Peace of Cake

Persuasive technology

A concept of mobile app that helps to quit drinking coffee (and can be expanded to quitting other bad habits)

mobile, ux, research × 2013
  • 1 week
  • In team with: Fereshteh Khodabakhshi, Den Tserkovnyi, Carmen van der Zwaluw
  • My contribution: UI prototyping; part of front-end coding

Coffee is considered as a fuel to those working in creative (and many other) industries, but it also highly dehydrates and can cause risks of cardiovascular diseases. Moreover, it’s a very strong habit, which we found a very interesting case to develop and apply some persuasive technology to help people reduce their coffee consumption.

Influencing behavior

We chose two ways to communicate the persuasive techniques to our users: a mobile application and text notifications (on the phone). By using the proper techniques considering the literature review, we try to keep them motivated. The following eight techniques helped to reach this goal.

  1. TTM. According to transtheoretical model of health behavior change, people in the contemplation phase (our target group) are aware of the pros and cons of their behavior. However, they need some help to proceed into the preparation and action phases.
  2. Fogg grid Additionally, since we aim at stopping a behavior (i.e. drinking coffee) for a period of time, we are seeking a Black Span Behavior (a prolonged cessation of a behavior), according to the Fogg Behavior Grid. To achieve this, we must remove or diminish at least one of the variables according to Fogg and Hreha (2010):
    • remove the trigger (avoid cues that remind the user of coffee),
    • reduce the motivation (increase motivation to do something else)
    • reduce the ability (don’t buy coffee, throw away the coffee machine, drink alternative drinks)
  3. Ambivalence. Negative and positive facts on coffee consumption will give users a minute of thought towards their future actions. The negative facts render the attitude and opinion of the user more ambivalent
  4. Fun theory We included fun elements in the app, which consisted of providing the goodybag with tea and cookies, and by adding a gaming element to the app (adding the stars in response to every tried out alternative).
  5. Self efficacy. Self-efficacy was enhanced by emphasizing the progress and achievements of the user. This was shown in the progress bar, the number of hours in the right side of the screen, and the number of stars for trying out alternatives.
  6. Autonomy. We aimed at enhancing feelings of autonomy by sending positive messages in a non-pushy tone of voice, plus there is an option to quit but with a possibility to go back.
  7. Cialdini. The main elements of Cialdini’s persuasion strategies included in the app were commitment, reciprocity, liking, and social proof. The latter was shown in the “friends” section of the app. The commitment and reciprocity principles were induced by the goodybag.
  8. Addiction theory Several parts from addiction theory were included to the app, mainly in the “I need help” section. They included social support (“find a friend to support you”), cue-avoidance (an explanation on why and how to avoid cues), distraction (provide alternative activities), alternative beverages, relaxation, and rationalization (i.e. “it’s only one day”).


We created a prototype of mobile application first on paper and then using HTML, Twitter Bootstrap and some jQuery. Several design decisions had to be made:

  • types of information to show (profile, achievements, progress)
  • making it persuasive
  • right time to show certain pieces of information
There was just one day for the prototyping, hence Bootstrap was used as fast and efficient way to code a mobile solution.

The app was personalized by adding the user’s photo and name to the first screen. Each participant received a goody bag including alternative drinks (tea) and cookies. The whole coffee-free process during one day further consisted of five steps.

  1. Users sign up or log in (this step is skipped in the app), and then wait a couple of days for the start of “a new experience” and see a countdown in the app, which will give them enough time to be prepared for the coffee-free day.
  2. After their counter has come down to zero, participants receive a message in the morning (7.30 h.).
    “Good Morning! Are you ready for a new experience? Today is your coffee-free day. Have a nice cup of tea (check your Goodybag)”
  3. “The new experience” begins. The profile page also shows several other options with alternative suggestions to replace coffee, finding friends for support, and facts about negative effect of drinking and positive effects of not drinking coffee. “I need help” button is used in case the user needs more support to overcome craving at that moment and an “I give up!” button in case user wants to quit.
  4. Receiving motivating and positive messages via notifications throughout the day, at the critical time (9.15 h., 13.00 h.) to help them stick to their decision. These messages contain different persuasive methods, such as social support, cue-avoidance, alternatives, self- efficiency and positive feedback techniques. Encouraging message
  5. At the end of the day participants we will encourage the ones who succeeded as well as those who gave up. The app will congratulate the first group and tell them they did a great job. For the ones who quit the experiment, we send a message to leave the door open so they can try again anytime.


The prototype was tested on several participants, who drank coffee on a daily basis. Before the testing process each participant was provided with a nice goody bag with herbal teas and cookies to motivate and cheer them up. Participants had to quit drinking coffee for one day and during that day the app was supporting them and provided alternatives for coffee, such as water, tea and different physical activities.


The evaluation showed that all participants refrained from drinking coffee during the whole day. As most of them beforehand indicated that they were only extrinsically motivated to participate, and thus were more precontemplators than the desired contemplators, this can be considered a highly successful result.

A future aim might be to examine how to sustain this behavior for a longer period of time. We used a goody bag to motivate a person to start this experiment, however, this is not something that we could and would provide the users every day. The application could be extended in the future to combine different kinds of addictions that users will want to get rid of, e.g. a smoking addiction could also be a part of the application.