We love stories of willpower. The runner who gets up at 5 AM. The student who powers through all-nighters. The person who kicks a habit through sheer determination. But in real life, sustainable behavior change rarely comes down to motivation alone.

If we want people to change – whether it’s exercising more, saving money, or engaging with a product – we need to look beyond what’s happening inside someone’s head. We need to zoom out and consider the world around them, too.

Behavior isn’t the result of a linear cause-and-effect process. Instead, there’s a constant interplay between three forces. Bandura’s concept of Reciprocal Determinism describes how personal factors, behavior, and environment are constantly influencing each other in a dynamic loop. None of them acts in isolation.

• Personal factors: what’s going on internally (our beliefs, attitudes, emotions, and self-perception)

• Behavior: what we do (our actions, choices, and habits)

• Environment: the social and physical world we live in (norms, people, structures, systems)

These three elements form a kind of behavioral triangle, all influencing each other. Change in one can ripple through the whole system.

Let’s have a look at an example. Imagine you decide to start going to the gym. That’s a behavioral shift. You’re taking action. After a few sessions, you notice something else happening. You start chatting with people in the weight room. You follow a couple of them on social media and start chatting with them about their favorite stretching exercises. The gym becomes a place you belong to, not just a task on your to-do list. That’s your environment evolving. Then, slowly, your self-perception begins to change. You start thinking of yourself as someone who’s ‘into fitness’ – a meaningful identity shift. That’s a personal factor. And guess what? That new belief makes it easier to stick with the gym routine. Which, in turn, deepens your identity as a fit person.

This is what Bandura was getting at. Behavior isn’t linear. It’s a loop. Round and round it goes – a feedback loop between behavior, personal factors, and environment.

Why this matters for your product strategy

Okay, but what does this have to do with product design or strategy? Well, a lot actually.

Too often, we design products (or campaigns, or policies) with a narrow focus on motivation. We try to inspire people. Convince them. Get them started. And sure, motivation has its place – especially at the start of a journey. But if we stop there, how do you make sure they keep going? 

Motivation tends to ebb and flow. Ups and downs are part of life. So the real question isn’t just how to start a behavior – it’s how to help people keep going, even when motivation dips. That’s where the loop comes in. To support lasting change, we need to design in a way that works across all three parts of the system: behavior, personal beliefs, and the surrounding environment.

Let’s break this down in product terms:

• Behavior: What is the user actually doing? What actions do you want to encourage? Are you tracking the right signals of progress?

• Personal factors: How does your product affect how people see themselves? Does it build confidence? Does it make users feel capable, competent, and seen?

• Environment: What’s the context in which your product is used? Are there social cues, defaults, or structures that make the behavior easier or harder? How does your product shape the user’s environment – and how can the environment reinforce the behavior?

Even small shifts in one part of the triangle can lead to changes elsewhere. For example:

• A meal-planning app simplifies healthy recipes and offers lots of choice (environment) reduces decision fatigue, which helps people feel more confident in their ability to cook and eat well (personal), leading to more consistent cooking at home (behavior).

• A budgeting app that celebrates small wins (behavior) can help users feel more financially savvy (personal), which might lead them to talk more openly about money with friends for mutual support (environment).

Design for loops, not just moments

Most product teams are great at designing features. Fewer are skilled at designing feedback loops. But the magic happens in the interactions. Loops are where long-term behavior changes lives.

If you’re curious how to put this into practice, here are a few ways to start exploring the framework:

1. Map the loop: For a behavior you care about, sketch out the triangle. What’s the target behavior? What personal factors are at play? What aspects of the environment support (or get in the way of) it?

2. Look for leverage: Where’s the easiest place to intervene? What can you influence? Can you simplify the behavior? Boost someone’s confidence? Tweak the environment?

3. Design for reinforcement: How will one small success ripple through the system? Are you making it easy for users to see their own progress and identity shift?

4. Watch for misalignment: Sometimes we ask people to act in ways that clash with their environment or identity. If the loop is pulling in opposite directions, change is hard. Instead of pushing harder, look for ways to realign the experience: can your product shift identity, reframe the context, or make the behavior feel easier?

People shape their own world – and are shaped by it

This framework reminds us that people aren’t just passive recipients of design. They shape their world, just as the world shapes them. The most effective behavior change strategies – in products, services, or systems – work with this loop, not against it.

Of course, no framework can fully capture the messy, layered reality – and all the nuance (pun intended) – of human behavior. Every model is a simplification of the real world – a starting point, not a conclusive solution. Behavior change is complex. What works for one audience, context, or behavior might not land in another. Just applying this triangle won’t magically fix every engagement or adoption challenge.

But what it can do is help us ask better questions. It pushes us to look beyond surface-level fixes and consider the deeper forces at play – how people think, feel, act, and interact with their environment. And in that way, it offers a useful lens for thinking more systemically about change.

So next time you're shaping a new onboarding flow, refining a habit-forming feature, or thinking through how to boost long-term engagement, try applying this triangle. It won’t give you all the answers, but it will help you see more of the (behavioral) picture.

And maybe, just maybe, it will help you design for real, long-lasting change.

Have a behavioral challenge in mind? Feel free to reach out – we're here to help!