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Behavioural Science

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What is Behavioural Science?

Evidence-based insights about how people think, decide, and act.

Behavioural science is the empirical study of how people think, decide, and act, with an emphasis on observation and experimentation. Behavioural science draws from multiple disciplines to understand how our innate human traits and the social and environmental contexts in which we live shape our perceptions, habits, and actions. Applied behavioural science leverages evidence and methods from the behavioural sciences to solve real-world problems.

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“Why do we put off HIV or STI testing?”

“Why do we forget to take our medication?”

“Why do we fail to save for unexpected needs?”

“Why do we put off HIV or STI testing?”

“Why do we forget to take our medication?”

Why do we fail to save for unexpected needs?

These are examples of challenges where evidence and insights from the Behavioural Sciences can help improve our understanding of what shapes people’s decisions–including our own–and better identify opportunities for positive change. Behavioural Science helps us understand why we all often struggle to follow through on our best intentions.

Why does Behavioural
Science Matter?

Behavioural science provides useful insights for policy and programming by investigating: 

What drives human behaviour?

Behavioural science suggests that human behaviour is influenced by a complex interplay of internal and external factors. People’s behaviour is not solely driven by rational decision-making but is often subject to mental shortcuts, emotional responses, and social and environmental cues. Understanding how these factors interact to shape people’s actions provides an evidence base for designing more effective initiatives aligned with the realities of human behaviour.

How do we motivate behaviour change?​

Behavioural science indicates that information and incentives may influence our intentions, but they are often not enough to change behaviours. 

In many cases, behaviour change depends on restructuring the decision environment to remove barriers, simplify options, and make it easier for people to follow through on their intentions. Because humans are social animals, behaviour change also often involves providing social cues to signal which behaviours are acceptable and desirable within the communities to which people belong.

How do we overcome the Intention-to-Action Gap?​

Behavioural science provides a growing body of evidence for strategies to help people overcome the gap between their intentions and actions. Examples of proven and promising approaches include:  

  • using subtle cues or “nudges” to guide people toward desired behaviours
  • designing environments or “choice architecture” to make the preferred behaviour the default or more accessible option
  • encouraging individuals to plan specific details about when, where, and how they will carry out their intentions
  • highlighting what is socially accepted and desirable behaviour within a particular group
  • providing regular feedback on progress, establishing mechanisms for self-monitoring, and providing symbolic recognition of achievements
  • fostering social connections, encouraging individuals to share their intentions with peers, and creating a sense of accountability within a community

How do features of the local environment and context shape people’s choices and actions?​

People’s decisions and behaviours are affected by the context in which they operate: what cues they receive, what options are available and most visible, which actions seem easiest, or what they see others around them doing. People’s decisions are also often a reflection of cultural values and beliefs. The effective application of behavioural science requires an understanding of context, including gender relations, socio-cultural factors, and power dynamics. The tailoring of initiatives to ensure they are effective and appropriate in a given context usually requires evidence and methods from multiple disciplines.

How to Put Behavioural Science to Work

There are many frameworks we can use when designing for behaviour change. For example, the EAST Framework is a simple acronym for four basic characteristics that translate insights from the behavioural sciences into principles for public policy design.


Decreasing effort involved in behaviour change makes action more likely.


Making information or messaging distinct, attention grabbing, or rewarding.


Understanding that people care a great deal what others are doing and look to people in their social network for cues about how to behave.


Timing initiatives or calls to action to take place when people will be most receptive and able to act on the prompt.

Overcoming Barriers

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Insights from the behavioural sciences enrich traditional models of human decision-making and cognition by:

Illuminating the role of mental shortcuts and emotions in shaping people’s actions.

Emphasizing the influence of social and cultural contexts on decision-making.

Recognizing that evidence about biases and blindspots applies to everyone, including development professionals, social and behaviour change (SBC) practitioners, and policy makers.