Brazil has been the Latin American country hardest-hit so far by the coronavirus pandemic, with many fearing that deaths from Covid-19 are rocketing well beyond the 2,588 officially recorded so far.

The situation is particularly dire for the millions of Brazilians living in densely populated favelas where physical distancing is almost impossible. But Brazilian president Jair Bolsonaro doesn’t seem to be taking concerns over the virus seriously, accusing the media of “hysteria”. And he has clashed with Rio de Janeiro’s governor, Wilson Witzel, who has ordered the state’s 17 million citizens to stay at home – and off the city’s beaches.

Helping in the effort to keep people safe and away from public areas is NudgeRio, a department in Rio’s city hall that uses behavioural science to influence people’s decisions. The team has helped produce messages to encourage people to stay at home, including a photograph of Sugar Loaf mountain with accompanying text that reads: “Rio’s landscape gives the hint. Let’s flatten the curve.”

The NudgeRio ‘Flatten the curve’ campaign. Photograph: Rafaela Bastos/NudgeRio

For the past week, city hall has been sending drones around the city with audio messages, created by NudgeRio, to remind people to avoid crowded areas and to wash their hands. “We have produced three messages so far, but will be doing more,” says Jose Moulin Netto, who set up NudgeRio in 2018.

The team is also involved in a project to combat growing domestic violence, a global problem exacerbated by lockdown situations. Moulin says the team is considering developing an app with a panic button for women, as well as one for men to deter them from committing acts of violence.

The nudge theory was put forward in a 2008 book of the same name by economist Richard Thaler and political scientist Cass Sunstein. One of Thaler’s insights is that people do not always behave in their own best interests. From this, he developed an argument that nuanced changes can trigger desirable shifts in behaviour for individuals and society.

Former UK prime minister David Cameron was a fan and in 2010 set up the first nudge unit, the Cabinet Office behavioural insights team. Its successes include sending letters to British GPs who were prescribing more than their peers, cutting unnecessary prescriptions by 3.3%.

The UK government’s early response to the pandemic was thought to be largely influenced by the behavioural insights team. But this was subsequently changed and, as Tony Yates, a former professor of economics at Birmingham University, pointed out in early March, the UK strategy was an outlier: “If the nudgers have got it right, why are so many other countries taking a very different view of the ‘science’?”

Before coronavirus took hold, the four permanent members of the Rio team were working onchanging messaging to tackle flooding. In April 2019, Rio de Janeiro recorded its worst level of rainfall in 22 years, with storms that left 10 people dead.



Monsoon rains impact poorer communities worst, especially those in favelas on steep hillsides. This year alone, about 150 Brazilians have been killed or are missing following heavy rains, landslides and flooding.

Firefighters and others take part in a rescue operation after heavy rains in Rio de Janeiro. Photograph: Mauro Pimentel/AFP via Getty Images

Summer in the city is always “problematic”, according to Thais Miguelino, a spokeswoman for the Rio operations centre that monitors traffic, accidents and weather and manages crisis situations, including the pandemic. “We need to know how to communicate with people so they know what they need to do,” she says. “The idea is to change people’s thinking so we can save lives.”

The centre wants to work out how best to use its social media channels to communicate messages that will encourage people to stay put and avoid travel during a storm, or advise them how to get to a place of safety. To do this, NudgeRio has created different personas, including a mother with a baby and an older person, and seen how they might react to events such as flooding or a landslide.

“The rain in Rio is unpredictable and varies according to which region of the city you’re in,” explains Rafaela Bastos, a member of the NudgeRio team. “It’s very important that the population knows how to take decisions in certain situations, to be prepared and reflect on what to do with the information available.”

Other NudgeRio projects relate to tax collection, school registration and reducing jaywalking and have led to savings. But the team faces challenges getting people to take nudge seriously and proving the impact of projects. “It’s hard to convince people and to get employees involved,” admits Moulin.

Rio de Janeiro Operations Centre, Brazil. Photograph: Sarah Johnson/The Guardian

Innovation in the public sector is always a challenge, he adds: “The public sector has to abide by certain rules. There are very specific definitions of what you can do. It’s so much harder.”

There has also been criticism of the nudge approach. Sometimes it’s seen as a sticking plaster for gaping holes in public services that need more investment. Rio’s summer weather, for instance, has always been unpredictable, yet the same problems keep reappearing, suggesting a more structural approach is required.

Moulin and the NudgeRio team acknowledge the pitfalls but remain excited by the potential impact. They cite a project with the city’s education department as an example.

Every two years, the Brazilian government holds a national exam to measure the academic performance of public school students aged 10-11 and 14-15, with a mock test a month beforehand. Last year NudgeRio was asked to try to increase participation and students’ grades.

On the eve of the mock exam, the department of education sent an inspirational message from the education secretary, for parents to pass on to their children the following morning. The result? On average, grades rose by 4.1%.

“I can’t emphasise it enough,” says Moulin. “This message was sent at 7.30pm in the evening on the day before the exam and yet there was a significant increase in grades. I still get goosebumps when I think about it.”

• This article was amended on 28 April 2020. An earlier version referred to a photograph of Ipanema beach, when a picture of Sugar Loaf mountain was meant. This has been corrected.