Social cognition requires, beside others, the understanding of another individual's feelings, intentions, desires and mental states, coined theory of mind or mindreading (Baron-Cohen et al., 2001). Successful social cognition is even more important during extraordinary situations such as the coronavirus disease 2019 (COVID-19) pandemic that has becoming a devastating sanitary and global emergency (Chen et al., 2020). In particular, handling such a situation necessitates optimal communication to understand the situation and related measures, and close cooperation between people. To prevent further spread of the disease several countries and authorities such as the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC) recommended using face masks among health-care workers and the general public (Greenhalgh et al., 2020; Peeples, 2020). This action intends protecting people from infection with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), from severe illness, and aims at reducing the need for isolation and quarantining. Here we want to discuss the impact of face masking on social cognition—with a focus on emotion recognition and theory of mind—in older adults and people with dementia with an emphasis on short- and long-term effects, and suggest actions to encounter these problems (for an overview and summary see Figure 1).

Although justified for disease prevention face masks cover parts of the face. As discussed by Carbon (2020) face masks or community masks shielding the mouth and the nose hide about 60–70% of the face area relevant for emotional expression, where the mouth region is of particular importance for emotion recognition. This author investigated the impact of face masking—with typical masks worn during the COVID-19 pandemic—on emotion recognition in a study (for example stimuli see Figure 1).

Face masks severely impaired the performance of assessing the emotional state of a face and the confidence of one's own assessment with medium/large effect size, respectively. Effects appeared emotion-specific in accordance with previous studies showing that the recognition of happiness and sadness, and to a smaller degree anger, rely strongly on the lower face, in particular the mouth. Recognition of disgust was also severely impaired by face masking. Only neutral and fearful faces could be detected in spite of masking, where it is well-known that for fear the eye region provides generally most relevant information for correct recognition. The author further discusses that aging might even boost this masking effect as older adults have more difficulty in recognizing some basic emotions such as disgust, happiness, and fear, and also problems in recognizing other basic emotions such as anger and sadness. However, as a limitation of the study, Carbon's (2020) study relied on visual static stimuli only. Accordingly, these results for static facial emotion recognition have to be confirmed with other stimuli and in other settings. Additionally, the impact of face masking on theory of mind has still to be tested.

Another study by Chaby et al. (2017) investigated gaze strategies accompanying facial emotional processing with aging. During looking at basic facial expressions gaze movements were recorded. Older adults performed worse than younger adults in identifying facial expressions, except for joy and disgust. Remarkably, older adults used a focused-gaze strategy as they focused their attention only on the lower part of the face. Contrary, younger adults used an exploratory-gaze strategy, repeatedly visiting the upper and lower facial areas. This finding is consistent with result of a meta-analysis showing that older adults display a bias to look more at the mouth and less at the eyes in facial emotion processing compared to younger adults (Grainger and Henry, 2020). Hence, older people might lack expertise in exploring upper face regions, which is necessary when the lower face is covered by a mask.

Beside emotion recognition, as shown at least for static facial emotions, other abilities for social cognition might be affected. With face masking people may rely on information from the eyes to attribute mental states to others and successfully interact with them, although in natural settings alternative ways of compensation involve also contextual information, body language, gestures, language, and non-verbal oral information. The “Reading the Mind in the Eyes” Test (Baron-Cohen et al., 2001) seems to be a good proxy to investigate social cognition abilities based on the eye region as it investigates mindreading ability from gaze. This test shows photographs of the eye-region of a person, where the term most appropriately describing the pictured mental state shall be selected. It is focused mainly on “affective” theory of mind, which enables understanding of others' emotions, affective states, or feelings (Henry et al., 2013). Recently, we investigated mindreading ability from gaze with this test in a very large population-based cohort including 1,603 persons aged between 19 and 79 years (Kynast et al., 2020).

The study revealed a linear relation between individual test performance scores and age for women and men. Performance declined with aging in both, women [F_{(1, 697)} = 78.8, p < 0.001] and men [F_{(1, 904)} = 90.6, p < 0.001], indicating an age-related decline in mindreading ability from the eyes. Effect size for the decline in performance above vs. below an age of 45 years was large in women (g = 0.75), and medium sized in men (g = 0.55; Hedges' g). A linear regression model confirmed that test performance declined with aging, and showed an association with lower verbal intelligence but not gender.

One might criticize that the “Reading the Mind in the Eyes” Test has limitations. Firstly, its stimulus material shows potential interactions between gender/sex, age, and emotional valence (Kynast and Schroeter, 2018). Generally cognitive tests shall be adapted to the age range of the cohort of interest, here for older adults. Secondly, the “Reading the Mind in the Eyes” Test investigates a very specific and rather artificial situation—mindreading only from the eyes—as in real life other information to infer mental state will be available from context, body language, gestures, language, and non-verbal oral information. Thirdly, Quesque and Rossetti (2020) recently have questioned the specificity of the “Reading the Mind in the Eyes” Test together with several other classic measures for theory of mind. Here, these authors also referred to a debate in the literature regarding the assumed processes assessed with this test, i.e., mental states inference vs. eye-region emotion recognition.

