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Strange Situation Experiment | Ainsworth | Attachment Styles

The Strange Situation Procedure | Scoring and Classification | Four Attachment Styles | Criticism & Alternative Theory

What Is The Strange Situation

In the 1960s, American-Canadian psychologist Mary Ainsworth created a standardized laboratory procedure, called The Strange Situation experiment to observe an infant’s response to separations and reunions with the parent in order to identify early attachment security depicted in the Attachment Theory

Attachment, originally introduced by John Bowlby in the 1950s, is an affectional tie that an infant forms with their parent. The hallmark behavior of attachment is that the child would seek contact and maintain proximity with the attachment figure.

In developmental psychology, an infant’s behavior related to exploration, separation anxiety, stress and fear of the unfamiliarity can predict the child’s attachment​1​. These attachment behaviors include proximity-seeking behaviors (such as approaching, following, and clinging) and signaling behavior (such as smiling, crying, and calling).

To examine these behavior patterns, Ainsworth designed a method carried out in an unfamiliar context.

baby girl plays with toys in a room in the strange situation experiment in which psychologists study the science of attachment

The Strange Situation Procedure

In Ainsworth’s procedure, a baby is observed in a room with furniture and toys. At one end of the experimental room is a child’s chair heaped with and surrounded by toys. Near the other end of the room, on one side, is a chair for the parent or primary caregiver, and on the opposite side near the door, a chair for the stranger. Researchers observe the interactions in an adjoining room through a one-way mirror.

Mary Ainsworth’s Strange Situation test comprises eight strange situation episodes in the following order (mothers were used in the original experiments).

  • Episode 1: Mother and baby are introduced to the room.
  • Episode 2: Mother and baby are alone. The child explores the room freely.
  • Episode 3: Stranger enters the room, talks with the mother, approaches the child, and tries to interact with the child. Mother exits the room after 3 minutes.
  • Episode 4 (First separation): Stranger remains in the room and interacts with the child when needed.
  • Episode 5 (First reunion): Mother re-enters and greets the child in the doorway. Stranger exits.
  • Episode 6 (Second separation): Mother leaves again. Baby is alone for 3 minutes.
  • Episode 7: Stranger re-enters and remains in the room and interacts with the child when needed.
  • Episode 8 (Second reunion): Mother returns and stranger leaves.
middle class mom and infant sit on the ground playing before stranger enters in the strange situation experiment

Scoring and Classification

An infant’s action was scored based on the following five types of behavior toward the adults.


Proximity-seeking behaviors include active behaviors such as greeting, approaching, clambering up, reaching, or leaning. Vocal signals such as crying at the adult’s direction are also proximity-seeking.


Proximity-avoiding behaviors usually apply when an adult enters the room or tries to engage the child. They include ignoring, looking away, turning away, and moving away from the adult.


After the baby has gained contact with the mother, they may show contact-maintaining tendencies. These behaviors include clinging, embracing, clutching, holding on, and resisting release. If they lose contact, they turn back and reach, and protest vocally.


Contact-resisting behaviors include angry, ambivalent attempts to push away, hit, or kick the mother who tries to make contact. The child may squirm to get down when they’re picked up. They push or throw away toys when the mother tries to interfere with the playing. Some babies may even scream angrily, throw themselves down, or kick the floor to protest.


Search behavior was evaluated based on the child’s reaction to the mother’s departure. These actions include following the mother to the door, trying to open the door, banging on it, remaining oriented to the door, glancing at it, going to the mother’s empty chair, or simply looking at it.

Other Behavior

In addition, the child was also observed for the following responses and interactions.

Exploratory (Episodes 2-7)
How much does the child explore with or without the mother’s presence?

Stranger anxiety (Episodes 3, 4, 7)
Does the child seek/avoid or maintain contact with the stranger?

Four Attachment Styles in Infants

The observed response in the Strange Situation procedure has proven to correlate closely with maternal and infant behavior in the home throughout a child’s first year of life​2​.

Initially, Ainsworth classified the nature of the infants’ attachment patterns into three groups​3​. Later on, the mother-child attachment classifications expanded into four attachment styles as follows.

Insecure Avoidant Attachment (Category A)

Infants with insecure-avoidant attachment style show no obvious sign of distress during separation and show little interest upon the parent’s reunion. They don’t seek contact upon the mothers’ return. If picked up, they show little tendency to cling or resist. These young children tend to avoid the mother by ignoring her, turning away, moving past, or moving away.

These babies tend to treat the strangers much as they treat the mothers, although with less avoidance.

The caregiver of an avoidant insecure infant dislikes physical contact with the infant. The caregiver is generally low in emotional expressiveness, even in response to the sometimes highly aggressive interaction of their infant. They likely had early experiences of rejection from their parents in their own childhood.

Secure Attachment (Category B)

Mary Ainsworth observed that securely attached infants used the parents as a secure base for exploration when the parents were present. They explore the novel environment contently when the mother is there.

