Mask Wearing May Result in Less Social Distancing
Studies suggest that wearing face masks effectively slows the spread of the coronavirus, but according to French researchers at the University of Lille, it does somewhat backfire in a key respect. Face masks seem to lull people into a false sense of security, leading them to socially distance less. Since distancing is arguably much better than mask-wearing at limiting the spread of the coronavirus, the net positive effect of public mask-wearing could be being blunted, though it's difficult to gauge exactly how much.
The researchers discerned the result from an Internet-based experiment with 457 volunteers. Participants were presented with virtual characters on their computers screens, some wearing masks and some not, at various distances away from the subject. Subjects were asked to judge whether the "interpersonal distance between themselves and a virtual character was appropriate for social interaction or not."
"Each virtual character was presented twice," the researchers explained. "Responses were provided by pressing the “L” (appropriate) or “S” (inappropriate) keyboard keys. Participants were instructed to respond spontaneously and as fast as possible."
Tallying the results, the researchers found that subjects permitted a much closer interpersonal distance for virtual characters with face masks compared to those without face masks. Volunteers allowed mask-wearing characters to be about 15% closer.
An obvious limitation to the study is that it was conducted online and not in a real-world context. However, its findings do line up with a CDC report published in late October which showed that as mask-wearing increased in the U.S., interventions like hand-washing, staying 6 feet away from other people, and avoiding public or crowded places all decreased.
"The mere sight of a person wearing a face mask is enough to trigger a strong feeling of safety that acts against the simplest rule of social distancing. Accordingly, general recommendations to wear a face mask in society as an efficient barrier gesture against Covid-19 must be accompanied by a strong incentive to respect social distancing," the researchers wrote.
The study was published in PLoS ONE.
Source: Cartaud A, Quesque F, Coello Y (2020) "Wearing a face mask against Covid-19 results in a reduction of social distancing." PLoS ONE 15(12): e0243023. https://doi.org/10.1371/journal.pone.0243023