Duration of face mask exposure matters: evidence from Swiss and Brazilian kindergartners' ability to recognise emotions.

Wearing facial masks became a common practice worldwide during the COVID-19 pandemic. This study investigated (1) whether facial masks that cover adult faces affect 4- to 6-year-old children's recognition of emotions in those faces and (2) whether the duration of children's exposure to masks is associated with emotion recognition. We tested children from Switzerland ( N  = 38) and Brazil ( N  = 41). Brazil represented longer mask exposure due to a stricter mandate during COVID-19. Children had to choose a face displaying a specific emotion (happy, angry, or sad) when the face wore either no cover, a facial mask, or sunglasses. The longer hours of mask exposure were associated with better emotion recognition. Controlling for the hours of exposure, children were less likely to recognise emotions in partially hideen faces. Moreover, Brazilian children were more accurate in recognising happy faces than Swiss children. Overall, facial masks may negatively impact children's emotion recognition. However, prolonged exposure appears to buffer the lack of facial cues from the nose and mouth. In conclusion, restricting facial cues due to masks may impair kindergarten children's emotion recognition in the short run. However, it may facilitate their broader reading of facial emotional cues in the long run.