Behavioural science is vast. There are a lot of theories. Behaviour change theories alone number over 100 and counting. But most are iterations on previous theories, and a small number are increasingly being used by behavioural designers.

Behaviour design divides behaviour into preset factors of influence. It looks at what individual people do, how people influence each other and extracts strategies from behaviour change theories.

These theories can be dissected into the same core components. Individual factors, social factors and behaviour change.

Start with these 12 theories to extract information and begin to synthesize your own insight.

Understanding individual factors of behaviour Understanding social factors of behaviour Understanding behaviour change
Antecedent- Behaviour- Consequence model (Miltenberger, 2008) Social cognitive theory on Self-regulation (Bandura, 1991) Drive model (Kelly, 2018)
Dual Process Theory (System 1 and System 2 thinking) (Chaiken et al., 1999, Kahneman, 2011) Social Cognitive Theory (SCT) (Bandura, 1986) COM-B and behaviour change wheel (Michie 2011)
Theory of cognitive Dissonance (Festinger, 1957) Social Ecological Model (SEM) (Bronfenbrenner, 1986) BMAP (Fogg 2009)
Theory of Planned Behaviour (Ajzen, 1991) Social Identity Theory (Tajfel et al. 1979; Tajfel 1982) Nudge (Thaler & Sunstein, 2008)

The theory of behaviour change

These are the ones to start with:


Kelly. 2019

Behaviour = Me, We, Oversee

Drive is a behaviour framework created for digital products and services. It combines theory from behaviour change with product and service design principles to drive change.

It has a wider focus than BMAP, looking at what influences behaviour outside of the touch points. It helps designers to define and explore the factors of hidden influence. Factors that have a big impact on user behaviour, that are often found outside of the initial point of interaction. It shifts the focus away from policy intervention (the COM-B model) to user and customer behaviour. It aligns behavioural science with who users are on a deeper level. What they want. How others influence them. And looks at how the context alters their actions.

The Drive model aligns product decisions with current behaviour. It looks to positively change user behaviour, and minimises unforeseen outcomes by measuring the impact of change.

Drive divides user behaviour into three drivers - What users think and feel. What other people think and do. And what is happening around a user that may influence them. Each informs and changes what people do. Often without them realising.

Explore how to use the Drive model. Read: Ways of working

Me drivers - What users think and feel.

People are driven by different things. Me drivers take a deep look at the user. The person at the centre of the action. What they are influenced by, the way they think and what they feel.

Me drivers include:

  1. Who people are - Persona
  2. What people feel - Emotion and attitudes
  3. What people want - Needs
  4. What people are driven by - Motivation
  5. What people plan to do - Intent
  6. What people think they can do - Self-efficacy
  7. Why people don’t do - Bounded rationality
  8. Ways people think - Cognitive biases

We drivers - What other people think and do.

People are influenced by others. We seek people’s approval, fear social rejection and tend to follow others. Our social groups and communities govern what we do and how we think. We follow unwritten rules on how to act, our social norms. Act the way we think we should, stick to social expectations, and follow others due to social compliance.

We drivers are:

  1. What other people do - Social influence
  2. What others expect people to do - Social expectation
  3. How group roles are defined - Social Norms
  4. How groups change - Group flux

Oversee drivers - What is happening around a user.

People live in a world of stimuli, rules and regulations. Our environment directs what we do. The information we pay attention to, what it communicates, structural barriers that stop us and the artefacts that give us clues on how to act. Each oversees what we do.

People also follow rules. Set by others, they govern and direct our behavior. We are driven to act in accordance with the rules, for the most part. We also break them. Laws set by our Governments, guidelines from our employers and agreements with companies. Each act as a guide so we know what is expected of us. To design for user behaviour, you have to understand what is currently overseeing their behaviour.

Oversee drivers are:

  1. Where people are - Context
  2. What stops people - Structural barriers
  3. What rules people  - The rules and laws
  4. What messages do people see - Communication environment
  5. What’s already designed - Artefacts
  6. What’s different - Emerging alternatives

Me We Oversee Checklist

Me Drivers

  1. What is people's identity?
  2. Is a person's identity related to the behaviour?
  3. What do people feel?
  4. Is the behaviour emotion driven?
  5. What are people motivated to do?
  6. What do people plan to do?
  7. What do people think they can do?
  8. Why don't people already do the behaviour?
  9. How do people process the information?
  10. What cognitive biases influence people?

