State supported Covid-19 nudges only really worked on the young

Who says young people never listen? A study in Sweden examining responses to state-backed nudges to get Covid-19 vaccination appointments booked has found that 16- to 17-year-olds responded much more strongly to prompts by letter, text, or email than 50- to 59-year-olds.

At first glance, the result, published in an article in Oxford Open Economics, is paradoxical. Older people who are much more vulnerable to the virus should have signed up more than younger people whose lives are much less at stake, but the reverse was the case. In fact, the study is consistent with the theory that nudges are more effective for decisions that don’t really matter to the person subjected to the nudge.

Politics, populations, and pandemic policies

‘Nudge theory’ has interested researchers and politicians for decades as a means to influence population-level behaviour such as how to get people to sign up for a donor card, or take out a pension earlier in life. And it works. Just ask any marketeer or social media influencer what the impact of a well-timed and skilfully worded notification can be. But the nudge effect is limited and often misses the target population.

Niklas Jakobsson from Karlstad University, and colleagues, saw an opportunity to empirically test nudge theories using data collected by the 21 regions of Sweden during the Covid-19 pandemic. While 20 regions sent out letters directing people to book their jabs by phone or online, one—Uppsala—nudged its citizens by summoning them to pre-booked appointments.

The researchers matched up vaccination rates in each age group in Uppsala against a synthetic control devised from a weighted combination of all the other Swedish regions. The results showed that Uppsala’s nudged, pre-booked appointments had only a small (if any) effect on older people, but boosted vaccination uptake among younger people by 10%.

“It makes sense that people who benefit a lot from vaccinations will take them even without a nudge,” Jakobsson explains. “For younger people, vaccinations were not as important and thus they were more affected by the nudge.”

When should a nudge become a push?

What is the behavioural mechanism behind such a counterintuitive finding?  One line of reasoning suggests that you can’t really nudge people into doing something they don’t want to do when their volition—that is, the power of free will—is high. However, you can change behaviour when people don’t really care either way, that is, when volition is low.

According to Kahneman’s theory of Fast and Slow Thinking, once the fast, unconscious, ‘System 1’ cognitive processes are passed, nudges get held up in the slower, deliberative, ‘System 2’ thoughts, and are less effective.

“People do actually think through their decisions and do not act randomly,” says Jakobsson. “The nudges that are most likely to work are changes of defaults that clearly decrease the costs of making a decision.”

Policymakers could take a closer look at this study to work out what they are doing right, as well as wrong, when developing future nudges. “This nudge worked, but more so for younger people,” says Jakobsson. “So, it could be a way to somewhat increase vaccinations at a low cost.”

_{Feature image by tortensimon via Pixabay, public domain.}