Mary Ainsworth was a psychologist born in 1913 who studied maternal-infant attachment. She worked with John Bowlby at the Tavistock Clinic in England where she began researching attachments between mothers and infants. Ainsworth is most known for her "Strange Situation" experiment which observed how children reacted to their mother briefly leaving an unfamiliar room. Based on her research, she identified three main attachment styles in children: secure, anxious-avoidant, and anxious-resistant.