AT EIGHT o鈥檆lock one Tuesday morning, first and second graders in the village
of Bwa Mawego on the Caribbean island of Dominica head for school. A line of
kids in brown uniforms snakes down the steep road towards a two-room, yellow
stucco schoolhouse. Girls, their hair plaited and tied with brightly coloured
plastic bows, swing satchels and murmur softly to their friends in lilting
Creole. Boys push toy wooden cars on sticks over the bumpy road. The sun
sparkles on the Atlantic Ocean below and as the kids reach out and pull bananas
off the trees, the villagers wave them along. Childhood in Dominica seems like a
slice of paradise.
This image is shattered when a loud commotion erupts at the school
gate鈥攁 child is screaming bloody murder. Seven-year-old Winston runs into
the yard followed by his mother, wielding a stick. She catches him by the
shoulder and whacks his bottom, over and over. Her face is stony as the boy
screams in pain and fury. 鈥淗e does not want to go to school,鈥� explains the
teacher as she ushers the other children inside. In the schoolroom, some show
their anxiety by holding hands, others cower in their seats. No one says a
word.
Childhood, no matter the setting, has its darker moments. We may expect
children to be happy-go-lucky, but in fact their lives are rocked by anxiety.
Children as young as eight say they are under stress because of school work and
relationships with their peers, according to a British study reported last
month. Kids in affluent societies worry about wearing the right designer labels
and meeting the expectations of pushy parents. Elsewhere, poverty is at the root
of childhood stress. And around the world there are kids who grow up amid
constant violence, either in the home or because of civil war and political
strife. Winston鈥檚 problems with school are common鈥攂ut he and his
classmates are in an unusual position because they are taking part in a unique
long-term study to uncover how stress affects their physical and mental
wellbeing.
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For the past 13 years, anthropologist Mark Flinn from the University of
Missouri has been studying the children of Bwa Mawego. His approach may seem
subversive to many parents鈥攈e encourages the kids to spit. But this is an
ideal way to find out what鈥檚 going on inside their bodies, because saliva
contains a hormone called cortisol, which is produced in response to stress.
Using this information, together with health records and the children鈥檚 own
reports about their daily goings-on, Flinn has been able to get an extraordinary
insight into their lives. The research shows which situations provoke most
anxiety in kids, and it is also starting to reveal how our experience of stress
in early life affects us in adulthood.
When you perceive a threat, cortisol and other hormones kick in to modulate
energy output and put the mind and body on alert. This is known as the 鈥渇ight or
flight鈥� response. 鈥淲ithout cortisol,鈥� says Flinn, 鈥渉umans can鈥檛 endure the ups
and downs of everyday life.鈥� But the physiological changes associated with
stress are designed for coping with emergencies. Sustained over time, they begin
to break the body down. For example, the immune system, which is dampened down
so that energy can be directed elsewhere, is eventually damaged. So a response
that has evolved to help us deal with incidental threats turns out to be bad
when the perceived danger goes on too long.
Persistently high cortisol levels can be especially damaging in children.
When stress continues over days, weeks or years, many of their developing
systems are put on hold, sometimes causing permanent damage. Unusually high
cortisol levels from constant stress slow physical growth, delay sexual maturity
and can slow the growth of brain cells. In the short term, stress makes children
prone to upper respiratory tract infections and diarrhoea鈥攄iseases that
can be fatal in the young.
There are also behavioural consequences. Studies of orphans kept in appalling
conditions in Romania, who were then adopted by families in the US, show that
such children soon catch up in terms of physical growth and maturation. But
those who spent the longest time in the orphanage, without affection or normal
social interactions and under great social stress, continue to have major
behavioural problems.
Of course, this sort of childhood is not usual, and extraordinary experiences
may lead to extreme responses. Yet almost all of what we know about stress in
children comes from studies of such shattered lives. Flinn wanted to get the
bigger picture. His aim was to look at a group of regular kids, casting his net
widely across family dynamics and over generations to understand how each child
navigates life鈥檚 emotional rollercoaster.
Flinn arrived on Dominica in 1988, hoping to find a culture where he could
observe children on a daily basis. It seemed like an ideal setting. The island
is home to 700 or so people of mixed African, Carib and European descent who
occupy about two hundred houses clustered into five hamlets. 鈥淵ou could never do
this kind of study in a typical Western urban environment,鈥� says Flinn. City
children spend their time inside homes or school and families are more guarded
about their behaviour, but in Bwa Mawego life is lived in the open. 鈥淚 know
hundreds of people here,鈥� he says. 鈥淏ack home, I don鈥檛 even know my
苍别颈驳丑产辞耻谤蝉.鈥�
Flinn knew that if he could measure cortisol in the local kids he would have
some idea of their levels of stress. So he and his assistants spend their days
visiting individual households or stopping kids on the road and asking them to
rinse their mouths with water, chew on a stick of gum to produce saliva, and
then spit into a cup. And while the kids are doing this, he asks about their
home life, school, friends and health. He then sends the samples to his
colleague Barry England at the University of Michigan Hospitals in Ann Arbor,
who measures the levels of cortisol and looks for other chemicals known as
immunoglobulins that indicate stress and health. Today Flinn has over 25,000
samples from 287 children aged between 3 months and 18 years. On average, each
child has spat into a cup 96 times.
After 13 years of spending many months each year gathering biological data
and being absorbed into life on Dominica, the message from Flinn鈥檚 research is
surprising. Social ills such as the hardships of poverty, competition in school
and interactions with peers don鈥檛 stress children much. A run-in with friends,
for example, often does not raise cortisol levels at all. But what really does
affect them is family issues. Over and over again, Flinn has found that when a
family experiences some sort of trauma鈥攆ather and mother have a fight,
father leaves, or grandmother hits a kid鈥攖here is a physiological effect
on the children. Their cortisol levels rise and stay high. And a few days later
they get sick.
