Persuasion In-Situ: Shopping for Healthy Food in Supermarkets Ole Kallehave, Mikael B. Skov, Nino Tiainen HCI Lab, Department of Computer Science, Aalborg University Selma Lagerlöfs Vej 300, 9220 Aalborg East, Denmark ole-kallehave@rocha.dk, dubois@cs.aau.dk, ninodk@gmail.com ABSTRACT products, e.g. they cannot understand nutrition labels or Healthy lifestyle is a strong trend at the moment, but at the how much sugar or fat the product contains [5]. Further, same time a fast growing number of people are becoming one of the fundamental problems resides in the fact that we over-weight. Persuasive technologies hold promising are confronted with an overwhelming number of different opportunities to change our lifestyles. In this paper, we food products and it is often difficult to identify and choose introduce a persuasive shopping trolley that integrates two the more healthy ones. Iyengar and Lepper showed in an tools of persuasiveness namely reduction and suggestion. experimental study that consumers were more satisfied The trolley supports shoppers in assessing the nutrition with their own selections when they have fewer options to level for supermarket products and provides suggestions for select from [5]. Schwartz refers to this as the paradox of other products to buy. A field trial showed that the choice claiming that the huge number of choices decreases persuasive trolley affected the behaviour of some shoppers people’s real choice and decision-making [10]. Thus, especially on reduction where shoppers tried to understand people are likely to continue their current routine type of how healthy food products are. On the hand, the suggestion behaviour (as illustrated by Park et al. [8]) and this could part of the system was less successful as our participants potentially prevent them from making healthier choices. made complex decisions when selecting food. Emerging technologies are increasingly being used to alter Author Keywords people’s opinions or behaviour, e.g. smoking cessation [4] Shopping, health, persuasive, supermarkets. or promoting sustainable food choices [7]. Fogg refers to such technologies as persuasive technologies or captology ACM Classification Keywords [3]. Fogg states that contemporary computer technologies H5.m. Information interfaces and presentation (e.g., HCI): are currently taking on roles as persuaders including Miscellaneous. classical roles of influence that traditionally were filled by INTRODUCTION doctors, teachers, or coaches [3]. Research studies within Healthy lifestyles is a hot topic in most Western societies as different disciplines are increasingly concerned with such a rapid growing number of citizens are either over-weight persuasive technologies that may be used to create or or obese, e.g. more than 50% of the adult population in change human thought and behaviour. As examples, Chang Denmark are either over-weight or obese [9]. Over-weight et al. [2] propose the Playful Toothbrush that assists parents problems come from several circumstances, e.g. the lack of and teachers to motivate young children to learn thorough exercise or unhealthy food, but in general people buy and tooth brushing skills while Arroyo et al. [1] introduce the consume food that contains a lot of sugar or fat. Thus, we Waterbot that motivates behaviour at the sink for increased need to alter people’s behaviour and attitude while they safety. Both these examples propose rather simple, yet shop groceries and other food products in supermarkets. potentially powerful input and feedback that aim to inform users of their own behaviour. When supermarket shopping, more studies have shown that consumer behaviour is highly controlled by routine and is Todd et al. [11] illustrate theoretically how nudging could not simply changed or altered [8]. In fact, even if shoppers persuade shoppers to select healthy food products based on want to change their shopping behaviour and patterns, they simplified information to the shoppers in-situ, but call for find it difficult to understand the nutritious values of many empirical understandings of persuasive shopping. We propose a persuasive shopping trolley application called iCART that attempts to motivate change towards more healthy shopping behaviour. First, we outline the idea Copyright © 2011 for the individual papers by the papers' behind the design of the trolley application and then reports authors. Copying permitted only for private and academic from field studies of use on its effects on behaviour change. purposes. This volume is published and copyrighted by the iCART: INFLUENCING SHOPPING BEHAVIOUR IN-SITU editors of PINC2011 iCART is a persuasive application mounted on a shopping trolley that attempts to persuade the shopper’s behaviour and awareness. The system was implemented in C# using Windows Presentation Foundation for the interface and a Reduction reduces complex behaviour to simple tasks in Microsoft SQL server. order to increase the benefit/cost ratio and thereby From our previous research [6], we learned that many influence the user to perform the behaviour [3]. As stated consumers actually attempt to buy healthy products when above, consumers find it difficult to assess the overall supermarket shopping, but often they would find it difficult nutrition level for products. The persuasive trolley reduces to assess the nutrition value or energy level. In fact, several this