Sarah Osman
If you work in global development, you’ve probably heard people throw around terms like Applied Behavioural Science, Social and Behaviour Change (SBC), and Behavioural Insights (BI). They all sound similar because they are: each draws on how people make decisions and behave.
But they come from different traditions, use different toolkits, and are useful in different ways. As someone who helps social impact organisations apply social and behavioural science in their projects, I see a lot of confusion about the labels. This piece is a practical guide to what each means, how they overlap, and how you can use them alone or together to make programmes more effective.
Applied behavioural science is the big umbrella: using insights from psychology, behavioural economics, cognitive science and more to explain why people do what they do and then designing policies, services, and products that help them follow through on their intentions. In my experience, many who use this term come from the behavioural economics space and tend to put more emphasis on cognitive biases and individual drivers of behaviour. They will often end up designing nudges and making tweaks to the choice architecture to drive behaviour change.
Generally, applied behavioural science will require a level of experimentation. This can include A/B tests, randomised control trials, and rapid learning cycles. A text message won’t end poverty or gender-based violence. But it can remove frictions, raise uptake, and improve service delivery as part of a bigger strategy. The art is pairing behavioural tweaks with social, structural and systemic change so interventions make meaningful difference. However, applied behavioural science in the global development space tends to overfocus on individual level barriers.
SBC is a holistic approach that came out of public health in the development space. If applied behavioural science grew up in labs, SBC grew up in clinics, communities and communication. It blends behaviour change theory with community engagement, participatory research, service improvements, and policy advocacy.
SBC looks beyond the individual to the wider ecosystem: beliefs and attitudes, family dynamics, community expectations, availability and quality of services, and enabling policies. It often uses a strategic mix of channels such as mass media, interpersonal communication, community mobilisation, and stakeholder advocacy, tailored to local culture, language and practices. Modern SBC explicitly draws on social and behavioural science and human-centred design, but keeps its strength: deep audience research, and long-term, norm-shifting work.
The evaluation toolbox for SBC can include the experimental style of applied behavioural science, but it is also broader and more grounded in reality, using qualitative methods to assess efficacy of interventions alongside experimental methods. Change is often assessed in the long term as the focus is not only on changing individuals’ behaviour, but also that of communities, societies and systems. SBC is comprehensive and systemic.
“Behavioural insights” is used in two ways. Small “b” and “i” refers to insights drawn from behavioural science, e.g., realising that confirmation bias makes farmers discount new advice. Big “B” and “I” usually refers to a particular approach popularised by government “nudge units”, like the UK’s Behavioural Insights Team and organisations such as the OECD.
The BI approach focuses on practical, testable changes to processes and communications (choice architecture) paired with rigorous evaluation. The ethos is “Test, Learn, Adapt”: identify a specific behavioural bottleneck, design a tweak (a message, form, incentive, or default), test it against the status quo, then scale what works.
Classic examples include adding a social norms line to tax letters to lift payment rates, or framing organ donation messages to tap into reciprocity, leading to more registrations. In development, units like the World Bank’s eMBeD add experiments into programmes: simplifying forms, re-framing incentives, testing outreach to boost uptake of cash transfers or new farming technologies. You can think of BI as a crisp, methods-forward subset of applied behavioural science, with a public policy focus and strong measurement discipline.
All three share the same foundation: people are not perfectly rational, context matters, and evidence beats assumptions. The differences are emphasis and scale:
In practice, the best programmes blend them. Imagine you want to increase rural girls’ attendance in secondary school. The SBC lens gets you engaging parents and elders, addressing gender norms, strengthening mentoring, and advocating for safer, more welcoming schools. The applied behavioural science/BI lens gets you redesigning the registration journey (simpler forms, clearer deadlines), sending timely SMS prompts, and using commitment cards at community meetings, then testing which tweaks actually lift enrolment and attendance.
This combination respects culture and community while addressing systemic barriers. It’s people-centred, evidence-based, and measurable.
You don’t need to pick a camp. Build a blended toolbox: do rich formative research (an SBC strength), map behavioural bottlenecks (an ABS/BI strength), co-design with communities, and iterate with data. Personally, I use the term ‘applied social and behavioural science’ because it is a reflection of my skill-set and how I work.
However, I think it is important to be clear about which lens you are going into programme design with. In global development, it probably makes the most sense to have an SBC lens as the primary one.
I’m planning to produce a more detailed resource on how each of these approaches have been used in the global development sector with comprehensive examples. If you are interested in contributing to this effort, please sign up here!