Mary Ainsworth was a researcher who developed a test for attachment – the strange situation. In this experiment a mother and a one-year-old enter a room full of toys. The child is given time to explore and play. Then a stranger enters the room. Next, the mother leaves the child alone with the stranger in the room. A few minutes later she returns to comfort her distressed child.

After this, the mother leaves the child completely on their own in the room for a minute. Then the stranger enters. Then, finally, the Mum comes back in. Developmentalists are able to view these separations and reunions and put the infants into different categories of attachment: Securely or insecurely attached.

Securely attached children use their mother as a secure base. This means they go to her when they feel distressed and then when they feel soothed, they go and explore the toys. When the mother leaves these children may or may not get distressed. When she returns their eyes light up and they run back to their mothers arms, feeling safe and secure again. It is the caregivers sensitivity to the signals from the infant that makes them securely attached.

Insecurely attached children behave in three different ways. Some infants are classified as avoidant. They act detached and rarely show separation anxiety. They don’t display much positive or negative emotion when the mother returns. They seemed disengaged and a bit ‘wooden’.

Babies with anxious attachment are too frightened to explore the toys. They cling to their mother and get very upset when she leaves. When she comes back they might cling to her but also get really angry and hit her. They find it hard to calm down and be comforted upon reunion.

Some children have a disorganised attachment style. They often ‘freeze’ or behave in confusing ways, sometimes looking frightened when the mother returns.

These insecure styles does not mean that the bond is not as strong. It is just that they have adapted to the caregiver by using the above behaviour as strategies to get their needs met. Every infant is closely attached.

What causes insecure attachment styles? If the caregiver responds to the infant’s signals in a rejecting way or if they are disengaged or depressed the infant is more likely to develop an insecure attachment style. Also if the caregiver’s wider attachments are weak – if the mother, for example, is in a bad relationship or not supported by the wider community – the child is more likely to be insecurely attached. There are wider social forces that influence the development of a child’s attachment style.

A child doesn’t just develop one attachment but many – to their mother, father, day care worker, extended family etc. They can therefore have different attachment styles in different relationships. An infant can be securely attached to their mother, while being insecurely attached to their father. But when they get upset they still run to their primary caregiver – the person with whom they spend the most time. Being securely attached to one attachment figure may be the main factor in determining future healthy development. Having one secure attachment helps prevent mental health problems later on in life.

The Efé are a hunter-gatherer tribe in Africa. New-borns nurse from any lactating female in the tribe, even when their parent is present. They are cared for and nurtured by the whole community. But each child still develops a primary attachment to their mothers.

Attachment in infancy determines how we relate to other people and how we feel about ourselves. Insecure attachment is a greater risk factor for mental health issues and conflict in relationships while securely attached children tend to be popular and socially skilled. Disorganised attachment, where the infant acts in confused and erratic ways, is a risk factor for aggression, and poor impulse control.

However, attachments can change throughout the life-time through the experience of sensitive, warm relationships. While secure attachment is a protective factor it does not prevent later problems in life. In one study that followed infants into adulthood a boy named Tony was securely attached at aged 1. This continued through childhood but when he was a teenager his parents got a divorce, his mother was killed in a car crash and his father moved away from him, leaving him to live with his aunt. He became angry and depressed as a teenager. But by 26 he was in a healthy marriage with a child of his own and his attachment status had moved back to secure. The lesson is that even if we received inadequate caregiving we are not destined for a life of problems. We can change.

Children who were left uncared for in Romanian orphanages often developed reactive attachment disorder. These children were not able to form an attachment to a caregiver and display an indiscriminate friendliness towards all adults. The lack of stimulation they receive is thought to account for emotional and cognitive problems that develop. It is thought that damage occurs if these orphans were adopted after 6 months. From 7-18months was found to be a critical period for receiving caregiving. Failures to receive this care resulted in developmental deficits.