Surgical face masks impair human face matching performance for familiar and unfamiliar faces

The social factors behind the mask: contextual effects on trait impressions from faces wearing a face mask

The presence of face masks can significantly impact processes related to trait impressions from faces. In the present research, we focused on trait impressions from faces either wearing a mask or not by addressing how contextual factors may shape such inferences. In Study 1, we compared trait impressions from faces in a phase of the COVID-19 pandemic in which wearing masks was a normative behavior (T1) with those assessed one year later when wearing masks was far less common (T2). Results at T2 showed a reduced positivity in the trait impressions elicited by faces covered by a mask. In Study 2, it was found that trait impressions from faces were modulated by the background visual context in which the target face was embedded so that faces wearing a mask elicited more positive traits when superimposed on an indoor rather than outdoor visual context. Overall, the present studies indicate that wearing face masks may affect trait impressions from faces, but also that such impressions are highly flexible and can significantly fluctuate across time and space.

Trust in automation and the accuracy of human-algorithm teams performing one-to-one face matching tasks

The human face is commonly used for identity verification. While this task was once exclusively performed by humans, technological advancements have seen automated facial recognition systems (AFRS) integrated into many identification scenarios. Although many state-of-the-art AFRS are exceptionally accurate, they often require human oversight or involvement, such that a human operator actions the final decision. Previously, we have shown that on average, humans assisted by a simulated AFRS (sAFRS) failed to reach the level of accuracy achieved by the same sAFRS alone, due to overturning the system's correct decisions and/or failing to correct sAFRS errors. The aim of the current study was to investigate whether participants' trust in automation was related to their performance on a one-to-one face matching task when assisted by a sAFRS. Participants (n = 160) completed a standard face matching task in two phases: an unassisted baseline phase, and an assisted phase where they were shown the identification decision (95% accurate) made by a sAFRS prior to submitting their own decision. While most participants improved with sAFRS assistance, those with greater relative trust in automation achieved larger gains in performance. However, the average aided performance of participants still failed to reach that of the sAFRS alone, regardless of trust status. Nonetheless, further analysis revealed a small sample of participants who achieved 100% accuracy when aided by the sAFRS. Our results speak to the importance of considering individual differences when selecting employees for roles requiring human-algorithm interaction, including identity verification tasks that incorporate facial recognition technologies.

Influence of protective clothing and masks on facial trustworthiness in an investment game: insights from a Chinese population study

Facial features are important sources of information about perceived trustworthiness. Masks and protective clothing diminish the visibility of facial cues by either partially concealing the mouth and nose or covering the entire face. During the pandemic, the use of personal protective equipment affected and redefined who trusts whom in society. This study used the classical investment game of interpersonal trust with Chinese participants to explore the impact of occlusion on interpersonal trust. Faces with moderate initial trustworthiness were occluded by a mask or protective clothing in Experiment 1 and were digitally occluded by a square in Experiment 2, and faces with three levels of initial trustworthiness were occluded by a mask in Experiment 3. Results showed that both undergraduates (Experiment 1a) and non-student adults (Experiment 1b) perceived the faces with protective clothing as more trustworthy than faces wearing standard masks and faces not wearing masks. Faces with the top halves showing were perceived as trustworthy as full faces, while faces with the bottom halves showing were perceived as less trustworthy. The effect of masks is weak and complex. Masks reduced participants' trust in faces with high initial trustworthiness, had no effect on faces with low and moderate initial trustworthiness, and only slightly increased the trust of undergraduates in faces with moderate initial trustworthiness. Our findings indicate that the lack of information caused by occlusion and the social significance associated with occlusion collectively affect people's trust behavior in Chinese society. We believe the findings of this study will be useful in elucidating the effects of personal protective equipment usage on perceptions of trustworthiness.

The impact of the use of masks on trait judgments and face recognition

Although effective in reducing virus transmission, face masks might compromise face recognition and trait judgments. With this study, we aimed to observe the influence of masks on face recognition and trait judgments-more specifically, in trustworthiness, dominance, and distinctiveness judgments. Also, we wanted to observe the possible influence of trait judgments on facial recognition for masked and unmasked faces, which has never been done before. For that, we conducted an online study where 140 participants observed and made trait judgments of masked and unmasked faces in a within-subjects design. After a distractive task, participants performed a recognition memory test. As expected, we observed a better recognition of faces shown without a mask during the study phase, which allowed the holistic processing of the faces. The worst performance was found for faces encoded with a mask but tested without it, occurring simultaneity disruption in holistic face processing and the violation of the encoding specificity principle. Regarding the trait judgments, unmasked faces were considered more distinctive, and masked faces were considered more trustworthy. More interestingly, we can conclude that facial distinctiveness predicts face recognition, regardless of mask use. In contrast, dominance judgments only predicted face recognition when faces were presented without a mask. When faces were exposed with masks, trustworthiness overrides dominance, becoming more critical to recognizing faces. We can interpret these results from an evolutionary perspective.

Does wearing a mask promote consumer uniqueness seeking?

As a motivational factor, uniqueness drives individuals to seek and choose unique goods or experiences. The act of wearing masks obscures individuals' facial features and influences their desire for uniqueness. This study aims to explore how wearing masks promotes individual uniqueness- seeking behavior. Three experiments were performed using various product categories (Starbucks coffee cups, sweatshirts, suitcases, and baseball caps) and sample types (college student and adult samples). Experiment results show that wearing masks obscures individuals' facial features and weakens their self- perceived uniqueness, thereby increasing their willingness to actively purchase unique products. This study is the first to examine the effect of wearing masks on individuals' choice of unique products. Practically, the results suggest that customized products can compensate for the lack of self-perceived uniqueness brought about by facial occlusion, thus providing valuable guidance for companies and retailers that offer customized services in formulating and designing marketing strategies.

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.

