They have discovered that earlier theories concerning ice friction have led in part to erroneous interpretation. (sciencedaily.com)
Thus, unlike earlier theories of parent - child relationships, which emphasized the role of (any) caregiver in satisfying the infant's physiological needs (e.g., hunger), attachment theory focuses on the selectivity of personal relationships providing protection and emotional security. (capmh.biomedcentral.com)
Building on early theory and research evidence, Hazan and Shaver (1987) examined attachment in adulthood and found that it does extend into the adult years. (link.springer.com)