As a class project, our professor gave us a theme related to food and cooking. After some ideation, we all grouped according to what we wanted to do and established teams. My team wanted to explore food waste and what we could do. Then we delved into using persuasion to do so. We called our app kiwi, because it all started with a team member and her expired kiwi in the fridge.

We reviewed literature around behaviour change and food waste. I was familiar with persuasive design from a different class, but our exploration showed something interesting: use of negative reinforcement and punishment in addition to positive reinforcement, to increase persuasiveness.

Our research on food waste (based on literature) showed:

• People didn't know what they had in their fridge

• There was lack of communication between household members

• People were buying in bulk

• Busy and erratic lives, and poor planning meant they wouldn't get to using things in their fridge, or would have trouble knowing what to do with things they had

Based on what we found, we decided to design an app to do:

• Help people keep track of what they have in their fridges

• Remind them when an item is about to expire

• Suggest recipes around each item

On top of functionalities, the app needed to be persuasive of course. So we used persuasive design principles, with use of messages to praise or blame the user, emotional expressions on food items, and achievements and rewards.

We prototyped the app using UXPin. We recruited 12 participants and tested the app with tasks, observing how they react to persuasive prompts. Half were exposed to a profile doing good and the other half to a profile doing bad to record their reaction. At the end of usability sessions, we had a short interview to better understand their experience, and a short survey for them to fill out.

• People reported being motivated by the app. Hurray!

• All participants stated the app would help them waste less food, woohoo!

• People reported feeling sad when wasting, one stating regret of decision

• Those who were unaffected by scoring/wording still stated being pushed by the app to do the “right thing” and still appreciated being able to keep track of their fridge

• Over half of the participants stated that they would download or share the application with others

Negative reinforcement and punishment increase motivation to change more than positive reinforcement, but positive reinforcement motivates users to maintain good behaviour.

Just like with every study, there are limitations; things we couldn't get to and things we observed as study moved on, which are:

• Limited sample size

• Limited timeframe, only potential for behaviour change could be explored

• Risk of getting used to reinforcements, and app losing its novelty

• Limitations of prototyping tool, it didn't feel like a native app