How does the presence of a surgical face mask impair the perceived intensity of facial emotions?

Abstract

The use of surgical-type face masks has become increasingly common during the COVID-19 pandemic. Recent findings suggest that it is harder to categorise the facial expressions of masked faces, than of unmasked faces. To date, studies of the effects of mask-wearing on emotion recognition have used categorisation paradigms: authors have presented facial expression stimuli and examined participants’ ability to attach the correct label (e.g., happiness, disgust). While the ability to categorise particular expressions is important, this approach overlooks the fact that expression intensity is also informative during social interaction. For example, when predicting an interactant’s future behaviour, it is useful to know whether they are slightly fearful or terrified, contented or very happy, slightly annoyed or angry. Moreover, because categorisation paradigms force observers to pick a single label to describe their percept, any additional dimensionality within observers’ interpretation is lost. In the present study, we adopted a complementary emotion-intensity rating paradigm to study the effects of mask-wearing on expression interpretation. In an online experiment with 120 participants (82 female), we investigated how the presence of face masks affects the perceived emotional profile of prototypical expressions of happiness, sadness, anger, fear, disgust, and surprise. For each of these facial expressions, we measured the perceived intensity of all six emotions. We found that the perceived intensity of intended emotions (i.e., the emotion that the actor intended to convey) was reduced by the presence of a mask for all expressions except for anger. Additionally, when viewing all expressions except surprise, masks increased the perceived intensity of non-intended emotions (i.e., emotions that the actor did not intend to convey). Intensity ratings were unaffected by presentation duration (500ms vs 3000ms), or attitudes towards mask wearing. These findings shed light on the ambiguity that arises when interpreting the facial expressions of masked faces.

Effects of wearing a transparent face mask on perception of facial expressions

“…With respect to emotion intensity analyses, we robustly observed that the perceived intensity of happy faces was reduced by wearing a surgical mask. These results are consistent with previous findings ( Pazhoohi et al, 2021 ; Ramachandra & Longacre, 2022 ; Sheldon et al, 2021 ; Tsantani et al, 2022 ). Taken together, the inhibition of reading facial expressions by surgical masks was significant and robust for happy faces with regard to both recognition and perceived intensity of facial emotions.…”

“…For example, Carbon (2020) demonstrated an impairment in recognizing happy, anger, disgust, and sad faces. This inconsistency was also observed for perceived intensity of emotion ( Pazhoohi et al, 2021 ; Ramachandra & Longacre, 2022 ; Tsantani et al, 2022 ). In addition, the results are also partially inconsistent with those of a previous study that tested emotion recognition by using the parts of faces ( Kotsia et al, 2008 ), suggesting that the occlusion of mouth impairs the recognition of anger, fear, happy, and sad emotions.…”

“…Being able to see the mouth region is crucial to recognize a happy face ( Boucher & Ekman, 1975 ; Calder et al, 2000 ; Calvo et al, 2014 ; Eisenbarth & Alpers, 2011 ; Hanawalt, 1944 ; Kotsia et al, 2008 ; Saumure et al, 2018 ; Schurgin et al, 2014 ). In addition, since many previous studies have reported impairments in emotion recognition ( Carbon, 2020 ; Grenville & Dwyer, 2022 ; Kim et al, 2022 ; Marini et al, 2021 ; Noyes et al, 2021 ; Parada-Fernández et al, 2022 ; Pazhoohi et al, 2021 ; Ramachandra & Longacre, 2022 ) and perceived emotion intensity ( Pazhoohi et al, 2021 ; Ramachandra & Longacre, 2022 ; Sheldon et al., 2021 ; Tsantani et al, 2022 ) of happy faces when wearing a surgical mask, we predicted to observe these impairments. We also expected that these impairments would be moderated by a transparent mask.…”

“…While mask-wearing is effective in controlling infection, many researchers have pointed to its negative side effects in interpersonal situations due to the partial occlusion of critical parts of the face. The occlusion significantly impairs recognition of facial emotions ( Carbon, 2020 ; Gori et al, 2021 ; Grenville & Dwyer, 2022 ; Grundmann et al, 2021 ; Kim et al, 2022 ; Marini et al, 2021 ; Noyes et al, 2021 ; Parada-Fernández et al, 2022 ; Pazhoohi et al, 2021 ; Ramachandra & Longacre, 2022 ) and perception of facial emotion intensity ( Pazhoohi et al, 2021 ; Ramachandra & Longacre, 2022 ; Sheldon et al, 2021 ; Tsantani et al, 2022 ). These negative effects on emotional facial communication occur because the features of the bottom half of the faces that signal effective cues for reading others’ facial expressions ( Blais et al, 2012 ; Bombari et al, 2013 ; Boucher & Ekman, 1975 ; Calder et al, 2000 ; Calvo et al, 2014 ; Eisenbarth & Alpers, 2011 ; Hanawalt, 1944 ; Kotsia et al, 2008 ; Saumure et al, 2018 ; Schurgin et al, 2014 ; Schyns et al, 2002 ; Wegrzyn et al, 2017 ) are occluded by the masks.…”

The Effect of Surgical Masks on the Featural and Configural Processing of Emotions

“…Many findings show that emotion perception is a complex phenomenon depending also on contextual factors and on the specific emotion perceived by the observer. In the last two years many studies have focused their attention on the role played by surgical masks in the recognition of facial characteristics such as age, identity, or emotions, highlighting the impact of multiple fields of social cognition [ 2 , 23 , 24 , 25 , 26 , 27 , 28 ]. Surgical masks have a detrimental effect on matching face identity [ 28 ].…”