Background to the Strange Situation Data

Data analysed in: Kroonenberg, P. M. (2008). Applied multiway data analysis. Hoboken NJ: Wiley.

The Strange Situation procedure was designed to assess the quality of infant--mother attachment and is considered appropriate for infants between 12 and 18 months (for details see, Ainsworth, 1978). The procedure consists of seven three-minute episodes arranged to continuously increase the stress , so that the infant's attachment system with respect to the mother is activated. The crucial episodes, the reunion episodes (R1 and R2), are those in which the mother returns after having been away, and the infant was left alone with a stranger. On the basis of the infant's behavior, especially during these episodes, the quality of the infant--mother attachment relationship is generally categorized as insecure-avoidant (A), secure (B),or insecure-resistant (C). According to the classification instructions (see Patterns of attachment, Ainsworth, M. D. S. 1978, pp. 59--63) the scores on five 7-point scales in the two reunion episodes play a crucial role in the clinical classification, that is, the Proximity Seeking (PS), Contact Maintaining (CM), Resistance (RS), Avoidance (AV), and Distance Interaction (DI) scales, where high scores on Avoidance are especially indicative for an A classification, and high scores on Resistance for a C classification. The aim of a three-mode cluster analysis on these data may be assessing whether the clinical A,B,C typology corresponds to the statistical grouping derived via the mixture method of clustering. A full three-mode analysis of these data was given by Kroonenberg, Basford, & Van Dam (1995).

References

• Kroonenberg, P. M., Basford, K. E., & Van Dam, M. (1995). Classifying infants in the Strange Situation with three-way mixture method clustering. British Journal of Psychology, 86, 397-418.
• Kroonenberg, P. M., & Van IJzendoorn, M. H. (1987). Exploring children's behavior in the Strange Situation. In L. W. C. Tavecchio and M. H. Van IJzendoorn, Attachment in social networks: Contributions to the Bowlby-Ainsworth attachment theory (pp. 379 --425). Amsterdam: North Holland.

Data description

De data set consists of 326 infants' scores on five 'interactive' scales during the two reunion episodes when the infant is reunited with its mother after having been alone with a stranger. Ths scales run from 1 to 7 with 7 indicating the highest intensity of the reaction.

Rows (1st mode): Infants

Columns (2nd mode): Scales

Slices (3rd mode): Episodes

Data arrangement

A three-way data array X = (x(i,j,k)) has the following form

                        |-----|i=1
                   |-----|    |i=2
              |-----|    |    |..
              |     |    |    |..
              |     |    |____|i=I=326    k=K=2
              |     |____|            k=2
              |_____|              k=1

            j=1,.,J=5

      

The actual data file has the following form:

          j=1,.,J=5
            |-----|i=1
            |     |i=2
            |     |..     k=1
            |     |..
            |_____|i=I=326
            |-----|i=1
            |     |i=2
            |     |..     k=2
            |     |..
            |_____|i=I=326
      

Thus the first mode (i) is nested in the third mode (k) and there are 326 (Infants) times 2 (Episodes) rows and 5 (Scales) columns.

Data handling

In mixture method of clustering the means and (co)variances are estimated, so that there is not preprocessing. For details see Kroonenberg (2008). Applied multiway data analysis. Hoboken NJ: Wiley (Chapters 6 and 16).

Permissions

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