The Guardians

Delphine Forneau, Craig Ferguson

Project Overview

The Guardians is a project designed to help people improve their lives using the power of mobile games and in-game rewards. Every year, hundreds of billions of US dollars are spent on in-game rewards, either through direct in-game player purchases or in advertising budgets that compensate players with rewards for watching in-game ads. The scale of this industry suggests how effective games are at contextualising in-game rewards and engaging players to obtain them. So we wondered, what if instead of asking people to watch ads or pay money to get these much-desired in-game rewards, we could make games that encourage people to improve their lives instead?

Here at the Affective Computing group, we know that forming healthy habits can be difficult. Whether it’s getting enough sleep, sticking to a diet, or going for a run, it’s tough to commit to a new schedule long enough to make it stick. This process is even harder when the target behavior focuses on long-term goals with no immediately noticeable benefits or rewards. But that's where mobile games come in. Mobile video games use common and well-known psychological techniques to give perceived value to in-game items and currencies, which can then be used to build long-term habits in the players.

The goal of The Guardians is to build a suite of mobile games that offer in-game rewards not for watching ads or paying money, but instead for doing healthy activities that help people to lead healthier and happier lives. By making these activities fun and rewarding, we can help people to convert them into long-term habits.

The Beginning: Guardians Beta


Copyright JMIR

Our first app, known simply as Guardians Beta, was a simple "idle game" that rewarded players with in-game pets every time they filled out a simple survey about their mood. It was targeted at a pediatric population (ie, children 18 and under) and was used to show that embedding a daily Patient Reported Outcome within a mobile game can drastically increase response rate and data quality in adolescents. It was an incredibly promising result that showed that rewarding a boring activity with in-game pets drastically increased long-term adherence.

Guardians: Unite the Realms

Inspired by the mental health strain caused by the recent pandemic and quarantine, we launched The Guardians: Unite the Realms on the Apple App Store and the Google Play Store in April 2020. Since then, it has been featured in multiple news articles and has been downloaded by over 10,000 users. To read more about the specific design and game mechanics within Guardians: Unite the Realms, please read our paper in IEEE CoG 2021.

Guardians: Unite the Realms aims to increase mental health and wellbeing in its users by providing immediate and gratifying rewards in exchange for completing a therapeutic technique known as behavioral activation. Behavioral activation is an effective and proven therapy that asks people to regularly choose and perform a meaningful and positive task, and then reflect on how that task made them feel. By rewarding players for completing and reflecting on these real-life activities, Guardians: Unite the Realms is designed to help people handle depression and live more fulfilling lives through the power of mobile games.

Based on the anonymized data gathered from our users, we have been able to show that Guardians: Unite the Realms has over double the long-term engagement of the typical mental health app. Not only that, but we have seen that the players complete real life tasks over 65% of the days they play, which is well above the target voluntary ad watch rate for major mobile games! Combine that with the fact that over 80% of behavioral activation tasks lead players to feel better, and Guardians: Unite the Realms has already been able to help people feel better during a really difficult time.

The behavioral activation techniques used within The Guardians were developed in collaboration with Chelsey Wilks, a graduate from the Nock Lab and current professor at University of Missouri-St Louis where she researches the use of technology to treat people at risk for suicide. As such, she has a uniquely suited background to not only deeply understand behavioral activation therapy, but how to modify it to be effectively embedded within a video game. Chelsey advises the Guardians team on which aspects of behavioral activation therapy are most effective and why, what types of real-world activities are the most effective, and how to maximize both engagement and benefits from within the unique context of a mobile game.

Guardians: Paradise Island

Using the techniques we learned while developing and analyzing Guardians: Unite the Realms, we developed a sequel, Guardians: Paradise Island. Like our first release, this game rewards players for completing and reflecting on behavioral activation tasks. This time, the focus is on helping avert the catastrophes facing the idyllic Paradise Island by teaching your pets mental health skills, all while practicing those skills in real life! We've cram-packed plenty of additions, upgrades, and improvements into this new game, and we can't wait to hear what you think of it!

...And More!

The techniques we have been developing for the Guardians Project can be used in many ways to help people form the beneficial habits they know they should do, but still don't. We're incredibly excited about the many directions we can take this project in to help more people, and we know we've only just scratched the surface of what's possible. If you have any ideas or would like to collaborate, please contact us at guardians[at]