Erikson’s psychoanalytic theories provide an overview of the emotional and social tasks of infancy and toddlerhood. According to Erikson, trust and autonomy grow out of warm, supportive parenting and reasonable expectations for impulse control during the second year.

Emotions play a powerful role in the organization of relationships with caregivers, exploration of the environment, and discovery of the self. Infants’ ability to express basic emotions and respond to the emotions of others expands over the first year. Researchers agree that signs of emotions such as happiness, interest, surprise, fear, anger, and sadness are present early in infancy and, over time, become well-organized signals. As toddlers become more self-aware, self-conscious emotions such as shame, embarrassment, and pride begin to emerge. The ability to self-regulate emotions improves with brain maturation, gains in cognition and language, and sensitive child rearing.

Children’s unique temperamental styles are apparent in early infancy. A growing body of research explores temperament, including its stability, its biological roots, and its interaction with child-rearing practices.

Ethological theory is the most widely accepted view of the development of the infant–caregiver relationship. According to this perspective, attachment evolved over the history of our species to promote survival. Well-coordinated, positive emotional communication between caregiver and baby supports secure attachment, while insensitive caregiving is linked to attachment insecurity. Infants form attachment bonds with a variety of familiar people, including mothers, fathers, siblings, grandparents, and substitute caregivers.

During the first 2 years the knowledge of the self as a separate, permanent identity emerges. The first aspect to emerge is the I-self, followed in the second year by the me-self. Empathy, the ability to categorize the self (according to age, sex, and goodness and badness), compliance, and self-control are all byproducts of toddlers’ emerging sense of self.