Accuracy and Speed of Emotion Recognition With Face Masks

Wearing face masks is one of the important actions to prevent the spread of COVID-19 among people around the world. Nevertheless, social interaction is limited via masks, and this impacts the accuracy and speed of emotional perception. In the present study, we assess the impact of mask-wearing on the accuracy and speed of emotion recognition. Fifty people (female n = 39, male n = 11) aged 19-28 participated in the study (M = 21.1 years). We used frontal photos of a Kosova woman who belonged to the same participants' age group, with a grey background. Twelve different pictures were used that showed the emotional states of fear, joy, sadness, anger, neutrality, and disgust, in masked and unmasked conditions. The experiment was conducted in a controlled laboratory setting. Participants were faster for identifying emotions like joy (1.507 ms) and neutral (1.971 ms). The participants were more accurate (emotions identification) in unmasked faces (M = 85.7%) than in masked faces (M = 73.8%), F(1,98) = 20.73, MSE = 1027.66, p ≤ .001, partial η² = 0.17. Masks make confusion and reduce the accuracy and speediness of emotional detection. This may have a notable impact on social interactions among peoples.

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 COVID-19 pandemic and changes in social behavior: Protective face masks reduce deliberate social distancing preferences while leaving automatic avoidance behavior unaffected

Protective face masks were one of the central measures to counteract viral transmission in the COVID-19 pandemic. Prior research indicates that face masks impact various aspects of social cognition, such as emotion recognition and social evaluation. Whether protective masks also influence social avoidance behavior is less clear. Our project assessed direct and indirect measures of social avoidance tendencies towards masked and unmasked faces in two experiments with 311 participants during the first half of 2021. Two interventions were used in half of the participants from each sample (Experiment 1: protective face masks; Experiment 2: a disease prime video) to decrease or increase the salience of the immediate contagion threat. In the direct social avoidance measure, which asked for the deliberate decision to approach or avoid a person in a hypothetical social encounter, participants showed an increased willingness to approach masked as opposed to unmasked faces across experiments. This effect was further related to interindividual differences in pandemic threat perception in both samples. In the indirect measure, which assessed automatic social approach and avoidance tendencies, we neither observed an approach advantage towards masked faces nor an avoidance advantage for unmasked faces. Thus, while the absence of protective face masks may have led to increased deliberate social avoidance during the pandemic, no such effect was observed on automatic regulation of behavior, thus indicating the relative robustness of this latter behavior against changes in superordinate social norms.

The role of inversion and face masks on simultaneous and delayed face matching tasks

Although it is generally accepted that face recognition relies on holistic processing, it has been suggested that the simultaneous face matching task may depend on a more analytical or featural processing approach. However, empirical evidence supporting this claim is limited. In two experiments, we further explored the role of holistic and featural processing on simultaneous face matching by manipulating holistic processing through inversion and presenting faces with or without face masks. The results from Experiment 1 revealed that both inversion and face masks impaired matching performance. However, while the inversion effect was evident in both full-view and masked faces, the mask effect was only found in upright, but not inverted, faces. These results were replicated in Experiment 2 but, the inversion and mask effects were stronger in delayed face matching than in simultaneous face matching. Our findings suggest that simultaneous face matching relies on holistic processing, but to a smaller extent compared to higher memory-demanding identification tasks.

Drift-diffusion modeling reveals that masked faces are preconceived as unfriendly

During the COVID-19 pandemic, the use of face masks has become a daily routine. Studies have shown that face masks increase the ambiguity of facial expressions which not only affects (the development of) emotion recognition, but also interferes with social interaction and judgement. To disambiguate facial expressions, we rely on perceptual (stimulus-driven) as well as preconceptual (top-down) processes. However, it is unknown which of these two mechanisms accounts for the misinterpretation of masked expressions. To investigate this, we asked participants (N = 136) to decide whether ambiguous (morphed) facial expressions, with or without a mask, were perceived as friendly or unfriendly. To test for the independent effects of perceptual and preconceptual biases we fitted a drift-diffusion model (DDM) to the behavioral data of each participant. Results show that face masks induce a clear loss of information leading to a slight perceptual bias towards friendly choices, but also a clear preconceptual bias towards unfriendly choices for masked faces. These results suggest that, although face masks can increase the perceptual friendliness of faces, people have the prior preconception to interpret masked faces as unfriendly.

Autistic traits modulate the influence of face masks on gaze perception

Detecting when others are looking at us is a crucial social skill. Accordingly, a range of gaze angles is perceived as self-directed; this is termed the "cone of direct gaze" (CoDG). Multiple cues, such as nose and head orientation, are integrated during gaze perception. Thus, occluding the lower portion of the face, such as with face masks during the COVID-19 pandemic, may influence how gaze is perceived. Individual differences in the prioritisation of eye-region and non-eye-region cues may modulate the influence of face masks on gaze perception. Autistic individuals, who may be more reliant on non-eye-region directional cues during gaze perception, might be differentially affected by face masks. In the present study, we compared the CoDG when viewing masked and unmasked faces (N = 157) and measured self-reported autistic traits. The CoDG was wider for masked compared to unmasked faces, suggesting that reduced reliability of lower face cues increases the range of gaze angles perceived as self-directed. Additionally, autistic traits positively predicted the magnitude of CoDG difference between masked and unmasked faces. This study provides crucial insights into the effect of face masks on gaze perception, and how they may affect autistic individuals to a greater extent.

Hemispheric lateralization and top-down regulation of the prefrontal cortex on sequential memory of familiar faces

Working memory of familiar faces involves the coordination of multiple brain regions in sensory processing, attention and memory, and relies on robust representations in long-term memory. It is not clear how prior knowledge interacts with bottom-up visual processing at different phases of working memory. In this study, we collected functional magnetic resonance imaging (fMRI) data of 40 right-handed participants during the sequential memory task and recognition task of familiar celebrity faces. We observed strong left-lateralized neural activity in the language-processing areas and right-lateralized activity for visual processing in the dorsal stream. Yet, no obvious hemispheric lateralization was found in either face-selective (fusiform gyrus) or memory-specific (hippocampus) areas. Besides, the left lateralization of prefrontal activity and its task-evoked regulation on visual areas boost face memory performance, i.e., faster reaction and higher accuracy. These findings suggest that the top-down prefrontal regulation plays a critical role in the successful memory of familiar faces. Our study provides neural substrates underlying how familiarity boosts face memory by endorsing prior/common knowledge through left-lateralized language network.

