squad down and change perspective in the VR program. Running the research in a real supermarket can give a definitive answer to this question.
the data). Further research may be done in product categories that might provoke stronger healthiness (or unhealthiness) associations.
Limitations
The main limitation of this research is that the majority of the sample has a healthy BMI. Since the higher goal of this research is to contribute to the decrease of the obesity problem, this research should be replicated with overweight and obese people as participants. It is possible that this adjusted replication will generate different results, compared to the present research. Indeed, previous research suggests that there are differences in grocery shopping behaviour when
comparing obese or overweight people to normal-weight people (van der Heide, van Ittersum, & van Doorn, 2016).
Another limitation is that in the present research only one product choice had to be made. As discussed, one product choice might influence subsequent product choices (Hui, Bradlow, & Fader, 2009; van der Heide, van Ittersum, & van Doorn, 2016). Furthermore, van der Heide and colleagues (2016) found that overweight people are more likely to choose healthy products in the first half of their shopping trip, while at the last half they are more likely to choose unhealthy products. When the current study is replicated with overweight and obese people as participant sample, it is important to also consider the effect of change in product healthiness during the shopping trip, as described by van der Heide and colleagues (2016).
another product, while the opposite is true. For future researches, it is recommended to consider providing the participants with definitions of healthy and unhealthy food.
Conclusion
Unfortunately, it is not possible to confirm or test any of the three hypotheses. However, there are strong indications that this new form of nudging if effective and thus that the vertical location of a product has a substantial influence on the choice a consumer makes.
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Appendices
Overview
Appendix A: General Health Interest (Roininen et al., 1999) Appendix B: Information text about obesity
Appendix C: VR instructions Appendix D: Survey
Appendix A: General Health Interest (Roininen et al., 1999)
1. The healthiness of food has little impact on my food choices. (R) 2. I am very particular about the healthiness of food I eat.
3. I eat what I like and I do not worry much about the healthiness of food. (R) 4. It is important for me that my diet is low in fat.
5. I always follow a healthy and balanced diet.
6. It is important for me that my daily diet contains a lot of vitamins and minerals. 7. The healthiness of snacks makes no difference to me. (R)
8. I do not avoid foods, even if they may raise my cholesterol. (R)
7-point Likert scale (1 = “Strongly disagree”, 7 = “Strongly agree”). Eigenvalue = 6.1, Variance % = 30.4, Cronbach’s α = 0.89.(R) = reversed coded.
Appendix B: Information text about obesity
The World Health Organization states the following facts about the causes of obesity and overweight on their website (WHO, 2018).
Key facts
Worldwide obesity has nearly tripled since 1975.
In 2016, more than 1.9 billion adults, 18 years and older, were overweight. Of these over 650 million were obese.
39% of adults aged 18 years and over were overweight in 2016, and 13% were obese.
Most of the world's population live in countries where overweight and obesity kills more people than underweight.
41 million children under the age of 5 were overweight or obese in 2016.
Over 340 million children and adolescents aged 5-19 were overweight or obese in 2016.
Obesity is preventable.
What causes obesity and overweight?
The fundamental cause of obesity and overweight is an energy imbalance between calories consumed and calories expended. Globally, there has been:
an increased intake of energy-dense foods that are high in fat; and
an increase in physical inactivity due to the increasingly sedentary nature of many forms of work, changing modes of transportation, and increasing urbanization. Changes in dietary and physical activity patterns are often the result of environmental and societal changes associated with development and lack of supportive policies in sectors such as health, agriculture, transport, urban planning, environment, food processing, distribution, marketing, and education.
Appendix C: VR instructions
Instructions VR part
When you put on the VR goggles, you will first see a few white screens which allow you to get used to the goggles and practice selecting options. On the first screen you have to focus for two seconds on the information icon ( ) for a message to
pop up.
Once you select ‘Start!’ (see image), you will enter the VR supermarket. In this VR supermarket, it is your task to choose one of the large sized Peijnenburg
gingerbread cakes (in Dutch: ontbijtkoek).
You can make a choice by focussing on your preferred product for two seconds.
Remember: If you choose to join the lottery, your prize will be based on the choice you make in the VR supermarket.
IMPORTANT As mentioned, you are not required to walk during the VR part. However, you are asked to remain standing up during the whole VR part. As the VR goggles might provoke dizziness and/or disorientation, you are advised to hold on to a chair or table to prevent you from falling.
Please let the researcher know you are ready to start with the VR part.
Appendix D: Survey
Please fill out this page BEFORE participating in the VR part Write the statement in the following box:
When you have written down the statement, please turn back to the information paper with the instructions for the VR part.
Please fill out this survey AFTER participating in the VR part
Please indicate on a scale of 1 (= strongly disagree) to 7 (= strongly agree) to which extend you (dis)agree with the following statements.
