Bowlby’s theory is an evolutionary theory because, in his view attachment is a behavioural system that has evolved because of its survival value and, ultimately, its reproductive value. According to Bowlby, children have an innate drive to become attached to a caregiver because attachment has long-term benefits. Both attachment and imprinting ensure that a young animal stays close to a caregiver who will feed and protect the young animal. Thus attachment and imprinting are adaptive behaviours. Infants who do not become attached are less likely to survive and reproduce. Attachment ‘genes’ are perpetuated, and infants are born with an innate drive to become attached.
Since attachment is innate, there is likely to be a limited window for its development i.e. a critical or sensitive period. Development of all biological systems takes place most rapidly and easily during a critical period. Bowlby applied the concept of a sensitive period to attachment. He suggested that the second quarter of the first year is when infants are most sensitive to the development of attachments.
The drive to provide caregiving is also innate because it is adaptive (i.e. enhances survival of one’s offspring). Infants are born with certain characteristics, called social releasers, which elicit caregiving. The social releasers include smiling and crying. Another social releaser is a baby’s face. Attachment is the innate behavioural system in babies; caregiving is the response in adults. Both provide protection and thereby enhance survival. The formation of attachments depends on the interaction of these systems.
Attachment is important for protection, and thus acts as a secure base from which a child can explore the world and a safe haven to return to when threatened. Thus attachment fosters independence. Bowlby also believed that infants form a number of attachments but one of these has special importance. The bias towards on