The Strange Situation procedure: The original test of the infant-parent bond
We hear a lot about "secure attachment relationships." But what exactly do researchers mean by this term? Psychologist Mary Ainsworth first devised the Strange Situation procedure to assess the quality of an infant's attachment to his or her mother.
It also considers an important question: To what extent has research over-emphasized the role of the mother? Shouldn't we also be talking about the role of fathers, grandparents, and other caregivers?
According to the theories of John Bowlby (1988), a child is securely-attached if she is confident of her caregiver’s support. The attachment figure serves as a "secure base" from which the child can confidently explore the world.
Secure attachment is also associated with
And, in the long-term, kids with secure attachments seem to have many advantages - emotional, social, medical, and cognitive.
But how can you know if researchers would classify your own baby as securely attached? How do they actually measure attachment security?
The original method, developed by the influential psychologist Mary Ainsworth, is the laboratory procedure called the "Strange Situation" (Ainsworth et al 1978).
Typically, the Strange Situation tests how babies or young children respond to the temporary absence of their mothers.
Here's how it works.
To test a child's "attachment style," researchers put the child and her mother (these studies almost always focus on the mother) alone in an experimental room.
The room has toys or other interesting things in it, and the mother lets the child explore the room on her own.
After the child has had time to explore, a stranger enters the room and talks with the mother. Then the stranger shifts attention to the child. As the stranger approaches the child, the mother sneaks away.
After several minutes, the mother returns. She comforts her child and then leaves again. The stranger leaves as well.
A few minutes later, the stranger returns and interacts with the child.
Finally, the mother returns and greets her child.
As suggested by its name, the Strange Situation was designed to present children with an unusual, but not overwhelmingly frightening, experience (Ainsworth et al 1978). When a child undergoes the Strange Situation, researchers are interested in two things:
1. How much the child explores the room on his own, and
2. How the child responds to the return of his mother
Typically, a child's response to the Strange Situation follows one of four patterns.
Free exploration, and happiness upon the mother's return
The securely-attached child explores the room freely when his mother is present. He may be distressed when his mother leaves, and he explores less when she is absent. But he is happy when she returns. If he cries, he approaches his mother and holds her tightly. He is comforted by being held, and, once comforted, he is soon ready to resume his independent exploration of the world. His mother is responsive to his needs. As a result, he knows he can depend on her when he is under stress (Ainsworth et al 1978).
Little exploration, and little emotional response to the mother
The avoidant-insecure child doesn't explore much, and she doesn't show much emotion when her mother leaves. She shows no preference for her mother over a complete stranger. When her mother returns, she tends to avoid or ignore her (Ainsworth et al 1978).
Resistant-insecure (also called "anxious" or "ambivalent") children:
Little exploration, great separation anxiety, and an ambivalent response to the mother upon her return
Like the avoidant child, the resistant-insecure child doesnt explore much on his own. But unlike the avoidant child, the resistant child is wary of strangers and is very distressed when his mother leaves. When the mother returns, the resistant child is ambivalent. Although he wants to re-establish close proximity to his mother, he is also resentful—even angry—at his mother for leaving him in the first place. As a result, the resistant child may reject his mother's attempts at contact (Ainsworth et al 1978).
Little exploration, and a confused response to the mother.
The disorganized child may exhibit a mix of avoidant and resistant behaviors. But the main theme is one of confusion and anxiety (Main and Solomon 1986). Disorganized-insecure children are at risk for a variety of behavioral and developmental problems
Although parenting alone doesn't determine your child's attachment status, it may play a very important role. How can we be sure? It's tricky because most studies report mere correlations, leaving us uncertain about causation.
For instance, secure attachments are associated with sensitive, responsive parenting. But why? Maybe infants develop secure attachments because they've inherited certain genes from their parents -- genes that give rise both to the tendency to develop secure attachments, and to the tendency to be sensitive and responsive toward infants.
A compelling argument against this possibility comes from adoption studies. Like other babies, adoptive infants are more likely to develop secure attachments when their parents are sensitive and responsive (Verissimo and Salvaterra 2006).
