The Gold Standard of Behaviour Change: Understanding COM-B

Author: Joe Gaunt, Health Psychologist & Founder of Health Labs HQ

Behaviour change research has advanced significantly in recent years, and one of the most respected, evidence-based frameworks to emerge is the COM-B model (Capability, Opportunity, Motivation; Michie et al., 2011; 2014). This model proposes that any behaviour is the result of the interaction between these three factors. When one is lacking, the behaviour becomes harder; when all three are aligned, meaningful change becomes far more likely.

In other words, behaviour isn’t just about willpower. It’s about whether we can, whether our environment allows it, and whether we want to - and these levers can be adjusted to heighten our chances of success.

1. Capability: Skills, Knowledge and Physical Ability

Capability refers to our psychological and physical capacity to perform a behaviour. Psychologically, this includes our knowledge, understanding, and cognitive skills. Physically, it includes strength, stamina, or practical ability.

Take nutrition, for example:
If your goal is to improve dietary habits, having a solid grasp of energy balance, portion sizes, or food labels increases your likelihood of success. Without this foundational knowledge, even strong motivation can fizzle out, because you don’t know what to change or how to do it consistently.

How to boost Capability

• Make learning accessible: use podcasts during commutes, short videos, or reliable written summaries.
  
• Focus on small, manageable skills first (e.g., mastering breakfast, learning two quick high-protein meals).
  
• Use spaced learning: revisit a concept repeatedly, in short bursts, to embed it more deeply. Research shows this significantly improves retention.
  

2. Opportunity: The Environment That Enables Action

Opportunity includes both physical opportunity (time, resources, access) and social opportunity (support, cultural norms). You may have the skills and the desire - but if your environment isn’t set up for the behaviour, progress will be slow and frustrating.

For example, if your goal is regular gym attendance:
Is there a gym nearby? Does it fit your schedule? Do you have childcare? Do work demands spike at certain hours? Can you afford additional support such as classes or a coach?

Even perceived friction can derail follow-through. Behavioural science shows that reducing friction (e.g., lowering time cost, simplifying steps) dramatically increases the likelihood of action.

How to shape Opportunity

• Set up systems that bypass obstacles: pack gym kit the night before, keep it in your car, or prepare food ahead of time.
  
• Adjust your environment so the desired behaviour becomes the easiest choice (e.g., keeping healthy foods visible, laying out running shoes by the door).
  
• Build supportive social opportunity: train with a friend, join a group, or share progress with someone you trust.
  

3. Motivation: The Desire to Act - and Why It’s the Most Volatile Variable

Motivation includes both reflective processes (intentions, plans, values) and automatic processes (habits, emotional responses). Importantly, motivation is fluid. Some days it’s high, other days life feels heavy, and enthusiasm drops.

This is why relying on motivation alone is a fragile strategy. When it’s high, ride the wave - but use these moments to strengthen your systems for when motivation dips.

How to support Motivation without depending on it

• When motivation is high: push forward, bank some early wins, and set up your systems for future challenges.
  
• When motivation is low: adopt a “just show up” mindset. Do the minimum viable version - the NATS principle (“Not As Tough as Simulated”) from The Journal reminds us that the anticipation of difficulty is usually far worse than the task itself.
  
• Remember: going light is still going. You maintain the habit, keep the identity intact, and reduce the psychological cost of the next session.

Behaviour Change Takes Time - Don’t Quit Early

It’s normal for attempts to feel messy at first. Behaviour change often demands a concentrated effort initially as we build new neural pathways, routines, and environmental structures. Progress isn’t linear; lapses aren’t failure - they’re data. The COM-B model encourages us to explore which part of the system needs attention, rather than assuming we’re “not motivated enough”.

References:

Michie, S., Atkins, L., & West, R. (2014). The behaviour change wheel: A guide to designing interventions. Silverback Publishing.

Michie, S., van Stralen, M. M., & West, R. (2011). The behaviour change wheel: A new method for characterising and designing behaviour change interventions. Implementation Science, 6(1), 42.