One might have a look at comprehensive meta-analyses to place this test into the framework of social cognition. Indeed, meta-analyses have confirmed effects of age on social cognition for both, “affective” and “cognitive” theory of mind, where the latter enables understanding of cognitive states, beliefs, thoughts, or intentions (see Henry et al., 2013). Note that this comprehensive meta-analysis involved 1,462 participants and several types of theory of mind tasks, i.e., inferring mental states from the eyes, stories where a character's behavior can be best understood by positing an underlying mental state, identification of emotions and cognitive states from video clips, understanding protagonist's false belief, and recognizing social gaffes (Faux pas). Overall, older adults performed more poorly than younger adults in these tests of theory of mind with moderate effect size (r = 0.41; r = 0.43 for inferring mental states from the eyes). Another meta-analysis by Ruffman et al. (2008) with 1,667 subjects has shown a general age-related decline in emotion recognition in faces, voices, bodies/contexts. Hayes et al. (2020) confirmed this finding in another more recent and more comprehensive meta-analysis on facial emotion recognition in 10,526 older and young adult samples.

Pronounced impairments in social cognition have been reported in frequent neurodegenerative dementia syndromes according to meta-analytical evidence (recently referred to as neurocognitive disorders; American Psychiatric Association, 2013). In particular behavioral variant frontotemporal dementia is characterized by early and severe deficits in social cognition with a strong effect size (d = 1.79; Cohen's d) as shown in a meta-analysis across several theory of mind tasks such as “Reading the Mind in the Eyes” Test, Faux pas task, sarcasm and first and second order false belief tasks (Bora et al., 2015). Here, the “Reading the Mind in the Eyes” test was one of the most impaired tasks (d = 1.38; Bora et al., 2015). Of note, deficits of social cognition are the core cognitive symptom in this disease beside executive dysfunction as shown in the meta-analysis by Dodich et al. (2021) for emotion recognition and theory of mind. Schroeter et al. (2014) aimed at conceptualizing bvFTD neuroscientifically by relating these behavioral deficits to their disease-specific neural correlates. A “Reading the Mind in the Eyes” Test predicted behavioral variant frontotemporal dementia even better than executive function tests (Schroeter et al., 2018) and indicated conversion to this disease early (Pardini et al., 2013).

Social cognition as tested with theory of mind tasks (for specific tests see above) is also impaired in the most frequent neurodegenerative syndrome, i.e., Alzheimer's dementia (d = 1.15), although deficits are modest compared with general cognitive impairment (Bora et al., 2015) affecting the memory domain firstly (Schroeter et al., 2009). Small vessel disease, a frequent cause of vascular dementia, has also been reported to be associated with severe deficits in social cognition as shown for the “Reading the Mind in the Eyes” Test beside altered attention and memory (Kynast et al., 2018; Schroeter, 2021). Even mild cognitive impairment, with an increased probability converting to dementia in the long-term, has been reported to be associated with significant (medium) impairments in theory of mind (d = 0.63) and facial emotion recognition (d = 0.58; Bora and Yener, 2017).

These findings are of particular interest during theCOVID-19 outbreak as widespread face masking is recommended for disease prevention (Greenhalgh et al., 2020; Peeples, 2020). As discussed before older people and persons with dementia are impaired in mindreading from the eyes and emotion recognition. Notably, those cohorts—old people (Chen et al., 2020) and subjects with dementia (Mok et al., 2020)—are also at important risk for COVID-19 itself and associated mortality. Holmes et al. (2020) and Pfefferbaum and North (2020) have discussed that the COVID-19 pandemic generally will lead to social isolation, emotional distress, and increase the risk for psychiatric illnesses, such as anxiety, depression, self-harm and suicide. High-risk populations such as older adults or people with dementia might be particularly affected by isolation and loneliness, supported by the “digital divide.” Recently, Mok et al. (2020) paid particular attention to the profound impact of the COVID-19 pandemic upon older people with Alzheimer's disease and other dementias. They discussed generally challenges encountered and suggested strategies coping with these issues. In the following, we want to discuss the specific impact generated potentially by face masking in aging and dementia. Note that—to date—no studies exist investigating these issues (beside Carbon, 2020), which is a desideratum for the future. As we want to initiate a new perspective/frontier of investigation here we cannot rely on published results sufficiently in the following sections so far.

In the beginning of the COVID-19 pandemic, governments and people hoped to encounter the disease early. Vaccination strategies have been developed. However, in the meantime, the second or even third pandemic wave have spread. New and prolonged lockdown has been initiated in several countries, where staying at home is recommended except for essential purposes. Simultaneously, face masking had to be prolonged resulting in durations of up to 1 year, e.g. in Germany, where face masking has been practiced continuously in medical and caregiving facilities, public transport, supermarkets and trading.

The COVID-19 pandemic will have a high impact on older adults and people with Alzheimer's disease and other dementias. Social cognition enables the understanding of another individual's feelings, intentions, desires and mental states, which is particularly important during the COVID-19 pandemic. To prevent further spread of the disease face masks have been recommended. Although justified for prevention, face masks cover parts of the face and impair recognition of emotions and probably mindreading. As social cognition is already affected by aging and dementia, strategies have to be developed to cope with these profound changes of communication. Face masking even could accelerate cognitive decline in the long run. Further studies are of uppermost importance to address face masks' impact on social cognition in aging and dementia, for instance by longitudinal studies comparing decline before and in the pandemic, and to design compensatory strategies. These issues are also relevant for face masking in general, such as in medical surroundings—beyond the COVID-19 pandemic.

MS wrote the first draft and revised the paper with comments and final agreement by all other authors. JK, AV, and SB-C commented. All authors agreed to its final version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.