The ability to recognize emotions begins developing in infancy and gradually evolves with age, progressing from

recognizing basic emotions to understanding more diverse and complex emotional states. Emotion recognition is crucial

for young children. It is positively associated with improved social skills and prosocial behaviors and negatively associated

with aggressive, oppositional, and other problematic behaviors. After the emergence of COVID-19 in December 2019, the

disease spread rapidly across the globe. By February 2020, the World Health Organization classified the global risk level

of the pandemic as “very high.” By May 2021, the World Health Organization estimated that the true death toll was 2 to 3

times higher than official reports, reaching at least 6–8 million people. Considering the pandemic’s severity, Taiwan’s Central

Epidemic Command Center mandated mask-wearing in eight key locations and implemented home isolation measures starting

in 2020. The pandemic persisted in Taiwan for approximately 3 years. During this period, preschool children in Taiwan rarely

encountered full facial expressions because mask-wearing became ubiquitous outside the home. In schools, masks were removed

only during meal times; even then, children sat behind partitions. Despite the lifting of restrictions, kindergartens continue to

require children to wear masks for safety. Moreover, parents have their children wear masks when going out. The effect of such

measures on Taiwanese children’s emotion recognition skills remains unclear. In general, young children rely on the facial cues

of others to recognize the other person’s emotions. Thus, relevant studies have focused on the recognition of facial expressions.

However, when facial information is incomplete, children rely on alternative sources, such as language, bodily movements, and

contextual cues, that masks do not obscure.

Child development research should thus address this unprecedented scenario and investigate how children rely on these

nonfacial cues to recognize the emotions of masked individuals. Studies outside of Taiwan have already started to do so.

Although most countries lifted restrictions relatively rapidly, Taiwan maintained the measures for > 3 years. Few studies have

investigated how Taiwanese children recognize emotions with incomplete facial information and how they use multiple cues

to identify expressions. Current research tools for evaluating children’s emotion recognition skills primarily use static images

of strangers’ faces as stimuli, which fail to capture real-world dynamics. In everyday life, children recognize the emotions of

familiar individuals during dynamic interactions by processing facial expressions, body movements, verbal cues (particularly

tone of voice), and contextual cues. Standardized emotion recognition tests often feature prototypical emotional expressions

displayed by professionals following specific instructions, but these expressions do not reflect the nuances of children’s real-life

interactions with peers.

Therefore, the present study explored children’s emotion recognition skills when interacting with masked peers, adapting

research tools to better reflect real-life conditions. Instead of relying on picture cards or strangers’ photos, this study used

videos, rather than static images, of real-life interactions with classmates. This approach facilitated an accurate understanding

of children’s emotion recognition skills and cue usage when interacting with masked peers. The present study included 151 children aged 3–6 years. V ideos of emotional interactions with peers were used to evaluate children’s emotion recognition

accuracy and cue usage. The results revealed marked reductions in children’s ability to recognize emotions, such as sadness,

surprise, fear, and disgust, in masked peers. Thus, children’s emotion recognition skills fell short of expectations; they

frequently confused emotions within the same category and struggled with classifying basic positive and negative emotions.

The analysis of emotional cues indicated that children who accurately recognized emotions used different cues for different

emotions. Peers expressed emotions in various ways, which led to variations in emotional cues. Appropriate cues had to be

adjusted for emotion recognition. Not all emotions could be identified through a single cue. Children who could not recognize

emotions effectively were not only unfamiliar with the definitions of and differences between emotional categories but also

struggled to identify appropriate emotional cues. Mask-wearing further reduced their ability to associate cues with the correct

emotions, causing confusion even in classifying basic positive and negative emotions. These findings underscore a need for

educational interventions to mitigate the effect of mask-wearing on children’s emotion recognition skills. Parents and educators

should actively teach children strategies for recognizing emotions. Mastering the use of emotion recognition cues can help

children accurately recognize the emotions of masked individuals. Thus, children should be taught various strategies and cues

for recognizing emotions in daily life and encouraged to observe and interpret the emotional states of masked individuals.

Understanding peers’ emotions can also enhance children’s emotion recognition skills. Thus, peer interaction opportunities

should be increased and children should be guided to pay attention to their peers’ emotional expressions and feelings. The

development of emotion recognition skills from infancy to early childhood involves progression from a basic to more nuanced

understanding of emotions, which is vital for social competence and behavioral regulation. However, mask-wearing measures

substantially reduced children’s exposure to full facial expressions during the pandemic. This reduction was particularly

prominent in Taiwan, where such measures were strictly enforced for an extended period. This unique context provided a

valuable opportunity for studies to investigate how children adapted to recognizing emotions when the primary cue—facial

expression—was partially obscured. Studies from other countries with relatively short pandemic restrictions have begun to

address these questions. However, the prolonged mask-wearing measures in Taiwan offers a unique opportunity to explore

how children develop emotion recognition skills under sustained conditions of incomplete facial cues. The use of videos of

interactions with classmates, rather than static images of strangers, in this study accurately reflected the real-world challenges

children face in recognizing emotions during social interactions. This approach also helped leverage children’s current

relationships with classmates and knowledge of their classmates’ typical behaviors and expressions. The approach was based

on an acknowledgment that children do not interact with strangers in isolation but rather engage in interactions in dynamic

social environments, where they use a combination of verbal and nonverbal cues to interpret emotions. The findings suggested

that more flexible and adaptive emotion recognition skills can be developed in children by subjecting them to a broader range

of cues beyond facial expressions. Moreover, this study highlighted the importance of contextualizing emotion recognition

within the lived experiences of children. Because a major portion of children’s early developmental years coincided with the

period of mask-wearing measures, understanding how they adapted—or struggled to adapt—to these restrictions is crucial. Such

knowledge can inform targeted interventions and educational strategies for enhancing children’s emotion recognition skills.

Regarding educational recommendations on the basis this study, parents and educators must proactively teach and reinforce

emotion recognition strategies—for example, by guiding children to use alternative cues such as body language, vocal tone, and

situational context to interpret emotions. Providing opportunities for meaningful peer interactions can further enhance children’s

ability to recognize and respond to others’ emotions. Encouraging children to practice these skills in both masked and unmasked

settings can equip them with a comprehensive toolkit for navigating social relationships. In conclusion, this study highlights

the profound effect of prolonged mask-wearing measures on the development of children’s emotion recognition skills. It calls

for collaborative efforts from parents, educators, and researchers to address these challenges and support children in cultivating

robust emotion recognition skills that extend beyond the pandemic. The present study clarifies how children adapt to evolving

social environments and offers practical guidance for fostering their emotional and social well-being.