IB Psychology SLTopic 2 — Development of the SelfPaper 1 & 2Core theory~13 min read
Bowlby and the Roots of Attachment
A human baby is born almost completely helpless. It cannot feed itself, move away from danger or keep itself warm. Bowlby’s answer to how any of us survived that is simple: babies come pre-loaded with a system for making an adult stay close.
📘 What you need to know
Bowlby argued that attachment is innate — shaped by evolution because it keeps infants alive.
The bond runs both ways: infants attach for protection, food and comfort; caregivers attach so they will provide it.
His theory is monotropic: one special bond sits above all the others, with a primary attachment figure.
Two principles of monotropy: the law of continuity (steadier care means better quality attachment) and the law of accumulated separation (every separation adds up).
Social releasers are innate baby behaviours — smiling, cooing, gripping, a “cute” baby face — that pull adults in.
Bowlby proposed a critical period of roughly three to six months in which attachment needs to form.
The internal working model is the template the first relationship leaves behind, which shapes later relationships.
Key study: Ainsworth (1970) measured attachment styles using the Strange Situation.
Why attachment exists at all
Bowlby’s starting point was evolution rather than emotion. An infant who stays close to an adult gets fed and defended. An infant who wanders off does not survive to have children. Over a very long time, that pressure builds the tendency to attach into the species.
So attachment is not something a baby learns because it is fed. Bowlby’s point was the opposite: the drive comes first, and food is one of the things it delivers.
Definition
Attachment = a strong, lasting emotional bond between an infant and a caregiver, which the infant is biologically prepared to form.
Social releasers
If attachment is innate, babies need equipment for it. Bowlby called that equipment social releasers: behaviours and features that trigger caregiving in adults almost automatically.
Smiling — extremely hard to ignore and very rewarding to the adult.
Cooing and crying — sounds that demand a response.
Gripping a finger — physical contact that feels like being chosen.
The baby face — big eyes, small nose, round cheeks, which adults reliably find appealing.
The more responsive the adult is to these signals, the stronger the attachment becomes. It is a two-way loop: the baby signals, the adult responds, the bond tightens, so the baby signals more.
Here is a neat piece of evidence. When caregivers were asked to deliberately ignore their baby’s crying and smiling, the babies became more and more distressed. The releasers only work if someone answers them — which tells you the system is designed for a response.
Monotropy: one bond above the rest
“Mono” means one. Bowlby argued the child forms a hierarchy of relationships with one at the top — the primary attachment figure. It is usually the mother, but it does not have to be. It is whoever gives the most sensitive, consistent care.
Note what monotropy does not say. It does not say a baby has only one relationship — it says one relationship counts for more than the rest.
The two principles of monotropy
The law of continuity
The more constant and predictable the care, the better the quality of the attachment.
It is not about the number of hours. A carer who is reliably there and reliably responsive builds a stronger bond than one who is present but unpredictable.
The law of accumulated separation
Every separation from the primary attachment figure has an effect, and the effects add up.
Bowlby’s blunt version: the safest dose of separation is zero. Most researchers now think that goes further than the evidence supports.
The critical period. Bowlby placed a window of about three to six months in which the attachment needs to form, with real difficulty forming attachments later if it does not. Later evidence found children who formed attachments well after this window, which is why most psychologists now call it a sensitive period instead.
The internal working model
This is the idea that turns a baby’s relationship into an adult’s personality. The first attachment becomes a template — a set of expectations about what relationships are like and what you can expect from other people.
This is the mechanism that links infancy to adulthood in Bowlby’s theory. Without the internal working model, attachment would only explain babies.
The key study
KEY STUDY
Ainsworth (1970) — the Strange Situation
Aim
To investigate attachment style in infants, drawing on Bowlby’s theory, by watching how they react to separation and reunion.
Sample
56 white, middle-class infants from the USA, aged roughly 49 to 51 weeks.
Method
A controlled observation lasting about 20 minutes, in an unfamiliar room with toys, following a fixed sequence of comings and goings.
Conclusion
Attachment can be measured by observing behaviour. Most infants were securely attached, but insecure patterns were linked to different long-term outcomes.
🧩 The Strange Situation, step by step
Mother and baby enter an unfamiliar room with interesting toys, and she sits down.
A stranger enters, talks to the mother, then approaches the baby with a toy.
