Mary Ainsworth was born on December 1, 1913, in Glendale, Ohio, USA.¹⁾

She grew up in a family that encouraged education and intellectual pursuits.²⁾

Ainsworth received her undergraduate degree in psychology from the University of Toronto.³⁾

She completed her master's degree in psychology at the University of Toronto under the guidance of Dr. Leta Hollingworth, a renowned psychologist.⁴⁾

During World War II, Ainsworth worked for the Canadian Women's Army Corps, where she conducted interviews and assessments of soldiers' fitness for military service.⁵⁾

In 1950, Ainsworth earned her Ph.D. in developmental psychology from the University of Toronto.⁶⁾

Ainsworth is best known for her work on attachment theory, which she developed based on her extensive research with infants and young children.⁷⁾

She conducted research on child development in various countries, including Canada, Uganda, and the United States.⁸⁾

Ainsworth's groundbreaking “Strange Situation” study, conducted in the 1970s, revolutionized our understanding of attachment patterns in children.⁹⁾

In the Strange Situation study, Ainsworth observed and categorized infants' reactions to separations from and reunions with their caregivers, leading to the identification of three main attachment styles: secure, insecure-avoidant, and insecure-ambivalent.¹⁰⁾

Her work with John Bowlby, who was a pioneer in attachment theory, greatly influenced her research.¹¹⁾

Ainsworth's work highlighted the importance of sensitive and responsive caregiving in the development of secure attachments.¹²⁾

She also identified a fourth attachment style, known as “disorganized,” which was added later by researchers to the attachment theory.¹³⁾

Mary Ainsworth taught at various universities throughout her career, including the University of Toronto, the University of Virginia, and Johns Hopkins University.¹⁴⁾

In 1953, she became a Canadian citizen.¹⁵⁾