American psychologist specializing in the study of infant attachment.

Mary D. Satler Ainsworth graduated from the University of Toronto in 1935 and earned her Ph.D. in psychology from that same institution in 1939. She is best known for her landmark work in assessing the security of infant attachment and linking attachment security to aspects of maternal caregiving.

Ainsworth began her career teaching at the University of Toronto before joining 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. Since he was a graduate student in the same department in which she held a faculty appointment, the couple decided to move to London...