Mary Ainsworth was born in Glendale, Ohio, in December of 1913. At age fifteen, Ainsworth read William McDougall’s book entitled Character and the Conduct of Life, which inspired her to become a psychologist. Ainsworth earned her BA in 1935, her Master’s degree in 1936, and her PhD in developmental psychology in 1939, all from the University of Toronto.

She joined the Canadian Women’s Army Corp in 1942. In 1950, she married Leonard Ainsworth and moved to London. Soon Ainsworth began a research position at the Tavistock Clinic with John Bowlby. The research focused on examining what effects interference in the mother and child bond may have on the development of the child. The findings revealed that when a bond between mother and child is broken, the child is at risk for developmental challenges. In 1954 Leonard Ainsworth accepted a job at the East African Institute of Social Research in Kampala, Uganda.

2 years later Ainsworth returned to US to teach at John Hopkins. She began working on creating an assessment to measure attachments between mothers and children. It was here that she developed her famous “Strange Situation” assessment Ainsworth taught at John Hopkins University from 1959 until 1975, when she accepted a position as professor of psychology at the University of Virginia.

She remained at the University of Virginia until her retirement in 1984. Ainsworth and her husband divorced in 1960. She died in 1999