We drivers

  1. What do other people do?
  2. What do other people expect them to do?
  3. What groups are people a member of?
  4. What are the social norms of those groups?
  5. Has the group changed?
  6. What caused the group to change?

Oversee drivers

  1. Where are people?
  2. What other objects or messages surround people?
  3. What do these messages say?
  4. What do other artefacts encourage people to do?
  5. What else grabs people's attention?
  6. What rules and regulations exist?
  7. What's different?


Susan Michie, Maartje M van Stralen & Robert West. 2011

Behaviour = Capability + Opportunity + Motivation

COM-B is a behaviour framework that is structured and analytical. It is used to solve broader, often complicated behaviour change challenges. Ones with multiple variables.

The 6 components of COM-B
It is similar to BMAP, in that it has three main components. For a behaviour to happen each component must be satisfied. Unlike in BMAP, the main components in this model can influence each other, apart from Motivation, which can only be influenced by just the other two. For example, if you increase capability, you can also increase motivation.

‘Capability is defined as the individual’s psychological and physical capacity to engage in the activity concerned. It includes having the necessary knowledge and skills. Motivation is defined as all those brain processes that energize and direct behaviour, not just goals and conscious decision-making. It includes habitual processes, emotional responding, as well as analytical decision-making. Opportunity is defined as all the factors that lie outside the individual that make the behaviour possible or prompt it.’

Michie et al. 2011

Each component is subdivided into two further sub-components.


People have the skills and mental ability to do the behaviour.

Physical capability
People need to be able to physically do the action. By either having a motor skill, like driving, or the physical strength to act.

Psychological capability
People need to be able to mentally process the action or have the mental skill. For example,

  • Have enough knowledge.
  • Have cognitive or mental ability.
  • Interpersonal skills - especially useful if a behaviour required interacting with someone else.
  • Be able to have control over their actions and behaviour. They need to be able to self-regulate.


People are given the opportunity to act. Defined by factors outside of the individual, in their environment that help or hinder potential behaviours.

Physical opportunity
Are people prompted to act, and once people start are all the resources and services available for them to continue?

Social opportunity
People are social animals. Often they will stop doing something if they think others disapprove or won't do it themselves. Peer pressure changes what we do. Same with social norms and expectations on how to act.


Drive. It’s important to all behaviour. What energises us and starts us off is very important.

Automatic responses
People act on impulse. Driven by habits and emotional responses, it can make people act quickly and impulsively. People are often unaware of habitual behaviours, they are also hard to change.

Reflective thought
People also consider their options. They think about what to do, how to reach their goals and what aligns with their beliefs and identity.

COM-B checklist

Psychological capability

  1. Do people know they have to change?
  2. Do people know what’s required to change?
  3. Do people understand the benefits?
  4. Do people understand what will happen if they do?
  5. Do people understand what will happen if they don’t?
  6. Do people find it easy to do?
  7. Do people need to pay attention to do the action?
  8. Do people remember to act?
  9. Do people feel in control?
  10. Do people understand what is required?
  11. Do people have the mental skills needed?
  12. Do people have the concentration to follow through?

Physical capability

  1. Do people have physical skills needed?
  2. Do people have dexterity and ease of movement?
  3. Do people have physical strength?
  4. Do people have the ability to overcome physical limitations?

Physical opportunity

  1. Do people have the time?
  2. Do people have the financial means?
  3. Do people need equipment or facilities?
  4. Do people have easy access to resources?
  5. Do people have competing tasks?
  6. Do people have reminders?

Social opportunity

  1. Do people have the social support required?
  2. Do other people help or hinder the behaviour?
  3. Do other people do different?
  4. Do other people remind them?

Reflective motivation

  1. Do people think the benefits outweigh the costs?
  2. Do people feel they want to do it?
  3. Do people care about the consequences?
  4. Do people have other goals that may stop them?
  5. Do people have enough incentives?
  6. Do people see the behaviour as everyday?
  7. Do people know how to do it?
  8. Do people have a plan to achieve it?

