Introduction

This book is concerned with one of the longstanding issues of developmental psychology: early experiences and their influence on child development. More specifically, it is concerned with the validity and usefulness of a particular procedure—Ainsworth’s Strange Situation—designed to permit assessment of the quality or security of infant-parent attachment and its ramifications for later development (Ainsworth, Blehar, Waters, & Wall, 1978; Ainsworth & Wittig, 1969). Clearly, Ainsworth’s was not the first attempt to assess the quality of infant-mother attachment and identify its impact on subsequent development. Such tasks had been undertaken earlier by psychoanalysts like Anna Freud (1965) and Melanie Klein (1957) and through the description of behavior by analytically oriented researchers like Sylvia Brody (1956), and Sibylle Escalona (Escalona & Leitch, 1953), to mention but a few. What made Ainsworth’s contribution so important was that she appeared to have found a remarkably simple, brief, and systematic way of assessing the security of infant-parent attachment in a manner that was to prove valid; that had never been achieved before. Furthermore, the Strange Situation was designed in light of the formulations of evolutionary biology, thus providing a crucial link between evolutionary theory and empirical developmental research. That we choose to explore the impact of early experience through near-exclusive focus on research employing one experimental procedure underscores the utility and importance of this procedure, and our collective debt to Mary Ainsworth, who has pioneered research on this topic.