Attachment theory emerged at a time when social scientists were discovering that affection and physical contact were crucial for healthy social and emotional development in primates, including humans. Bowlby's seminal work on children in institutions produced similar findings. His observations, which provided the foundation for attachment theory, demonstrated that children who are deprived of loving interaction with their mothers tend to show three progressive stages of distress indicative of insecure attachment. The theory has been used extensively by psychologists and family scholars. Clinicians have also developed therapies for couples and families that are rooted in attachment theory. Early work on attachment theory focused on the effect that interaction between infants and caregivers had on personality development, including emotional health. Initially, many theorists believed that attachment styles remain fairly stable throughout one's life.