When the mother of a securely attached baby leaves the room, the baby becomes visibly distressed and cries or searches for her. Despite the high levels of stress, the baby smiles and greets the parent happily when she returns. They actively seek contact, comfort, and support. These babies can re-establish emotional stability. They then resume exploring the environment.

A child with a secure type of attachment is more interested in interacting with the mother than with the stranger. Roughly 50-70% of children in the United States have secure attachment​4​.

Infants who are classified as securely attached are more likely to have mothers or caregivers who are sensitive to their signals during feeding, face-to-face play, physical contact, and distress episodes, especially in the first 3 months. These parents respond promptly and appropriately to the crying early on, resulting in less crying by the time the children reach age one​5​.

Mom watches toddler explores content in the strange situation psychology. Mom and child share a life history as the child grows.

Insecure Ambivalent Attachment (Category C)

Insecurely ambivalent infants are very wary of the stranger and highly distressed on separation. When the parents return, the babies show ambivalent behavior by seeking close contact and showing angry resistance at the same time. After the mothers’ return, the babies cannot settle and re-establish emotional stability for a long time. They cannot use the parents for emotional regulation.

The caregiver of an ambivalently attached infant show inconsistency in responding to the child’s needs.

Disorganized Attachment (Category D)

An infant’s responses to the parent in the Strange Situation test reflect the history of interaction the child has with that parent at home. The pattern of these “organized” responses can predict the later functioning of the child.

Attachment research has also found that many children do not fall into any of the above three organized categories. These kids’ behaviors do not resemble one another in coherent, organized ways. The only commonalities in their actions are sequences of incoherent reactions that lack a readily observable goal, intention, or explanation. The diverse, unclassified patterns were disorganized​6​.

Developmental psychologists later on defined this category of attachment as the disorganized attachment (also known as the disoriented attachment or attachment disorganization)​7​.

The caretaker of a disorganized infant is both the source of fright and the only haven of safety known to the child. They are the child’s attachment figure but they also display frightening behavior. The anomalous parental behavior was due to the unresolved state of mind. These parents may be abusive, threatening, frightened, or dissociated because of an unresolved loss or their own experience in childhood.

Criticism & Alternative Theory

Many studies and research findings have since supported the caregiver sensitivity theory illustrated in the Strange Situation. However, a meta-analysis including nonclinical samples has found evidence that although parental sensitivity plays a role in determining children’s attachment results, it’s likely not the only condition​8​.

Psychologist Jerome Kagan argued that the individual differences in attachment could result from the diverse infant temperament and their reactions to unfamiliarity, rather than to sensitive parenting​9​.

His point of view is that babies with a “difficult” temperament are likely to have insecure attachment. Child rearing quality is not necessarily the reason of the child’s attachment type.


  1. 1.
    Ainsworth MDS, Bell SM. Attachment, Exploration, and Separation: Illustrated by the Behavior of One-Year-Olds in a Strange Situation. Child Development. Published online March 1970:49. doi:10.2307/1127388
  2. 2.
    Bretherton I. Attachment Theory: Retrospect and Prospect. Monographs of the Society for Research in Child Development. Published online 1985:3. doi:10.2307/3333824
  3. 3.
    Bowlby J, et. al. Attachment and loss: Retrospect and prospect. American Journal of Orthopsychiatry. Published online October 1982:664-678. doi:10.1111/j.1939-0025.1982.tb01456.x
  4. 4.
    van Ijzendoorn MH, Sagi-Schwartz A. Cross-cultural patterns of attachment: Universal and contextual dimensions. In: Handbook of Attachment: Theory, Research, and Clinical Applications. The Guilford Press; 2008:880–905.
  5. 5.
    McCabe A, Peterson C, Connors DM. Attachment security and narrative elaboration. International Journal of Behavioral Development. Published online September 2006:398-409. doi:10.1177/0165025406071488
  6. 6.
    Main M, Hesse E. Parents’ unresolved traumatic experiences are related to infant disorganized attachment status: Is frightened and/or frightening parental behavior the linking mechanism. In: Attachment in the Preschool Years: Theory, Research, and Intervention. University of Chicago Press; 1990:161–182.
  7. 7.
    Hertsgaard L, Gunnar M, Erickson MF, Nachmias M. Adrenocortical Responses to the Strange Situation in Infants with Disorganized/Disoriented Attachment Relationships. Child Development. Published online August 1995:1100. doi:10.2307/1131801
  8. 8.
    De Wolff MS, van Ijzendoorn MH. Sensitivity and Attachment: A Meta-Analysis on Parental Antecedents of Infant Attachment. Child Development. Published online August 1997:571-591. doi:10.1111/j.1467-8624.1997.tb04218.x
  9. 9.
    Kagan J. Temperament and the Reactions to Unfamiliarity. Child Development. Published online February 1997:139. doi:10.2307/1131931

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