Bowlby's evolutionary theory of attachment

Attachment is innate

There is a critical period for attachment formation

Infant attachment styles predict adult relationship styles

Attachments are formed as a monotropy and hierarchy
Evolutionary theory explains attachment is an innate behaviour that has evolved over millions of years because it increases chances of survival

Attachment is innate
Bowlby (1969) proposed that millions of years of evolution had produced a behaviour that is essential to the survival chances of human infants. Humans are born helpless and totally dependent on the actions of a caregiver for food, warmth, shelter and safety for their well being and survival. If babies did not behave in a way that made it more likely an adult would care for them, and if adults did not become attached to babies, then human infants would not survive to reproductive age. Therefore natural selection has passed on genes that lead to attachment forming behaviours.

The innate nature of attachment was illustrated by Lorenz (1952) in his studies of imprinting in geese. Lorenz hatched two groups of geese eggs - one group stayed with their natural mother and the other group were hatched in an incubator. The first moving thing the incubator group saw when they hatched was Lorenz himself, and the geese immediately started to follow him around. When the incubator geese and natural mother geese were mixed together, they would quickly separate into the two original groups and follow either Lorenz or their natural mother. Imprinting of this nature in animals has a clear survival advantage as it keeps them close to their mother who would naturally protect them from predators and increase their chances of survival.

The types of attachment an infant experiences form a template for that infant’s future attachments. This template is called an internal working model and plays a role in guiding future adult relationships.

Bowlby’s theory has three main features:
  1. Infants and caregivers (usually mothers) are innately programmed to become attached.
  2. Attachment is a biological process that takes place during a critical period or not at all.
  3. Attachment styles developed in infancy play a role in later attachment styles through the continuity hypothesis.

Critical period for attachment formation
Most developmental processes take place during a critical period. This is a time frame or window of opportunity in which development of a behaviour or characteristic occurs. If the behaviour does not happen during the critical period then it may well not develop at all. Bowlby argued that there is a critical period between the ages of birth and 2.5 years (0-30 months) in which conditions must be right for an attachment to form, and if it does not form in this time then it is not possible to develop thereafter.

Rutter et al (1998) studied Romanian orphans who had been placed in orphanages with minimal adult contact. When these children were adopted by US and UK families in their first year of life, they were able to form strong and stable attachments with their adopted parents. Bowlby’s theory argues that after 2.5 years of age the infants would not be able to form an attachment, however when older infants were also adopted by US and UK families they made slower progress than their younger counterparts, but they did develop attachments. This shows that attachments can be formed outside the critical period, but that they develop much more slowly, and that the idea of a critical period outside of which an attachment cannot be formed should be modified to a sensitive period during which attachments form more easily.

Bowlby argues that infants form a single special attachment with one primary attachment figure, usually the mother. This is called monotropy (moving towards one). Other attachments may develop in a hierarchy below this. An infant may therefore have a primary monotropy attachment to its mother, and below her the hierarchy of attachments my include its father, siblings, grandparents, etc.

The idea of monotropy and hierarchy is supported by research into attachments formed by the Efe tribe of Congo. Efe women share the care of infants in the tribe and take turns to breast feed them, however the infants return to their natural mother at night and form a stable bond with the mother.

Fox (1977) studied attachment styles in Israeli kibbutzim. In a kibbutz infants are cared for by a primary caregiver (a metaplet) during the day while their mothers work, and they return to their mothers in the evenings. Despite the fact that the mothers were not the infants’ primary caregivers, the infants still formed strong emotional attachments with their mothers.

Continuity hypothesis
A key feature of Bowlby’s evolutionary theory of attachment is that the attachment style formed as an infant provides the infant with an internal working model of relationships, and that in turn guides relationship behaviour as an older child and adult. A secure child will develop a positive internal working model of itself because it has received sensitive emotional care from its primary attachment figure. An insecure-avoidant child will develop an internal working model in which it sees itself as unworthy because its primary attachment figure has reacted negatively to it during the sensitive period for attachment formation.

Hazan and Shaver (1987) researched the link between infant or childhood attachment types and adult relationships. They found that securely attached children, who had secure and close relationships with their parents, developed secure, stable and loving relationships with their adult partners. Insecure-avoidant children, who had cold and rejecting mothers, developed insecure adult relationships with high levels of jealousy and fear of rejection. This shows that childhood attachment styles correlate strongly with adult relationship styles, however the research is based on a self-report questionnaire with retrospective questions that try to explore childhood attachments through the participant’s own (biased) childhood memories. Check your romantic attachment style on our games and tests page.

Social releasers
Babies behave in ways that adults find ‘cute’ and that release emotions, particularly in females. Cooing, gurgling, smiling and laughing create happy emotions in adults. Crying, distressed facial expressions, and frustration create ‘care giving’ emotions in adults that make them want to alleviate the infant’s distress. This is an essential behaviour for survival as it makes adults want to care for infants.

Evaluating Bowlby’s theory
Bowlby evolutionary theory of attachment evaluation

A Level exam tips
Answering exam questions (PSYA1 AQA A specification)
Outline and evaluate Bowlby’s evolutionary theory of attachment (12 marks)
6 AO1 marks: It is essential to briefly describe how attachment formation has evolved through natural selection to create human behaviours that aid survival. You must state that attachment is innate, occurs during a critical period, and forms an internal working model for childhood and adult relationships. Key words to use are innate, continuity hypothesis, internal working model, and critical period. You could describe monotropy and hierarchy as well, but only if time allows.

6 AO2 marks: You must use research evidence to support the features of Bowlby’s evolutionary theory of attachment that you have described in the AO1 section. For attachment being an innate behaviour use Lorenz (1952). For the critical period use Rutter et al (1988) and discuss sensitive period rather than critical period. For continuity hypothesis use Hazan and Shaver (1987). Three well used pieces of evidence that clearly state how they support or modify Bowlby’s theory will be more than sufficient for 6 AO2 marks.