describing and evaluating Ainsworth's study.


  • To investigate individual variation in infants attachments; in particular the nature of attachment relationship between the caregiver and the infant and the differences between secure and insecure attachments.
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A sample of 100 middle class American infants ages 12-18months and their mothers were used.

A controlled, structured observation was used where observers recorded infants and mothers behaviour during a set of 7 pre-determined stages.

The procedure lasted 20 minutes.

  1. The mother and infants are escorted into the laboratory room that contains toys for the infant to play with. The mother sits quietly on a chair and the child is placed on the floor and is free to explore.
  2. A stranger enters the room and talks briefly to the mother. The stranger approaches the child and tries to interact with the child.
  3. The mother leaves the room. Baby alone with the stranger. The stranger tries to comfort the baby if they get upset, and tries to play with them.
  4. The mother returns, stranger leaves. The mother tries to console and play with the infant.
  5. Mother leaves infant alone in room.
  6. Instead of the mother returning to the room, the stranger returns and tries to comfort and play with the baby.
  7. The mother re-enters the room to console the child and the stranger leaves.
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Ainsworth found 3 distinc attachment types using this procedure: securely attached, insecure avoidant and insecure resistant.

70% of infants = SECURE ATTACHMENT type B

15% of infants = INSECURE RESISTANT type C

15% of infants = INSECURE AVOIDANT type A

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The strange situation is a good measure of attachment in so far as being able to discriminate between attachment types. Secure attachment is the preferred type of attachment.

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EVALUATION: reliability (2)

  • Ainsworth followed a standardised procedure, each child had the same experience as the 7 stages were predetermined. The stranger and mother followed precise timings as when to exit and return. Therefore this structured procedure means the study can be replicated to establish reliability.
  • Another strength of the study is that it involves high inter-observer reliability, more than one observer recorded the results and behaviour of the child when left with the stranger. This eliminates an bias as others found similar results, and the procedure was recorded which improves the overall reliability as other researchers can rewatch and assess the study.
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EVALUATION: validity (3)

  • As the study was in a laboratory setting, the children were not in their natural environment and the behaviour shown doesnt truly reflect everyday behaviour. For example the separatoin anxiety may have increaed because they werent in a familiar and comfortable setting such as at home. Therefore, Ainsworths study lacks ecological validity.
  • Ainsworths study was a structured observation, the lab setting included a one way mirror to observe the child behaviour. The variables such as timings of the stranger and mothers entry and exit were precise and highly controlled. Therefore the study has high internal validity.
  • As the study used 100 middle class, American participants, this means that the results only reflect one specific culture and the findings cannot be generalised to other cultures or social classes. Therefore the study lacks generalisability which makes it highly ethnocentric.
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EVALUATION: ethics (2)

  • Ainsoworths procedure does not consider protection from harm. The child was distressed by being left alone with the stranger. Therefore it can be considered unethical. However the procedure demanded distress was caused so Ainsowrth could measure what she set out to measure, it has positive implications in terms of parenting skills.
  • Ainsworths participants were aged 12-18 months old, they were taking part in the study as their parents had agreed on their behalf, at this young age, participants are not capable of giving informed consent, therefore this breeches ethics.
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Throughout the procedure the 4 key behaviours were assessed to assess the security/ inesecurity of the attachment:

  • Secure base behaviour: if the child explores environment
  • Separation anxiety: does the child get upset if PCG leaves?
  • Reunion behaviour: reaction when reunited..happy/sad.
  • Stranger anxiety: distressed around strangers?
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