American psychologist Mary Ainsworth developed an observation called the Strange Situation in 1969. The experiment aimed to observe the quality and nature of attachments and how they may vary between different infants, aged typically between twelve and eighteen months. The Strange Situation involves a controlled environment, where the child is placed in an unfamiliar room with a one-way window. Their behaviour is observed covertly by psychologists. Observations are reported on how the children handle reunions with their mothermothers, following a brief separation, when alone and when in the presence of a stranger (Bergman et al., 2014). The purpose of the experiment is to measure how the child responds to four key behaviours. This includes separation anxiety, which is the response the infant giveshas to being separated from their mother. Reunion; reunion behaviour, which is the way the infant acts when they are reunited with their mother; and stranger anxiety, which is how the infant reacts when presented with being alone with a stranger. The last key behaviour is exploration, which looks at the infant who freely explores the environment around them using the caregiver as a secure base because they allow the infant to feel safe.