As we can see, infants and toddlers develop many social and emotional skills in the first three years of life. They are learning to express and temper their feelings and how to positively engage with others. They are also developing a sense of who they are in the world. Every child develops in their own way and time. Social emotional development begins with a caring and loving attachment to primary caregivers and is enhanced through meaningful interactions with others and the environment.

Next, we will look at three different theories that have been used to explain social and emotional development over the lifespan. The following section will list the common developmental milestones expected for social emotional development.

Erikson’s Theory of Psychosocial Development

Researcher Erik Erikson believed that children learn through their social interactions. As children grow and expand their experiences, they encounter various “conflicts” that they must overcome. Once children successfully overcome these conflicts, they build valuable skills that will aid them later in their lives. He labeled these as “virtues,” which are strengths that a child can use to resolve future conflicts. Erikson’s theory includes eight stages, the first two of which coincide with infancy and toddlerhood. Erikson agreed with attachment theorists that establishing a basic sense of trust in one’s caregivers sets the stage for future development.

Stage 1: Trust versus Mistrust (0 to 18 months)

The first stage of Erikson’s theory of psychosocial development is trust versus mistrust (Erikson, 1982). In this stage, children spend the first 18 months of their lives trying to understand the world that they live in. Children rely solely on their caregivers for food, comfort, and security. Responsive caregivers respond to a child’s innate needs and positively interact with them as much as possible. This allows the child to feel secure in the world. Children who successfully achieve trust in this stage will earn the virtue of “hope,” which allows them to believe that future others will be available to support them.

If there is a disruption in this process, a child will not develop a basic sense of trust. Perhaps a caregiver is emotionally unavailable to the child or they consistently fail to meet the child’s basic needs. These types of deprivations lead a child to mistrust their caregivers, thereby impacting their future relationships with others. The child may view the world as an unpredictable and scary place.

Stage 2: Autonomy versus Shame and Doubt (18 months to 3 years)

The second stage of Erikson’s Theory of Psychosocial Development is autonomy versus shame and doubt (Erikson, 1982). In this stage, children spend their toddler years establishing their independence and refining their skills. Responsive caregivers allow children to have a sense of control over their decisions and abilities. Children who successfully achieve autonomy in this stage will earn the virtue of “will,” which allows them to have a feeling of control over their lives.

Children may experience a disruption in this process if their caregivers are too controlling or judgmental. They may develop low self-esteem or a sense of doubt or shame in their abilities to control their lives.

The other stages of Erikson’s theory include:

• Stage 3: Initiative versus guilt (3 to 5 years)
• Stage 4: Industry versus inferiority (middle childhood)
• Stage 5: Identity versus confusion (adolescence)
• Stage 6: Intimacy versus isolation (adolescence to early adulthood)
• Stage 7: Generativity versus stagnation (adulthood)
• Stage 8: Integrity versus despair (older adulthood)

Social Learning Theory

Psychologist Albert Bandura proposed that children learn through the imitation and modeling of others’ behavior. This is known as social learning theory. Bandura claims that we are not simply a product of our environment but that we also have an influence on what we learn from the environment (Bandura, 1977). Bandura used experiments with a Bobo doll to demonstrate that children learned from watching others. In the experiment, adults acted violently toward a Bobo doll while children observed. Later, the children were allowed to play with the Bobo doll, and they copied the aggressive behaviors witnessed.

This type of observational learning means that a child can learn by watching others in real time; by watching real or fictional characters through television, books, or other media; and by listening to others. The child’s cognitive capacity and motivation determine how much of the behavior is learned or not learned. This theory has been used in discussions about young children’s exposure to television and other types of media.

Attachment Theory

The 20th century became a time of scientific interest and inquiry into child development. The formation of attachments in infancy has been the subject of considerable research. Attachments have been viewed as foundations for future relationships, self-concept, and identity (figure 6.5). Next, we will highlight theories and research studies of attachment.

The Harlows’ Studies

In one classic study, Wisconsin University psychologists Harry and Margaret Harlow investigated the responses of young rhesus monkeys to explore if breastfeeding was the most important factor in attachment.

