Over the next decade or so, Ainsworth worked through the statistical analysis of her observations, painstakingly trained a cadre of other researchers in these methods, and finally completed her book Patterns of Attachment in 1978. But the word gradually spread through the research community that this research was a game-changer. The Strange Situation experiments, based as they were on exhaustive buttressing research (between 66 and 80 hours of observation of each mother–child dyad over the year prior to the experiment), for the first time provided empirical evidence for what had been purely an intuitive belief in the emotional significance of the mother–child bond. While child cognition had been studied exhaustively, emotion hadn't.
The Strange Situation became the most widely used standardized way of measuring what never before had been measured—the subtle, elusive quality of the shifting emotions between a mother and child over the course of a short period of time. Moreover, the observations made by Ainsworth and her colleagues demonstrated that infants weren't passive recipients of oral gratification—the Freudian view—but actively sought contact with their mothers and vigorously protested when it was denied. The mother–child dyad was very definitely a two-person, emotionally resonant relationship.
Through the years, attachment theory began to acquire converts, at least among developmental psychology researchers. Between 1969 and 1980, John Bowlby, bringing together both older research on infants and the growing body of attachment research, published his "Attachment and Loss" trilogy, now considered a classic: Attachment; Separation: Anxiety and Anger; and Loss: Sadness and Depression. The first book, Attachment, was received poorly by the usual psychoanalytic suspects, but 11 years later, when Loss was published, Bowlby—who'd spent two decades as persona non grata in analytic circles—was being "rehabilitated." During the '80s, he was actually appointed the Freud Memorial Professor of Psychoanalysis at University College in London. Attachment research was becoming respectable.
Still, clinical professionals remained largely uninvolved and unmoved until at least the early 1990s. A client's early childhood relationship with a primary caregiver was largely a matter of indifference for therapists who were purveying the popular brief, pragmatic approaches with short-term, problem-solving goals. Academic psychiatrists of the day were increasingly oriented toward single-minded psychopharmaceutical approaches, and many psychoanalytic holdouts remained true to their orthodox roots, while behaviorists had never paid much attention to emotion, much less attachment angst.
Certainly psychodynamic therapists understood the enduring impact of childhood experiences, but even if they'd been fascinated by attachment studies, it was still an open question how these early mother–child bonds might play out in adult psychopathology. From early in his career, Bowlby was convinced that childhood attachment patterns—good or bad—could have a profound impact on a person's psychological development and capacity for intimate relationships throughout life. The question was how did this happen. "How does it come about that one or another of the events included under the general heading of maternal deprivation produces this or that form of psychiatric disturbance?" he wrote in the preface to Attachment. "What are the processes at work? Why should things happen this way?" The next, obvious question was how these attachment processes in young children somehow leaped ahead over the years, influencing and even predicting adult behavior.
Beginning in the 1970s and throughout the '80s, Mary Main, a protégé of Ainsworth and research psychologist at the University of California, Berkeley, began interviewing parents and studying their interactions with their babies. They found that attachment rejection or trauma in a mother's childhood was systematically related to the same sort of attachment issues between her and her child. From this kind of research, Main and her colleagues devised an interview method—the Adult Attachment Interview (AAI). It contained 20 open-ended questions about people's recollections of their own childhood, for example: Describe your relationship with your parents. Think of five adjectives that reflect your relationship with your mother. What's the first time you remember being separated from your parents? Did you ever feel rejected? Did you experience the loss of someone close to you? How do you think your experience affected your adult personality?
More important than the specific content gathered from the interview—which could be more or less accurate—was the way people responded. Whether their personal narratives were coherent or confused, whether they dismissed the questions with short, uninformative answers, or rambled on pointlessly, for example, provided real—and ultimately, empirically validated—insights about their state of mind, emotional processes, and capacity to form relationships. Main's goal, she said, was to "surprise the unconscious" into revealing itself. Furthermore, the interview has, over the years of repeated use, been found capable of targeting, with more than 80-percent predictability, how a child of the adult interviewee would be attached to his/her parent. While other variants of adult attachment measures have been developed, the AAI set the stage for an empirically validated way of following the transmission of attachment patterns from generation to generation—documenting a kind of psychic lineage from parent to child to grandchild. In fact, according to psychology researchers Howard and Miriam Steele in Clinical Applications of the Adult Attachment Interview, the AAI was "the single most important development in attachment research over the last 25 years."