Face masks can make it harder to recognize facial expressions that stimulate empathy, such as sadness, according to new research published in the scientific journal Psychophysiology.
Previous research has indicated that masks can impair the recognition of basic facial expressions. But little is known about neurophysiological implications of this phenomenon. The authors of the new study set out to investigate how face masking could affect different stages of neural processing involved in facial expression comprehension.
“After a 2-year pandemic era, necessarily characterized by a pervasive and worldwide use of surgical masks, we studied in the laboratory the neural and behavioral responses of observers exposed to faces wearing or not wearing surgical masks. We wished to understand the specific effects of facial expression deprivation on the human mind and brain,” explained study author Alice Mado Proverbio, a professor of cognitive neuroscience at the University of Milano-Bicocca and head of the Cognitive Electrophysiology Lab.
The study involved 26 right-handed university students (13 women and 13 men) with an average age of 22.35 years. They participated in a facial expression categorization task involving six emotions while EEG was continuously recorded. The task used pictures of 5 female and 5 male actors/actresses displaying 6 spontaneous emotional expressions in masked and unmasked conditions. Emotional prime words were presented before the faces to create congruent or incongruent conditions.
The researchers found that response times were slower in the incongruent condition compared to the congruent condition, indicating an emotional priming effect. In other words, participants were faster to identify a sad-looking facial expression when the prime was “SAD” compared to when the prime was “HAPPY.”
But masks appeared to have a detrimental impact on emotion recognition. This was particularly true for disgust, sadness, and fear, which were not recognized more quickly when preceded by congruent primes.
When faces were shown with masks, a specific brain response called N170 became larger compared to when the faces were shown normally (unmasked). This suggests that the brain had to work harder or for a longer time to process the limited information in the masked faces. The N170 response is associated with the “fusiform face area,” which is involved in encoding facial features and affected by various factors such as familiarity and expression.
“It was found not only that face masking reduced the ability to read facial expressions but also that it polarized the spectrum of emotional signals conveyed to others toward the negative/positive dimension of happiness/anger,” Proverbio told PsyPost. “It seems that face masking specifically impairs the communication of softer emotions such as sadness, fear or disgust, which usually trigger an empathic resonance in the observer. The limited recognition of people’s distress might lead to a reduction of personal concern and empathic response in the observers.”
Interestingly, masks did not exhibit any negative effects on the accuracy or response times to angry faces. “We were surprised to find out that mask covering did not impair at all the recognition of angry faces, which may increase even more the likelihood of getting angry in social interactions,” Proverbio remarked.
“It must be understood whether this deficit in social cognition can have direct consequences on people’s aggressiveness, their inclination to help, cooperate or forgive others,” Proverbio said. “Indeed, the lack of facial cues about the others’ suffering might impair the ability to understand people’s emotions, and to experience feelings of tenderness, pity or sympathy.”
“It also remains to be clarified whether not being able to perceive pitying, empathic, understanding or loving facial expressions (but simply happy or angry ones) would increase stress levels in individuals seeking psychological comfort,” the researcher added. “Further studies will also have to clarify whether perceiving masked human faces for continued and enduring periods would be able to affect the development of children’s empathic capacity.”
The study, “Facemasks selectively impair the recognition of facial expressions that stimulate empathy: An ERP study“, was authored by Alice Mado Proverbio, Alice Cerri, and Cristina Gallotta.