Peer Facial Impression Evaluation and Bias in Preschoolers: Social Decision-Making Based on Trustworthiness

Objectives: Adults make rapid judgments and biased decisions based on impressions of facial trustworthiness. This study examines whether preschoolers can evaluate peer trustworthiness from facial impressions and whether these evaluations influence their resource allocation and peer preferences. Most previous studies on facial impression bias have focused on adults, leaving a significant gap in our understanding of the development and manifestation of these biases in early childhood.Methods: This study included 150 five-year-old preschoolers (75 boys and 75 girls) from kindergartens and daycare centers in Seoul and Gyeonggi provinces. After a preliminary survey to create facial stimulus pairs with high- and low-trustworthiness impressions, the participants completed facial-impression evaluation and bias tasks involving resource allocation and preferences. Data were analyzed using various statistical methods including t-tests, frequency analyses, binomial tests, and chi-square tests.Results: Preschoolers demonstrated the ability to evaluate peer trustworthiness from facial impressions similar to those of adults, with girls displaying higher sensitivity in these evaluations. They demonstrated bias by allocating more resources to, and preferring, peers with highly trustworthy impressions. In forced-choice situations, most preschoolers favored peers with high-trustworthiness impressions for both resource allocation and friendship selection.Conclusion: This study shows that preschoolers, similar to adults, evaluate and exhibit biases based on facial impressions, which significantly influences their social decision-making despite not reflecting their actual character. These findings suggest that facial-impression biases affect early peer interactions and social development, thereby emphasizing the necessity for awareness and intervention in early-childhood education.