Table 1 Summary of Aim2Be© features and behavior change techniques

 Profile/Onboarding PT, T

After a user creates an Aim2Be account, the user can play the game, “What animal are you?” The game involves answering a variety of questions about the user’s preferences, with various question formats. For example, users might be asked whether they prefer spending time with people or spending time alone. At the end of the game, the user is presented with an animal avatar recommendation (e.g., lynx, tiger, panda, etc.) along with adjectives describing that identify profile (e.g., “wild, determined, unafraid, intelligent, & habitual”). The users are given the option to select a different animal avatar, if they wish, to represent them in the app and the option to further customize their animal avatar, by selecting clothes and accessories.

13.4 Valued self-identity

 Daily Bonus PT, T

Each time a user opens the app, the user is invited to break a piñata from which extra currency can be gained.

10.2 Material reward (behavior)

 Quick Wins PT, T, P

Each day, a new Quick Wins appear on a side bar of the users home page. Quick Wins are quick, simple, and straightforward tasks that prompt the user to do something positive for their health that day (e.g., “Stand up. Shake it out. Stretch. Reach up to the sky, then to the floor.”) or to encourage them to explore a new aspect of the app (e.g., “Check out Aimbot for help.”). Users earn currency dollars for each day they complete a Quick Win.

4.1 Instruction on how to perform a behavior

8.1 Behavioral practice/rehearsal

8.2 Behavior substitution

8.3 Habit formation

8.4 Habit reversal

8.7 Graded tasks

10.4 Social reward

 Quizzes PT, T

Users can complete short quizzes within the app. Whether the user selects the correct or incorrect answer, a pop up appears after each question with an explanation of the correct answer. Users earn currency diamonds for each quiz they complete.

2.2 Feedback on behavior

4.2 Information about antecedents

5.1 Information about health consequences

5.3 Information about social and environmental consequences

5.6 Information about emotional consequences

6.2 Social comparison

 Currencies PT, T

Users collect currency dollars and currency diamonds for engaging with different components of the app. These currency dollars and diamonds can be used to purchase collectibles and stories, respectively.

10.2 Material reward (behavior)

 Collections PT, T

Collections include a variety of virtual items (e.g., skateboard, phone, lipstick, sneakers, etc.), divided by level, that a user can purchase with a certain number of currency dollars.

10.2 Material reward (behavior)

 Stories PT, T

Users can use their currency diamonds to purchase interactive and/or engaging stories. Each story is divided into multiple chapters that are “unlocked” as a user reaches a new level.

10.2 Material reward (behavior)

Stories present users with a fictional situation and character who is faced with a series of decisions. Users guide the fictional character through the situation by making decisions in a choose-your-own-adventure format. A recent study suggests that when individuals “lose themselves” in the world of a fictional character, they change their own behavior and thoughts to match that of the character. This phenomenon has been termed experience-taking [48]. Stories are designed such that users will empathize and identify with the fictional characters, allowing them to have experiences that they may not have yet had the chance to encounter in their regular lives. This allows them to shift their self-perception to include their “new experiences” and begin to identify themselves as the type of person who chooses healthy patterns of action.

9.3 Comparative imagining of future outcomes

16.1 Imaginary punishment

16.2 Imaginary reward

6.1 Demonstration of behaviors (symbolic role modeling)

 Aim PT, T, P

Aims are high-level goals that users can choose to pursue, such as “Be sugar smart.” Users may pursue one aim at a time or may pursue up to three aims concurrently.

1.3 Goal setting (outcome)

1.4 Action planning

Once a user selects an aim to pursue, the user is first asked to indicate why they selected the aim, by completing the sentence, “I want this because....” Next, the user is asked to indicate on a Likert scale the importance of the aim, and their confidence in being able to achieve it. Following this, the user is asked to note any obstacles they might face in working toward the aim. Lastly, the user is asked to adopt a time frame for achieving their aim; they can either accept a recommended time frame or create a custom time frame.

1.6 Discrepancy between current behavior and goal

1.9 Commitment

13.5 Identity associated with changed behavior

Users also have the option to request support from their parent or guardian or from a peer. Users can write their specific needs related to tasks and aims and send these to their desired recipient in email form through the application.

Users are given daily tasks related to the aim they set and are congratulated and awarded currency as they complete tasks and stages. When an aim is completed (all the tasks have been accomplished), the aim is moved to the “Completed aims” folder.

