Behaviour Change and Sustainability Practice

If organisational culture sets the conditions for responsible change, behaviour change is how that change practically happens at the level of individual people. The starting point is understanding why sustainable behaviour is so hard to achieve. The value-action gap describes the well-documented mismatch between the sustainable values people hold and the actions they take. People are not simply being dishonest; the gap arises because behaviour is shaped by far more than values and information. Habit, convenience, social norms, cost, time pressure, and the design of the environment all influence what people do, often more powerfully than their stated beliefs. This is why information campaigns alone, telling people why sustainability matters, often fail to change behaviour. 

The COM-B model, developed at University College London by Michie and colleagues, offers a powerful way to understand this. It proposes that any behaviour (B) requires three things to be present at once: Capability (C), the physical and psychological ability to perform the behaviour, including the knowledge and skills it needs. Opportunity (O), the external conditions that make it possible, including both the physical environment and the social environment, and Motivation (M), the internal drivers, both reflective (conscious intentions) and automatic (habits and impulses). The model’s key insight is that all three must be present. If any of them is missing, the behaviour will not happen. An employee may be motivated to recycle and capable of doing so, but if there is no recycling bin nearby (no physical opportunity), they will not. Diagnosing which of the three is missing tells the practitioner exactly where to intervene.

The EAST framework, developed by the UK’s Behavioural Insights Team, translates this understanding into practical action. It holds that to encourage a behaviour, you should make it Easy, Attractive, Social and Timely. Easy means reducing the effort and hassle involved and using sensible defaults to make the sustainable option the path of least resistance. Attractive means drawing attention to the behaviour and making it appealing, sometimes through incentives. Social means showing that other people already do it because people are strongly influenced by what those around them do. Timely means prompting the behaviour at the moment people are most receptive, such as during a change of routine. EAST is rooted in the idea of choice architecture, or nudging, designing the environment so that the sustainable choice becomes the natural one, without removing freedom of choice.

These frameworks apply directly to sustainability practice. Consider reducing single-use cups in an office. An information poster alone rarely works. A COM-B diagnosis might reveal that staff are motivated and capable but lack opportunity. An EAST-informed response would make the reusable option easy (provide free reusable cups and remove disposable ones), attractive (a well-designed cup), social (show that most colleagues already use them) and timely (launch it alongside an office move). The same logic applies to energy use, travel choices, recycling, sustainable procurement, and countless other behaviours that a CR&S strategy depends on. The practitioner’s skill lies in diagnosing why a behaviour is not happening, then designing an intervention that addresses the real barrier rather than assuming people simply need more information.

Behaviour change also has limits and ethical dimensions a practitioner must respect. Nudging works best for small, specific behaviours, as it is less effective for large, complex changes, and it does not substitute for systemic change where the real barrier is structural. There is also an ethical line between helping people act on values they already hold and manipulating them. Responsible practitioners keep interventions transparent and in the person’s genuine interest. Crucially, individual behaviour change sits within the organisational culture explored in the previous activity: where the culture genuinely supports sustainability, behaviour change is far easier. Where it does not, individual nudges will struggle against the grain. Behaviour change is most powerful when combined with the cultural, change-management and engagement approaches explored across the rest of this learning cycle.