Bowlby found the existence of the following stages with regards to infant-mother relationships:
- Up to 3 months of age – Indiscriminate attachments. The newborn is predisposed to attach to any human. Most babies respond equally to any caregiver.
- After 4 months – Preference for certain people. Infants they learn to distinguish primary and secondary caregivers but accept care from anyone.
- After 7 months – Special preference for a single attachment figure. The baby looks to particular people for security, comfort and protection. It shows fear of strangers (stranger fear) and unhappiness when separated from a special person (separation anxiety). Some babies show stranger fear and separation anxiety much more frequently and intensely than others, but nevertheless they are seen as evidence that the baby has formed an attachment. This has usually developed by one year of age.
- After 9 months – Multiple attachments. The baby becomes increasingly independent and forms several attachments.
The results of the study indicated that attachments were most likely to form with those who responded accurately to the baby’s signals, not the person they spent most time with. Schaffer and Emerson called this sensitive responsiveness.
Many of the babies had several attachments by 10 months old, including attachments to mothers, fathers, grandparents, siblings and neighbors. The mother was the main attachment figure for about half of the children at 18 months old and the father for most of the others. The most important fact in forming attachments is not who feeds and changes the child but who plays and communicates with him or her.