DOUBLE TAP TO ZOOM WITH PHONE OR TABLET HOW WHAT WE FEEL CREATES WHAT WE KNOW presence of the caregivers that they do not get from the presence of just any other adult (National Research Council and Institute of Medicine 2000). Thus, primary caregivers are still crucial to the growth and development of their children and are not easily replaced by other adults. The “Strange Situation” Experiment Researchers have developed creative ways to measure the attachment rela- tionship between a young child and caregiver. The classic study of differ- ences in attachment patterns is called the “Strange Situation” experiment developed by Mary Ainsworth in the 1970s (Ainsworth et al. [1978] 2014; Bowlby 1982). In this experiment, a young child (one to two years of age) and a parent or guardian are brought into a research laboratory room con- taining toys and are encouraged to play. Then, an adult that the child does not know enters the room and converses with the parent. After a few minutes, the parent is instructed to leave the room. Researchers observe the young child’s behavior at the caregiver’s departure. Children are typically distressed when their parent leaves the room. The other adult stranger offers comfort to the child if the child is very upset but otherwise remains a neutral presence. After a short time, the parent returns to the room, and researchers observe the characteristics of the reunion between the parent and child (Ainsworth et al. [1978] 2014). In general, researchers gauge the child’s level of exploration of the new environment, the child’s reaction to the parent leaving, the child’s anxiety response to the strange adult, and the child’s reunion behaviors with the parent. The child’s response to the parent’s return is the most telling mea- sure of attachment security. In a secure attachment relationship, the young child may show some anx- iety when first entering the room, but at the parent’s coaxing and encour- agement may begin to explore the room and engage in play with the parent. When a new adult enters the room, the child may seem unsure at first, but once determining from the parent that the other adult is not a threat, may even play with the other adult. Once the parent leaves the room, a child with a secure attachment style will likely express distress and cry for the caregiver to return. Her source of comfort and safety has left her in a potentially scary situation, leaving her upset and uncertain. The child will likely eventually COPYRIGHTED MATERIAL 13