The Domesticated Brain (19 page)

What happens to children who lack self-control when they grow up into adults? Terrie Moffitt and her team followed up over 1,000 children who had been born in the New Zealand city of Dunedin in 1972–3 and studied them from birth to the age of thirty-two years.
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Each child was assessed for measures of self-control from three years of age based on reports from the parents, teachers, researchers and the
children themselves. The results were startling. Children with high self-control were healthier, happier, wealthier and less likely to commit crime. These effects still held when intelligence and social background were taken into consideration. However, this was an observational study so it is difficult to know exactly what aspect of self-control was responsible for the outcome. What aspects of EFs were playing a major role in the children’s entry into society? To answer that, we need a marshmallow, or possibly two.

Tempting marshmallows

In Germany, there was a tradition dating back to the Middle Ages that to determine whether a child was suitable for schooling you would offer them the choice of an apple or a coin.
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If the child chose the apple, they had to remain in maternal custody. If the child chose the coin instead, they were considered ‘worthy of instruction in knightly arts’. The logic behind the test was that a child who chose the apple was simply attracted by the desire to eat the apple, whereas a child who chose the coin could ignore the immediate gratification of the apple in favour of the greater rewards a coin would bring later.

This capacity to delay gratification has become a famous measure of children’s self-control in a task known as the
marshmallow test
.
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There are different variations of the test but they all involve presenting the child with a tempting reward. In the marshmallow version, children are instructed that the experimenter has to leave the room and that they can eat the treat now but if they wait until the experimenter
returns they can have two – a much better deal but one that requires them to delay the gratification. This test has even entered popular culture as a UK confectionery manufacturer in 2011 ran an ad campaign using the same principle to demonstrate how tempting their products were.

Stanford psychologist Walter Mischel used the marshmallow test in the 1960s to measure how long children could delay gratification before giving into temptation. Around 75 per cent of four-year-olds failed to wait, with an average delay of six minutes. The most impulsive children simply gobbled the marshmallow up, but the others with more self-control resisted the urge. Not only did this measure indicate their capacity for self-control, but it predicted how well they got on with classmates and how well they performed academically when they were teenagers. It even predicted which males would later develop drug problems.
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All of these achievements of studying, getting on with others and avoiding drugs are components of domestication that require self-control. Studying can be boring and it is all too easy to find other, more interesting things to do. Getting on with others means that you have to be less selfish and more willing to share your time and resources. Avoiding drug use, a complex behaviour, requires at its heart the ability to simply say ‘no’.

The marshmallow test seems to tap into an individual’s natural impulsiveness. You might think that this self-control is all to do with the brain mechanisms for resisting temptation, but families also play a role. Different parenting strategies have been found to be associated with different self-regulatory behaviours in toddlers. In 1963, the famous
child psychologist Erik Erikson wrote that ‘the gradual and well-guided experience of the autonomy of free choice’ will contribute to enhancing self-control, whereas over-control by the parent will produce the opposite effect.
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In the decades following that statement, toddler research has generally provided support for this view. When asked to tidy up their toys, toddlers are more likely to be defiant if their mothers apply an over-control strategy of anger, criticism and physical punishment to control the child.
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One explanation is that children with strict parents have less self-control because they rarely have the opportunity to exercise their own regulatory behaviour, which is necessary in order to learn to internalize as a coping response. The process of domestication does not simply mean learning what the rules are, but when and how to apply them. This fits with classic studies that show that threats of punishment may work in the short term but persuasion is more effective when the potential threat is no longer around. Likewise, children of parents who use assertive persuasion exhibit more self-control because they have to develop self-regulation or suffer the consequences of being too impulsive. So the finding that less discipline leads to better adjustment runs completely contrary to the old saying that by ‘sparing the rod, you spoil the child’. However, children of indulgent parents like Veruka Salt’s also fail to exhibit self-control, indicating that allowing the child to run amok is also not a good strategy.

Of course, domestication strategies depend on how many children you are trying to raise. Clearly there is often competition between siblings and so single-child environments will be different from situations where there is more than
one child. Whether such singletons differ from other children raised with siblings is controversial, but in China, which introduced a one-child policy in 1979, grandparents, teachers and employers believe that singletons are spoiled, selfish and lazy because they have been over-indulged by their parents. A 2013 study of these
Little Emperors
published in the prestigious journal
Science
found that children born just after the policy was introduced grew up into more selfish adults compared to those born just before.
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They were also less trusting and helpful towards others.

The issue of trust plays an important role in our decisions to delay immediate rewards. After all, we are basing our decision on a promise that we will get something in the future. But what if a child is raised in an unpredictable environment where there is poor supervision as well as others who might steal their possessions or food? For these children, why should they take the risk if all they have known are broken promises? In this situation it would be foolish to wait. This reinterpretation of the delay of gratification finding is supported by studies on trust. If an experimenter promises but fails to give a sticker to four-year-olds in a drawing task, then these children are less likely to delay gratification on a subsequent marshmallow task.
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It’s not just children who do this. Adults will also forego an immediate financial reward for the promise of a greater reward in the future if they are told that the other person is trustworthy or indeed nothing is said about them at all. We are more likely to trust someone if we know nothing about them. However, as soon as the promiser is described as untrustworthy, then adults do not
delay and take whatever is on offer. Our decision-making is greatly influenced by who we think we are dealing with.

