People felt comfortable sitting or standing closer to others while wearing a mask, according to a team of behavioural scientists at Warwick Business School.
The research also indicates people would keep a smaller distance from others wearing masks.
It further suggests that those who believe face masks are effective at preventing the spread of coronavirus are more likely to relax the distance, if they or the other person is wearing a mask.
Wearing masks brings down the overall risk of spreading Covid-19, so people feel safer and are more willing to take other risks
The scientists say their findings could make it difficult to re-establish social distancing measures if they are needed to help control the virus in the event of a second wave of cases.
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.”
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, the pre-print study, which is yet to be peer-reviewed, found.
On average, participants wearing a mask felt comfortable standing 1.8 metres from another person.
Without a mask, they preferred to remain more than two metres apart.
We need more evidence to determine at what point the risks of reducing physical distance outweigh the benefits of wearing a mask
Those with the strongest belief that masks prevented them catching Covid-19 were prepared to stand closer to others if they wore masks.
People who believed they were at the greatest risk of being admitted to hospital due to 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 study was conducted before it became mandatory for face coverings to be worn in shops in England.