Face masks disrupt holistic processing and face perception in school-age children

Beyond the Whole: Reduced Empathy for Masked Emotional Faces Is Not Driven by Disrupted Configural Face Processing

Sharing of emotional states is reduced for individuals wearing face coverings, but the mechanism behind this reduction remains unknown. Here, we investigated if face occlusion by masks reduces empathy by disrupting configural processing of emotional faces. Participants rated their empathy for happy and neutral faces which were presented in upright or inverted orientation and wore opaque, clear, or no face masks. Empathy ratings were reduced for masked faces (opaque or clear) as well as for inverted faces. Importantly, face inversion disrupted empathy more for faces wearing opaque masks relative to those wearing clear or no masks, which stands in contrast to the predictions generated by the classic configural processing models. We discuss these data within the context of classic and novel configural face perception models, and highlight that studying inverted occluded faces presents an informative case worthy of further investigation.

Children's experiences of mask-wearing: a systemic review and narrative synthesis

RATIONALE

Masks have been widely used as a preventative tool during the COVID-19 pandemic. However, the use of masks by children has been controversial, with international guidelines recommending a risk-based approach to national policymakers.

AIMS AND OBJECTIVES

We aimed to conduct a systematic review that explores children's experiences of mask-wearing, drawing on an evidence base that describes mask-wearing in different contexts including air pollution, and to prevent the spread of infectious disease.

METHODS

We searched MEDLINE, Embase and PsycINFO in June 2021, with repeat searches in August 2022 and January 2024, for primary research studies exploring children's experiences of masks. Included studies reported on participants between 4 and 14 years (inclusive), with no restrictions on language where an English translation was available. Two reviewers independently screened titles and abstracts and reviewed full texts, with discrepancies resolved by a third reviewer. We used the Mixed Methods Appraisal Tool for quality appraisal and narrative synthesis to identify key findings. We also conducted stakeholder consultation (Patient and Public Involvement (PPI)) with nine children, where they submitted annotated drawings of their preferred masks to complement our review findings.

RESULTS

We screened 982 titles and abstracts and reviewed 94 full texts. 45 studies were included in the synthesis. Children's experiences of mask-wearing were influenced by their perceived necessity, social norms around their use and parental attitudes. Challenges related to mask-wearing were described, including difficulty reading facial expressions and physical discomfort. Children found it easier to wear masks when sitting and in cooler environments, and they benefited from unmasking during outdoor break time at school. As part of the PPI consultation, children highlighted the importance of mask design and the environmental impact of masks.

CONCLUSION

Children's experiences of mask-wearing were varied and context-dependent, with several mask-design challenges raised. Future policy on mask-wearing needs to consider the context in which mask-wearing would be most beneficial, and how local adaptations to policy can respond to children's needs.

In masks we trust: explicit and implicit reactions to masked faces vary by political orientation

Previous studies in the context of the COVID-19 pandemic indicated that wearing a medical-style mask affects whether a stranger's face is judged as more trustworthy, socially desirable, or likely to be ill. However, given political controversies around mask use, these effects might vary by political orientation. In a pre-registered online experiment, we measured evaluations of trustworthiness, social desirability and perceived illness in masked and unmasked faces by 1241 British and US participants. We included questions on political orientation, along with the implicit online-VAAST approach/avoid task to test reaction times to masked/unmasked faces. There was a medium-sized effect of masks on trustworthiness and a significant interaction with political orientation, in that conservatives found masked faces less trustworthy than did liberals. Participants were quicker to approach masked than unmasked faces, but conservatives were relatively slower than liberals. The effects on trustworthiness suggest that differential moralization of novel social norms can affect how their adherents are evaluated in terms of their suitability for social interactions. Furthermore, the congruence between implicit and explicit methods implies that such differences can have deep-seated effects on reactions.

Face masks degrade our ability to remember face-name associations more than predicted by judgments of learning

In response to the COVID-19 pandemic, face masks became required attire. Face masks obstruct the bottom portion of faces, restricting face processing. The present study examined the influence face masks have on memory predictions and memory performance for new face-name associations. Participants studied face-name pairs presented for 8 s (Experiment 1) or 10 s (Experiment 2). Half of the face-name pairs included a face mask obstructing the nose and mouth of the pictured face, counterbalanced across participants. Participants provided item-by-item judgements of learning (JOLs) and completed subsequent cued recall and associative recognition memory tests. Both experiments demonstrated that face masks impaired memory for newly-learned names, however, the magnitude of the mask impact was under-predicted by JOLs. The presence of a face mask negatively influenced memory performance to a greater degree than participants' JOLs predicted. Results have implications for name learning during pandemics, as well as in settings where face masks are common (e.g., medical field).