Automatic motivation

  1. Do people have an emotional response?
  2. Do people feel good about doing/not doing it?
  3. Do people feel bad about doing/not doing it?
  4. Do people do it repeatedly? Can they start to form a habit
  5. Do people need a way to avoid actions?


Fogg, 2009

Behaviour =  Motivation + Ability + Prompt

Behaviour is the result of three elements, coming together at the same moment.

Motivation and Ability are a tradeoff. If people have high motivation, then they can have a low ability and still act. Their drive will push them through the barriers and hurdles. If ability is high, people will likely do an action with low motivation. The barrier to entry is low. So people are more likely to give it a go.

BMAP goes by a couple of names. Including Fogg Behavioral Model (FBM) and BMAT, with triggers used instead of prompts.

BMAP is used more in design than COM-B - which is generally used in policy intervention. BMAP lends itself more to persuasion, with its more focused approach and inclusion of prompts to initiate behaviour. With BMAP, designers can identify gaps in influence and persuasion, exploring factors that may be stopping or limiting action within a digital product or service.


People aren’t motivated by the same thing. Instead, motivation falls into three sub-categories. These are sensation, anticipation and belonging. In essence, this means motivation can be broken down into three distinct levels:

  1. A physical level (sensation)
  2. An emotional level (hope/fear)
  3. A social level (acceptance/rejection)
Motivation - sensation

Sensation - Physical motivation
As humans, we are motivated to seek pleasure and to avoid pain. Sensation is the only motivation type that has an immediate effect. People react instinctively towards pleasurable experiences and away from painful ones. ‘Pain’ in this context doesn’t just mean actions that hurt us physically, it includes cognitive pain. Behavioural economics shows that we tend to feel a loss about twice as severely as we experience a gain. This loss stems from a loss of resources, like money and time.

The pleasure driver is one of the reasons gamification is so effective for new users. We enjoy feeling like our effort is being rewarded with signifiers, like badges and awards.

Caution. Avoid using pain as a primary motivator, it is difficult to achieve without hurting people or your business.

Motivation - anticipation

Anticipation - Emotional motivation
We are driven by anticipation. The hope of something good, and fear of something bad.

People do uncomfortable things in the hope they will have a good outcome. For example, you may sign up to a dating site in the hope you will meet someone. If you’ve ever signed up to a dating site, you’ll know that signing up is hard. It takes a long time, you agonise over what to share and how to share it. You may even have paid hard earned cash for the privilege. The barriers are high. But anticipation keeps you going.

People anticipate the worst. They fear something bad happening if they don't act. Fear motivates action. Getting a flu jab is never fun, but people do it to overcome the fear of getting this year’s flu.

Anticipation has a big part in Persuasive Design, as most design solutions are focused on either hope or fear.

Motivation - belonging

Belonging - Social motivation
We are social animals. Other people have a big influence on what we do. We are highly driven by social acceptance and status.

We’ve all heard of, and likely experience FOMO. The fear of missing out a part of social rejection. So is social compliance. We want to feel like a part of the group, so we act similarly to others.

To see social motivation, look to social media platforms. Social belonging motivates you to continually post content, follow others and in turn get followers yourself. It embraces your desire to be socially accepted.


With all the will in the world, if people can’t do it, they won’t.

If people can’t act, they won't. Motivation is powerless when faced with huge hurdles. Ability is as important as motivation. People need to have the ability to act in the moment when they are prompted. In Fogg’s model, ability is less about having the required skills, and more about the action being as easy to do as possible.

'Simplicity is a function of your scarcest resource at that moment. Think about time as a resource, If you don’t have 10 minutes to spend, and the target behavior requires 10 minutes, then it’s not simple. Money is another resource. If you don’t have $1, and the behavior requires $1, then it’s not simple.'

Fogg defines 6 ability types. Each focusing on a different resource that people have. He also stresses that different people will have different ability types. When designing it’s important to cover as many as possible. One user may be short on money, another on mental bandwidth.

Types of ability

Time is sacred. And people are in a rush.

Money is limited. And people need it to pay the rent and for food. They are unlikely to spend it without thinking about it first.

Physical effort
People only have so much strength and resilience. Avoid asking people for over strenuous actions.

Brain cycles / Mental bandwidth
If people need to think hard, then they won't. Especially when their minds are already full of other things. Thinking deeply and in a new way is hard and taxing.

