Maternal Deprivation

Ainsworth's Strange Situation and Types of Attachment

Mary Ainsworth (1970, 1978) developed a standardised laboratory procedure — the Strange Situation — to systematically observe and classify the nature of the attachment bond between infants and their caregivers. Her research identified distinct, replicable patterns of attachment behaviour that she classified into types, and her findings have become the foundation of modern attachment research.

The Strange Situation Procedure

The Strange Situation is a controlled observational procedure in which an infant (typically 12–18 months old) is exposed to a series of eight short episodes, each lasting approximately three minutes, in an unfamiliar playroom. The episodes systematically vary the presence and absence of the caregiver and a stranger, creating situations of mild to moderate stress designed to activate the infant's attachment system. The key behaviours observed and coded are:

• Exploration — the degree to which the infant explores the environment and plays with available toys.
• Separation anxiety — the infant's response when the caregiver leaves the room.
• Stranger anxiety — the infant's response to an unfamiliar adult entering the room.
• Reunion behaviour — how the infant responds when the caregiver returns.
• Use of the caregiver as a secure base — whether the infant uses the caregiver's presence to facilitate exploration.

Crucially, Ainsworth's research identified that reunion behaviour was the most diagnostically important episode: how an infant responds when the caregiver returns reveals the quality of the attachment relationship more reliably than how they respond to separation alone.

Secure Attachment (Type B)

Securely attached infants (approximately 60–65% of UK infants) use the caregiver as a secure base for confident exploration. They show moderate distress when the caregiver leaves but are readily comforted at reunion and quickly return to exploration. They are cautious with strangers but can be soothed by them to some extent. The associated caregiving style is sensitive and responsive — the caregiver reliably notices and responds to the infant's signals in a timely and appropriate way. Bowlby regarded secure attachment as the normative, adaptive pattern — the one associated with the most positive developmental outcomes.

Insecure-Avoidant Attachment (Type A)

Insecure-avoidant infants (approximately 20–25% of UK infants) show little apparent distress when the caregiver leaves, continue playing relatively undisturbed in the presence of a stranger, and importantly ignore or actively avoid the caregiver at reunion — showing little positive greeting behaviour. This pattern can be misread as independence, but Ainsworth showed that physiological measures (heart rate, cortisol) indicate that these infants are actually stressed — they have simply learnt to suppress their attachment behaviours. The associated caregiving style is characterised by insensitivity and emotional unavailability: caregivers consistently discourage emotional expression and fail to respond to the infant's signals of distress.

Insecure-Resistant Attachment (Type C)

Insecure-resistant infants (approximately 10–15% of UK infants) show extreme distress when separated from the caregiver, are very difficult to console, and at reunion display an ambivalent pattern: they simultaneously seek proximity to the caregiver and resist the comfort offered — pushing away whilst also clinging. They typically show high stranger anxiety and are unable to use the caregiver as a secure base for exploration, remaining highly preoccupied with the caregiver even before separation. The associated caregiving style is inconsistent — the caregiver is sometimes responsive and sometimes not, making the caregiver's behaviour unpredictable and amplifying the infant's proximity-seeking.

Evaluation

The Strange Situation is the most widely used and validated measure of attachment in developmental psychology, with high inter-rater reliability and strong predictive validity — attachment type at 12–18 months predicts social and emotional outcomes in later childhood and adolescence. However, the procedure was developed in the United States using American middle-class samples, and cross-cultural research has found systematic variations in the distribution of attachment types — challenging the assumption that the classification system is universal. The laboratory setting also means it measures attachment behaviour in a specific, mild-stress context rather than in the natural environment. Behaviours that appear avoidant in one cultural context may reflect culturally valued independence rather than insecure attachment.