World Heath Day: What science teaches us about behaviour change in WASH

For Tater Alphonsina, a parent of two in Ghana’s Nandom district, her family’s health is paramount. That is why she keeps a jerrycan at the entrance of her home and fills it with clean water from a nearby handpump. Every drop into the jerrycan reminds them that regular handwashing is essential for good health. 

These daily reminders and intentional choices have helped Tater’s family and community safeguard against contagious diseases and infections.  

While many associate health with hospitals or medicines, its critical determinants often lie closer to home: in everyday environments, decisions, and habits. Simple behaviours, such as how people wash their hands, use toilets, or handle water, could be as significant as access to medical care.  

The evaluation of the project’s first phase (March 2022–June 2025) showed meaningful progress: households with functional handwashing stations rose by 19%, access to toilet facilities by nearly 11%, and access to water services increased sixfold. However, at that point, there was still work to be done on the uptake of behaviours such as regular handwashing with soap and consistent toilet use, which did not improve as much as expected. 

In light of this evidence, the initiative turned to behavioural science to better understand the impediments to change. It asked the fundamental question: why? Why are some households not washing their hands with soap, even when water is available? Why are toilets not being used? To find answers, HF4A conducted research together with Upward Spiral.    

The research used the Behaviour Centred Design (BCD) framework, which was developed by Robert Aunger and Valerie Curtis from the London School of Hygiene and Tropical Medicine. The framework is built on insights from evolutionary and environmental psychology, marketing, and neuroscience. 

The research comprised focused group discussions with community members, observations, and interviews with families, government partners, and project personnel. It revealed that knowledge alone was insufficient to change behaviours: social and cultural factors as well as practical constraints were equally significant determinants. Understanding these drivers allows behaviour-change efforts to move beyond raising awareness and address the underlying motivations behind daily decisions. 

The study found that homes often lacked a convenient and dedicated handwashing station and soap. Where toilets were available, they were not weather-resistant and became rundown over time. People did not know how to maintain them using locally available materials and stopped using them. In some homes, cultural norms discouraged men and women from sharing a toilet.  

Identifying these barriers helped develop strategies to promote recommended behaviours. For example, building climate-resilient toilets using locally available materials such as treated logs and mud to increase their durability. Where resources are not a constraint, gender-segregated toilets become an option. Setting up a handwashing station in a prominent location at home could serve as a constant reminder to family members to wash their hands with soap. 

Behaviour change is rarely driven by information alone. It is shaped by social norms, aspirations, convenience, and trust. By featuring families, community members and frontline health workers, the videos reflect real decision-making contexts rather than idealised behaviours. Testimonials from early adopters reinforce a key lesson: when facilities are durable and convenient, healthy behaviours become easier to adopt and sustain.

Through this approach, HF4A will continue to assess how behaviours shift over time and work with communities, partner organisations, and the local governments to refine its strategies. As this year’s World Health Day theme “Together for health. Stand with science” emphasises, collaboration and science are foundational pillars of public health. It is essential that work in this direction goes beyond the conception of science as technological advancement and applies it to the understanding of human behaviour. To support people in making healthier choices, there is an urgent need to comprehensively address social, economic, and institutional factors. 

While there is work to be done together with partners, the results are taking shape. Take the case of Columbus Yerdey, a local role model who has had an upgraded toilet in his home for 29 years.

The project featured his story in a testimonial video, which will hopefully inspire many more members of the community to make their toilets climate-resilient.  

The journey to improved hygiene and sanitation will not be easy, but as Columbus and Tater’s experiences show, meaningful progress is within reach. By using scientific frameworks to understand human behaviour and evaluate impact, project stakeholders can begin to determine what works, what does not, and how to strengthen their strategies.