The Domesticated Brain (14 page)

James’s account of emotions following responses failed to take into consideration situations where the body responds more slowly to stressful situations than our thought processes.
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Also, people are not always sensitive to the changes in their body in stressful situations. Sometimes emotions can precede bodily changes, which is why we can feel embarrassment before we blush. Maybe you burped in public accidentally, looked around at others and then felt your cheeks burning bright red with heat as the emotional significance of your
faux pas
sunk in. The thought was almost immediate but the change in blood flow took longer. So which is it? Does fleeing cause fear or do we run away because we are frightened?

The answer is both. In some situations, the need to respond as fast as possible trumps the need to think (the sudden bear attack), whereas in others we need to consider the situation and respond accordingly (blushing in public). However, in both situations, experience and expectations
play a role. If we know that the bear is actually stuffed, then we are less likely to be frightened. If we are among family when we burp, we do not feel so socially awkward.

As these different examples reveal, there are fast and slow pathways to emotion that depend on the circumstances and how we interpret the situation.
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Our emotions are also largely influenced by others. In a classic study of the importance of social context,
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naïve subjects were given an injection of adrenaline and told they were receiving vitamins that would boost performance on a visual test. This was all a sham to get at the real purpose of the study – how do those around us influence emotional experiences? Some of the participants were correctly informed that the injection would make their hands tremble, give them a flushed face and increase their heart rate. Others were told incorrect symptoms of a mild headache and itching skin.

While the participants sat around in the waiting room, they were asked to fill out mood questionnaires. Seated among them was an experimenter who acted in one of two ways. This confederate had not been injected with adrenaline but behaved either negatively, complaining about the study, or positively, by saying how much they were enjoying the experience and acting up playfully.

Meanwhile, in the real participants, the adrenaline triggered their HPA axis and produced the bodily symptoms associated with the fight-or-flight response. Suddenly they had these sensations, but what did they make of them? Those who had been warned correctly about the effects of adrenaline interpreted their sensations correctly (‘I’m feeling a little revved up because of the shot’). But those who did
not expect the increased heart rate and tremors were in a state of ignorance and needed to make sense of the signals their bodies were sending them. This is where others play a critical role. The emotions experienced by the naïve participants depended on the influence of the stooge in the room. Those seated with the playful experimenter rated their mood much more positive compared to those seated with the irritated experimenter. They were using the social context of others to interpret their own bodily sensations. Whether we are enjoying a rock concert, a football game or a day at the funfair, our emotional experience depends heavily on how others respond.

The importance of interpretation explains why some of us feel anxious and some of us feel excited. We learn to interpret situations based on experiences that we accumulate over our lifetime. This is why children raised in an environment where there is excessive conflict come to expect this as normal. If there is one thing that is predictable in conflict households, it is anger. When there is anger, violence soon follows, which is why abused children tend to see anger earlier in faces and interpret faces as being angrier whereas they show no higher sensitivity for other emotional expressions. Having a bias for interpreting anger means that children can be prepared for fight-or-flight.

Knowing this enables us to change the way troubled teenagers behave. Colleagues in my department at Bristol produced a series of computer-generated faces made up from morphed real faces that varied on a continuum from happy through neutral to anger.
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The teenagers, most already with criminal convictions and attending a programme for
high-risk repeat offenders, saw the ambiguous faces as more aggressive. However, in a clever twist, half of the teenagers were given false feedback on a task where they had to judge the expression, which eventually shifted their bias away from angry faces. In other words, after training, they were much more likely to see ambiguous faces as happy and happy faces as even happier.

The psychologists were able to shift the teenagers’ perception to a more positive interpretation. More remarkably, the effect was long lasting and altered their behaviour in general. The teenagers kept diaries and were evaluated by staff who were unaware of which condition each teenager had been in. After only two weeks, those teenagers who had their anger bias shifted were happier, less aggressive and involved in less conflict incidents as rated by the staff.

Domestic violence

We all need someone from the very start. This imperative to have someone in your life explains the paradox of children’s attachment to abusive parents and why domestic violence can persist. According to the UK’s National Society for the Prevention of Cruelty to Children statistics published in 2012, one in four young adults were severely maltreated as children. You would think that we have evolved brains that learn to avoid danger, yet when social workers, doctors, or police officers attempt to rescue these victims from an abusive situation, the child will often lie to protect the parents. Harry Harlow also demonstrated similar phenomena in his rearing studies, when frightened infant rhesus
monkeys would cling to a surrogate mother made of wire, cloth and a plastic head. Even when they were punished for this attachment with an aversive puff of air, they would still hang on for dear life. How can we understand such strange love?

Regina Sullivan, a neuroscientist who studies the neurobiological basis of attachment, believes an answer might be found by looking at rat pups.
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Rats are smart and can quickly learn what is painful. They can learn to associate an odour with a painful shock. Surprisingly, the brain area responsible for fear and avoidance learning is turned off by the presence of the mother. Even though rat pups can associate a smell with a painful shock, they do not avoid the odour when the mother is present and will in fact approach the smell associated with punishment. Somehow the presence of the mother switches avoidance into approach behaviour in painful situations. The explanation for this masochistic behaviour is that learning about painful situations requires the activity of the rat’s equivalent of the stress hormone, corticosterone, but the presence of the mother turns this off in the young pups in the nest.

