Social Development

At birth, babies differ in temperament—their characteristic patterns of emotional reactivity—and these differences tend to remain stable across the lifespan. Some babies react fearfully to loud sounds or strangers, whereas others react with curiosity. The source of these differences lies in the limbic areas of the brain, particularly the amygdala, which influences fear responses. Babies with a highly reactive limbic system are more likely to have strong reactions to potentially stressful situations.

Attachment refers to the bond that forms between newborns and their primary caregivers. The strength and health of this bond depends on an infant's temperament and the parenting style of their caregivers. These effects are bi-directional. It is easier for a caregiver to bond with a calm infant than an upset one, and it is easier for an infant to bond with a nurturing caregiver than a negligent one. The quality of the infant-caregiver bond strongly influences an individual's social relationships throughout the lifespan.

Stranger anxiety refers to the tendency for infants to feel uncomfortable or frightened when approached by someone they do not know. Separation anxiety involves a developmentally normal fear of being away from a trusted caregiver. These forms of anxiety occur even when the child is with a trusted caregiver or in a safe environment.

In 1978 psychologist Mary Ainsworth introduced a behavioral experiment to measure the quality of infant-caregiver attachment, called the Strange Situation. This task measures stranger anxiety and separation anxiety. In this experiment, a child is brought to an unfamiliar room with their caregiver. Next, a stranger joins the child and caregiver. The caregiver then exits the room, leaving the child alone with the stranger. After a few minutes, the stranger leaves and the child is completely alone. Finally, the caregiver returns.

The child's reactions are observed throughout these changes. Four attachment styles have been recorded over decades of research using this technique. Infants with a secure attachment style may or may not become distressed when the caregiver leaves, but they will respond positively when the caregiver returns. For example, they will smile or hug the caregiver. Infants who show an insecure-avoidant attachment style do not exhibit distress when the caregiver leaves and will not acknowledge the caregiver when he or she returns. Those with an insecure-ambivalent attachment style show distress when the caregiver leaves but will rebuff the caregiver when he or she returns rather than seeking comfort. Infants with a disorganized-disoriented attachment style show no consistent response pattern to their caregiver's departure or return.

In 1958, psychologist Erik Erikson proposed a theory that described psychosocial (social and behavioral) development as a series of stages in which major challenges must be confronted. Infants learn about trust versus mistrust through their caregivers, namely by the extent to which their needs for food, comfort, and security are met. Environments that do not meet their needs will lead infants to mistrust others or doubt themselves. In early childhood, children learn about autonomy versus doubt as they begin to develop preferences and make their own choices, such as for foods, toys, or clothes.

In the conflict of initiative versus guilt, preschoolers (play age) learn to take initiative as they discover the consequences of their actions and interact with others. Harsh reactions to mistakes can lead children to feel guilty or fearful of trying new things. School-aged children confront industry versus inferiority as they learn to engage in focused work and skill-building. Challenges at this stage may lead to low self-esteem and a sense of inferiority.

According to Erikson, adolescents should begin to develop a sense of identity independent from their families. They should also start to develop a sense of their adult role as a member of the community. Difficulty in this stage of identity versus confusion can lead to role confusion (being unsure of who one is). In early adulthood, young adults enter the state of intimacy versus isolation as they begin building lasting intimate relationships and establishing their own families. Challenges during this stage, such as a series of unsuccessful relationships, can lead to isolation.

During adulthood, people confront the challenge of generativity (concern for people besides self and family) versus stagnation (failure to contribute) as they work to make their mark on the world. In this stage, people may engage with their community through work, parenting, and volunteering. People who have not found a way to make a contribution that feels meaningful to them may feel stuck, or stagnant. In old age, people face the challenge of integrity (pride in one's life path) versus despair as they reflect on their lives and determine their level of overall satisfaction or regret.