Interactive behaviors and attachment patterns in the strange situation procedure: A validation of the Ainsworth model

The Strange Situation Procedure (SSP; Ainsworth, Blehar, Waters, Wall, 1978) is the most widely used procedure to assess attachment in early childhood (Bowlby, 1969). In the original text by Ainsworth et al. (1978), the video coding is carried out by means of a two-step procedure: in the first part, coders apply a series of observational scales with graduated scores on a Likert scale, whereas during the second part, a descriptive category of attachment is assigned, which somehow “summarizes” the general quality of the child’s behaviour, already assessed by means of scales. Obviously, the system validation study highlights a discriminant correspondence between the scores which are assigned through the scales and the descriptive category which is assigned in the end. The aim of the present study was to test this specific aspect of the Strange Situation coding procedure: in order to do so, and similarly to what had been done in the original work in 1978, we compared the categorical attachment classification system with the ordinal one provided by the scales, which describe the child’s behaviors in the various procedure episodes. 76 12-month-old infants were observed in the Strange Situation Procedure in order to compare the classification of attachment by the global descriptive patterns with the Ainsworth’s microanalytic coding system (Interactive Behavior Scales). Results: Discriminant function analysis (MDFA) and classification weights confirm the discriminant functions of the interactive behavior to differentiate between patterns of attachment and attesting good validity of the methodology and the coding system.