Reactive attachment disorder
The broad theoretical framework for current versions of RAD is attachment theory, based on work conducted from the 1940s to the 1980s by John Bowlby, Mary Ainsworth and René Spitz. Attachment theory is a framework that employs psychological, ethological and evolutionary concepts to explain social behaviors typical of young children. Attachment theory focuses on the tendency of infants or children to "seek proximity" to a "particular attachment figure" (familiar caregiver), in situations of alarm or distress, behavior which appears to have survival value. This is known as a discriminatory or selective attachment. Subsequently, the child begins to use the caregiver as a base of security from which to explore the environment, returning periodically to the familiar person. Attachment is not the same as love and/or affection although they are often associated. Attachment and attachment behaviors tend to develop between the ages of six months and three years. Infants become attached to adults who are sensitive and responsive in social interactions with the infant, and who remain as consistent caregivers for some time. Caregiver responses lead to the development of patterns of attachment, that in turn lead to internal working models which will guide the individual's feelings, thoughts, and expectations in later relationships. For a diagnosis of reactive attachment disorder, the child's history and atypical social behavior must suggest the absence of formation of a discriminatory or selective attachment.
Caring in intimate relationships
Attachment theory, an influential theoretical framework for the study of intimate relationships and personality development, argues that all humans are born with the capacity and motivation to engage in caregiving behaviours aimed at providing protection and support to close others. These behaviours are organized by an innate behavioural system, called the "caregiving system", which is believed to have emerged over the course of primate evolution to ensure the survival of vulnerable offspring. That is, because infants in many primate species, including humans, are highly altricial ("i.e.", developmentally immature and helpless at birth), they cannot survive without caregiver support and protection. Attachment theory proposes that this evolutionary pressure favoured the emergence of the caregiving behavioural system, which functions to safeguard the vulnerable dependent from harm by providing him or her with protection, comfort, and help during times of threat or need. Although this system was first conceptualized in child–parent bonds, its operation has since been established in adult intimate relationships, where both partners may occasionally take on the role of caregiver.