And studies show that early intervention -- teaching new parents how to increase their sensitivity -- improves attachment security (Mountain et al 2017).
What else do we know about parenting and attachment?
Avoidantly-attached children tend to have parent(s) who are emotionally unavailable or rejecting.
In theory, children learn that their caregivers will not respond to their emotional needs. As a result, they gives up on trying to signal their needs. The avoidantly-attached child is relatively common in Western Europe (van IJzendoorn and Kroonenberg 1988; see below). This prevalence of avoidant attachments may reflect traditional Western European child-rearing values, which de-emphasize physical contact and discourage parents from comforting children who cry (e.g., Suizzo 2002; Valentin 2005).
Compared with avoidantly-attached kids, anxious or resistant-insecure children may have parent(s) who are more emotionally demonstrative, but not tuned into their children's needs.
However—according to popular theory—these parents tend to be inconsistent, and they aren't particularly sensitive. They offer comfort, but in a way that answers a child's needs. on their own terms, rather than according to a child's needs.
Disorganized attachment is linked with caregiver behavior that (intentionally or unintentionally) frightens children.
Children who are abused or neglected are more likely to suffer from disorganized attachment (Barnett et al 1999). But babies don't have to be abused or neglected to develop disorganized attachment.
In some cases, parents themselves may be anxious or frightened, and transmit these emotions to their infants (Main and Hess 1990). And parents might simply be insensitive to what babies find disturbing--like suddenly looming over a baby's face (David and Lyons-Ruth 2007; Gedaly and Leerkes 2016).
If this sounds like you, is there anything you can do about it? Research suggests you can. In studies where parents from at-risk families were coached on how to better read their children's cues, kids were less likely to develop disorganized attachments (Wright et al 2017).
Like adults, infants differ in temperament, and these temperamental differences might play a role in the development of an infant's attachment relationships (Fuertes et al 2006; Seifer at al 1992).
For instance, when researchers tested oxytocin levels in 18 newborns, they found that babies with higher oxytocin levels were more likely to solicit parental soothing and show greater interest in social interaction (Clark et al 2013). Perhaps it's easier for such babies to learn that they have a secure base.
By the same token, infants who are "difficult," or more reactive to stressful situations, may require higher levels of parental responsiveness to develop secure attachments (van den Boom 1994).
In theory, stress could cause insecure attachment by interfering with a child's ability to perceive and interpret his mother's behavior. Stress could also make it difficult for a child to select the most appropriate, healthy response to being separated from, and reunited with, his mother (Waters and Valenzuela 1999).
Environmental stressors—like poor nutrition—may therefore be responsible for high rates of insecure attachment among some populations (like impoverished Chilean children, see below).
In addition, stress may interact with parenting and epigenetics -- variations in the way our genes get expressed. In one study, children who experienced high levels of stress and low levels of maternal support were more likely to develop anxious attachments -- but only if they also had a highly methylated NR3C1 gene (Bosmans et al 2018).
Studies have reported links between disorganized-insecure attachment and the variants of several genes, including the dopamine D4 receptor gene (e.g., Lakatos et al 2000). The pattern makes sense if these polymorphisms render the brain less sensitive to neurotransmitters that make friendly social interactions feel pleasurable. Affected babies would be less motivated to seek comfort from their caregivers, and therefore less likely to develop secure attachments.
But do the data tell us a clear story? Not yet. Some studies have failed to replicate key findings (Roisman et al 2013). One possibility is that the effects of the gene depend the presence or absence of sensitive maternal care, as well as other characteristics of the child (Wazana et al 2015).
Studies have consistently failed to find that time spent in daycare is linked with insecure attachment. But it's possible that the risk increases when children spend an unusually long time away from parents. In a study of mother-infant attachment security, researchers found that babies were more likely to show evidence of disorganized attachment if they spent more than 60 hours per week in non-maternal care (Hazen et al 2015).
International studies of the Strange Situation
In studies recognizing three attachment classifications (secure, avoidant-insecure, and resistant-insecure), about 21% of American infants have been classified as avoidant-insecure, 65% as secure, and 14% as resistant-insecure. The same distribution is found when researchers pool the results of studies conducted worldwide (van Ijzendoorn and Kroonenberg 1988).