Hidden faces, altered perceptions: the impact of face masks on interpersonal perception

The pandemic has made wearing masks commonplace, prompting researchers to investigate their effects on interpersonal perception. Findings indicate masks obstruct face identification and expression recognition, with lower face cues being most affected. When judging attractiveness, masks can enhance the appeal of less attractive faces, but reduce the appeal of more attractive faces. Trust and speech perception outcomes are inconclusive. Future studies could focus on individual differences in how masks influence our perception of others.

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.

Face masks are less effective than sunglasses in masking face identity

The effect of covering faces on face identification is recently garnering interest amid the COVID-19 pandemic. Here, we investigated how face identification performance was affected by two types of face disguise: sunglasses and face masks. Observers studied a series of faces; then judged whether a series of test faces, comprising studied and novel faces, had been studied before or not. Face stimuli were presented either without coverings (full faces), wearing sunglasses covering the upper region (eyes, eyebrows), or wearing surgical masks covering the lower region (nose, mouth, chin). We found that sunglasses led to larger reductions in sensitivity (d') to face identity than face masks did, while both disguises increased the tendency to report faces as studied before, a bias that was absent for full faces. In addition, faces disguised during either study or test only (i.e. study disguised faces, test with full faces; and vice versa) led to further reductions in sensitivity from both studying and testing with disguised faces, suggesting that congruence between study and test is crucial for memory retrieval. These findings implied that the upper region of the face, including the eye-region features, is more diagnostic for holistic face-identity processing than the lower face region.

Remembering to whom we transmit information during pandemics: the effect of face masks on destination memory

Considering the global pandemic we currently experience, face masks have become standard in our daily routine. Even though surgical masks are established as a safety measure against the dissemination of COVID-19, previous research showed that their wearing compromises face recognition. Consequently, the capacity to remember to whom we transmit information-destination memory-could also be compromised. In our study, through a between-participants design (experiment 1) and a within-participants design (experiment 2), undergraduate students have to transmit Portuguese proverbs to masked and unmasked celebrity faces. Following our hypothesis, participants who shared information with masked faces had worse destination memory performance than those who shared information with unmasked faces. Also, we observed lower recognition for masked faces compared to unmasked faces. These results were expected since using a surgical mask affects facial recognition, thus making it harder to recognize a person to whom information was previously transmitted. More importantly, these results also support the idea that variables associated with the recipient's face are important for destination memory performance.

The impact of briefly observing faces in opaque facial masks on emotion recognition and empathic concern

Since the outbreak of SARS-CoV-2 in 2019, there have been global public health initiatives that have advocated for the community use of face masks to reduce spread of the virus. Although the community use of facial coverings has been deemed essential for public health, there have been calls for enquiries to ascertain how face masks may impact non-verbal methods of communication. This study aimed to ascertain how the brief observations of faces in opaque facial coverings could impact facial emotion recognition. It was also an aim to ascertain if there was an association between the levels of empathic concern and facial emotion recognition when viewing masked faces. An opportunity sample of 199 participants, who resided in the United Kingdom, were randomly assigned to briefly observe either masked (n = 102) or unmasked (n = 97) faces. Participants in both conditions were required to view a series of facial expressions, from the Radboud Faces Database, with models conveying the emotional states of anger, disgust, fear, happiness, sadness, and surprised. Each face was presented to participants for a period of 250 ms in the masked and unmasked conditions. A 6 (emotion type) x 2 (masked/unmasked condition) mixed ANOVA revealed that viewing masked faces significantly reduced facial emotion recognition of disgust, fear, happiness, sadness, and surprised. However, there were no differences in the success rate of recognising the emotional state of anger between the masked and unmasked conditions. Furthermore, higher levels of empathic concern were associated with greater success in facially recognising the emotional state of disgust. The results of this study suggest that significant reductions in emotion recognition, when viewing faces in opaque masks, can still be observed when people are exposed to facial stimuli for a brief period of time.

Effect of mask coverage on face identification in Taiwanese men and women

Mask wearing is the easiest and most effective way to avoid COVID-19 infection; however, it affects interpersonal activities, especially face identification. This study examined the effects of three mask coverage levels (full coverage, FC; coverage up to the middle [MB] or bottom of the nose bridge [BB]) on face identification accuracy and time. A total of 115 university students (60 men and 55 women) were recruited to conduct a computer-based simulation test consisting of 30 questions (10 questions [five face images each of men and women] for the three mask coverage levels). One unmasked target face and four face images with a specified mask coverage level were designed for each question, and the participants were requested to select the same face from the four covered face images on the basis of the target face. The ANOVA results indicated that identification accuracy was significantly affected by sex (p < 0.01) and the mask coverage level (p < 0.001), whereas identification time was only influenced by sex (p < 0.05). The multiple comparison results indicated that the identification accuracy rate for faces wearing a mask with FC (90.3%) was significantly lower than for those wearing masks with coverage up to the MB (93.7%) and BB (94.9%) positions; however, no difference in identification accuracy rate was observed between the MB and BB levels. Women exhibited a higher identification accuracy rate than men (94.1% vs. 91.9%) in identifying unfamiliar faces, even though they may spend less time identifying the images. A smaller mask coverage level (i.e., the BB level) does not facilitate face identification. The findings can be served as a reference for people to trade-off between wearing a mask and interpersonal interaction in their daily activities.

