attachment theory, in developmental psychology, the theory that humans are born with a need to form a close emotional bond with a caregiver and that such a bond will develop during the first six months of a child’s life if the caregiver is appropriately responsive. Developed by the British psychologist John Bowlby, the theory focused on the experience, expression, and regulation of emotions at both species (normative) and individual (person-specific) levels of analysis.

Bowlby believed that the attachment system, as he and others called it, served two primary functions: to protect vulnerable individuals from potential threats or harm and to regulate negative emotions following threatening or harmful events. The normative component of attachment theory identifies the stimuli and contexts that normally evoke and terminate different kinds of emotions, as well as the sequence of emotions usually experienced following certain relational events. The individual-difference component addresses how people’s personal histories of receiving care and support from attachment figures shape their goals, working models (i.e., interpersonal attitudes, expectations, and cognitive schemas), and coping strategies when emotion-eliciting events in relationships occur.

Normative features of attachment theory

Bowlby’s fascination with the emotional ties that bind humans to each other began with an astute observation. In all human cultures and indeed in primate species, young and vulnerable infants display a specific sequence of reactions following separation from their stronger, older, and wiser caregivers. Immediately following separation, infants protest vehemently, typically crying, screaming, or throwing temper tantrums as they search for their caregivers. Bowlby believed that vigorous protest during the early phases of caregiver absence is a good initial strategy to promote survival, especially in species born in a developmentally immature and very dependent state. Intense protests often draw the attention of caregivers to their infants, who would have been vulnerable to injury or predation during evolutionary history if left unattended.

If loud and persistent protests fail to get the caregiver’s attention, infants enter a second stage, known as despair, during which they usually stop moving and become silent. Bowlby believed that from an evolutionary standpoint, despondency is a good second strategy to promote survival. Excessive movement could result in accident or injury, and loud protests combined with movement might draw predators. According to this logic, if protests fail to retrieve the caregiver quickly, the next best survival strategy would be to avoid actions that might increase the risk of self-inflicted harm or predation.

After a period of despair, infants who are not reunited with their caregivers enter a third and final stage: detachment. During this phase, the infant begins to resume normal activity without the caregiver, gradually learning to behave in an independent and self-reliant manner. Bowlby believed that the function of emotional detachment is to allow the formation of new emotional bonds with new caregivers. He reasoned that emotional ties with previous caregivers must be relinquished before new bonds can fully be formed. In terms of evolution, detachment allows infants to cast off old ties and begin forming new ones with caregivers who might be able to provide the attention and resources needed for survival. Bowlby also conjectured that these normative stages and processes characterize reactions to prolonged or irrevocable separations in adult relationships, which might also have evolutionary adaptive value in terms of maintaining, casting aside, or forming new romantic pairings.

In addition to identifying the course and function of these three distinct stages, Bowlby also identified several normative behaviors that infants commonly display in attachment relationships. Such hallmark behaviors include sucking, clinging, crying, smiling, and following the caregiver, all of which serve to keep the infant or child in close physical proximity to the caregiver. Bowlby also documented unique features of caregivers and their interactions with the infant that are likely to promote attachment bonds. The features include the competence with which the caregiver alleviates the infant’s distress, the speed with which the caregiver responds to the infant, and the familiarity of the caregiver to the infant. These behaviors and features are also believed to be critical to the development of adult attachment relationships.