The message that home life has the power to rock children was recently echoed
by neuroendocrinologist Sonia Lupien of McGill University in Montreal. She
collected a sample of saliva from 217 urban schoolchildren in Canada on two
separate mornings. As expected, Lupien found that children from low
socioeconomic households had higher cortisol levels than their more affluent
peers鈥攖hree times as high. But she concludes that it is not just economics
per se that affects children, but the atmosphere at home. Her psychological
tests and interviews with 139 of the children鈥檚 mothers revealed that those with
low socioeconomic status were more likely to suffer from depression. And she
suspects that this partly accounts for their children鈥檚 stress levels.
The people of Dominica are also poor, but here what particularly affects the
kids is the comings and goings of their parents in search of work. Fathers
typically go off-island at harvest time to find jobs on farms in the US or
Canada, and mothers may work away from the village at tourist resorts. At any
time, kids might live with their biological parents, step-parents, grandparents,
or in houses with various relatives. In a typical year, perhaps a third of all
households with children change composition at least once. Analysis of the kids鈥�
saliva shows that when a mother or father leaves for a few days鈥攅ven when
the trip is expected鈥攃ortisol levels rise. Usually they return to normal
within no more than a day if the trip is short and expected, but longer absences
can result in protracted responses, with the possibility of long-term
physiological and behavioural consequences.
Of course, individual children may respond differently to the same situation.
Personality and temperament play a role in how people perceive threat, so an
experience that might seem frightening to one kid might be considered normal by
another, and this will be reflected in their cortisol levels. But by monitoring
fluctuating hormone levels throughout the day, Flinn is able to identify trends
and patterns. He has found, for example, some intriguing difference between the
responses of boys and girls. Girls between the ages of 9 and 16 are much more
affected by the absence of their mother than are boys of this age. And infant
boys鈥攂ut not girls鈥攔espond to the absence of their father with
abnormally low cortisol levels and slow growth.
One of Flinn鈥檚 most disturbing findings is that no matter how often parents
fight or leave home, the kids react just as strongly every time. Unlike adults,
who adapt psychologically to a repeated stressful situation, children always
react as if they were encountering it for the first time.
This makes evolutionary sense, as Flinn points out. Human young are dependent
on their carers to help them navigate through their crucial early years. So to
get the emotional and physical help they need, they must be highly sensitive to
the behaviour of their carers鈥攁nd that makes them particularly vulnerable
to family strife. Several studies have shown that it鈥檚 unpredictability that
really stresses kids. British researchers found, for example, that the cortisol
levels of some children are lower at school, where life is predictable and
stable, and higher at home, where they believe anything can happen.
Normally, their reaction to stress helps kids cope by directing energy to
parts of the body that need it most, but if stressful situations are not
resolved, the damage can be far-reaching. Megan Gunnar, an expert on stress in
children at the Institute of Child Development at the University of Minnesota,
points to a growing awareness that stress in childhood is a major mental and
physical health risk.
鈥淥ne reason to worry about stress in childhood is that this is the time when
we learn how to manage stress鈥攑atterns that we will carry forward into our
adult lives,鈥� says Gunnar. 鈥淎nd we don鈥檛 take the hit on some of the health
consequences until we are older. Increasingly, we are finding that many of those
adult diseases that knock us down when we are 40 or 50鈥攈eart disease, high
blood pressure and so on鈥攁re detectable in childhood, when the patterns
are set.鈥�
Gunnar and others have shown that when very young children are abused,
neglected or bond poorly with their carers, their cortisol levels are high even
in mildly stressful situations such as play, and they are unable to cope. And
several recent studies of women who had been abused as children show that they
are biologically vulnerable to depression and anxiety as adults because early
experiences permanently altered their hormonal responses, making them
hypersensitive to stress.
Flinn has uncovered two abnormal patterns of cortisol production in children
under continued stress from family trauma. Usually, kids have a constant low
background level of cortisol, which peaks when they are under stress. But some
highly stressed children have chronically high levels of cortisol. They are also
shy and anxious. Another group of children has abnormally low basal cortisol
levels interspersed with spikes of unnaturally high levels. They also show what
Flinn calls 鈥渂lunted鈥� cortisol responses鈥攖heir levels don鈥檛 rise as they
should during physical activity. Just as worrying, they are less sociable and
more aggressive than kids with normal profiles.
Some of these kids have been stressed since they were conceived, and they
probably missed certain sensitive periods for obtaining normal cortisol
profiles, though how exactly the response develops is still unknown. These
children also have weakened immune responses, fall ill more frequently, are
easily fatigued and don鈥檛 sleep well. Looking at his record of children who are
now adults, Flinn is finding that some of them seem to be permanently affected
by stressful events that happened while they were in the womb, in infancy or
during early childhood.
But despite the comings and goings of their parents, Flinn suspects that the
children of Bwa Mawego may be less susceptible to family stress than children in
the West. In the Caribbean, and most other less industrialised regions, families
are bigger, more tightly connected, and more involved in the lives of their
children than the typical nuclear family. So when it comes to dealing with
stress, these poor kids may be richer than children in affluent nations.
鈥淲e have a ton to learn about kin networks and family,鈥� says Flinn. 鈥淲e take
our system for granted鈥擿that鈥檚 how it is so that鈥檚 how it should be鈥�. It鈥檚
not informed by cross-cultural information, not informed by evolutionary theory.
Not informed by anything.鈥