Strongly disagree Strongly agree
1. The healthiness of food has little impact on my food choices.
1 2 3 4 5 6 7
2. I am very particular about the healthiness of food I eat.
1 2 3 4 5 6 7
3. I eat what I like and I do not worry much about the healthiness of food.
1 2 3 4 5 6 7
4. It is important for me that my diet is low in fat.
1 2 3 4 5 6 7
5. I always follow a healthy and balanced diet.
1 2 3 4 5 6 7
6. It is important for me that my daily diet contains a lot of vitamins and minerals.
1 2 3 4 5 6 7
7. The healthiness of snacks makes no difference to me.
1 2 3 4 5 6 7
8. I do not avoid foods, even if they may raise my cholesterol.
1 2 3 4 5 6 7
Please indicate on a scale of 1 to 7 to which extend you believe the following products are (un)healthy, to which extend they are (not) preferred by you, and how certain you are you did (not) see the product during the VR part of this study.
Very unhealthy 1 2 3 4 5 6 7 Very healthy
Not at all preferred 1 2 3 4 5 6 7 Very preferred Definitely did not
see this product
1 2 3 4 5 6 7 Definitely did
see this product Very unhealthy 1 2 3 4 5 6 7 Very healthy
Not at all preferred 1 2 3 4 5 6 7 Very preferred Definitely did not
see this product
1 2 3 4 5 6 7 Definitely did
see this product Very unhealthy 1 2 3 4 5 6 7 Very healthy
Not at all preferred 1 2 3 4 5 6 7 Very preferred Definitely did not
see this product
1 2 3 4 5 6 7 Definitely did
see this product Very unhealthy 1 2 3 4 5 6 7 Very healthy
Not at all preferred 1 2 3 4 5 6 7 Very preferred Definitely did not
see this product
1 2 3 4 5 6 7 Definitely did
Have you ever eaten gingerbread cake (in Dutch: ontbijtkoek)? □ Yes, I eat gingerbread cake frequently (i.e., daily or weekly). □ Yes, I have eaten gingerbread cake multiple times before. □ Yes, I have eaten gingerbread cake once.
□ No, I have never eaten gingerbread cake before. Have you ever bought gingerbread cake?
□ Yes, I buy gingerbread cake regularly.
□ Yes, I have bought gingerbread cake multiple times. □ Yes, I have bought gingerbread cake once.
□ No, I have never bought gingerbread cake before.
If yes: Which type(s)/flavour(s) of gingerbread cake do/did you buy? Answer: __________________________________
To what extent did you keep the statement you wrote on the front page of this booklet in mind during the VR part of the study?
Not at all 1 2 3 4 5 6 7 Very much
What is your gender ? □ Male
□ Female
□ Other/I prefer not to say
What is your age? ______ years What is your length* ______ cm What is your weight* ______ kg
What is your nationality? □ Dutch
□ German
□ Other, namely: ______________ Do you understand (written) Dutch?
□ Yes, Dutch is my mother tongue. □ Yes, I do understand (written) Dutch. □ I understand some (written) Dutch.
□ No, I do not understand (written) Dutch at all. Please indicate your education level (current or highest).
□ Primary education □ Secondary education
□ Secondary vocational education (Dutch: MBO) □ Higher vocational education (Dutch: HBO) □ University education (Dutch: WO)
If you wish to participate in the lottery, please write down your email address below Email address: ___________________________________
If you have any comments, please feel free to write them in the box below.
Appendix E: VR Walkthrough
Figure E1 Start screen 1: the message that appears when the participant looks at the
information icon on the start screen. When the participant focusses on the Continue-button, Figure E2 will appear.
Figure E2 Start screen 2: explanation message. When the participant focusses on the
Figure E3 Start screen 3. When the participant focusses on the Start!-button, the
participant will be redirected to the VR supermarket. If the participant is assigned to the healthy products on knee level condition, (s)he will see the environment depicted in Figure E4. If the participant is assigned to the healthy products at eye level condition, (s)he will see the environment depicted in Figure E5.
Figure E4 VR supermarket with unhealthy products at eye level (the healthy products are
Figure E5 VR supermarket with healthy products at eye level (the unhealthy products are
just below the lowest shelf visible in this image). N.B. The title ‘Welcome in the supermarket’ disappears after 3.5 seconds.
Figure E6 Example of when the participant focusses on Peijnenburg whole grain in the
Figure E7 Example of when the participant focusses on Peijnenburg Zero% Sugar in the
healthy at eye level condition. The pop-up message is: “Do you want to buy this product?” When the participant selects “No” (s)he will stay at the VR supermarket to choose another product. When the participant selects “Yes” (s)he will go to the next screen (Figure E9).
Figure E8 Confirmation screen for the unhealthy products at eye level condition. The
supermarket as depicted in Figure E4. When the participant selects “Confirm”, (s)he will go to the final screen (Figure E10).
Figure E9 Confirmation screen for the healthy products at eye level condition. The
pop-up message is: “Please confirm your choice. Once you have confirmed, you cannot alter your choice anymore.” When the participant selects “Go Back”, (s)he will go back to the VR supermarket as depicted in Figure E5. When the participant selects “Confirm”, (s)he will go to the final screen (Figure E10).
