Bruce Hood - The Domesticated Brain - A Pelican Introduction (Pelican Books)

Harlow discovered that it was not just the amount of time that animals spent in isolation that was critical, but also when they were separated. Those born into isolation were at risk if they spent longer than the first six months without the company of their mother. In comparison, monkeys who were isolated only after the first six months of normal maternal rearing did not develop abnormal behaviour, indicating that the first six months was a particularly sensitive period. Bowlby had originally thought that the primary reason for attachment was to ensure that biological needs for food, safety and warmth were satisfied, but Harlow proved that he was only partly correct – monkeys also needed social interaction from the very beginning.

It turns out that human social development, like that of the monkey, is also shaped by a similar sensitive period of socialization. Back in 1990, following the collapse of Nicolae Ceauşescu’s dictatorship, the world discovered thousands of Romanian children abandoned in orphanages. Ceauşescu had outlawed family planning in an attempt to force women to have more children to increase Romania’s dwindling population. The trouble was that families were unable to support these children and so they were abandoned in the orphanages.

On average, there was only one caregiver for every thirty babies, so there was little social interaction and none of the cuddling or intimacy that you would find in a normal, caring environment. The babies were left to lie in their own faeces, fed from bottles strapped to their cots and hosed down with cold water when the smell became unbearable. When these children were rescued, many of them were fostered out to good homes in the West. Sir Michael Rutter, a British psychiatrist, studied just over one hundred of these orphans who were less than two years of age to see how their early experiences would shape their development. 18

On arrival, the orphans were all malnourished and scored low on psychological tests of mental well-being and social interaction. That was to be expected. As time passed, they recovered much of this lost ground in comparison to other adopted children of the same age who had not been raised in the Romanian orphanages. By four years of age, most of this impairment had gone. Their IQs were still below average in comparison to other four-year-olds, but within the normal range that could be expected. However, it soon became apparent that not all was back on track.

Children who had spent longer than six months in the orphanages were failing to catch up with their matched group. Only the children who were rescued before they were six months old went on to a full recovery. The children were followed up again at six, eleven and fifteen years of age. Again as a group they fared much better than expected, given such a horrific start in life, but problems started to appear. Those who had spent the longest time in the orphanage were beginning to show disturbed hyperactive behaviour and difficulties in forming relationships. Just like Harlow’s monkeys, social interaction during that first year was crucial for normal development. To understand what is so important about having someone around to look after you and not just to give you food and warmth, we have to consider what upsets babies.

Why not knowing is stressful

Have you ever waited for someone to call you with important news? Maybe it was an exam result, the outcome of a job interview or, worse, a call from the hospital. The reason that waiting for important news produces anxiety is that brains are pattern detectors that have evolved to seek out regularities in life; not being able to predict what will happen next is therefore upsetting. We can brace ourselves for important events, but it is stressful to maintain that level of preparedness for a long time. The stress comes from high levels of arousal – a state of readiness and expectation. Just like the US Army, when we face a threat, we enter a defence-readiness condition (DEFCON). When that threat is at a peak, it’s like being at DEFCON 1. This is why we jump at the slightest sound, because we are in a state of heightened alertness. It is not until we can stand down our defences that we can relax.

Even though we may not be actively dealing with a threat, nevertheless the uncertainty of threat still makes the situation stressful. In fact, our brains are not very good at dealing with random events, which is why we tend to see structure and order everywhere. That is why when you are in the woods late at night or an old spooky house, every noise sounds like a threat. Adults start to see patterns in random noise when you remove their ability to control outcomes or remind them of times when they were helpless. 19

This lack of control is not only psychologically distressing, but it also affects how our bodies respond. Even our tolerance to pain is reduced. Adults can withstand much more painful electric shocks if they think they can stop the punishment at any point in comparison to those who do not think they have this option. 20Believing you can stop the pain whenever you want means that you can tolerate more. However, when faced with unpredictable and uncontrollable shock, both animals and humans develop both psychological and physiological illness.

This need for control and predictability is present from the very start. Babies prefer regularity and predictability, which is why they startle to sudden unpredictable noises, lights or movement. In fact, there is a reflex controlled by the brain stem – the most primitive part of the brain that controls vital functions – known as the startle reflex , that jolts the child to attention. If a newborn does not startle, there is a chance that they have some form of damage to their nervous system. This need for predictability forms the basis for contingent behaviour where the baby starts to learn how they are synchronized with others. Such a sensitivity to external events means that a nurturing domestic environment is one that is going to be predictable and less threatening – attributes that can be controlled by caregivers.

Infants thrive on predictable contingent behaviour, but the flipside is that they find unpredictable or non-contingent events upsetting, especially when they involve their mother. When mothers are depressed, they often have flattened emotions and so the quality of their interaction with their infants is impoverished. 21Other depressed mothers, rather than being sad and dull, over-compensate in an animated, exaggerated form of communication, which can be equally distressing to the infant because it is not contingent with their own efforts at communication. Early experiences like this, where the baby’s needs for contingent responses are not met, can lead to social and cognitive difficulties many years later.

Other people provide reassurance in an uncertain world. The stress of uncertainty is reduced if there is an adult around, so our brain benefits not only from the wisdom of others but their presence as well. As the saying goes, a problem shared is a problem halved because there is strength in numbers. If you think about it, the world is full of surprises for the young infant and development must include discovering what is going to happen next. With knowledge and experience, the world becomes more predictable. That understanding takes time to acquire, but until then, adults provide protection and reassurance, which is why babies cry if there is uncertainty because it is how they signal to the adult to resolve the situation.

Taken together, these studies indicate that extreme early environments can have long-term effects on developing monkeys and humans. It would seem that primates need some form of contact from the very start, especially in environments that are particularly threatening or socially vacant. However, it is not just the deprivation of not having others around, but not having others around who are reliable. How do such stressful environments shape who we become and what role do others play in our reaction to stress?