The infant monkeys were separated from their biological mothers, and two surrogate mothers were introduced to their cages. The first mother (the wire mother) consisted of a round wooden head, a mesh of cold metal wires, and a milk bottle from which the baby monkey could drink. The second mother was a foam-rubber form wrapped in a heated terry cloth blanket. The infant monkeys went to the wire mother for food, but they overwhelmingly preferred and spent significantly more time with the warm terry cloth mother. The warm terry cloth mother provided no food but did provide comfort (Harlow, 1958).

The infant’s need for physical closeness and touching is referred to as contact comfort. Contact comfort is believed to be the foundation for attachment. The Harlows’ studies confirmed that babies have social and physical needs. Both monkeys and human babies need a secure base that allows them to feel safe. From this base, they can gain the confidence they need to venture out and explore their worlds.

Bowlby’s Theory

Building on the work of the Harlows and others, John Bowlby developed the concept of attachment theory. He defined attachment as the affectional bond or tie that an infant forms with their mother (Bowlby, 1969). An infant must form this bond with a primary caregiver to have normal social and emotional development. In addition, Bowlby proposed that this attachment bond is very powerful and continues throughout life. He used the concept of a secure base to define a healthy attachment between parent and child (Bowlby, 1982). A secure base is a parental presence that gives the child a sense of safety as the child explores their surroundings (figure 6.6).

Bowlby said that two things are needed for a healthy attachment: the caregiver must be responsive to the child’s physical, social, and emotional needs, and the caregiver and child must engage in mutually enjoyable interactions (Bowlby, 1969). Additionally, Bowlby observed that infants would go to extraordinary lengths to prevent separation from their parents, including crying, refusing to be comforted, and waiting for the caregiver to return.

Bowlby also observed that these same expressions were common to many other mammals and consequently argued that these negative responses to separation serve an evolutionary function. Because mammalian infants cannot feed or protect themselves, they are dependent upon the care and protection of adults for survival. Thus, those infants who were able to maintain proximity to an attachment figure were more likely to survive and reproduce.

Mary Ainsworth and the Strange Situation

Developmental psychologist Mary Ainsworth, a student of John Bowlby, continued studying the development of attachment in infants. Ainsworth and her colleagues created a laboratory test that measured infants’ attachment to their parents. The test is called the Strange Situation because it is conducted in a context that is unfamiliar to the child and, therefore, likely to heighten the child’s need for their parent (Ainsworth, 1979).

During the procedure, which lasts about 20 minutes, the parent and the infant are first left alone while the infant explores the room full of toys (figure 6.7). Then a strange adult enters the room and talks for a minute to the parent, after which the parent leaves the room. The stranger stays with the infant for a few minutes. Then the parent reenters the room, and the stranger leaves. During the entire session, a video camera records the child’s behaviors, which are later coded by the research team. The investigators were especially interested in how the child responded to the caregiver leaving and returning to the room, referred to as the “reunion.”

On the basis of their behaviors, the children are categorized into one of four groups. Each group reflects a different kind of attachment relationship with the caregiver. One style is secure, and the other three styles are insecure.

• Secure attachment refers to a bond in which a child feels secure with their caregivers and uses them as a base from which to explore their environment. A child with a secure attachment style usually explores freely while the caregiver is present and may engage with the stranger. The child will typically play with the toys and occasionally bring one to the caregiver to show and describe. The child may be upset when the caregiver departs but is also happy to see the caregiver return.
• Ambivalent attachment refers to a bond in which the child seeks closeness to the caregiver and is hesitant to explore the environment. A child with an ambivalent attachment style (sometimes called resistant or anxious-ambivalent) is wary about the situation in general, particularly the stranger, and stays close or even clings to the caregiver rather than exploring the toys. When the caregiver leaves, the child is extremely distressed. However, when the caregiver returns, the child is ambivalent. The child may rush to the caregiver but then fail to be comforted when picked up. The child may still be angry and even resist attempts to be soothed.
• Avoidant attachment refers to a bond in which the child avoids or is dismissive of their caregivers and may not explore the environment. A child with an avoidant attachment style will avoid or ignore the caregiver, showing little emotion when the caregiver departs or returns. The child may run away from the caregiver when they approach. The child will not explore very much, regardless of who is there, and the stranger will not be treated much differently than the caregiver.
• Disorganized attachment refers to a bond in which a child demonstrates an inconsistent relationship to their caregiver and how they interact with the environment. A child with a disorganized (or disoriented) attachment style seems to have a confused or apprehensive way of coping with the stress of the Strange Situation test. The child may cry during the separation but avoid the caregiver when they return, or the child may approach the caregiver but then freeze or fall to the floor.

