Emotion understanding in infants and young children: How input shapes emotional development

Here, we will review the developmental literature on how infants and young children learn about emotions. We take a process-based perspective, highlighting how the protracted trajectory of emotional development unfolds concurrently with changes in children's cognitive abilities, and how variability based on context, culture, and experience shape this trajectory over time. We will also emphasize the role of input into this development, a factor that has often been ignored. Indeed, little research has systematically sought to understand how children's emotional development is shaped by the emotional input they receive. We focus on the development of three abilities that comprise emotion understanding. First, we will discuss the developmental trajectory of emotional expression, and how infants and young children come to express emotions and behave emotionally. Second, we will discuss how infants and young children learn to regulate those emotional responses, and how different environmental inputs affect that ability. Third, we will discuss the development of emotion perception, or how infants and young children learn how to perceive, categorize, and identify the emotions of others over time. Finally, we will discuss mechanisms for developmental change in all of these domains, and how other concurrent domains of development-including motor skill, language, theory of mind, and attachment-might have cascading effects on changes in emotion understanding.