These findings with adults seem obvious but they do cast a new light on understanding the relationship between self-control and sociability in at-risk children. Psychologist Laura Michaelson proposes that the classic relationship between failure of self-control as a child and later delinquency and criminality as an adult may actually reflect the lack of trust experienced at an early age as much as the biological factors that enable us to delay gratification.
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Children from broken homes who grow up in impoverished households do not trust as much as those raised in supportive environments. No wonder they will take what they can get because, for them, the metaphorical bird in the hand is worth more than two in a bush.

If domestication means encoding our early experiences as contingencies in the neural circuits of the PFC, at the very least our capacity to learn from experience and moderate our behaviour suggests that self-control and life events probably work together in shaping our capacity for trust. Trusted adults strengthen the child’s capacity for self-control. If a child has been told that they are ‘patient’ before the marshmallow test, they will wait significantly longer than children not given this label.
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It may be a simple case of not giving a dog a bad name, as the old saying goes, but rather a good one. It is a simple
nudge
by an authority figure to help the child to strengthen its own resolve.
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Another revealing facet of self-control is what children do to regulate their behaviour. While waiting for the marshmallow, children who performed best on the task did not
necessarily show more self-control but rather they seemed to find ways of taking their minds off the temptation. Many of them used distractions such as not looking at the marshmallow or singing to themselves. They were adopting a strategy known as
self-binding
– an action that one takes now in order to secure a better future. According to the Greek story, Ulysses wanted to hear the song of the Sirens but knew that their singing lured sailors to their deaths. To outwit them, he poured wax into the ears of his crew and had them bind him to the mast so that he would not leap from the ship and drown. Distraction turns out to be a better way of controlling urges because the act of resisting temptation by confronting it and trying to stop thoughts and behaviours can actually produce the opposite result in a psychological rebound effect.

Rebounding earworms and white bears

Rebound effects can happen when you least expect them and often can be very irritating.

Have you ever had that annoying experience where a tune gets stuck in your head – even one that you really hate? No matter how you try, it will simply not go away. The more you try to ignore it, the stronger the song becomes. Like some type of musical itch you cannot scratch.

This is because you are experiencing an
earworm
. Earworm is a direct translation of the German term
ohrwurm
, which means ‘earwig’. These are the tunes that we can’t forget, no matter how hard we try. It may be a catchy pop song or some advert jingle. Often we hate the tune but it
simply will not go away. They intrude into our consciousness uninvited and, once there, overstay their welcome.

Around nine out of ten have experienced an earworm and diary studies indicate that most of us have an earworm episode at least once per week.
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Most people find them annoying, but no matter how hard they try, these earworms just will not go away on command. And it is not just tunes that get stuck in our head; mental images can lodge in your mind as well.

You can assess your own mental-image suppression with the following test. Say out loud each thought or image that comes into your head over the next five minutes. Time yourself. You can say anything, but the only rule is that you must not think about a
white bear
. Remember that – anything but a
white bear
. Now try it.

Did the image of a polar bear pop into your mind? When my Harvard colleague Dan Wegner conducted this simple experiment, he found that participants could not help but think of a white bear and the more they tried to suppress the thought of a white bear, the more it rebounded back.
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The reason for this obstinate effect is that in attempting not to think about the white bear, processes in our mind actively seek out white bears so as to monitor them and prevent them from entering awareness. However that monitoring in itself brings them into consciousness.

When people try to suppress unwanted thoughts, they come thundering back into consciousness with even greater strength. This failure of self-control can have implications for our domestication. Inappropriate sexual thoughts and racist stereotypes are both things that we would rather not
think about, but in doing so, they become all the more vivid in our minds. In one study, adults were shown a picture of a skinhead and asked to write an essay about a day in the life of the individual portrayed in the photograph. Half of them were instructed not to use any stereotypes. After the essay, they were taken to a room with a row of eight empty chairs and told that the jacket on the end chair belonged to the skinhead they had just written about and were about to meet. Those who had suppressed the stereotype positioned themselves further away from where they thought the skinhead would be sitting than those who had not been given such instructions. This is the rebound effect in action. Even though these adults had not used stereotypes, actively suppressing the thoughts had altered their behaviour to make them even more susceptible to acting in a prejudiced way.
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Sometimes we cannot help ourselves, especially when our capacity for self-control has been compromised. After sustaining a concussion to his head, Basil Fawlty, the hapless hotel owner in the British classic comedy
Fawlty Towers,
was at pains not to mention the war when a group of German tourists came to stay. The more he tried to avoid mentioning the war, the more he let it slip during conversation. For children it may be marshmallows, but for adults it is all the thoughts and actions that we would rather not express in public because of the consequences they would have in terms of what others might think about us. Domestication means behaving in ways that are socially acceptable, something that requires sufficient self-control. Such self-control is difficult for young children, but for some adults, particularly those
whose EFs are compromised by damage, disease or drugs, it continues to represent a considerable challenge.