1950s John Bowlby emphasizes the significance of the mother-child bond.
1959 Harry Harlow’s research with infant macaque monkeys demonstrates that they use an attachment figure as a secure base from which to explore their environment.
1980 American psychologist Brian E. Vaughn shows that the attachment figure may change, according to variations in a family’s circumstances.
1990 American psychologist Mary Main identifies a fourth attachment type in young children—“disorganized”—to describe an infant who is fearful of both the environment and the attachment figure.
In the early 1950s, Mary Ainsworth, working ...