Social deviance
People rarely go against the norm. They conform to others.

Non-routine / habit
People do things on autopilot. Sticking to familiar routes and routines.


Doing or not doing is sometimes a fine line. A line that can be defined by the type of prompt you use. It may be about pinpointing the best time to prompt someone. Their opportune moment of persuasion. Or selecting the best prompt to get people over the threshold.

If people lack motivation, you can spark them into action. Triggers are designed in combination with motivation. Sparks leverage one of the motivation types in their design. They highlight benefits, introduce social influence or use emotion.

Sometimes people need a leg up. If they have the motivation, but lack the ability a facilitator prompt can bridge the gap. They trigger the behaviour by making it easier to do. Self checkouts in supermarkets make it easier for time-short shoppers to buy their goods. Social media connects with your contacts to automatically add friends. Amazon offers purchasing with one click.

When people are ready, they just need a signal. They have both motivation and ability, but need to know when to act. A green traffic light doesn’t aim to motivate you. Instead it just communicates ‘act, and act now’.

BMAP checklist


  1. Are people motivated by something visceral and automatic? Like, desire, pain, hunger or thirst?
  2. Are people motivated by fear or hope?
  3. Are people motivated by a desire to belong?
  4. Are people motivated by avoiding rejection by peers?


  1. Do people have the time?
  2. Do people feel like they have the time?
  3. Do people have other time demands?
  4. Do people have enough money to act?
  5. Do people feel it’s worth it?
  6. Do people know others also do it?
  7. Do people have any habits that block the action?
  8. Do people have the mental capacity?


  1. Do people need a motivation boost? - Spark prompt
  2. Do people need it to be easier? - Facilitator prompt
  3. Do people need an in-context cue? - Signal prompt


Thaler and Sunstein. 2008.

Nudges aim people in a desired direction. They use how information is presented to nudge people towards a choice and action.

As Richard Thaler and Cass Sunstein wrote the book ‘Nudge’ in 2008,

'[You should] offer nudges that are most likely to help, and least likely to inflict harm.
Thaler and Sunstein

They are most useful when people are faced with difficult decisions and find it difficult to accurately assess the options. People are prone to mistakes in their thinking, often succumbing to bias and heuristics that push them towards less beneficial choices. Nudges help stop this by using choice architecture. How information is presented and when to help nudge people towards better choices.

Nudge is defined as:

'any aspect of the choice architecture that alters people’s behavior in a predictable way without forbidding any options or significantly changing their economic incentives. To count as a mere nudge, the intervention must be easy and cheap to avoid. Nudges are not mandates. Putting the fruit at eye level counts as a nudge. Banning junk food does not.'
Thaler and Sunstein

In short, a nudge is any small feature in our environment that attracts our attention and alters our behaviour. They don’t use economic incentives, remove choices or provide new information. Instead a nudge uses how options are presented to people.

There are two nudge categories. A nudge either influences aspects of the environment, or placements within it.

Properties of the environment.

The objects and artefacts that you come across, and which subtly influence you. These objects are designed to influence you by how they grab your attention. Their properties, like size, and the way they communicate information, start to create the choice architectures where nudges reside. People don't want to make hard choices. Especially when they are about events in the future. Saving for retirement is one such event. When the UK switched from an opt-in to an opt-out system, the number of people with a workplace pension jumped from 2.7 million to 7.7 million in 2016.

Placements within the environment.

Objects don't stand alone. They sit in a context. How those objects interact with others around them has influence. Are they more or less easy to interact with? How are they positioned in relation to other artefacts? To encourage people to eat healthy, put fruit at the front and brownies towards the back. A simple buffet rearrangement can increase fruit intake by 84% and cut brownies eaten by 39%. You still give people the option, but people on average are more likely to pick up the fruit.

There are a number of nudge types. Including:

  • Defaults
    Make the wanted choice a default. People are unlikely to change the preselected option, especially when it is hard to make a decision.
  • Social proof heuristics
    We follow others. Tell people or show people what other people chose.
  • Framing.
    How information is framed changes people’s choices. Salience.
    How much an option stands out. Draw attention to it.

Now we've started to explore the theory. You need to know how to apply it. See how the theory fits into a design process. Next read → Ways of working.