The effect of surgical masks on identification decisions from masked and unmasked lineups

While research has shown that wearing a disguise hinders lineup identifications, less is known about how to conduct lineups in cases of disguised perpetrators. We examined the influence of surgical masks, worn during a crime event (encoding) and within lineups (retrieval), on eyewitness identification accuracy. In our experiment, 452 participants watched a mock-crime video and identified the perpetrator from either a target-present or a target-absent simultaneous lineup. Contrary to expectations based on the encoding specificity principle, we did not find that matching the presence of masks in the lineup to the encoding condition increased identification accuracy. Instead, compared to the condition with no masks at encoding and retrieval, the presence of masks at either stage negatively affected discriminability and undermined the predictive utility of confidence and decision time. Our findings indicate that when a witness has encountered a masked perpetrator, presenting them with a masked lineup may not be necessary.

Influence of child and adult faces with face masks on emotion perception and facial mimicry

Emotional mimicry, the imitation of others' emotion expressions, is related to increased interpersonal closeness and better interaction quality. Yet, little research has focused on the effect of face masks on emotional mimicry and none on (masked) child faces. To address this gap, we conducted an online experiment (N = 235, German sample, adult perceivers). Masks reduced emotion recognition accuracy for all expressions, except in the case of anger in masked child faces, where perceived anger was even increased. Perceived interpersonal closeness was reduced for masked happy and sad faces. For both child and adult expressers, masks reduced facial mimicry of happy expressions, with no mask effects for sadness and anger expression. A stronger mask effect on facial happiness mimicry of child faces was mediated by the degree of emotion recognition accuracy. Smiles shown by masked children were not recognized well, likely due to the absence of wrinkles around the eyes in child faces. Independent of masks, sadness shown by children was mimicked even more strongly than when shown by adults. These results provide evidence for facial mimicry of child expressions by adult perceivers and show that the effects of face masks on emotion communication may vary when children wear them.

When less is not more: the effect of transparent masks on facial attractiveness judgment

During the COVID-19 pandemic, face masks have been widely used in daily life. Previous studies have suggested that faces wearing typical masks that occlude the lower half of the face are perceived as more attractive than face without masks. However, relatively little work has been done on how transparent masks that reveal the lower half of the face affect the judgment of facial attractiveness. To investigate the effect of transparent masks on the perceived attractiveness, in the current study, we asked participants to rate the attractiveness of faces without masks and with a typical opaque mask and a transparent mask. The results showed that faces wearing opaque masks were evaluated as more attractive than those wearing transparent masks or no masks. The benefit of opaque masks was more pronounced in faces that were initially evaluated as unattractive. Interestingly, wearing transparent masks decreased the perceived attractiveness of faces but only for the faces initially rated as attractive, possibly because of the visual distortion of the lower half of the face by transparent masks. In summary, we found that opaque and transparent masks have different effects on perceived attractiveness, depending on the attractiveness of faces. Given benefits of transparent masks in socio-emotional and cognitive processing, it would be important to further understand the effect of transparent masks on face information processing.

A Trained Humanoid Robot can Perform Human-Like Crossmodal Social Attention and Conflict Resolution

To enhance human-robot social interaction, it is essential for robots to process multiple social cues in a complex real-world environment. However, incongruency of input information across modalities is inevitable and could be challenging for robots to process. To tackle this challenge, our study adopted the neurorobotic paradigm of crossmodal conflict resolution to make a robot express human-like social attention. A behavioural experiment was conducted on 37 participants for the human study. We designed a round-table meeting scenario with three animated avatars to improve ecological validity. Each avatar wore a medical mask to obscure the facial cues of the nose, mouth, and jaw. The central avatar shifted its eye gaze while the peripheral avatars generated sound. Gaze direction and sound locations were either spatially congruent or incongruent. We observed that the central avatar's dynamic gaze could trigger crossmodal social attention responses. In particular, human performance was better under the congruent audio-visual condition than the incongruent condition. Our saliency prediction model was trained to detect social cues, predict audio-visual saliency, and attend selectively for the robot study. After mounting the trained model on the iCub, the robot was exposed to laboratory conditions similar to the human experiment. While the human performance was overall superior, our trained model demonstrated that it could replicate attention responses similar to humans.

