Discerning the specific attachment behaviors--which include signaling (e.g., crying, reaching, smiling) and approaching (e.g., moving toward, following, clinging)--is relatively simple; however, of greater interest to attachment researchers has been the organizational nature of attachment systems (Sroufe & Waters, 1977). Several important components of this organization have been explored in depth elsewhere (Bowlby, 1969/1982; Bretherton, 1985); these include the infant having a set goal that governs the timing and degree of proximity maintenance; the balance of proximity and distance/exploration, which is often called secure-base behavior; and the relative activation of the attachment (proximity) system in circumstances of danger, illness, or separation.
As Bowlby's collaborator Mary Ainsworth has shown, a child's initial distress at mother's departure is usually a sign of secure attachment. In Summarizing Ainsworth's research, Bowlby noted: "A secure child shows an organised sequence of goal-corrected behaviour: after welcoming mother and approaching her, he either seeks to be picked up and to cling or else remains close to her. Responses shown by other children are of two main sorts: one is an apparent disinterest in mother's return and/or avoidance of her, the other an ambivalent response, half wanting and half resisting her" (337).
Attachment researchers agree that, given the opportunity, all normal human infants become attached to their primary caregiver, typically within the first 8 months of life. Whether secondary attachments to other people are formed simultaneously or only after a primary attachment has been established is open to debate, but there is no doubt that infants and children do form multiple attachments. Bonds that satisfy the criteria for being attachments-- that is, that include proximity maintenance and safe-haven and secure-base behaviors-- are commonly developed with other adults as well as with older siblings.
In middle-class families with stable environments, attachment classifications have been found to be highly constant over time. However, there is a broad consensus that changes in patterns of care during infancy and early childhood can lead to changes in the attachment relationship (Thompson, Lamb & Estes, 1983; Vaughn et al., 1979; Waters, 1983). Accordingly, it is important to identify the conditions that either promote stability or bring about change in a relationship that exists in dynamic transaction with a multitude of sociocultural and environmental influences.
Bowlby (1982) argues that the self-reliant person appears quite independent because of the variety of supportive attachments the individual has formed. Where this ability to form health attachments is interfered with, the individual becomes vulnerable to various environmental risks due to their isolation. Hence, attachment theory is the underlying theoretical basis for explaining the process whereby an individual uses available social supports to avert distress.
To our knowledge, caregiving has never been described by attachment theorists as motivated by self-interest, except in the sense that the caregiving system, like all biobehavioral adaptions, evolved because it increased parents' inclusive fitness. Attachment theory's concepts of sensitive and responsive parenting clearly point to a parent's focus on his or her child's needs and signals, not on the parent's more directly selfish concerns.
In sum, attachment theory proposes that heightened attachment behavior and increased fearfulness characteristic of the Strange Situation behavior of insecure/ambivalent infants ought to (a) result from experiences contributing to uncertainty about maternal availability, and (b) lead to incompetent exploration. In the following section, infant attachment research that addresses these and related issues is reviewed.
Attachment theory is rich in descriptions and explanations of human behavior and mental processes, both normative and pathological. Mary Ainsworth expanded the principles and perspectives of attachment theory and contributed a procedure and theory for describing and explaining individual differences in infant attachments to caregivers (Ainsworth, Blehar, Waters, & Wall, 1978). From Ainsworth's perspective, individual differences are categorical-- differences in kind rather than amount. Ainsworth and her associates (1978) identified three patterns or styles believed to reflect infants' coping responses to their caregivers' interactive styles.
A child is said to seek the attachment figure when under stress but to seek a playmate when in good spirits. Because the two roles are not incompatible, it is possible for one person (e.g., the caregiver) to fill both. With respect to the formulation of attachment theory, this position has a number of implications. First, it is now clear that the term "attachment" used in this narrower, technical sense does not cover the playful interactions studied by Brazelton (e.g., Brazelton, Koslowski, & Main, 1974) and Stern (e.g., Stern, 1977), even though these play an important role in mother-infant relationships. This point is treated at much greater length in Bretherton (1980).
Originally introduced by Bowlby (1969) as an alternative to psychoanalytic object-relations theory, attachment theory postulates a primary, biosocial behavioral system in the infant that was "designed" by evolution primarily to maintain proximity of the infant to its mother. According to Bowlby, such a system was favored by natural selection due to its function in providing protection for the helpless infant, just as particular foraging and sexual behavior patterns evolved to promote nutritive and reproductive goals. However, Bowlby argued that the basic mechanisms of the attachment system are active and influential throughout the lifespan.