Strange Situation procedure
A standardized observation of infant–caregiver attachment behavior during separations and reunions.
Structured observation The format describes how observations are obtained, not an evidence rating.
What it measures
Patterns of attachment behavior in a particular infant–caregiver relationship under the procedure.
What people do
Standard protocols observe infants aged roughly 12 to 18 months across an 8-episode laboratory sequence of introductions, caregiver separations, stranger interactions and reunions. Trained observers examine exploration, distress, proximity seeking, contact maintenance, avoidance and resistance rather than merely noting whether a baby cries.
What the scores mean
Trained coders classify the infant–caregiver dyad’s pattern (classically secure, insecure-avoidant or insecure-resistant/ambivalent, with disorganized/disoriented classification added later) using interactive behavior ratings especially during reunion episodes. It is not a numerical ranking of parenting quality or an infant’s permanent personality.
This explains the logic of a score. It does not supply a test form, individual result or administration manual.
Development and versions
Mary Ainsworth and Silvia Bell published an influential Strange Situation study in 1970, and Ainsworth, Blehar, Waters and Wall detailed the three main attachment classifications in 1978; Mary Main and Judith Solomon introduced the disorganized/disoriented classification in 1986 and 1990.
Evidence: (Ainsworth & Bell, 1970); (Spielman et al., 2020)
Reliability and validity evidence
This profile relies on the PubMed bibliographic record for Ainsworth and Bell (1970) and the textbook’s account, not a direct inspection of the original datasets or coding manual. Interobserver reliability, cultural interpretation and relationship-specific prediction require dedicated sources.
Evidence belongs to a version, sample and interpretation. Read the source notes for what was actually inspected.
Evidence: (Ainsworth & Bell, 1970); (Spielman et al., 2020)
Where it is used
Developmental attachment research under an appropriate observation and coding protocol.
Limits and common misreadings
- Attachment classification is relationship- and context-dependent.
- Distress alone does not determine classification.
- Infant classifications are not interchangeable with adult romantic attachment questionnaires.
Read an example
Original teaching example
An original teaching scenario compares an infant’s behavior before separation and after reunion. A coder considers the organization of behavior across episodes rather than using a single moment of crying as the classification.
Constructed for learning; this is not a result from the instrument’s validation study.
Access and permission
Published coding manuals and training materials have their own rights and training requirements. No observation protocol or certification is supplied here.
Textbook connection
Direct coveragePsychology 2e: 9.3 Stages of Development
The section discusses this measure or instrument family.
Related measures
Read a measure critically · Explore score examples · Review research methods
Sources and inspection notes
Checked October 22, 2026. An inspection date is not a publication date. Publisher information is not presented as independent validation; abstract-only and indexed-excerpt access are identified below.
- Ainsworth, M. D., & Bell, S. M. (1970). Attachment, exploration, and separation: Illustrated by the behavior of one-year-olds in a strange situation. Child Development, 41(1), 49–67. https://doi.org/10.1111/j.1467-8624.1970.tb00975.xConsulted sourcePrimary research: PubMed bibliographic record
PubMed citation record (Child Development, 1970, 41(1), 49–67) inspected; PubMed displays no abstract text, and full coding manuals were not directly inspected.
- Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020). Psychology 2e. OpenStax. https://openstax.org/books/psychology-2e/pages/9-3-stages-of-developmentTextbook: direct discussion
The section discusses this measure or instrument family.