The mother leaves quietly. The stranger tries to interact and comforts the baby if it is distressed.
The mother returns and greets the baby, the stranger leaves, then the mother leaves too, saying goodbye.
The baby is left completely alone.
The stranger returns and tries to play with the baby, offering comfort if needed.
The mother returns, greets the baby and picks it up. The stranger leaves quietly.
The two moments that carry the whole study are the separations and the reunions. What matters most is not how upset the baby gets when the mother leaves — it is whether the baby is comforted when she comes back.
What Ainsworth found
Type
Roughly
Behaviour in the room
Linked to later on
Type B Secure
About 70%
Uses the mother as a safe base to explore from, is distressed when she leaves, is comforted when she returns, avoids the stranger.
Shows little interest in the mother, little distress when she leaves, and is not bothered by the stranger.
Detachment, low intimacy, less empathy.
Type C Insecure-resistant
10–15%
Clingy even while the mother is present, extremely distressed when she leaves, hard to settle on her return, mixed anger and anxiety.
Insecurity, jealousy, neediness, emotional ups and downs.
Evaluating Bowlby’s theory
Strengths
Limitations
Animal evidence. Lorenz (1935) found goslings imprint on the first moving thing they see, supporting the idea that attachment is innate and evolved.
Multiple attachments. Children form real attachments to several people from around 10 to 11 months, so strict monotropy may not hold.
Social releasers are supported. Babies whose signals were deliberately ignored became increasingly distressed, showing the signals are aimed at getting a response.
The critical period is too strict. Some children have formed attachments well after three to six months.
Huge real-world impact. It changed how hospitals and care homes treat separated children, and made family visits normal.
Extrapolating from animals. Imprinting in birds is not the same process as human attachment.
Explains continuity between infancy and adult relationships through the internal working model.
Cultural bias. The theory grew out of Western family structures, and shared caregiving is normal in many cultures.
Link to concepts
Measurement: attachment is complex, and a 20-minute observation is a snapshot. Clear behavioural categories help reliability, but they may miss most of what the relationship is. A longitudinal design would test whether classifications stay stable.
Responsibility: the procedure deliberately upsets an infant, which is ethically uncomfortable. The child cannot meaningfully consent or withdraw, and the mild distress is built into the design because it is what makes the results valid.
Bias: 56 white, middle-class American infants is a narrow sample from which to draw conclusions about attachment everywhere.
Exam practice
EXAM QUESTION
Discuss Bowlby’s theory of attachment. [22]
The commonest mistake is describing the Strange Situation for two pages and never evaluating anything. Description sets up the argument; it is not the argument.
Set out the theory
Innate and evolved, monotropy, social releasers, critical period, internal working model.
Support with research
Ainsworth (1970): 56 US infants, controlled observation, three attachment types, about 70% secure. Lorenz for the innate claim.
Argue forevolutionary logic + releaser evidence + massive real-world impact on childcareArgue againstmultiple attachments + critical period too strict + animal studies + narrow sampleAdd an ethics or methods point
The Strange Situation deliberately distresses infants who cannot withdraw.
Judgement: powerful and useful, but monotropy is the weakest partname the specific weak part — a vague “it has limitations” earns nothing
💡 Exam tips
Say attachment is innate and adaptive in your first sentence. It shows you understand the evolutionary basis straight away.
Name all five parts of the theory: monotropy, the two laws, social releasers, the critical period, the internal working model.
Use the percentages from Ainsworth. Precise figures look like real revision.
Reunion behaviour is the key to the attachment types. Say so.
Keep the multiple-attachment criticism ready — it is the sharpest attack on monotropy.
Mention “sensitive period” rather than “critical period” when you evaluate. It shows the theory has moved on.
⚠ Common mix-ups
Thinking monotropy means only one attachment. It means one attachment matters most within a hierarchy.
Assuming the primary figure must be the mother. Bowlby said whoever gives the most sensitive, consistent care.
Confusing Type A and Type C. A is avoidant and under-reacts; C is resistant and over-reacts.
Judging attachment by how upset the baby gets. The reunion is what classifies the type.
Saying the internal working model cannot change. It is a strong starting position, not a fixed destiny.
Calling the Strange Situation an experiment. It is a controlled observation.
Up next: What Happens When Attachment Is Missing — if the bond is this important, the obvious next question is what happens to children who never get one, or who lose it.
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