We are writing as behavioural scientists to express concern about the timing of UK delay measures involving social distancing. As is clear from the disaster unfolding in Italy, there is a unique window for delaying the spread of COVID-19. Current government thinking seems to crucially involve the idea of “behavioural fatigue”. This is the worry that, if implemented too early, measures limiting social contact will be undercut just at the point at which they are most required, because people will have tired of the limitations and will revert to prior behaviour –in part precisely because those measures are effective in reducing spread and hence perceived risk.

While we fully support an evidence-based approach to policy that draws on behavioural science, we are not convinced that enough is known about “behavioural fatigue” or to what extent these insights apply to the current exceptional circumstances. Such evidence is necessary if we are to base a high-risk public health strategy on it. In fact, it seems likely that even those essential behaviour changes that are presently required (e.g., handwashing) will receive far greater uptake the more urgent the situation is perceived to be. “Carrying on as normal” for as long as possible undercuts that urgency.

More broadly, it appears that concerns about behavioural fatigue lead the government to believe that halting the spread of the disease is impossible, and the only solution is to slow the progress of the disease across most of the population, until herd immunity is achieved. But radical behaviour change may be able to do much better than this, and would, if successful, save very large numbers of lives. Experience in China and South Korea is sufficiently encouraging to suggest that this possibility should at least be attempted.

If “behavioural fatigue” truly represents a key factor in the government’s decision to delay high-visibility interventions, we urge the government to share an adequate evidence base in support of that decision. If one is lacking, we urge the government to reconsider these decisions.

Signed,

UK Behavioural Scientists