[Paleopsych] NS: Teenagers special
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Teenagers special: The original rebels
* 05 March 2005
* Lynn Dicks
* Lynn Dicks is a writer based near Cambridge, UK
EAST Africa, one-and-a-half million years ago: a group of women sit
with their young children. They are heavy-browed with small skulls -
not quite human, but almost. Some are checking their children for
ticks, others teaching them how to dig tubers out of the ground. Not
far off, a gaggle of teenage girls lounge under a tree, sniggering and
pointing at some young men who are staging fights nearby. The older
women beckon: "Come and help us dig out this root - it will make a
great meal," they seem to say. But the girls reply with grunts and
slouch off, sulkily.
Could this really have happened? Our immediate ancestors, Homo
erectus, may not have had large brains, high culture or even language,
but could they have boasted the original teenage rebels? That question
has been hotly contested in the past few years, with some
anthropologists claiming to have found evidence of an adolescent phase
in fossil hominids, and others seeing signs of a more ape-like pattern
of development, with no adolescent growth spurt at all. This is not
merely an academic debate. Humans today are the only animals on Earth
to have a teenage phase, yet we have very little idea why.
Establishing exactly when adolescence first evolved and finding out
what sorts of changes in our bodies and lifestyles it was associated
with could help us understand its purpose.
We humans take twice as long to grow up as our nearest relatives, the
great apes. Instead of developing gradually from birth to adulthood,
our growth rate slows dramatically over the first three years of life,
and we grow just a few centimetres a year for the next eight years or
so. Then suddenly, at puberty, growth accelerates again to as much as
12 centimetres a year. Over the following three years adolescents grow
an astonishing 15 per cent in both height and width. Though the
teenage years are most commonly defined by raging hormones, the
development of secondary sexual characteristics and attitude problems,
what is unique in humans is this sudden and rapid increase in body
size following a long period of very slow growth. No other primate has
a skeletal growth spurt like this so late in life. Why do we?
Until recently, the dominant explanation was that physical growth is
delayed by our need to grow large brains and to learn all the complex
behaviour patterns associated with humanity - speaking, social
interaction and so on. While such behaviour is still developing,
humans cannot easily fend for themselves, so it is best to stay small
and look youthful. That way you do not eat too much, and your parents
and other members of the social group are motivated to continue
looking after you. What's more, studies of mammals show a strong
relationship between brain size and the rate of development, with
larger-brained animals taking longer to reach adulthood. Humans are at
the far end of this spectrum.
If this theory is correct, the earliest hominids, Australopithecus,
with their ape-sized brains, should have grown up quickly, with no
adolescent phase. So should H. erectus, whose brain, though twice the
size of that of Australopithecus at around 850 cubic centimetres, was
still relatively small. The great leap in brain capacity comes only
with the evolution of our own species and Neanderthals, starting
almost 200,000 years ago. Brains expanded to around 1350 cm3 in our
direct ancestors and 1600 cm3 in Neanderthals. So if the development
of large brains accounts for the teenage growth spurt, the origin of
adolescence should be here. The trouble is, some of the fossil
evidence seems to tell a different story.
The human fossil record is extremely sparse, and the number of
fossilised children minuscule. Nevertheless in the past few years
anthropologists have begun to look at what can be learned of the lives
of our ancestors from these youngsters. One of the most studied is the
famous Turkana boy, an almost complete skeleton of H. erectus from 1.6
million years ago found in Kenya in 1984. The surprise discovery is
that there are some indications that he was a young teenager when he
Accurately assessing how old someone is from their skeleton is a
tricky business. Even with a modern human, you can only make a rough
estimate based on the developmental stage of teeth and bones and the
skeleton's general size. For example, most people gain their first
permanent set of molars at age 6 and the second at 12, but the
variation is huge. Certain other features of the skull also develop
chronologically, although the changes that occur in humans are not
necessarily found in other hominids. In the middle teenage years,
after the adolescent growth spurt, the long bones of the limbs cease
to grow because the areas of cartilage at their ends, where growth has
been taking place, turn into rigid bone. This change can easily be
seen on an X-ray.
