Mary Salter Ainsworth

Mary Dinsmore Salter was born on December 1, 1913,  in  Glendale,  Ohio,  but  grew  up  in Toronto, Canada. As a psychology student at the University of Toronto, she became drawn to William Blatz’s “security theory,” which inspired her dissertation, completed in 1939.

After a stint as instructor at the University of Toronto, Mary entered the Canadian Women’s Army Corps in 1942, gaining substantial clinical and diagnostic skills. She returned to the University of Toronto in  1946  and  married  Leonard Ainsworth,  a WWII veteran and graduate student in 1950.

Serendipitously,  Leonard’s  decision  to  complete his doctoral studies in London led to Mary’s collaboration with John Bowlby at the Tavistock Institute for Human Relations, where she was exposed to Bowlby’s emerging ideas about the evolutionary foundation of infant–mother attachment. She also admired the naturalistic observations of mother–child separation conducted by Bowlby’s research assistant, James Robertson. In 1953, when Leonard accepted a postdoctoral position at the East African Institute for Social Research in Kampala, Uganda, Mary was able to undertake a short-term longitudinal study of mother–infant attachment interactions in Ganda villages. This made her the first researcher to apply and  extend the insights of attachment theory, but her book, Infancy in Uganda, was not published until 1967.

After the Ainsworths’ move to Baltimore in 1954, Mary performed diagnostic work at a psychiatric hospital and lectured at the Johns Hopkins University, where she was offered a professorship in developmental psychology in 1958. Shortly thereafter, she and Leonard divorced.

In 1963, Mary Ainsworth launched the Baltimore Project, modeled on her work in Uganda. Monthly home visits of 26 families began after a child’s birth and ended at 12 months. Detailed narratives captured mother–infant interaction quality during feeding, contact, play, and distress episodes. The final observation, at 12 months, consisted of a mother–infant

separation and reunion procedure now known as the “strange situation.” Patterns of infant behavior during this laboratory procedure were predicted by maternal sensitivity  and  harmonious  interaction  qualities  at home. Journal articles and a book, Patterns of Attachment, based on the findings were published over the next decade and inspired major longitudinal attachment studies in the United States, Germany, and Israel.

At Johns Hopkins, Ainsworth attracted many graduate  students,  whose  work  expanded  her  findings. This continued at the University of Virginia, where she  became  Commonwealth  Professor  in  1975.  In 1978, Ainsworth was elected president of the Society for Research in Child Development. Despite mandatory retirement in 1984, she remained professionally  active  until  1992,  when  her  health  began  to fail. Among her many honors was the American Psychological Association’s Gold Medal Award for Life Achievement in the Science of Psychology in 1998, a few months before her death on March 21, 1999, in Charlottesville, Virginia. Her conceptual contributions and empirical findings have revolutionized how psychologists think not only about infant– caregiver attachment but about close human relationships at all ages.


  1. Ainsworth, M. D. S. (1967). Infancy in Uganda: Infant care and the growth of love. Baltimore: Johns Hopkins University
  2. Ainsworth, D. S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of attachment: A psychological study of the strange situation. Hillsdale, NJ: Erlbaum.
  3. Ainsworth, D. S., & Wittig, B. A. (1969). Attachment and the exploratory behaviour of one-year-olds in a strange situation. In B. M. Foss (Ed.), Determinants of infant behaviour (Vol. 4, pp. 113–136). London: Methuen.
  4. Attachment Theory  and  Research  at  Stony  Brook,
  5. Bengston, V. , & Schrader, S. (1982). Parent-child relations: The measurement of intergenerational interaction and affect in old age. In D. Mangen & W. Peterson (Eds.), Research instrument in social gerontology. Minneapolis: University of Minnesota Press.
  6. Bretherton, (2003). Mary Ainsworth: Insightful observer and courageous theoretician. In G. A. Kimble & M. Wertheimer (Eds.), Portraits of pioneers in psychology (Vol. 5). Washington, DC: American Psychological Association.