Changing the vertical location of healthy
products on supermarket shelves:
A VR supermarket study on healthiness of food choices.
M. G. Groot Beumer
S2561891
21-01-2019
Table of Content
Background and theoretical framework
• Obesity
• How can the food choices of consumers in supermarkets be altered
from an unhealthy to a healthier food choice within the same product
category?
• Nudging
• Majority studies not about healthy food choices
• Vertical location of healthy products
• Implementation intentions
• Task related or task unrelated
• General health interest
Conceptual model
Vertical
Location of
Healthy Product
(Eye level vs Knee level)
Intention
(Did vs did not have task related
implementation intention)
General Health
Interest
(Average score on the 8 item
7-point Likert scale)
Food choice
(Did vs did not choose the
healthier product)
H3 (-)
H1 (+)
H2 (-)
Methods
• 4 conditions
• Peijnenburg gingerbread cake
• Procedure
Store set up
Results
• Chi-Square Test of the healthiness of the food
choice..
• ..and vertical location of the healthy product: Χ
2(1) =
69.84, p < .001
• ..and implementation intention: Χ
2(1) = .334, p = .564
• Subsets of the data
• No sign. results
Discussion
• Vertical location effect much stronger than expected
• None of the hypotheses could be tested
• Implementation intention: no effect
• Possible causes:
• Large vertical location effect
• Implementation intention was not generated by participants themselves
• No effect to be found
• Future research
• ‘Longer’ shopping trip
• Real supermarket
• Other product categories
Discussion
• Limitations
• Majority of participants has a healthy BMI
• Obese people shop differently
• Only one product choice
• Dynamic shopping trip
• ‘Healthy’ was not specifically defined
• Back of package was not visible
Conclusion
• Strong indications vertical location of healthy products has an effect
on healthiness of food choices
• Relatively easy to apply in supermarkets
• Helps to reduce the obesity problem
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• Cohen, D.A., & Babey S.H. (2012). Candy at the cash register - a risk factor for obesity and chronic disease. The New England Journal of Medicine, 367, 1381–1383. doi:10.1056/NEJMp1209443. • Drèze, X., Hoch, S. J., & Purk, M. E. (1994). Shelf Management and Space Elasticity. Journal of Retailing, 70(4), 301–326.
• Fenko, A., Nicolaas, I., & Galetzka, M. (2018). Does attention to health labels predict a heathy food choice? An eye-tracking study. Food Quality and Preference, 69, 57-65.
• Gollwitzer, P. M., & Sheeran, P. (2006). Implementation intentions and goal achievement: A meta-analysis of effects and processes. Advances in Experimental Social Psychology, 38, 69-119.
• Gollwitzer, P., & Sheeran, P. (2009). Self-regulation of consumer decision making and behavior: The role of implementation intentions. Journal of Consumer Psychology, 19(4), 593-607. doi:10.1016/j.jcps.2009.08.004 • Honkanen, P., Verplanken, B., & Olsen, S. O. (2006). Ethical values and motives driving organic food choice. Journal of Consumer Behaviour, 5(5), 420–430. https://doi-org.proxy-ub.rug.nl/10.1002/cb.190
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• Medical Dictionary (n.d.). Unhealthy food. Retrieved from: https://medical-dictionary.thefreedictionary.com/unhealthy+food
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References
• North, A. C., Hargreaves, D. J., & McKendrick, J. (1999). The Influence of In-Store Music on Wine Selections. Journal of Applied Psychology, 84(2), 271–276.
• Rogers, T., Milkman, K. L., John, L. K., & Norton, M. I. (2015). Beyond good intentions: Prompting people to make plans improves follow-through on important tasks. Behavioral Science & Policy, 1(2), 33-41. • Roininen, K., Lähteenmäki, L., & Tuorila, H. (1999). Quantification of consumer attitudes to health and hedonic characteristics of foods. Appetite, 33(1), 71–88.
• Romero, M., & Biswas, D. (2016). Healthy-Left, Unhealthy-Right: Can Displaying Healthy Items to the Left (versus Right) of Unhealthy Items Nudge Healthier Choices? Journal of Consumer Research, 43(1), 103-112. doi:10.1093/jcr/ucw008.
• Sheppard, B. H., Hartwick, J. & Warshaw, P. R. (1988). The theory of reasoned action: A meta-analysis of past research with recommendations for modifications and future research. Journal of Consumer Research, 15, 325-343.
• Sunaga, T., Park, J., & Spence, C. (2016). Effects of Lightness-Location Congruency on Consumers’ Purchase Decision-Making. Psychology & Marketing, 33(11), 934–950. https://doi-org.proxy-ub.rug.nl/10.1002/mar.20929.
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• WHO (2014). Global Status Report on Noncommunicable Diseases, Technical Report, World Health Organization.
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