Is Nudge Theory the Right Approach to Coronavirus?

Making sense of the UK’s unusual approach to coronavirus.

Posted Mar 14, 2020

As countries worldwide respond to the coronavirus pandemic by locking down borders, shutting schools, banning large gatherings and quarantining travellers, the United Kingdom’s government has just announced a very different and unusual approach. It will use a behavioural science theory called ‘nudge theory’ that places the responsibility for containing coronavirus on the individual. Authorities have told the UK public that most people will contract coronavirus, that there will be many fatalities, and that the aim is to achieve ‘herd immunity’ against coronavirus within the UK. The UK’s approach is different from many other countries where governments want to minimise the spread of coronavirus, minimise the number of people with coronavirus and minimise the number of fatalities. But can it work? 

The UK government drew advice from experts including virologists, epidemiologists and behavioural scientists who suggest that the UK should apply nudge theory in making people individually responsible for containing coronavirus by washing their hands, coughing into tissues, and self-isolating if they have symptoms. The experts advised the UK government to not do what other countries are doing yet (such as closing schools, universities and large events). The UK public has been told by the government to accept that at least 60% of the population will get coronavirus, that there will be many fatalities and that the UK is aiming for ‘herd immunity’ against coronavirus. This can leave you wondering how to feel about it all. 

You may be wondering whether there is published evidence showing that applying nudge theory to something like coronavirus is empirically accurate. Looking at the published evidence, the answer is no. It is difficult to find any randomised controlled trials, systematic reviews or meta-analyses showing that nudge theory works in the context of infections or illnesses. Therefore, using nudge theory to tackle coronavirus is a very risky gambit. 

Even outside epidemiology, the evidence suggests that the impact of ‘nudge’ interventions on behaviour change is quite small. In the context of coronavirus this can mean that few people are likely to significantly improve their hand washing, coughing and self-isolation behaviours. The risk that the virus will spread is therefore likely to be much higher than the mathematical modelling used by the UK government’s experts. Their hypothesis that the strategy will flatten the curve of the spread of coronavirus might be incorrect because people do not behave exactly as theory predicts they will behave. 

There is very little published evidence showing that nudge theory works in epidemiology (managing the spread of disease) at the scale of infections like coronavirus. Relying on the public to limit the peak of coronavirus virus is a big risk because of the lack of actual published evidence showing that this works in the context of coronavirus or similar infections. This means that the mathematical modelling is based on assumptions from nudge theory about how people will behave but the assumptions are unlikely to be accurate. 

Let's also consider the hypothesis that there can be ‘herd immunity’ to coronavirus. Is it a scientifically valid approach? The hypothesis is untested within the context of coronavirus because it is a new virus and little is known about the long term impact or whether there is such a thing as herd immunity against it in the long run.

Though the virus’s genetic mutations might be few, little is known about whether people can be reinfected and if so and whether the consequences become less or more serious across time. You may also wonder what happens even if the UK does achieve herd immunity against coronavirus whereas other countries do not. It could affect international travel between countries and make it difficult for people to visit other countries as freely as they did before.

Finally, there is the matter of access to healthcare. More people with coronavirus will place a big strain on the UK’s National Health Service (NHS) by increasing the need for intensive care, and this will likely increase mortality from non-coronavirus conditions because of the shortage of intensive care beds and staff within the NHS. Most people in the UK rely on public healthcare, funded through taxes and national insurance payments, therefore an epidemic will have an impact on people with other illnesses.

If you live in the UK, deciding what approach to coronavirus works best for you requires you to have a global outlook. Definitely follow official guidance to wash your hands properly and frequently, cough or sneeze into tissues and self isolate if you have symptoms. However, you do not have to accept that getting coronavirus is inevitable, and you should use advice from other countries about things that you can do to protect yourself and other people.