Outside the nest, when they are older, exploratory rats will avoid potential dangers but they do this by returning to the nest for comfort and safety.
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This response is
social buffering
and we see it in humans faced with stressful situations where the presence of a loved one makes the experience more bearable. Even having the photograph of a loved one is sufficient to alleviate pain.
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The problem arises when that loved one is also the source of pain and danger. When rats return to their nest, their corticosterone mechanisms
are switched off and they forget what a monster their mother can be. So unpredictable environments are stressful but less stressful than consistently abusive situations. For some, uncertainty of the future is worse than the predictability of the current situation, albeit abusive, which is the origin of the saying ‘Better the devil you know’.

Clearly early domestic violence can leave a lasting impression, but not everyone responds to adversity in the same way and not everyone develops stress-related illness. Not everyone stays in an abusive situation. Given our understanding of stress as a biological phenomenon, how is it that individuals can respond to it so differently?

Two peas in a pod

I have a collection of rare postcards from the sideshow era that I described in the opening to this chapter. They fascinate me since they are a reminder of how social history and attitudes can change so dramatically. One of the cards is a rare photograph of Daisy and Violet Hilton as babies. Daisy and Violet were Siamese twins – two identical sisters conjoined at the hips. They were born in 1908 in Brighton and immediately rejected by their unmarried mother, who thought they were a curse from God for being born out of wedlock. Daisy and Violet were adopted by their midwife and raised to be talented musicians who went on to achieve fame and even appeared in the movies, most notably Tod Browning’s infamous production of
Freaks
in 1932.

Identical twins occur when a fertilized egg splits in two soon after conception. In the rare cases of conjoined twins,
that separation is incomplete. Identical twins share all their genes whereas non-identical twins, who come from two separate fertilized eggs, share only half of their genes. Like Tweedledum and Tweedledee from
Alice in Wonderland
, identical twins look the same, behave the same and often think the same thoughts. There is even a popular myth that twins are telepathically connected and read each other’s minds.

Studying twins is important for working out the roles of genes and environment in shaping the course of development. Like Daisy and Violet, twins are sometimes adopted, but unlike conjoined twins, they can be fostered out to different households. By comparing twins, identical and non-identical, raised in the same or different households, you can estimate how similar they are and then work out the relative contribution of genes and the relative contribution of the environment.

These adoption studies show that identical twins raised separately are more similar than non-identical twins raised by different families. This proves that aspects of personality and intelligence must be heritable. But identical twins are not identical. Even as conjoined twins, Daisy and Violet had marked differences in personality and allegedly even different sexual orientations, but they were hardly the same person.
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When it comes to personality and intelligence, heritability only accounts for, at best, half of the overall similarity. This is an important point that Judith Rich Harris draws our attention to in her book
No Two Alike
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. We are so used to thinking of identical twins as being identical, we fail to
realize how different they actually can be. If you think about it, Daisy and Violet Hilton not only shared the same genes but they literally shared the same environment. How could they be so different?

Most people believe that one of the main reasons that individuals can be so different is because they were raised in different homes. The history of parenting is full of advice about how best to raise children and the bookstores have whole sections dedicated to parenting manuals. This comes from an understandable concern to look after our offspring and give them the best start in life as well as deep-seated beliefs about the forces that shape individual development. We have all grown up in a variety of households with different experiences that have shaped us, which is why there is a common assumption that we are what we are because of the way we were raised. When we blame delinquent children, we typically look to the parents. However, Harris spent many years surveying the fields of developmental psychology and concluded that when it comes to psychological outcomes such as intelligence and personality, neither genes nor the household environment can predict how we will turn out.

Ironically, that is a message that most parents probably do not want to hear, but they should be the first to agree with Harris. Any parent should be able to confirm that no matter how much they try to treat their various children equally, they end up very different. In fact, when the proper measurements are done, two siblings raised in the same household are not much more similar than two randomly selected individuals of roughly the same age plucked from the same
population. Despite what most parents want to believe and parenting manuals promote, the home environment plays a relatively minor role in shaping the development of children.

If it isn’t the home environment and it cannot all be the genes, then what explains individuality? Harris argues that the major determinant of a child’s intellect and personality is the influence of their peer group – other children. While the child may behave according to their parents’ expectations in the home, they put on a different face in the playground and shopping mall. Children act and respond to others differently in different situations. This is why children of immigrants do not learn their parents’ accents when learning English, but adopt the local dialects and accents of the neighbourhood kids.

Harris’s thesis is highly controversial as it goes against the modern trend for parenting expertise. It is also leaves out the extreme environments of Romanian orphanages and depressed mothers who have been shown to affect long-term development. Moreover, parents indirectly influence which peer groups children are exposed to because they choose the neighbourhoods and schools that their children end up in. That said, the goalposts are likely to shift again when one considers the pervasive role that social networking sites such as Facebook and Twitter now play in teenagers’ lives. However, even if today’s extensive networks outside the home play a greater role in shaping children, this cannot explain why Daisy and Violet, who shared the same genes, the same environment and the same peers, were still different. Perhaps it’s because people treat identical twins, even those conjoined at the waist, differently so as to distinguish
them. That seems plausible, but a more likely explanation is in itself unlikely – and that is the role of random events in development: an area of research known as
epigenetics
.