The US needs a little nudge theory to boost its jab campaign

Joe Biden is engaged in a race against time. Earlier this year, the US president said he wanted 70 per cent of adults to have received at least one Covid-19 vaccine shot by July 4, so Americans could celebrate Independence Day together.

Vaccination rates soared from late winter through early spring, and by early this week 164 million people (or 64 per cent of adults) had received at least one dose, while 136 million were fully jabbed, according to Centers for Disease Control and Prevention data. But the number of new doses administered weekly has fallen almost continuously since April.

What is going wrong? The problem cannot be blamed on a shortage of vaccines, nor mere logistics. The distribution is being organised well now, contrary to my earlier fears.

Instead, the problem is something much harder to shift: culture. A recent survey of 15 developed countries by London’s Institute of Global Health Innovation showed that unvaccinated people in the US had the highest level of mistrust towards all vaccine brands. The challenge for the Biden team is how to start changing these attitudes, and fast. For this they need not medical, management or data science, but social science instead.

The good news is that they seem to recognise this. Under President Barack Obama, the government would ask behavioural scientists for advice when devising policies, but that unit was allowed to lapse by Donald Trump. Now Biden is doubling down on Obama’s approach.

Cass Sunstein, a leading behavioural scientist who helped to popularise the concept of the “nudge”, a policy technique that steers people towards certain actions, has written that Biden’s plan to embrace evidence-based policymaking incorporates “an explicit endorsement of behavioural science — and it calls for much more of it”. Sunstein himself has been hired by the Department of Homeland Security.

Meanwhile, aside from any White House policy, the federal structure in the US is already enabling numerous local experiments with different tactics. Many colleges will bar unvaccinated students this autumn. Some military bases are imposing tougher restrictions on soldiers who refuse the jab.

In other cases, economic incentives — or, put plainly, bribes — are being used. These range from free Krispy Kreme doughnuts for people who get the jab to the offer in Ohio of a million-dollar lottery prize for those who’ve been vaccinated. In West Virginia, officials are even floating the idea of giving away guns as vaccine lottery prizes.

But perhaps the most interesting experiments involve non-monetary persuasion. Harvard Business Review, for example, recently featured a study from Jersey, a UK dependency off the coast of France. Last autumn, the leaders of this tiny island decided to conduct their own vaccination campaign using persuasion, rather than coercion or bribery, and asked a behavioural scientist, Steve Martin, to work alongside the Jersey government’s associate chief nurse, Becky Sherrington, to find ways to do so. “I hadn’t done this before but we felt it was important to know how to get the message across effectively,” Sherrington says.

They settled on three tactics drawn from behavioural science. One of these borrowed an idea developed by a 1970s Harvard psychologist called Ellen Langer, who showed that using “because” in a sentence is an effective way to grab attention and be persuasive. A second imported a concept explored in a recent Wharton study into the flu jab, which showed that messages are also more powerful when they create “ownership” with “you” words — for example, “A flu shot has been reserved for you.”

But alongside these two psychological tools, they used a quasi-anthropological perspective to look at community hierarchies and local patterns of trust. This convinced them that it would be a big mistake to rely on scientific experts or doctors to communicate messages; a better bet was, as the HBR study reports, an “age-appropriate, relevant and trusted person known to each target group”.

Thus adverts featuring nurses who had rejected the jab but then changed their mind were shown to care home workers. This apparently produced a 93 per cent acceptance rate (compared to the 80 per cent typically found in major UK centres).

“We are not trying to manipulate people, but talk in ways they understand,” explains Sherrington, who believes one of the reasons the tactics worked was that they used behavioural science in a grassroots manner. Another was that Martin shared ideas with staff throughout the process, rather than just offering advice at the start.

Can this approach be used elsewhere? The Jersey government thinks so. And more municipalities in the US are starting to experiment with persuasion techniques and compare notes about what works. Indeed, Martin hopes that one consequence of Covid-19 is that it will create a greater willingness to incorporate behavioural science into public medicine in a wider sense.

That would be a good thing in the longer term. One reason why the pandemic spun out of control last year was that many governments initially thought — wrongly — that they only needed to use medical science. But right now, that July 4 target looks dicey. It’s a sign of why the slippery question of “culture” matters — and not just for politicians but for (frustrated) scientists too.

Follow Gillian on Twitter @gilliantett and email her at gillian.tett@ft.com

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