Occlusion of faces by sanitary masks improves facial attractiveness of other races

Recent studies provide mixed results regarding whether the perception of facial attractiveness is increased or decreased by partial occlusion with a sanitary mask. One set of studies demonstrated that occluding the bottom half of a face increased facial attractiveness. This effect is thought to occur because the occluded area is interpolated by an average facial representation that is perceived as attractive. However, several groups of studies showed that partial occlusion can increase or decrease perceived attractiveness depending on the attractiveness of the original (unoccluded) face, due to regression to the mean. To reconcile this inconsistency, we propose that the occluded area is interpolated not by an average facial representation, but by a template of moderate attractiveness, shaped by the distribution of each viewer's experience. This hypothesis predicts an interaction between occlusion and the attractiveness of the original face so that occluded attractive faces are rated as less attractive, while occluded unattractive faces are rated as more attractive. To examine this hypothesis, the present study used attractiveness-rating tasks with mask-free versus masked faces in own-race and other-races categories. Viewers were familiar with own-race faces and unfamiliar with other-races faces. If moderate-attractiveness interpolation were the explanatory factor, the interaction between the occlusion and the attractiveness of the original face should be found only in the rating of own-race faces. Consistent with this hypothesis, the interaction between the occlusion and the attractiveness of the original faces was significant only for the own-race faces. Specifically, wearing a sanitary mask decreased the facial attractiveness of attractive faces in the own-race, while it increased the attractiveness regardless of the level of facial attractiveness in other-races. These findings suggest that the occluded area of own-race faces is interpolated by a facial template of moderate attractiveness. The other-races template could be developed using familiar exemplars such as celebrities. Thus, interpolation by such a template should result in elevated attractiveness relative to that by an own-race template. Accordingly, the apparent inconsistency in the literature regarding the effect of partial occlusion on physical attractiveness can be explained in terms of differences in the template involving interpolation of the occluded area.

Two face masks are better than one: congruency effects in face matching

Although the positive effects of congruency between stimuli are well replicated in face memory paradigms, mixed findings have been found in face matching. Due to the current COVID-19 pandemic, face masks are now very common during daily life outdoor activities. Thus, the present study aims to further explore congruency effects in matching faces partially occluded by surgical masks. Observers performed a face matching task consisting of pairs of faces presented in full view (i.e., full-view condition), pairs of faces in which only one of the faces had a mask (i.e., one-mask condition), and pairs of faces in which both faces had a mask (i.e., two-mask condition). Although face masks disrupted performance in identity match and identity mismatch trials, in match trials, we found better performance in the two-mask condition compared to the one-mask condition. This finding highlights the importance of congruency between stimuli on face matching when telling faces together.

Does Prolonged FFP2 Mask Use Cause Changes in Nasal Cytology? A Pilot Observational Study on Healthcare Workers

TheCOVID-19 pandemic has rapidly spread worldwide. Individual prevention approaches include FFP2/N95 mask use. Healthcare (HC) workers wear face masks for a long time during their work shifts and often complain of nasal symptoms. Current data on mask-associated symptoms or upper airway epithelium transformations are limited. Nasal cytology (NC) is a useful, non-invasive diagnostic method to assess cellular alterations. The aim of this study is to compare NC in HC workers before and after the continuous wearing of FFP2 face masks. We conducted a pilot observational study on 10 volunteer HC workers, who continuously used FFP2 masks during the work shift. All subjects underwent NC at the beginning (T0) and at the end of their workshift (T1) and the cytological findings were compared. Moreover, nasal symptoms were collected. Rare inflammatory cells were detected at T0 and, comparing cytological data about T0 and T1, no significant differences were observed. The most reported nasal symptoms were itching (70%) and a dry nose (60%). Difficulty of breathing and nasal blockage were not relevant. These preliminary data seem to suggest that wearing an FFP2 mask does not determine observable alterations in NC in daily work. However, further studies on a larger population for a longer period are needed.

COVID-19 masks increase the influence of face recognition algorithm decisions on human decisions in unfamiliar face matching

Face masks, recently adopted to reduce the spread of COVID-19, have had the unintended consequence of increasing the difficulty of face recognition. In security applications, face recognition algorithms are used to identify individuals and present results for human review. This combination of human and algorithm capabilities, known as human-algorithm teaming, is intended to improve total system performance. However, prior work has shown that human judgments of face pair similarity-confidence can be biased by an algorithm's decision even in the case of an error by that algorithm. This can reduce team effectiveness, particularly for difficult face pairs. We conducted two studies to examine whether face masks, now routinely present in security applications, impact the degree to which this cognitive bias is experienced by humans. We first compared the influence of algorithm's decisions on human similarity-confidence ratings in the presence and absence of face masks and found that face masks more than doubled the influence of algorithm decisions on human similarity-confidence ratings. We then investigated if this increase in cognitive bias was dependent on perceived algorithm accuracy by also presenting algorithm accuracy rates in the presence of face masks. We found that making humans aware of the potential for algorithm errors mitigated the increase in cognitive bias due to face masks. Our findings suggest that humans reviewing face recognition algorithm decisions should be made aware of the potential for algorithm errors to improve human-algorithm team performance.

Mask-wearing selectivity alters observers’ face perception

Face masks became prevalent across the globe as an efficient tool to stop the spread of COVID-19. A host of studies already demonstrated that masks lead to changes in facial identification and emotional expression processing. These changes were documented across ages and were consistent even with the increased exposure to masked faces. Notably, mask-wearing also changes the state of the observers in regard to their own bodies and other agents. Previous research has already demonstrated a plausible association between observers’ states and their perceptual behaviors. Thus, an outstanding question is whether mask-wearing would alter face recognition abilities. To address this question, we conducted a set of experiments in which participants were asked to recognize non-masked faces (Experiment 1), masked faces (Experiment 2) and novel objects (Experiment 3) while they were either masked or unmasked. Mask wearing hindered face perception abilities but did not modulate object recognition ability. Finally, we demonstrated that the decrement in face perception ability relied on wearing the mask on distinctive facial features (Experiment 4). Together, these findings reveal a novel effect of mask-wearing on face recognition. We discuss these results considering the plausible effect of somatosensory stimulation on visual processing as well as the effect of involuntary perspective taking.

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.