 Stage T, P

Aims consist of several stages that break the high level goal into more focused components. For example, the aim “Be sugar smart” includes the stages “Be sugar aware,” “Swap some sugar out,” and “Find a balance.” The Preteen app does not include stages, only aims and tasks.

1.1 Goal setting (behavior)

1.5 Review behavior goal(s)

1.7 Review outcome goal(s)

 Task PT, T, P

Stages consist of a number of tasks that break the aim and stage down into small, achievable tasks. For example, the stage “Swap some sugar out” contains tasks such as replacing sugary drinks with water, reading a specific article in the app, reading labels to identify sugary foods in the home, and making a list of snacks eaten and circling those that are high in sugar.

1.2 Problem solving

1.4 Action planning

4.1 Instruction on how to perform a behavior

4.2 Information about antecedents

7.1 Prompt/cues

8.1 Behavioral practice/rehearsal

8.2 Behavior substitution

8.3 Habit formation

8.4 Habit reversal

8.7 Graded tasks

10.4 Social reward

13.2 Framing/reframing

 Check-In PT, T, P

At any time, users can access and update their health behavior status. The Check-In area provides a graph-formatted overview of how they are doing in terms of six self-rated health behaviors: sugary drinks, veggies and fruit, activity, family meals, screen time, and sleep. Each behavior has a short description of the health behavior recommendation, and users are asked to rate how they think they’re doing on a scale from poorly to not very well to okay to well to great.

2.2 Feedback on behaviors

2.3 Self-monitoring of behaviors

2.4 Self-monitoring of outcome(s) of behavior

 Discover PT, T, P

Articles are an in-app resource for users who wish to learn more about particular topics. The Discover Center allows users to explore educational content at their own pace. Content is organized by health behavior topic and takes the form of relevant health articles that users can consume quickly and refer back to over time. Users are prompted to provide a short written response to a question related to the article content (e.g., “What is your biggest challenge in sticking to a healthy breakfast routine?”). They are provided with currency when they respond. Users are also prompted to indicate the value they derived from articles; user ratings are combined to indicate popular articles.

4.1 Instruction on how to perform a behavior

4.2 Information about antecedents

5.1 Information about health consequences

5.3 Information about social and environmental consequences

5.6 Information about emotional consequences

7.1 Prompts/cues

 Social Wall PT, T, P

The Social Wall offers a safe social space within the application where users can come together and share thoughts, feelings, successes, and challenges around their healthy lifestyle goals. Prompts guide behavior change through feeling connected, listening, having a voice, and shifting norms. Humans are social creatures and our social networks play a huge part in our lives. Social networks have been shown to influence health outcomes like weight and medication adherence. This is especially true if the health issue has stigma surrounding it. When uncertainty is high, users are more influenced by their peers. Offering a safe social space where users can come together around common health goals is therefore considered imperative for long-term success. Self-efficacy, the most important influence on behavior change, is boosted by having access to a social space that is promoting healthy behaviors. The social wall will be moderated by the health coach and has some automated moderation built in to hold posts with inappropriate language. The moderator can review and approve the held posts; otherwise, posts go live immediately.

3.1 Social support (unspecified)

3.2 Social support (practical)

3.3 Social support (emotional)

6.1 Demonstration of behaviors

6.2 Social comparison

13.1 Identification of self as role model

 Virtual Coach PT, T, P

The Virtual Coach, Aimbot, is a digital bot with a range of pre-programmed prompts, questions, and answers designed to guide users in the app with behavior change in an empathetic way. All app users can access Aimbot. The content is based on queries that arose during the pilot.

3.2 Social support (practical)

 Health coach PT, T, P

The health coach, trained in motivational interviewing, provides support to app users through an in-app coaching interface in which the Coach and user can have one-on-one messaging conversations to provide more tailored and more personal health behavior guidance.

2.2 Feedback on behavior

3.1 Social support (unspecified)

3.2 Social support (practical)

3.3 Social support (emotional)

10.4 Social reward

 Parent Companion App P

The Parent Aim2Be Companion App complements the child’s Aim2Be app. It includes many of the same components (Quick Wins, Aims, Stages, Tasks, Health Behavior Check-Ins, Articles, Social Wall, Virtual Coach, health coach) and similar nutrition, activity, screen time, and sleep related content, but focuses primarily on how parents can support their children in making healthy behavior changes. The child and parent apps are not connected. The parent app is not gamified.

3.1 Social support (unspecified)

3.2 Social support (practical)

3.3 Social support (emotional)

12.1 Restructuring physical and social environment