Face masks negatively skew theory of mind judgements

Face masks obscure a significant portion of the face, reducing the amount of information available to gauge the mental states of others-that is, to exercise the Theory of Mind (ToM) capacity. In three experiments, we assessed the effect of face masks on ToM judgements, measuring recognition accuracy, perceived valence, and perceived arousal in various sets of facial expressions comprising 45 different mental states. Significant effects of face masks were found in all three variables. Judgements of all expressions are less accurate when masked, but, while judgements of negative expressions do not show consistent changes in valence or arousal, positive expressions are perceived to be less positive and less intense. In addition, we identified face muscles associated with changes in perceived valence and arousal, shedding light on the mechanisms through which masks impact ToM judgements, which might be relevant for mitigation strategies. We discuss the implications of these findings in the context of the recent pandemic.

Biases in human perception of facial age are present and more exaggerated in current AI technology

Our estimates of a person's age from their facial appearance suffer from several well-known biases and inaccuracies. Typically, for example, we tend to overestimate the age of smiling faces compared to those with a neutral expression, and the accuracy of our estimates decreases for older faces. The growing interest in age estimation using artificial intelligence (AI) technology raises the question of how AI compares to human performance and whether it suffers from the same biases. Here, we compared human performance with the performance of a large sample of the most prominent AI technology available today. The results showed that AI is even less accurate and more biased than human observers when judging a person's age-even though the overall pattern of errors and biases is similar. Thus, AI overestimated the age of smiling faces even more than human observers did. In addition, AI showed a sharper decrease in accuracy for faces of older adults compared to faces of younger age groups, for smiling compared to neutral faces, and for female compared to male faces. These results suggest that our estimates of age from faces are largely driven by particular visual cues, rather than high-level preconceptions. Moreover, the pattern of errors and biases we observed could provide some insights for the design of more effective AI technology for age estimation from faces.

Wearing face masks impairs dyadic micro-activities in nonverbal social encounter: A mixed-methods first-person study on the sense of I and Thou

The COVID-19 pandemic has manifold negative consequences for people around the world, of which the psychosocial ones have been rather underrepresented in the public eye. Regarding social distancing measures, there is already some experimental work demonstrating that the use of face masks has detrimental effects on various aspects of social cognition such as emotion reading, face identification, and perceived closeness of persons. However, while these findings provide important clues, they do not shed light on what people experience when interacting in real life in a masked society. Therefore, in critical distance to cognitivist accounts and taking Direct Social Perception (DSP) approaches seriously, we developed a first-person experimental design and conducted a study with thirty-four participants in a dyadic setting with two conditions (without vs. with face mask). Data were analyzed with mixed methods including in-depth qualitative coding at three levels, code relations analyses, and various statistical tests. Results yielded significant differences across conditions at all qualitative levels, comprising, for example, expressive behavior, and, in particular, significant decreases of content-independent, complimentary mental micro-activities. In the context of DSP, we argue in the paper that these activities suggest the constitution of a quasi-sensory modality - conceived as I-Thou sense - that oscillates between strongly and weakly embodied mental activities, as the analyses show. In sum, this study suggests that mask-wearing impairs both functional directions of mental activity in relation to more or less embodied experience and thus intervenes deeply in fundamental processes of social perception and interaction.

Face masks affect emotion categorisation, age estimation, recognition, and gender classification from faces

Although putting on a mask over our nose and mouth is a simple but powerful way to protect ourselves and others during a pandemic, face masks may interfere with how we perceive and recognize one another, and hence, may have far-reaching impacts on communication and social interactions. To date, it remains relatively unknown the extent to which wearing a face mask that conceals the bottom part of the face affects the extraction of different facial information. To address this question, we compared young adults' performance between masked and unmasked faces in four different tasks: (1) emotion recognition task, (2) famous face recognition and naming test, (3) age estimation task, and (4) gender classification task. Results revealed that the presence of face mask has a negative impact on famous face recognition and emotion recognition, but to a smaller extent on age estimation and gender classification tasks. More interestingly, we observed a female advantage in the famous face recognition and emotion recognition tasks and a female own-gender bias in gender categorisation and age estimation tasks. Overall, these findings allude to the lack of malleability of the adulthood face recognition and perceptual systems.