The impact of COVID-19 on memory: Recognition for masked and unmasked faces

Considering the current state of the worldwide pandemic, it is still common to encounter people wearing face protection masks. Although a safety measure against COVID-19, face masks might be compromising our capacity for face recognition. We conducted an online study where 140 participants observed masked and unmasked faces in a within-subjects design and then performed a recognition memory task. The best performance was found when there were no masks either at study and test phase, i.e., at the congruent unmasked condition. The worst performance was found for faces encoded with a mask but tested without it (i.e., masked-unmasked incongruent condition), which can be explained by the disruption in holistic face processing and the violation of the encoding specificity principle. Interestingly, considering the unmasked-masked incongruent condition, performance was probably affected by the violation of the encoding specificity principle but protected by holistic processing that occurred during encoding.

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.

How facial masks alter the interaction of gaze direction, head orientation, and emotion recognition

The COVID-19 pandemic has altered the way we interact with each other: mandatory mask-wearing obscures facial information that is crucial for emotion recognition. Whereas the influence of wearing a mask on emotion recognition has been repeatedly investigated, little is known about the impact on interaction effects among emotional signals and other social signals. Therefore, the current study sought to explore how gaze direction, head orientation, and emotional expression interact with respect to emotion perception, and how these interactions are altered by wearing a face mask. In two online experiments, we presented face stimuli from the Radboud Faces Database displaying different facial expressions (anger, fear, happiness, neutral, and sadness), gaze directions (−13°, 0°, and 13°), and head orientations (−45°, 0°, and 45°) – either without (Experiment 1) or with mask (Experiment 2). Participants categorized the displayed emotional expressions. Not surprisingly, masks impaired emotion recognition. Surprisingly, without the mask, emotion recognition was unaffected by averted head orientations and only slightly affected by gaze direction. The mask strongly interfered with this ability. The mask increased the influence of head orientation and gaze direction, in particular for the emotions that were poorly recognized with mask. The results suggest that in case of uncertainty due to ambiguity or absence of signals, we seem to unconsciously factor in extraneous information.

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.

Smiling makes you look older, even when you wear a mask: the effect of face masks on age perception

The widespread use of face masks in the era of the Covid-19 pandemic has promoted research on their effect on the perception and recognition of faces. There is growing evidence that masks hinder the recognition of identity and expression, as well as the interpretation of speech from facial cues. It is less clear whether and in what manner masks affect the perception of age from facial cues. Recent research has emphasized the role of the upper region of the face, a part not covered by a mask, in the evaluation of age. For example, smile-related wrinkles in the region of the eyes make smiling faces appear older than neutral faces of the same individuals (the aging effect of smiling, AES). In two experiments, we tested the effect of face masks on age evaluations of neutral and smiling faces in a range of different age groups from 20 to 80 years. The results showed that smiling faces were perceived as older than neutral faces even when individuals were wearing a face mask—and there was no effect of masks on bias in age evaluations. Additional analyses showed reduced accuracy in age evaluations for smiling compared to neutral faces and for masked compared to unmasked faces. The results converge on previous studies emphasizing the importance of the upper region of the face in evaluations of age.

Wearing the face mask affects our social attention over space

Recent studies suggest that covering the face inhibits the recognition of identity and emotional expressions. However, it might also make the eyes more salient, since they are a reliable index to orient our social and spatial attention. This study investigates (1) whether the pervasive interaction with people with face masks fostered by the COVID-19 pandemic modulates the processing of spatial information essential to shift attention according to other’s eye-gaze direction (i.e., gaze-cueing effect: GCE), and (2) whether this potential modulation interacts with motor responses (i.e., Simon effect). Participants were presented with face cues orienting their gaze to a congruent or incongruent target letter location (gaze-cueing paradigm) while wearing a surgical mask (Mask), a patch (Control), or nothing (No-Mask). The task required to discriminate the identity of the lateralized target letters by pressing one of two lateralized response keys, in a corresponding or a non-corresponding position with respect to the target. Results showed that GCE was not modulated by the presence of the Mask, but it occurred in the No-Mask condition, confirming previous studies. Crucially, the GCE interacted with Simon effect in the Mask and Control conditions, though in different ways. While in the Mask condition the GCE emerged only when target and response positions corresponded (i.e., Simon-corresponding trials), in the Control condition it emerged only when they did not correspond (i.e., Simon-non-corresponding trials). These results indicate that people with face masks induce us to jointly orient our visual attention in the direction of the seen gaze (GCE) in those conditions resembling (or associated with) a general approaching behavior (Simon-corresponding trials). This is likely promoted by the fact that we tend to perceive wearing the mask as a personal safety measure and, thus, someone wearing the face mask is perceived as a trustworthy person. In contrast, people with a patch on their face can be perceived as more threatening, therefore inducing a GCE in those conditions associated with a general avoidance behavior (Simon-non-corresponding trials).

Are Face Masks a Problem for Emotion Recognition? Not When the Whole Body Is Visible

The rise of the novel COVID-19 virus has made face masks commonplace items around the globe. Recent research found that face masks significantly impair emotion recognition on isolated faces. However, faces are rarely seen in isolation and the body is also a key cue for emotional portrayal. Here, therefore, we investigated the impact of face masks on emotion recognition when surveying the full body. Stimuli expressing anger, happiness, sadness, and fear were selected from the BEAST stimuli set. Masks were added to these images and participants were asked to recognize the emotion and give a confidence level for that decision for both the masked and unmasked stimuli. We found that, contrary to some work viewing faces in isolation, emotion recognition was generally not impaired by face masks when the whole body is present. We did, however, find that when viewing masked faces, only the recognition of happiness significantly decreased when the whole body was present. In contrast to actual performance, confidence levels were found to decline during the Mask condition across all emotional conditions. This research suggests that the impact of masks on emotion recognition may not be as pronounced as previously thought, as long as the whole body is also visible.

