A surprising effect: People wearing masks may have trouble identifying other faces

The use of face masks as a way to preserve public and private health against the spread of COVID-19 became widespread during the period of the pandemic. A recent study carried out by the University of York found that it can be more difficult to identify someone while you are wearing a mask, even if the other person isn't wearing one.

Prior studies have shown that adults and children have difficulties identifying faces while parts of their own faces were covered by masks like those worn during the COVID-19 pandemic, and it doesn't get better over time. The new series of trials done in York shines a light on how the ability to identify people gets impacted when wearing a mask, regardless of whether the identified person is masked or not.

"We wanted to investigate the influence of wearing a mask on the identification of faces, something that as far as we know wasn't done in the past, in order to see how a masked observer's perceptual abilities differ in relation to others," said the professor's assistant Erez Freud of the Health Faculty in York, who wrote the study together with Bachelor students Daniela di Giammarino and Karmel Kamiler.

How does wearing a mask make you unable to recognize other faces?

As part of the study, four trials including 80 participants were carried out. They were shown pictures of masked and unmasked people while wearing or not wearing a mask themselves. The results were surprising - wearing a mask influenced the ability of the participants to recognize other people's faces. The deciding factor wasn't if the presented face wore a mask or not, but if the participant wore a mask during the identification attempt. 

Freud says that one of the explanations could be that while people are wearing masks, they think others can't identify them. "Masked people might think that their own face is less identifiable and this can lead to a reduction in face processing capabilities. It may be tied to the way in which people see things from other people's viewpoint, a process called 'alter-centric intrusion.'"

Another reason, says Freud, could be related to the constant tactile stimulation of the lower part of the mask wearer's face, which is a constant reminder that this part of their face isn't visible and this might create difficulty for them to identify this part on other faces. The effect, however, only worked when wearing a mask in the typical way - covering the nose and mouth.

"We found out that the effect of wearing a mask is specific to cases where the mask is worn over the nose and the mouth," said Freud. "When we asked the participants to wear the mask on the forehead, we found no influence on the ability to identify faces." In addition, the effect only occurred with faces, not with things. When the participants were asked to identify things like for example an orange, there was no effect of wearing a mask.

"I was a bit surprised by the findings of this study," said Freud. "I didn't think we would find such a pronounced effect of wearing a mask on the ability to identify faces, but I guess that's one reason we are doing science."