Four different patterns of attachment identified by researchers.

According to Bowlby and Ainsworth, by 8 to 12 months, infants develop an internal working model, or expectation system, about the reliability, consistency, warmth, and effectiveness of caregiver responses. Most infants form a secure attachment relationship with the primary caregiver.

The Strange Situation is a procedure for measuring attachment. The infant experiences separating from and reuniting with the primary caregiver. Four patterns of attachment emerge based on infant responses to the Strange Situation (Ainsworth et al., 1978; Solomon & George, 2016):

1. Secure attachment: Infants use the mother as a secure base to explore the room. When separated from the mother, they don't always become unduly distressed, but if they do, they seek contact with the mother and are quickly comforted. They prefer the mother to the stranger. About 62 percent of U.S. and Canadian toddlers between 12 and 18 months of age display secure attachment (Thompson, 2006).

2. Insecure-avoidant attachment: Infants don't seem to use the mother as a secure base to explore the room. They show little distress when she leaves and actively avoid her or resist her efforts to pick them up upon her return. They often treat the mother and stranger similarly. About 15 percent of U.S. and Canadian children show this pattern (Thompson, 2006).

3. Insecure-ambivalent attachment: Infants often cling to the mother and fail to explore the room. They are usually quite distressed when she leaves, and when she returns they behave ambivalentlythey are likely to seek contact with her and then angrily resist being held. About 8 percent of U.S. and Canadian children fit this pattern (Thompson, 2006).

4. Insecure-disorganized attachment: This pattern was not identified by Ainsworth but by later researchers (Main & Solomon, 1990; van IJzendoorn, Scheungel, & Bakermans-Kranenburg, 1999). Infants seem to lack any organized way of dealing with the stress of separation. They show contradictory patterns of behavior, such as approaching the mother and freezing, and often appear confused, dazed, or fearful of the mother. About 15 percent of infants show this pattern (Thompson, 2006).

Think about the Four patterns of Attachment in the above slide. How might these patterns be implicated in later development? For instance, consider how each of these early attachment patterns may impact/inform the development of relationships later in the child's life.