nutrition value assessment through the simplification in consumers are actually unsure what a healthy food product the Eat Most classification and thereby the assessment now is. Shoppers find it difficult to understand the nutrition becomes a simple task. This is illustrated in figure 2 where information labels on the food products and they usually different products have been classified, e.g. milk as eat less don’t bother consulting this information. Supermarket (middle picture). products and groceries are rather diverse, e.g. ranging from simple non-processed products (e.g. an apple) to more complex processed products (e.g. a pizza). Usually people find it difficult to assess how healthy processed products are. Furthermore, people find it difficult to change behavior and usually choose well-known products while shopping. The overall idea of iCART is that all food products and items in a supermarket can be classified according to nutrition level and this classification will be presented to the user of the trolley every time the shopper puts an item Figure 3: Example of reduction in persuasion: Classification of the cereal product Havrefras as Eat Least into the trolley. For our persuasive system, we adapt the nutrition label initiative called Eat Most from the Danish We colour-coded the three categories with green, yellow, Veterinary and Food Administration. For our purpose, it and red. Figure 3 shows the classification for a cereal provides a simple classification of food products based on product called Havrefras and this product is an eat least the nutrition values of a product. The classification label product. The implementation in iCART reduces the action includes a table for calculating the value of all food of assessing the nutrition value of a product by providing a products. According to the label, all products can be simple classification of only three categories. classified as Eat Most, Eat Less, or Eat Least. The typical use situation could be as follows (illustrated in figure 1): The user walks around the supermarket with the trolley, chooses food products and places them in the trolley (a), the trolley recognizes the product and displays its classification according to the Eat Most label (b), and the system updates the status for the entire trolley on numbers of Eat Most, Less, and Least food products (c). Figure 4: Examples of suggestion in persuasion: Two alternative cereal products that are both Eat Most products. Suggestion means that persuasive technologies have greater power if they offer suggestions at opportune moments [3]. (a) (b) (c) Consumers find it difficult to choice healthier alternatives Figure 1: Illustrating the process of using iCART as they often have limited understanding of the relative Interaction Design levels of nutrition between more products. The persuasive We adapted three persuasive design tool principles from trolley offers suggestions for alternative products (Eat Fogg namely reduction and suggestion [1]. The persuasive Most) within the same product group when the shopper shopping trolley should 1) present or visualize product choices an Eat Less or Eat Least product in the trolley. We nutrition in a simple way and 2) present alternatives to less consider this an opportune moment as the shopper often healthy products. Finally, we decided that the system will find the alternatives in their present supermarket area should be a walk-up-and-use system on a shopping trolley. (as illustrated in figure 4 where two alternative cereals are suggested for the cereal in figure 3). FIELD TRIALS We conducted field trials with the shopping trolley at the Figure 2: Three classifications of the Eat-Most nutrition label local supermarket called føtex. It was rather important to us with eat most (left), eat less (middle), and eat least (right). to understand the use of the system in-situ to facilitate the whole shopping experience. 11 shoppers were recruited through public announcements guided the shopper while shopping. This also had the and we required that they shopped for food products on a advantage that shoppers always knew where to look for the regular basis. The shoppers were between 27 and 58 years nutritious information for all products. Today, this old and represented different kinds of households and information is located on the packaging of the product and worked in diverse job professions. We asked them to fill in thereby distributed in the store. a questionnaire on their supermarket shopping experiences The reduction element of iCART was quite successful. Out prior to the trials. Some of the participants were highly of the 60 food products selected by the participants using concerned with nutritious food while others were less the system, 30 were classified as Eat Less or Eat Least. concerned. The participants were divided into two groups - Thus, half of the selected products were less healthy. In one group used iCART while the other group served as a several cases, the participants were surprised to realize that control group using a regular shopping trolley. We a certain product was less healthy. For example, one of the balanced them in the two groups based on their self- participants chose a bag of carrot buns and got surprised to reported knowledge and attitudes towards nutritious food. see that these buns were Eat Least: “I thought they were Before the trials, we carried out a