Wearing face masks can adversely affect attitudes towards social distancing, a new study shows. People felt comfortable sitting or standing closer to others while wearing a mask, a team of behavioural scientists at Warwick Business School found.

They also indicated that they would maintain a smaller distance from others who wore masks.

Those who believed face masks were effective at preventing the spread of Covid-19 were more likely to relax the distance, if they or the other person were wearing a mask.

That could make it harder to re-establish social distancing measures if they are required to help control the virus in the event of a second wave of cases.

The findings are revealed in a new pre-print paper, Risk compensation during Covid-19: The impact of face mask usage on social distancing.

Ashley Luckman, a research fellow at Warwick Business School and lead author of the study, said: “Our findings appear to be a classic case of risk compensation.

“Wearing masks brings down the overall risk of spreading Covid-19, so people feel safer and are more willing to take other risks, such as decreasing the physical distance between them and others.

 “If the government’s aim is to minimise transmission of the virus, its guidelines must be clear enough to prevent this trade-off, emphasising that masks are not an alternative to social distancing.”

The researchers showed 800 participants in the UK pictures of people sitting, standing, or walking and asked them to indicate how close they would be willing to stand in different scenarios.

These included indoor and outdoor settings and whether both people, just one, or neither wore a mask.

In each scenario, people were more likely to tolerate a reduced distance if they or the other person wore a mask. On average, participants wearing a mask felt comfortable standing 1.8 metres from another person. Without a mask they preferred to remain more than 2 metres apart.

This contradicted expectations that people would politely keep a greater distance from others who wore masks.

Those with the strongest belief that masks prevented them catching Covid-19 were prepared to stand closer to others if they wore masks, while those who believed they were at the greatest risk of being hospitalised by the virus were more likely to keep a larger distance.

Daniel Read, Professor of Behavioural Science at Warwick Business School, said: “Our results could be particularly relevant for countries where mask usage is now high, but social distancing guidelines have been relaxed.

“If countries need to return to greater levels of physical distancing due to a second wave of cases, that may be harder to implement than it was when mask use was low at the start of the pandemic.

"We need more evidence to determine at what point the risks of reducing physical distance outweigh the benefits of wearing a mask.

“Clearly, the greatest benefit results from using masks to complement social distancing, rather than replacing it."

• The paper, Risk compensation during COVID-19: The impact of face mask usage on social distancing, was researched and written by Dr Ashley Luckman, Dr Hossam Zeitoun, Professor Andrea Isoni, Professor Graham Loomes, Professor Ivo Vlaev, Professor Nattavudh Powdthavee and Professor Daniel Read, who are all members of the Behavioural Science group at Warwick Business School.