Reading language of the eyes

The need for assessment of social skills in clinical and neurotypical populations has led to the widespread, and still increasing use of the 'Reading the Mind in the Eyes Test' (RMET) developed more than two decades ago by Simon Baron-Cohen and colleagues for evaluation of social cognition in autism. By analyzing most recent clinical and brain imaging data, we illuminate a set of factors decisive for using the RMET. Converging evidence indicates: (i) In neurotypical individuals, RMET scores are tightly correlated with other social skills (empathy, emotional intelligence, and body language reading); (ii) The RMET assesses recognition of facial affect, but also heavily relies on receptive language skills, semantic knowledge, and memory; (iii) RMET performance is underwritten by the large-scale ensembles of neural networks well-outside the social brain; (iv) The RMET is limited in its capacity to differentiate between neuropsychiatric conditions as well as between stages and severity of a single disorder, though it reliably distinguishes individuals with altered social cognition or elevated pathological traits from neurotypical persons; (v) Merely gender (as a social construct) rather than neurobiological sex influences performance on the RMET; (vi) RMET scores do not substantially decline in healthy aging, and they are higher with higher education level, cognitive abilities, literacy, and mental well-being; (vii) Accuracy on the RMET, and engagement of the social brain, are greater when emotions are expressed and recognized by individuals with similar cultural/ethnic background. Further research is required to better inform usage of the RMET as a tool for swift and reliable examination of social cognition. In light of comparable visual input from the RMET images and faces covered by masks due to COVID-19 regulations, the analysis is of value for keeping efficient social interaction during the current pandemic, in particular, in professional settings related to social communication.

The Recognition of Facial Expressions Under Surgical Masks: The Primacy of Anger

Background

The need to wear surgical masks in everyday life has drawn the attention of psychologists to the negative effects of face covering on social processing. A recent but not homogeneous literature has highlighted large costs in the ability to recognize emotions.

Methods

Here it was investigated how mask covering impaired the recognition of facial mimicry in a large group of 220 undergraduate students. Sex differences in emotion recognition were also analyzed in two subgroups of 94 age-matched participants. Subjects were presented with 112 pictures displaying the faces of eight actors (4 women and 4 men) wearing or not wearing real facemasks, and expressing seven emotional states (neutrality, surprise, happiness, sadness, disgust, anger and fear). The task consisted in categorizing facial expressions while indicating the emotion recognizability with a 3-point Likert scale. Scores underwent repeated measures ANOVAs.

Results

Overall, face masking reduced emotion recognition by 31%. All emotions were affected by mask covering except for anger. Face covering was most detrimental to sadness and disgust, both relying on mouth and nose expressiveness. Women showed a better performance for subtle expressions such as surprise and sadness, both in masked and natural conditions, and men for fear recognition (in natural but especially masked conditions).

Conclusion

Anger display was unaffected by masking, also because corrugated forehead and frowning eyebrows were clearly exposed. Overall, facial masking seems to polarize non-verbal communication toward the happiness/anger dimension, while minimizing emotions that stimulate an empathic response in the observer.

Eyes versus Eyebrows: A Comprehensive Evaluation Using the Multiscale Analysis and Curvature-Based Combination Methods in Partial Face Recognition

This work aimed to find the most discriminative facial regions between the eyes and eyebrows for periocular biometric features in a partial face recognition system. We propose multiscale analysis methods combined with curvature-based methods. The goal of this combination was to capture the details of these features at finer scales and offer them in-depth characteristics using curvature. The eye and eyebrow images cropped from four face 2D image datasets were evaluated. The recognition performance was calculated using the nearest neighbor and support vector machine classifiers. Our proposed method successfully produced richer details in finer scales, yielding high recognition performance. The highest accuracy results were 76.04% and 98.61% for the limited dataset and 96.88% and 93.22% for the larger dataset for the eye and eyebrow images, respectively. Moreover, we compared the results between our proposed methods and other works, and we achieved similar high accuracy results using only eye and eyebrow images.

The Attractiveness of Masked Faces Is Influenced by Race and Mask Attitudes

This study tests the influence of wearing a protective face mask on the perceived attractiveness of the wearer. Participants who identified as White, and who varied in their ideological stance toward mask wearing, rated the attractiveness of facial photographs. The photos varied in baseline attractiveness (low, medium, and high), race (White and Asian), and whether or not the face was wearing a protective mask. Attitudes regarding protective masks were measured after the rating task using a survey to identify participants as either pro- or anti-mask. The results showed that masked individuals of the same race were generally rated as more attractive than unmasked individuals, but that masked individuals of another race were rated as less attractive than unmasked individuals. Moreover, pro-mask participants rated masked individuals as generally more attractive than unmasked individuals, whereas anti-maskers rated masked individuals as less attractive. A control experiment, replicating the procedure but replacing the protective masks with a partially occluding notebook, showed that these effects were mask-specific. These results demonstrate that perceived attractiveness is affected by characteristics of the viewer (attitudes toward protective masks), their relationship to the target (same or different race), and by circumstances external to both (pandemic).

The influence of familiarity on memory for faces and mask wearing

During the COVID-19 pandemic, the wearing of face masks became mandatory in public areas or at workplaces in many countries. While offering protection, the coverage of large parts of our face (nose, mouth and chin) may have consequences for face recognition. This seems especially important in the context of contact tracing which can require memory of familiar and unfamiliar contacts and whether they were wearing a mask. In this study, we tested how well participants perform at remembering faces and whether they wore a mask, and if this depends on familiarity. Our results show that: (a) Participants remembered familiar faces better than unfamiliar ones, regardless of mask wearing. (b) Participants remembered unmasked faces better than masked faces, regardless of familiarity. (c) Participants were significantly worse at remembering whether an unfamiliar face was wearing a mask or not-even if they indicated remembering the face. (d) Participants showed a bias to indicate no memory of unfamiliar faces. (e) Participants showed a bias to indicate that unfamiliar faces wore a mask, even if they did not. In sum, it was harder to remember both, the identity of unfamiliar faces and whether they wore a mask. These findings have practical relevance for contact tracing and epidemic control.

Face masks have a limited influence on first impressions: evidence from three experiments

Considering the widespread use of face masks during the COVID-19 pandemic, the goal of the current study was to examine how occlusion of the lower half of the face may impact first impression formation. We conducted three experiments, each building on previous research, investigating the effect of face masks on first impressions of faces across the lifespan (children, young and older adults). Experiment 1 examined whether the mandatory influence of happy facial expressions on perceived trustworthiness in young adult faces is influenced by face masks. Experiment 2 examined behavioural consequences of adults' first impressions of child faces to determine whether masks reduce the effect of facial niceness on interpretations of ambiguous behaviour. Experiment 3 investigated consensus for first impressions of trustworthiness and competence in older adult faces with and without masks, as well as consensus on underlying facial cues. The results of all three experiments present converging evidence that masks do not have a significant impact on first impressions and their behavioural consequences.

