After completing her doctoral dissertation at the University of Toronto, Ainsworth worked as a lecturer at the university. When the war broke out, many of her colleagues were called away to serve in the armed forces. In 1942, Ainsworth joined the Canadian Women’s Army Corps. In this position, she used her psychology background to assess recruits and recommend placement. A few months later, she transferred to Ottawa to become an army major.
As a psychology professor, Ainsworth was concerned with the plight of children in hospitals. This prompted her to work for a research team at the Tavistock Institute. In this role, she helped develop psychological testing scales that are used in psychological evaluations of individuals. She also met and married Leonard Ainsworth, a graduate student who had been accepted to the University College of London after completing his master’s degree in Toronto.
Ainsworth continued her studies on attachment. She developed the “Strange Situation” experiment, which aims to measure the degree of an infant’s attachment to its parent in a foreign setting. The “strange” environment is an environment that will increase a child’s need for a parent.
Ainsworth’s research also highlighted the importance of family security. She was influenced by the work of her mentor, William Blatz, who had developed a security theory in psychology. Blatz encouraged Ainsworth to write her doctoral dissertation on the topic of security. It involved the development of psychometric scales and a quantitative evaluation of children’s relationship with their parents.
Ainsworth’s work has influenced numerous child development studies. She argued that different subtypes of the primary attachment style could exist and that there are cross-cultural variations in the patterns of attachment. In 1975, she and her colleague Klaus and Karin Grossman examined a group of mother-infant pairs in Bielefeld, Germany. Both authors studied infants as young adults and attributed the differences between the two groups to differences in the way they raise their children.
Her methods for longitudinal observation in the home were controversial and criticized by many of her contemporaries. This approach was unorthodox in the research psychology field at the time. In addition, Ainsworth was unable to secure a grant to carry out her longitudinal study, and most funding entities considered her small sample size and clinically-focused interview technique too far out. She was also attacked for using “non-objective” language. Many scientists believed that the study of concrete and measurable phenomena was more valuable.
Ainsworth’s early love of academics was evident in her early childhood. She learned to read at age three. Her parents, Charles and Mary Salter, both Dickinson College graduates, had high academic expectations for their daughters. The Ainsworths’ parents became naturalized citizens of Canada in 1931.
Ainsworth’s study also highlighted differences between children with secure attachment and those with insecure-avoidant attachment. Infants with secure attachments were typically less likely to show negative reactions when separated from their mother.