pilot test to verify and healthy as they contain carrots”. adjust the process and our instructions. Participants were not informed about the purpose of the study in order to On the other hand, several shoppers chose less healthy food minimize study impact and iCART participants were told products and were aware of it – even without the help from about the system but not its focus on healthy food products. iCART. But the classification made them reflect upon their choices and several of them started talking about nutrition The trials consisted of a three parts namely an introduction, and healthy food. One participant said: “But the Eat-Least the actual shopping, and a debriefing. We instructed the classification makes you think and questions whether you participants to shop items from a pre-generated shopping have made the right choice”. From our analysis, it seemed list using their own normal criteria for food selection. Thus, that they acted out of routine behaviour and that they they should try to shop as they normally would. The partially knew the consequences of these choices. This shopping list contained 12 items, e.g. milk, cheese, pate. confirms the findings by Park et al. [8] on changing The list included only general product groups (except for shopping routine behaviour. In summary, the reduction one item) leaving the participants to choose within the element of iCART was quite successful as it raised the group, e.g. cheese where they could choose more 20 awareness of the shoppers on the nutritious level of the different cheese products. They were free to choose in chosen products. which order they would collect the items. The suggestion component of iCART was less successful 303 food items were entered into a SQL database compared to the reduction. The participants changed their representing all items in the store within the groups from choices 3 times out of 30 (10%). This low number was the shopping list. Data collection was done through 1) a somewhat surprising, but shoppers gave several reasons for trolley-mounted video camera that captured verbal this. Some would not change their choice, as they would comments and shopping behaviour and 2) the system rather buy an unhealthy food product that was biodynamic logged and time stamped all user interactions enabling to than buy a healthy product that was not. So the shoppers reproduce action sequences afterwards. The sessions were would implement their own classification schemes based done during normal trading hours and they were not on other aspects than nutrition. Also, some shoppers stated required to check out the collected items. that they never bought any light or zero products, which We evaluated iCART as a Wizard of Oz experiment where often were the products suggested by our system. They said one of the authors acted as wizard implementing the actions that they would rather eat less of the unhealthy products taken by the participant. When a food product was put into than buy a light product. the trolley, the wizard would update this information in the During the field trials, 18 times did the shoppers take a look system. Another person observed the participant while at the suggestions made by iCART, but in most situations shopping in order to facilitate the following interview. The (14 times) they chose not to follow the suggestion. This same procedure was used for the control group, but without indicates that the shoppers are interested in receiving the trolley-mounted display. The total time spent ranged suggestions but the actual suggestions made by the system from 12:08 to 40:28 minutes. Finally, a debriefing session in the situation were not good enough. As illustrated above, including questionnaires and semi-structured interview was they had different objectives when shopping and perhaps conducted immediately afterwards, e.g. they were asked to suggestion functionality should be carefully organized. assess their own session and the collected items. We identified an interesting observation concerning trust to OBSERVATIONS AND DISCUSSION the system. Some users expressed scepticism towards the The five participants using iCART expressed that they suggestion part of the system while none of them really liked the system and they would possibly use it if available questioned the reduction part. Most of them stated that in supermarkets. While food products in supermarkets nutrition labelling whether on the actual product or already have different labels for determining the health or implemented in an interactive system on the trolley should nutritious level, iCART became a personal technology that be controlled and accredited by public authorities. They were more critical when it concerned suggestions than REFERENCES reductions. The problem with suggestion could reside in 1. Arroyo, E., Bonanni, L., and Selker, T. (2005) that it could feel like ads or commercials for other products. Waterbot: exploring feedback and persuasive techniques That could be a potential problem when implementing at the sink. In Proceedings of the 23rd Annual SIGCHI suggestion tools. However, as expressed by one of the conference on Human factors in Computing Systems female participants: “It is cool to be guide. I don’t mind (CHI’05), ACM Press, pp. 631-639 help or receive suggestions, I’m a grown-up who can make 2. Chang, Y-C, Lo, J. 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