Attachment theory describes the dynamics of long-term relationships between humans. John Bowlby is considered to have provided the most comprehensive and influential account of attachment formation. His contributions are heavily influenced by ethology (the scientific study of human and animal behavior), including an emphasis on the evolutionary origins and biological purposes of behavior. Children are biologically predisposed to develop attachments to caregivers as the result of genetics. Bowlby studied parent-infant interactions and concluded that infant smiling, babbling, crying and cooing are built-in mechanisms to encourage parents to attach to, and thereby care for, the infant. Keeping the parent in close proximity ensures the child will avoid danger; the development of parent-infant attachment is a complex process that leads to deeper and deeper attachments as the child ages. This attachment (or lack thereof) has lifelong implications for the child as he/she reaches adulthood.
Bowlby conceived of four stages of attachment that begin during infancy. These are preattachment, attachment-in-the-making, clear-cut attachment and formation of reciprocal relationships.
- Preattachement (birth to 6 weeks) - Built-in signals, such as crying and cooing, bring a newborn baby into close proximity with his or her caregiver. Babies recognize a mother's smell and sound of her voice, and they are comforted by this. When the mother picks up the baby or smiles at him/her, the beginnings of attachment are forming. However, complete attachment has not yet occurred, so the baby is still comfortable being left with an unfamiliar person.
- Attachment-in-the-making (6 weeks to 8 months) - Attachment is beginning to get stronger during this stage, and infants respond differently to familiar people than they do to strangers. For example, a 5-month old baby will be more "talkative" with his mother rather than an uncle he only sees once per month. He will also be calmed more quickly by the mother's presence than the uncle's. Separation anxiety (becoming upset when a trusted caregiver leaves) has not set in yet, but will be seen in the next stage. Parents continue to build attachment by meeting the baby's basic needs for food, shelter and comfort.
- Clear-cut attachment (8 months to 18 months) - Attachment to trusted caregivers continues to strengthen in this stage, and separation anxiety is likely in a caregiver's absence. Toddlers generally want to be with their preferred caregiver at all times, and they will follow him/her, climb on him/her or otherwise do things to keep the caregiver's attention. Parents and other important adults in the child's life continue to strengthen attachment by being receptive to the child's needs for attention through meeting of basic needs and playing with the child.
- Formation of reciprocal attachment (18 months to 2 years) - Rapid language growth facilitates the understanding of new concepts, and children begin to understand a parent's coming and going. For example, children can now understand that a parent returns home from work at a certain time each day, so separation anxiety lessens, although the child may do things to gain extra time with the parent prior to departure (or to keep him/her from leaving). Parents can help a child form secure attachment by explaining things to him/her, by being present as much as possible and by continuing to meet basic needs.
Mary Ainsworth also studied attachment, and her contribution comes in the form of the Strange Situation. This situation was a study done with children ages 1 to 2, and involved placing the child in unfamiliar situations to assess the type and level of the child's attachment to his/her caregiver. Her research showed that children generally use the parent as a secure base from which to explore the unfamiliar room, and become upset or uncomfortable when the parent leaves and a new individual (not known to the child) enters the room.
Ainsworth identified four primary types of attachment - secure, avoidant, resistant/ambivalent and disorganized. Depending upon how the child attached to the parents, he or she would act in predictable ways in the unfamiliar or Strange Situation experiment. The following is a description of the types of attachment children might show:
- Secure - The child uses the caregiver as a secure base from which to explore the room. The child is comforted by the parent and shows a clear preference for the caregiver (protests or avoids the unfamiliar person).
- Avoidant - The child avoids contact with the caregiver and shows little interest in play. He or she does not seem to mind when the caregiver leaves, and he/she treats the stranger in similar fashion to the caregiver. The child may act in rebellious manner and have lower self-esteem as he/she gets older. Parents who do not meet the basic needs of their child or are inattentive to the child may have children who form avoidant attachment.
- Resistant/Ambivalent - The child is unable to use the caregiver as a secure base, and he or she seeks out the caregiver prior to separation. The child is distressed upon the caregiver's departure, but he/she becomes angry upon the caregivers return. He or she is not easily calmed by the caregiver or the stranger, and he/she feel anxiety with the caregiver due to inconsistent attachment patterns.
- Disorganized - The child engages in stereotypical behavior such as freezing or rocking. He/she acts strangely with the caregiver and does not appear to know how to attach, doing such things as approaching with his/her back turned or hugging the stranger upon his or her entry to the room. Disorganized attachment generally results from the child being maltreated or neglected in some way.