Mary Ainsworth

An American psychologist specializing in the study of infant attachment.

Mary D. Satler Ainsworth (1913–1999) is best known for her landmark work in assessing the security of infant attachment and linking attachment security to aspects of maternal caregiving.

Mary Ainsworth was born December 1, 1913, in Glendale, Ohio. She was an avid reader and was inspired at the age of 15 to pursue a career in psychology. She attended the University of Toronto where she received her B.A. in 1935, her master's degree in 1936, and her Ph.D. in 1939. Ainsworth stayed at the University of Toronto to begin her career in teaching until she joined the Canadian Women's Army Corp in 1942 during World War II. After a brief period of post-war government service as the superintendent of Women's Rehabilitation in the Canadian Department of Veteran's Affairs, Ainsworth returned to Toronto to teach personality psychology and conduct research in the assessment of security. She married Leonard Ainsworth in 1950, a graduate student in the same department in which she held a faculty appointment. The couple decided to move to London where he finished his degree at University College.

In England Mary Ainsworth began work at the Tavistock Clinic on a research project investigating the effects of early maternal separation on children's personality development. The project director, John Bowlby, had studied children's reactions to separation during the war years in England. He had brought an evolutionary and ethological perspective to the problems of attachment, separation, and loss. Her work with Bowlby brought Ainsworth's earlier interest in security into the developmental realm, and she planned to conduct a longitudinal study of mother-infant interaction in a natural setting.

That opportunity came when Ainsworth's husband accepted a position in the East African Institute of Social Research in Kampala, Uganda. In Uganda Mary Ainsworth studied mothers and infants in their natural environment, observing and recording as much as possible and analyzing and publishing the data years later after joining the faculty at Johns Hopkins University in Baltimore.

Based on her original observations in Uganda and subsequent studies in Baltimore, Ainsworth concluded that there are qualitatively distinct patterns of attachment that evolve between infants and their mothers over the first years of life. Although a majority of these patterns are marked by comfort and security, some are tense or conflicted. Ainsworth found evidence suggesting that these tense or conflicted relationships were related to the level of responsiveness that mothers showed toward their infants from the earliest months. In one study she found mothers who responded more quickly to their infants' cries at three months were more likely to have developed secure attachments with their babies by one year.

Measuring the security of a relationship was a problem Ainsworth and her colleagues solved by devising a system for assessing individual differences in infants’ reactions to a series of separations and reunions with their mothers. This method, called the Strange Situation, has become one of the most widely used procedures in child development research.

In this scenario, an observer takes a mother and a young child to an unfamiliar room containing toys. There are a series of separations and reunions. For example, mother and child are left alone in the room for several minutes, the observer re-enters, remains, and after a few minutes, the mother leaves and then returns after a few more minutes. Both observer and mother may comfort the distressed child.

Ainsworth found that key individual differences among children are revealed by the child's reaction to the mother's return. She categorized these responses in three major types:

The development of this procedure led to a body of literature examining the development of motherchild attachment, the role of attachments to other caregivers, and the correlates and consequences of secure and insecure attachments.

Ainsworth's work caused some controversy. Attempts to replicate her link between response to early crying and later attachment met with mixed success, and there was much debate about the origins of children's reactions in the Strange Situation. Still, Mary Ainsworth made a lasting contribution to the study of children's affective growth and the role of supportive relationships in many aspects of development.

After 15 years as a professor emeritus at the University of Virginia, Ainsworth died on March 21, 1999, at the age of 86.

See also Bowlby, John.



Ainsworth, Mary D. Salter. Infancy in Uganda: Infant Care and the Growth of Love. Baltimore: Johns Hopkins University Press, 1967.

Ainsworth, Mary, et al.. Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale, NJ: Erlbaum, 1978.

Otto, Hiltrud and Heidi Keller, eds. Different Faces of Attachment: Cultural Variations on a Universal Human Need. Cambridge, UK: Cambridge University Press, 2014.


Pederson, David R., et al. “Understanding Sensitivity: Lessons Learned from the Legacy of Mary Ainsworth.” Attachment & Human Development 16, no.3 (2014): 261–70.

WEBSITES “Mary Ainsworth (1913–1999).” (accessed July 22 2015).

McLeod, Saul. “Mary Ainsworth.” (accessed July 22, 2015).