The COM-B Model of Behaviour Social Change UK1
The COM-B Model
of Behaviour.
A guide on
Introduction.
There are a number of models of behaviour, each one designed
to help us better understand what drives behaviour and how
decisions are made. Having this knowledge is key when trying to
facilitate behaviour change. If we do not understand behaviour,
how can we know what it takes to change it?
The COM-B model provides insight into three components, which it suggests
play a pivotal role in producing, and therefore changing, behaviour. Below
we explain what this model is, its three components and how it can change
behaviour.
The COM-B Model of Behaviour Social Change UK2
Fig.1:
The COM-B Model.
The COM-B model proposes that there are three components to any
behaviour (B): Capability (C), Opportunity (O) and Motivation (M). In order to
perform a particular behaviour, one must feel they are both psychologically
and physically able to do so (C), have the social and physical opportunity for
the behaviour (O), and want or need to carry out the behaviour more than
other competing behaviours (M). As each of these components interact,
interventions must target one or more of these in order to deliver and
maintain effective behaviour change.
The COM-B Model.
Behaviour
MotivationCapability Opportunity
As can be seen in figure 1 (see above), capability and opportunity influence
motivation, and not only do all three influence behaviour change but are
also influenced by the change which occurs. For example, the opportunity
component may be targeted to encourage someone who is inactive to be
active, i.e. providing social and physical opportunity through free, group
exercise sessions. If this individual initially thought that they did not have the
appropriate skills to take part in an activity (capability) but were still provided
with the opportunities to attend a class, then by going to this class they
The COM-B Model of Behaviour Social Change UK3
reinforce the idea that they do have the capabilities required. This suggests
that this is an interactional model, and that by changing behaviour we are
also impacting on determinants of behaviour, which allows for long-term
behaviour change.
Each component of the COM-B model can be broken down into further
components, which are as follows:
Capability: Capability refers to whether we have the knowledge,
skills and abilities required to engage in a particular
behaviour. Its two components are:
•	 Psychological Capability: our knowledge/
psychological strength, skills or stamina
•	 Physical Capability: our physical strength, skill
or stamina
Opportunity: In the context of this model, opportunity refers to
the external factors which make the execution of a
particular behaviour possible. Its two components are:
•	 Physical Opportunity: opportunities provided
by the environment, such as time, location and
resource
•	 Social Opportunity: opportunities as a result of
social factors, such as cultural norms and social
cues
Motivation: Motivation refers to the internal processes which
influence our decision making and behaviours. Its two
components are:
•	 Reflective Motivation: reflective processes, such
as making plans and evaluating things that have
already happened
•	 Automatic Motivation: automatic processes, such
as our desires, impulses and inhibitions
The COM-B Model of Behaviour Social Change UK4
Putting COM-B into Practice.
According to the model, one or more of its components must be changed in
order to facilitate effective and long-standing behaviour change. By changing
both perceived capabilities and opportunities, we can influence a person’s
motivation for executing a particular behaviour and therefore encourage
behaviour change. If this change is powerful enough, it will impact on their
determinants of behaviour and lead them to favour the new behaviour over other
competing behaviours, therefore reinforcing long-term behaviour change.
Below we have provided an example of how the COM-B model can be utilised
for behaviour change. This example involves encouraging an inactive person to
be active.
Capability.
The inactive individual may not think they have what they consider to be
the appropriate physical skills (physical capability) or knowledge of exercise
techniques (psychological capability) to take part in physical activity. This
perception of not having the capability to carry out a particular behaviour would
negatively impact their motivation to do so. In order to change this, the individual
needs to be given the physical and psychological capabilities they think they
need to engage in physical activity – they may already have these capabilities, so
it may be a case of helping them to realise this.
When considering psychological capability, workshops or training sessions can
help an individual develop their knowledge or skills in a particular area. In this
case, a personal trainer or training app could show them what exercises they
will benefit from and how to complete these. With regards to physical capability,
individuals need to be reminded that there are classes available for all skill levels,
and that strength, stamina and skill will improve over time.
Opportunity.
The perceived cost and time constraints on an individual (physical opportunity)
alongside the lack of a companion (social opportunity) may be barriers to their
participation in physical activity. In order to overcome these barriers, individuals need
to be shown what opportunities are already available or, alternatively, opportunities
need to be provided which encourage individuals to take part in physical activity.
The COM-B Model of Behaviour Social Change UK5
An individual may already be aware of the opportunities available but feel
unable to utilise these. This could be due to monetary issues (physical
opportunity) or because it may not be something that any of their friends take
part in (social opportunity). Providing free exercise classes which encourage
people to attend with a group of friends may override these barriers, making
physical activity seem more feasible and opportune for the individual.
Motivation.
With regards to motivation, an individual’s lack of capability and opportunity may
result in their ‘need’ to be physically active being overshadowed by their ‘want’ to
relax and remain inactive; being inactive is likely to be a behaviour that they have
high capability and opportunity for. However, if the above changes are made to
the individual’s perceptions of capability and opportunity, then their motivation
to carry out the behaviour may be increased.
Based on this assumption, the key to behaviour change would be to establish
physical activity as something the individual not only ‘needs’ but also ‘wants’ to
do. This can be done by encouraging the individual to consider the long-term
benefits of physical exercise (reflective motivation) and use these benefits to
make physical activity seem the more desirable option as opposed to inactivity
(automatic motivation). Framing physical activity as something they both need
and want could motivate them to execute the behaviour, and override the
competing behaviour of remaining inactive.
Behaviour.
If the above interventions are successful, the individual’s behaviour will change and
they will be more physically active. By engaging in physical activity, the individual may
improve their skills and knowledge of exercise (capability) and begin to see the activity
as a normal part of their routine (opportunity). Alongside this, they may experience
a range of health and social benefits as a result of being physically active, making it
something they see as a positive and therefore desirable activity (motivation).
This shows how successful behaviour change can link into maintaining the new
behaviour, as it is not just the behaviour that is changed but also its determinants.
These changed determinants may then go on to have an impact on other behaviours,
making behaviour change even more widespread.
The COM-B Model of Behaviour Social Change UK6
Fig.2:
The BCW.
The Behaviour Change Wheel.
The Behaviour Change Wheel (BCW) model was adapted from the COM-B and is
another tool that can be utilised to encourage behaviour change. It uses the initial
three components of capability, opportunity and motivation to provide seven ‘policy
categories’ and nine ‘intervention functions’, which can be used to develop
effective behaviour change interventions (see figure 2). The policy categories
facilitate the interventions, allowing them to be used to encourage change in one
of the three main areas of the COM-B model.
Guidelines
Environmental/
Social planning Communication/
Marketing
Leg
islation
Service provision
Regulati
on
Fiscalmeasures
Restrictions Education
P
ersuasionIncentivisation
Coer
cion
Training
Enab
lement
ModellingEnvironm
en
tal
restructurin
g
Capabili
ty
Op
portunity
Motivation
Physical
Social
Reflective
Automatic
Psychological Physical
The COM-B Model of Behaviour Social Change UK7
Conclusion.
The COM-B model is an appropriate starting point for any social marketing
campaign, as it provides insight into the determinants of behaviour and how
changes to these can encourage changes in behaviour. Once this model has
been used to understand what needs to be altered to facilitate behaviour
change, it would be beneficial to use the BCW model to understand how this
may be possible.
Why and How to use Video in Research Social Change UK7
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The Behaviour Change Wheel (BCW) and COM-B model was developed from 19 frameworks of
behaviour change identified in a systematic literature review by UCL, Centre for Behaviour Change:
Authors: Susan Michie, Maartje M van Stralen, Robert West