Technology-assisted Persuasion for Dietary Habit Change

New technology provides an opportunity for people to accesstheir shopping data digitally. With an increasing prevalenceof overweight and obesity and the implications that follow,research on diet interventions is in high demand. This paperdescribes a study of the Food4Thought system: an approachto persuasive technology that focuses on providing informa-tion to users just-in-time and in-situ. A smartphone appli-cation was implemented and deployed to eleven participantsover a period of three to five weeks. The application noti-fied the participants of how their dietary habits related to thefood pyramid when they entered a supermarket. Activity datawas recorded and interviews were conducted. The findings il-lustrate that most participants reflected on their dietary habits,while almost half described a change in their shopping habits.Conflicting statements showed that most of these participantswere unaware of having been influenced, which suggests anudging effect. Author KeywordsBehavior change; in-situ; mobile persuasion; nudge;nutrition; reflection; shopping patterns; tailoring. ACM Classification KeywordsH.5.m. Information Interfaces and Presentation (e.g. HCI):Miscellaneous INTRODUCTIONWithin the field of HCI, a large and growing body of researchhas been conducted on how to design persuasive technolo-gies that are effective in the intervention of unhealthy eatinghabits [25]. With an increasing prevalence of smartphones, itis interesting to explore the technological opportunities thatthese devices provide. This paper presents how previouswork on technology-assisted intervention design has primar-ily been concerned with interactivity and features. Commonthemes of previous work have been the design and usage of Permission to make digital or hard copies of all or part of this work for personal orclassroom use is granted without fee provided that copies are not made or distributedfor profit or commercial advantage and that copies bear this notice and the full citationon the first page. Copyrights for components of this work owned by others than theauthor must be honored. Abstracting with credit is permitted. To copy otherwise, orrepublish, to post on servers or to redistribute to lists, requires prior specific permissionand/or a fee. Request permissions from the author.shopping assistants, situated displays in the home, text mes-sages, and mobile applications. While previous work on per-suasive technologies has touched upon context-specific inter-ventions, a gap in the work has been observed in when andwhere the opportune moment for persuasion occurs. Whilecandidates for opportune moments to intervene unhealthy eat-ing habits are numerous, the focus of this paper is on shop-ping habits, under the assumption that what is bought is aclose reflection of what is eaten. This paper is concerned withthe design of shopping habit interventions that are conductedin-situ and just-in-time. In this paper, just-in-time persuasionis defined as interventions that are conducted at opportunemoments. In 2013, a preliminary, unpublished study was conducted ina grocery store in El Paso, TX, USA on an idea involvinga mirror at the end of a shopping cart [17]. The study wasconducted by associate professor Payne, Collin and assistantprofessor Niculeascu, Mihai, both working for the Market-ing Department of New Mexico State University, NM, USA.While no data from the study was published, it was indicatedthat the gentle nudge provided by the mirror resulted in an in-crease in produce sales as well as a decrease in sales of otherfood products. It was claimed by several participants that themirror had an effect on their self-perception. Along with in-creased sales of produce, this suggests that a mirror has a di-rect influence on a shopper’s food-purchasing patterns. Figure 1. The Food4Thought prototype viewed in-situ. Based on the idea of this study, the Food4Thought proto-type application for smartphones has been developed to fa-cilitate in-situ, technology-assisted self-reflection. The pro-totype is presented in Figure 1. New technology provides an