Impact of mask use on face recognition: an eye-tracking study

We examined how mask use affects performance and eye movements in face recognition and whether strategy change reflected in eye movements is associated with performance change. Eighty-eight participants performed face recognition with masked faces either during learning only, during recognition only, or during both learning and recognition. As compared with the baseline condition where faces were unmasked during both learning and recognition, participants had impaired performance in all three scenarios, with larger impairment when mask conditions during learning and recognition did not match. When recognizing unmasked faces, whether the faces were learned with or without a mask on did not change eye movement behavior. Nevertheless, when recognizing unmasked faces that were learned with a mask on, participants who adopted more eyes-focused patterns had less performance impairment as compared with the baseline condition. When recognizing masked faces, participants had more eyes-focused patterns and more consistent gaze transition behavior than recognizing unmasked faces regardless of whether the faces were learned with or without a mask on. Nevertheless, when recognizing masked faces that were learned without a mask, participants whose gaze transition behavior was more consistent had less performance impairment as compared with the baseline condition. Thus, although eye movements during recognition were mainly driven by the mask condition during recognition but not that during learning, those who adjusted their strategy according to the mask condition difference between learning and recognition had better performance. This finding has important implications for identifying populations vulnerable to the impact of mask use and potential remedial strategies.

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.

That person is now with or without a mask: how encoding context modulates identity recognition

Previous research has mostly approached face recognition and target identification by focusing on face perception mechanisms, but memory mechanisms also appear to play a role. Here, we examined how the presence of a mask interferes with the memory mechanisms involved in face recognition, focusing on the dynamic interplay between encoding and recognition processes. We approach two known memory effects: (a) matching study and test conditions effects (i.e., by presenting masked and/or unmasked faces) and (b) testing expectation effects (i.e., knowing in advance that a mask could be put on or taken off). Across three experiments using a yes/no recognition paradigm, the presence of a mask was orthogonally manipulated at the study and the test phases. All data showed no evidence of matching effects. In Experiment 1, the presence of masks either at study or test impaired the correct identification of a target. But in Experiments 2 and 3, in which the presence of masks at study or test was manipulated within participants, only masks presented at test-only impaired face identification. In these conditions, test expectations led participants to use similar encoding strategies to process masked and unmasked faces. Across all studies, participants were more liberal (i.e., used a more lenient criterion) when identifying masked faces presented at the test. We discuss these results and propose that to better understand how people may identify a face wearing a mask, researchers should take into account that memory is an active process of discrimination, in which expectations regarding test conditions may induce an encoding strategy that enables overcoming perceptual deficits.

Improving face identification of mask-wearing individuals

Research has consistently shown that concealing facial features can hinder subsequent identification. The widespread adoption of face masks due to the COVID-19 pandemic has highlighted the critical and urgent need to discover techniques to improve identification of people wearing face coverings. Despite years of research on face recognition and eyewitness identifications, there are currently no evidence-based recommendations for lineup construction for cases involving masked individuals. The purpose of this study was to examine identification accuracy of a masked perpetrator as a function of lineup type (i.e., unmasked or masked lineups) and perpetrator presence (i.e., absent or present). In both experiments, discriminability was superior for masked lineups, a result that was due almost exclusively to higher hits rates in target-present conditions. These data suggest that presenting a masked lineup can enhance identification of masked faces, and they have important implications for both eyewitness identification and everyday face recognition of people with face coverings.

The impact of face masks on emotion recognition performance and perception of threat

Facial emotion recognition is crucial for social interaction. However, in times of a global pandemic, where wearing a face mask covering mouth and nose is widely encouraged to prevent the spread of disease, successful emotion recognition may be challenging. In the current study, we investigated whether emotion recognition, assessed by a validated emotion recognition task, is impaired for faces wearing a mask compared to uncovered faces, in a sample of 790 participants between 18 and 89 years (condition mask vs. original). In two more samples of 395 and 388 participants between 18 and 70 years, we assessed emotion recognition performance for faces that are occluded by something other than a mask, i.e., a bubble as well as only showing the upper part of the faces (condition half vs. bubble). Additionally, perception of threat for faces with and without occlusion was assessed. We found impaired emotion recognition for faces wearing a mask compared to faces without mask, for all emotions tested (anger, fear, happiness, sadness, disgust, neutral). Further, we observed that perception of threat was altered for faces wearing a mask. Upon comparison of the different types of occlusion, we found that, for most emotions and especially for disgust, there seems to be an effect that can be ascribed to the face mask specifically, both for emotion recognition performance and perception of threat. Methodological constraints as well as the importance of wearing a mask despite temporarily compromised social interaction are discussed.

Masked face recognition in patients with relapsing–remitting multiple sclerosis during the ongoing COVID-19 pandemic

Background

Face and facial expression recognition abilities have been frequently evaluated in the assessment of social cognition disorders in patients with MS. Investigation of the effect of new difficulties emerging in the field of face recognition with the widespread use of masks during the ongoing COVID-19 pandemic on patients with MS may make new contributions to the literature.

Material and methods

The study included 44 patients with relapsing–remitting MS (RRMSp) and 51 controls who were matched to the case group in terms of age and education level. The Benton face recognition test-short form (BFRT-sf), Beck Depression Inventory, a close-ended 13-item survey on face recognition difficulties due to mask use during the pandemic was administered to all groups.

Results

In the RRMSp, the mean disease duration was 8.2 ± 5.6, the mean EDSS score was 1.2 ± 1.0, and the mean MOCA test score was 27.23 ± 2.08. The mean BFRTsf was 19.9 ± 2.4 in the RRMSp and 21.6 ± 1.8 in the healthy controls.Twenty-five percent of RRMSp and 4% of the healthy controls required people to remove their masks to be able to recognize their faces. Improvement in face recognition difficulty over time was reported as 80% in the healthy controls and 34% in the RRMSp.