However, there are local variations. A study conducted in Bielfeld, Germany has reported relatively high rates of avoidantly-attached infants (52%--Grossman et al 1981). And research conducted elsewhere--in Indonesia, Japan, and the kibbutzim of Israel—has reported relatively high rates of resistantly-attached infants (Zevalkink et al 1999; van IJzendoorn and Kroonenberg 1988).
Studies recognizing a fourth classification--disorganized attachment--also vary by local population. The prevalence of disorganized attachment among middle class, white American children is about 12% (Main and Solomon 1990). Among the children of American adolescent mothers, the rate is over 31% (Broussard 1995).
Disorganized attachment has also been reported to be relatively common among the Dogon of Mali (~25%, True et al 2001), infants living on the outskirts of Cape Town, South Africa (~26%, Tomlinson et al 2005), children from low income families in Zambia (~29%, Mooya et al 2016), and undernourished children in Chile (Waters and Valenzuela 1999).
Why local populations differ
In some cases, these outcomes may reflect differences in the way infants perceive the Strange Situation, rather than real differences in attachment.
For instance, Israeli children raised in kibbutzim rarely meet strangers. As a result, their high rates of resistant behavior during the Strange Situation test may have had more to do with heightened fear than with the nature of their maternal bonds (Sagi et al 1991).
Similarly, the Japanese results were probably skewed by the facts that Japanese infants are virtually never separated from their mothers (Miyake et al 1995). Nor do Japanese people value independence and independent exploration to the same degree that Westerners do, with the result that otherwise securely-attached babies may explore less (Rothbaum et al 2000).
But in other cases, results of the Strange Situation may reveal genuine cultural differences in the way that children have attached to their mothers. For example, researchers analyzing a variety of attachment studies concluded that German and American infants perceived the Strange Situation in similar ways (Sagi et al 1991). So the relatively high incidence of avoidant-insecure attachments in Germany may reflect real differences in the way that some Germans approach parenting.
One criticism of the Strange Situation procedure is that it has focused almost exclusively on the mother-infant bond.
In part, this may reflect a cultural bias. Many people who study attachment come from industrialized societies where mothers usually bear most of the responsibility for childcare.
But in some families, fathers spend a great deal of time with their children.
And in many parts of the world, grandmothers, aunts, uncles, and siblings make substantial--even crucial--contributions to childcare.
In fact, among some modern-day foragers, like the Aka and Efe of central Africa, infants spend the much of the day being held by someone other than their mothers (Hewlett 1991; Konner 2005).
Such evidence has inspired evolutionary anthropologists to "rethink...assumptions about the exclusivity of the mother-infant relationship" (Hrdy 2005).
For instance, anthropologist Sarah Blaffer Hrdy has argued that non-maternal caregivers may have played an important role in human evolution (Hrdy 2005). When infants have multiple caregivers, their mothers bear less of the cost of child-rearing. Mothers can afford to have more children, and their children can afford to grow up more slowly.
Interestingly, these life-history traits—higher fertility and an extended childhood—distinguish humans from our closest living relatives, the great apes (Smuts et al 1989). And ape mothers—unlike many human mothers—must raise their kids without helpers.
So perhaps "allocare" (non-maternal childcare) gave our ancestors the edge—allowing us to reproduce at faster rates than our nonhuman cousins.
If so, it's foolish to assume that human babies are designed for exclusive attachments to a single, maternal caregiver.
While this point doesn't detract from the importance of Strange Situation studies, it reminds us that infants can bond with more than one person.
Research confirms that infants form secure attachment relationships with both their mothers and their fathers (Boldt et al 2017). Studies show that toddlers can form secure attachments to their daycare providers (Colonnesi et al 2017). School children can form secure attachments with their teachers (Verschueren 2015).
And when they do -- when children expand their network of secure relationships -- they are more likely to thrive.
For more readings about the importance of secure, personal relationships, see these articles
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Content last modified 1/2018
Image credits for "The Strange Situation":
Title image by Maria Grazia Montagnari / flickr
Photo of mother and infant by Chilobiamo_P