You need as many of these developmental markers as possible to get an
estimate of age. The Turkana boy did not have his adult canines, which
normally erupt before the second set of molars, so his teeth make him
10 or 11 years old. The features of his skeleton put him at 13, but he
was as tall as a modern 15-year-old. "By human standards, he was very
tall for his dental age," says anthropologist Holly Smith from the
University of Michigan at Ann Arbor. But you get a much more
consistent picture if you look at Turkana boy in the context of
chimpanzee patterns of growth and development. Then, his dental age,
bone age and height all agree he was 7 or 8 years old. To Smith, this
implies that the growth of H. erectus was primitive and the adolescent
growth spurt had not yet evolved.
Susan Anton of New York University disagrees. She points to research
by Margaret Clegg, now at the University of Southampton in the UK,
showing that even in modern humans the various age markers often do
not match up. Clegg studied a collection of 18th and 19th-century
skeletons of known ages from a churchyard in east London. When she
tried to age the skeletons blind, she found the disparity between
skeletal and dental age was often as great as that of the Turkana boy.
One 10-year-old boy, for example, had a dental age of 9, the skeleton
of a 6-year-old but was tall enough to be 11. "The Turkana kid still
has a rounded skull, and needs a lot of growth to reach the adult
shape," Anton adds. Like apes, the face and skull of H. erectus
changed shape significantly between youth and adulthood. Anton thinks
that H. erectus had already developed modern human patterns of growth,
with a late, if not quite so extreme, adolescent spurt. She believes
Turkana boy was just about to enter it.
If she's right, and small-brained H. erectus went through a teenage
phase, that scuppers the orthodox idea linking late growth with
development of a large brain. Anthropologist Steven Leigh from the
University of Illinois at Urbana-Champaign is among those who are
happy to move on. He believes the idea of adolescence as catch-up
growth is naive; it does not explain why the growth rate increases so
dramatically. He points out that many primates have growth spurts in
particular body regions that are associated with reaching maturity,
and this makes sense because by timing the short but crucial spells of
maturation to coincide with the seasons when food is plentiful, they
minimise the risk of being without adequate food supplies while
growing. What makes humans unique is that the whole skeleton is
involved. For Leigh, this is the key. Coordinated widespread growth,
he says, is about reaching the right proportions to walk long
distances efficiently. "It's an adaptation for bipedalism," he says.
According to Leigh's theory, adolescence evolved as an integral part
of efficient upright locomotion, as well as to accommodate more
complex brains. Fossil evidence suggests that our ancestors took their
first steps on two legs as long as six million years ago. If
proficient walking was important for survival, perhaps the teenage
growth spurt has very ancient origins. Leigh will not be drawn,
arguing that there are too few remains of young hominids to draw
definite conclusions. While many anthropologists will consider Leigh's
theory a step too far, he is not the only one with new ideas about the
evolution of teenagers.
A very different theory has been put forward by Barry Bogin from the
University of Michigan-Dearborn. He believes adolescence in our
species is precisely timed to improve the success of the first
reproductive effort. In girls, notes Bogin, full adult shape and
features are achieved several years before they reach full fertility
at around the age of 18. "The time between looking fertile and being
fertile allows women to practise social, sexual and cultural
activities associated with adulthood, with a low risk of having their
own children," says Bogin. When they finally do have children, they
are better prepared to look after them. "As a result, firstborns of
human mothers die much less often than firstborns of any other
In boys, you see the opposite. They start producing viable sperm at 13
or 14 years of age, when they still look like boys. The final increase
in muscle size that turns them into men does not happen until 17 or
18. In the interim boys, who feel like men, can practise male
rivalries without being a threat to adult men or an attractive option
to adult women. When boys do become sexually active, they have
practised and are more likely to be successful without getting hurt.
Bogin's theory makes totally different predictions to Leigh's. If the
timing of adolescence is related to uniquely human cultural practices,
our species should be the first and only one to have a teenage phase.
"H. erectus definitely did not have an adolescence," he asserts. Such
strong and opposing views make it all the more necessary to scour the
fossil record for clues.
One approach, which has produced a surprising result, relies on the
minute analysis of tooth growth. Every nine days or so the growing
teeth of both apes and humans acquire ridges on their enamel surface.
These perikymata are like rings in a tree trunk: the number of them
tells you how long the crown of a tooth took to form. Across mammals,
the speed of tooth development is closely related to how fast the
brain grows, the age you mature and the age you die. Teeth are good
indicators of life history because their growth is less related to the
environment and nutrition than is the growth of the skeleton. Slower
tooth growth is an indication that the whole of life history was
slowing down, including age at maturity.