Conclusion

RRMSp had worse performance in masked face recognition and required removal of the facial masks more often than healthy controls to recognize the faces. RRMS patients did not show as much improvement in recognizing masked faces over time according to the onset of the pandemic as healthy controls.

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

From the start of the COVID-19 pandemic, the use of surgical masks became widespread. However, they occlude an important part of the face and make it difficult to decode and interpret other people's emotions. To clarify the effect of surgical masks on configural and featural processing, participants completed a facial emotion recognition task to discriminate between happy, sad, angry, and neutral faces. Stimuli included fully visible faces, masked faces, and a cropped photo of the eyes or mouth region. Occlusion due to the surgical mask affects emotion recognition for sadness, anger, and neutral faces, although no significative differences were found in happiness recognition. Our findings suggest that happiness is recognized predominantly via featural processing.

Face Processing in Early Development: A Systematic Review of Behavioral Studies and Considerations in Times of COVID-19 Pandemic

Human faces are one of the most prominent stimuli in the visual environment of young infants and convey critical information for the development of social cognition. During the COVID-19 pandemic, mask wearing has become a common practice outside the home environment. With masks covering nose and mouth regions, the facial cues available to the infant are impoverished. The impact of these changes on development is unknown but is critical to debates around mask mandates in early childhood settings. As infants grow, they increasingly interact with a broader range of familiar and unfamiliar people outside the home; in these settings, mask wearing could possibly influence social development. In order to generate hypotheses about the effects of mask wearing on infant social development, in the present work, we systematically review N = 129 studies selected based on the most recent PRISMA guidelines providing a state-of-the-art framework of behavioral studies investigating face processing in early infancy. We focused on identifying sensitive periods during which being exposed to specific facial features or to the entire face configuration has been found to be important for the development of perceptive and socio-communicative skills. For perceptive skills, infants gradually learn to analyze the eyes or the gaze direction within the context of the entire face configuration. This contributes to identity recognition as well as emotional expression discrimination. For socio-communicative skills, direct gaze and emotional facial expressions are crucial for attention engagement while eye-gaze cuing is important for joint attention. Moreover, attention to the mouth is particularly relevant for speech learning. We discuss possible implications of the exposure to masked faces for developmental needs and functions. Providing groundwork for further research, we encourage the investigation of the consequences of mask wearing for infants' perceptive and socio-communicative development, suggesting new directions within the research field.

Are estimates of faces' ages less accurate when they wear sunglasses or face masks and do these disguises make it harder to later recognise the faces when undisguised?

This study examined whether our ability to accurately estimate unfamiliar faces’ ages declines when they are wearing sunglasses or surgical-style face masks and whether these disguises make it harder to later recognise those faces when undisguised. In theory, both disguises should harm age estimation accuracy and later face recognition as they occlude facial information that is used to determine a face’s age and identity. To establish whether this is the case, we had participants estimate the age of unfamiliar faces that were pictured wearing no disguises, sunglasses, or face masks. The participants then completed a face recognition test where they had to distinguish between the previously seen faces and new faces. Importantly, none of faces wore disguises in this latter test. Participants’ estimates of the undisguised faces’ ages were inaccurate by a Median of 5.15 years. Their accuracy barely changed when the faces wore sunglasses but declined by a Median of 1.30 years when they wore face masks. Moreover, subsequent undisguised face recognition was less likely to occur when the faces previously wore sunglasses or face masks, with large effects observed. These findings demonstrate the relative importance of different facial areas when estimating faces’ ages and later recognising them. They also have implications for policing as they suggest it may be harder for eyewitnesses to accurately estimate the age of criminals who wear face masks during offences, and it may be harder for them to later recognise criminals in line-ups if the criminals wear sunglasses or face masks during offences.

Face masks versus sunglasses: limited effects of time and individual differences in the ability to judge facial identity and social traits

Some research indicates that face masks impair identification and other judgements such as trustworthiness. However, it is unclear whether those effects have abated over time as individuals adjust to widespread use of masks, or whether performance is related to individual differences in face recognition ability. This study examined the effect of masks and sunglasses on face matching and social judgements (trustworthiness, competence, attractiveness). In Experiment 1, 135 participants across three different time points (June 2020–July 2021) viewed unedited faces and faces with masks, sunglasses, or both. Both masks and sunglasses similarly decreased matching performance. The effect of masks on social judgements varied depending on the judgement and whether the face was depicted with sunglasses. There was no effect of timepoint on any measure, suggesting that the effects of masks have not diminished. In Experiment 2, 12 individuals with developmental prosopagnosia (DP) and 10 super-recognisers (SRs) completed the same tasks. The effect of masks on identity matching was reduced in SRs, whereas the effects of masks and sunglasses for the DP group did not differ from controls. These findings indicate that face masks significantly affect face perception, depending on the availability of other facial information, and are not modified by exposure.

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

Face perception is considered a remarkable visual ability in humans that is subject to a prolonged developmental trajectory. In response to the COVID-19 pandemic, mask-wearing has become mandatory for adults and children alike. Recent research shows that mask-wearing hinders face recognition abilities in adults, but it is unknown if the same holds true in school-age children in whom face perception is not fully developed. Here we tested children (n = 72, ages 6-14 years old) on the Cambridge Face Memory Test - Kids (CFMT-K), a validated measure of face perception performance. Faces were presented with or without masks and across two orientations (upright/inverted). The inclusion of face masks led to a profound deficit in face perception abilities. This decrement was more pronounced in children compared to adults, but only when task difficulty was adjusted across the two age groups. Additionally, children exhibited reliable correlations between age and the CFMT-K score for upright faces for both the mask and no-mask conditions. Finally, as previously observed in adults, children also showed qualitative differences in the processing of masked versus non-masked faces. Specifically, holistic processing, a hallmark of face perception, was disrupted for masked faces as suggested by a reduced face-inversion effect. Together, these findings provide evidence for substantial quantitative and qualitative alterations in the processing of masked faces in school-age children.