Detecting a familiar person behind the surgical mask: recognition without identification among masked versus sunglasses-covered faces

Previous research has shown that even when famous people’s identities cannot be discerned from faces that have been filtered with monochromatic noise, these unidentifiable famous faces still tend to receive higher familiarity ratings than similarly filtered non-famous faces. Experiment 1 investigated whether a similar face recognition without identification effect would occur among faces whose identification was hindered through the wearing of a surgical mask. Among a mixture of famous and non-famous faces wearing surgical masks and hoods, participants rated how familiar each person seemed then attempted to identify the person. Though surgical masks significantly impaired identification of the famous faces, unidentified masked famous faces received higher familiarity ratings on average than the non-famous masked faces, suggesting that a sense of familiarity could still occur even when identification was impaired by the mask. Experiment 2 compared faces covered by surgical masks with faces covered by sunglasses. Though sunglasses impaired face identification more than surgical masks, the magnitude of the face recognition without identification effect was the same in both cases. This pattern suggests that holistic face processing is not a requirement for the sense of familiarity with a face, and that different facial feature types can contribute.

Inhaled CO2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography

Background

Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO2) concentration, when wearing masks.

Methods

We measured end-tidal CO2 using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO2 concentration was computed as: ([mask volume × end-tidal CO2] + [tidal volume - mask volume] × ambient air CO2)/tidal volume.

Results

With surgical masks, the mean CO2 concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO2 concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors.

Conclusion

If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.

Recognition of Masked Faces in the Era of the Pandemic: No Improvement Despite Extensive Natural Exposure

Face masks, which became prevalent across the globe during the COVID-19 pandemic, have had a negative impact on face recognition despite the availability of critical information from uncovered face parts, especially the eyes. An outstanding question is whether face-mask effects would be attenuated following extended natural exposure. This question also pertains, more generally, to face-recognition training protocols. We used the Cambridge Face Memory Test in a cross-sectional study ( N = 1,732 adults) at six different time points over a 20-month period, alongside a 12-month longitudinal study ( N = 208). The results of the experiments revealed persistent deficits in recognition of masked faces and no sign of improvement across time points. Additional experiments verified that the amount of individual experience with masked faces was not correlated with the mask effect. These findings provide compelling evidence that the face-processing system does not easily adapt to visual changes in face stimuli, even following prolonged real-life exposure.

Mask-Wearing Perception of Preschool Children in Korea during the COVID-19 Pandemic: A Cross-Sectional Study

As the COVID-19 pandemic continues, wearing a mask has become a daily routine in Korea over the last two years. This study aims to investigate the mask-wearing perception of preschoolers (ages 4-6). The questionnaire comprised 17 yes-no closed-ended questions and two open-ended questions, and interviews of the children were conducted from January to February 2022, 15 months after mandatory mask wearing. Results showed that children were aware of the need to wear a mask to protect themselves and others from the coronavirus, and they perceived it as necessary and a good thing. Most children responded that they did not feel uncomfortable wearing a mask at preschool. This perception was thought to be influenced by the caregivers' perceptions of the mask in Korea. The way in which 4-5-year-olds perceived the mask differed from the way 6-year-olds did. Children aged between four and five seemed to perceive the mask as a physical self, while children aged six did not. As children who have experienced COVID-19 are growing up, attention is being focused on how the experience of wearing a mask affects their early childhood development.

Masked face identification is improved by diagnostic feature training

To slow the spread of COVID-19, many people now wear face masks in public. Face masks impair our ability to identify faces, which can cause problems for professional staff who identify offenders or members of the public. Here, we investigate whether performance on a masked face matching task can be improved by training participants to compare diagnostic facial features (the ears and facial marks)-a validated training method that improves matching performance for unmasked faces. We show this brief diagnostic feature training, which takes less than two minutes to complete, improves matching performance for masked faces by approximately 5%. A control training course, which was unrelated to face identification, had no effect on matching performance. Our findings demonstrate that comparing the ears and facial marks is an effective means of improving face matching performance for masked faces. These findings have implications for professions that regularly perform face identification.

Inhaled CO2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography

BACKGROUND

Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO₂) concentration, when wearing masks.

METHODS

We measured end-tidal CO₂ using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO₂ concentration was computed as: ([mask volume × end-tidal CO₂] + [tidal volume - mask volume] × ambient air CO₂)/tidal volume.

RESULTS

With surgical masks, the mean CO₂ concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO₂ concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO₂ concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors.

CONCLUSION

If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.