Final dates! Join the tutor2u subject teams in London for a day of exam technique and revision at the cinema. Learn more

Study Notes

Ainsworth’s ‘Strange Situation’

AS, A-Level
AQA, Edexcel, OCR, IB

Last updated 22 Mar 2021

Ainsworth’s Strange Situation (1970) used structured observational research to assess & measure the quality of attachment.

It has 8 pre-determined stages, including the mother leaving the child, for a short while, to play with available toys in the presence of a stranger & alone and the mother returning to the child.

  • Stage 1 – Mother and child enter the playroom
  • Stage 2 – The child is encouraged to explore
  • Stage 3 – Stranger enters and attempts to interact
  • Stage 4 – Mothers leaves while the stranger is present
  • Stage 5 – Mother enters and the stranger leaves
  • Stage 6 – Mothers leaves
  • Stage 7 – Stranger returns
  • Stage 8 – Mother returns and interacts with child

Ainsworth & Bell (1970) used 4 criteria (separation/ stranger anxiety, reunion behaviour & willingness to explore the room) to classify 100 middle class American infants into 1 of 3 categories. Children were observed through a one-way mirror and were classed as one of the 3 attachment types below based on their responses to the 8 stages:


  • 70% Secure
  • 15% Avoidant insecure
  • 15% Resistant insecure

Therefore most US children appeared to be securely attached. The results highlight the role of the mother’s behaviour in determining the quality of attachment.

This led to the conceptualisation of the Caregiver Sensitivity Hypothesis, which suggests that a mother’s behaviour towards their infant predicts their attachment type.

Evaluation of Strange Situation


Replicable/ high inter-observer reliability

As the research is highly operationalised, observers have a clear view of how a securely attached infant should behave, due to the 4 specific criteria that Ainsworth used. For this reason, the research should have high inter-observer reliability & it is also replicable so its reliability can be checked.

Reliability of classifications

Waters (1978) assessed 50 infants at 12 and at 18 months of age using the SS procedure. Waters found clear evidence for stable individual differences using Ainsworth’s behavior category data. The greatest consistency was seen in reunion behaviours after brief separations. 48 of the 50 infants observed were independently rated as being classified in the same category at 18 months.


Low Population Validity

A major methodological criticism of Ainsworth’s research is that the sample was restricted to 100 middle class Americans & their infants, so it is unlikely that findings would be representative of the wider population.

Categories are not always applicable

A further classification group (disorganised) was subsequently identified by Main & Cassidy (1988), which would suggest that infants do not all fit into the three categories introduced by Ainsworth.

Procedure is culturally biased

The SS was designed by an American according to observations of US children. Consequently, the criteria used to classify infants are based on US values, relating to child-parent behaviour. It could be argued that this is Eurocentric, so observations of non-Americans will judged according to American standards. E.g. Japanese infants were judged as being resistant due to high levels of distress that were observed but this reflects their lack of experience during the “infant alone” part of the research, rather than an resistant attachment type.

© 2002-2024 Tutor2u Limited. Company Reg no: 04489574. VAT reg no 816865400.