How common are the attachment styles among children in the United States? It is estimated that about 65 percent of children in the United States are securely attached (Moullin et al., 2014). About 20 percent exhibit avoidant styles, and 10 percent to 15 percent are ambivalent. Another 5 percent to 10 percent of children may be characterized as disorganized.

Some cultural differences in attachment styles have been found (Rothbaum et al., 2010). For example, German parents value independence, and Japanese mothers are typically by their children’s sides. As a result, the rate of insecure-avoidant attachment is higher in Germany, and the rate of insecure-resistant attachment is higher in Japan. These differences reflect cultural variation rather than true insecurity, however (van Ijzendoorn & Sagi, 1999). Overall, secure attachment is the most common type of attachment seen in every culture studied thus far (Thompson, 2006).

Most developmental psychologists argue that a child becomes securely attached when there is consistent contact from one or more caregivers who meet the physical and emotional needs of the child in a responsive and appropriate manner. However, even in cultures where mothers do not talk, cuddle, and play with their infants, secure attachments can develop (LeVine et al., 1994).

Severe deprivation of parental attachment can lead to serious problems. According to studies of children who have not been given warm, nurturing care, they may show developmental delays, failure to thrive, and attachment disorders (Bowlby, 1982). Non-organic failure to thrive is the diagnosis for an infant who does not grow, develop, or gain weight on schedule, and there is no known medical explanation for this failure. Poverty, neglect, inconsistent parenting, and severe family dysfunction are correlated with non-organic failure to thrive. In addition, postpartum depression can cause even a well-intentioned mother to neglect her infant.

Children who experience social neglect or deprivation, repeatedly change primary caregivers in a way that limits opportunities to form stable attachments, or are reared in unusual settings (such as institutions) can have difficulty forming attachments. According to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, Text Revision (American Psychiatric Association, 2022), reactive attachment disorder refers to a diagnosable mental disorder characterized by inappropriate attachment behaviors such as being inhibited and withdrawn, demonstrating minimal social and emotional responsiveness to others, having limited positive affect, and exhibiting developmental delays, especially in cognitive and language domains.

Fortunately, the majority of severely neglected children do not develop reactive attachment disorder. This disorder occurs in less than 10 percent of children (Irfan et al., 2022). The quality of the caregiving environment after serious neglect affects the development of this disorder. Being able to overcome challenges and successfully adapt is known as resiliency. Even young children can exhibit strong resiliency to harsh circumstances. Resiliency can be attributed to certain personality factors, such as an easy-going temperament. Receiving support from others also leads to resiliency.

Social and Emotional Milestones

Young children begin learning social and emotional skills at birth. These skills are mainly directed toward their primary caregivers but eventually extend to others in their environments. Below is a list of the most common social and emotional milestones typically displayed during the first 3 years. It is important to remember that each child is unique and may develop these skills at different rates than outlined in Figure 6.8.

Licenses and Attributions for Social and Emotional Theories and Milestones

“Social and Emotional Theories and Milestones” by Christina Belli is licensed under CC BY 4.0.

“Attachment Theory” from Lifespan Development – A Psychological Perspective by Martha Lally and Suzanne Valentine-French is licensed under CC BY 4.0 with minor edits.

Figure 6.5. Image by Andres and Antoinette Ricardo used with permission.

Figure 6.6. Image is licensed under CC0.

Figure 6.7. Image is in the public domain.

Figure 6.8. Developmental Milestones by the CDC, 2022.