Back in the 1980s Christopher Dean, an anatomist at University College
London, was the first to measure tooth growth in fossils using
perikymata. He found that australopithecines dating from between 3 and
4 million years ago had tooth crowns that formed quickly. Like apes,
their first molars erupted at 4 years old and the full set of teeth
were in place by 12. Over the years, Dean's team has collected enough
teeth to show that H. erectus also had faster tooth growth than modern
man, but not so fast as earlier hominids. "Things had moved on a bit,"
he says. "They had their full set of teeth by about 15." Modern humans
reach this stage by about age 20. The change in H. erectus seems to
imply that the growth pattern of modern humans was beginning to
develop, with an extended childhood and possibly an adolescent growth
spurt. Dean cautions, though, that the link between dental and
skeletal development in ancestral hominids remains uncertain.
These findings could equally support Leigh's or Bogin's theories. A
more decisive piece of evidence came last year, when researchers in
France and Spain published their findings from an analysis of
Neanderthal teeth. A previous study of a remarkably well-preserved
skeleton of a Neanderthal youth, known as Le Moustier 1, from
south-west France had suggested that, with a dental age of 15 and the
frame of an 11-year-old, the kid was about to undergo an adolescent
growth spurt. But the analysis of his perikymata reveals quite a
different picture. Rather than continuing the trend towards slower
development seen in H. erectus, Neanderthals had returned to much
faster tooth growth (Nature, vol 428, p 936) and hence, possibly, a
Does this mean they didn't have an adolescence? Lead researcher
Fernando Ramirez-Rozzi, of the French National Centre for Scientific
Research (CNRS) in Paris thinks Neanderthals died young - about 25
years oldprimarily because of the cold, harsh conditions they had to
endure in glacial Europe. Under pressure from this high mortality,
they evolved to grow up quicker than their immediate ancestors. "They
probably reached maturity at about 15," he says, "but it could have
been even younger." They would have matured too fast to accommodate an
adolescent burst of growth. He points to research showing that
populations of Atlantic cod have genetically changed to mature more
quickly under the intense fishing pressure of the 1980s. Others
contest Ramirez-Rozzi's position. "You can't assume, just because
Neanderthals' teeth grew faster, that their entire body developed
faster," says Jennifer Thompson of the University of Nevada, Las
Vegas, one of the researchers involved in the Le Moustier 1 study.
Controversy rages, but these latest findings at least highlight one
aspect of adolescence that most scientists can agree on. Whatever the
immediate purpose of the late growth spurt, it was made possible by an
increase in life expectancy. And that being so, one way to work out
when the first teenagers originated is to look at the lifespan of a
species. This is exactly what Rachel Caspari of the University of
Michigan at Ann Arbor has been doing. Her most recent study, published
in July 2004, shows an astonishing increase in longevity that
separates modern Homo sapiens from all other hominids, including
Neanderthals (Proceedings of the National Academy of Sciences, vol
101, p 10895). She categorised adult fossils as old or young by
assessing whether they had as much wear on their last molar, or wisdom
tooth, as on other molars. "In modern humans we see a massive increase
in the number of people surviving to be grandparents," she says. The
watershed comes as recently as 30,000 years ago.
On this evidence, Neanderthals and H. erectus probably had to reach
adulthood quickly, without delaying for an adolescent growth spurt. So
it looks as though Bogin is correct we are the original teenagers.
Whether he is right about the purpose of adolescence is another
matter. He admits we will never know for sure. "Fossils will never
give us growth curves," he says, "and we should not expect our
ancestors to grow like we do."
Printed on Tue Mar 08 20:56:28 GMT 2005
Instant Expert: Teenagers
The teenager is a uniquely human phenomenon.
Adolescents are known to be moody, insecure, argumentative,
angst-ridden, impulsive, impressionable, reckless and
rebellious. Teenagers are also characterised by odd sleeping
patterns, awkward growth spurts, bullying, acne and
slobbish behaviour. So what could be the possible benefit of the
Most other animals - apes and human ancestors included - skip that
stage altogether, developing rapidly from infancy to full adulthood.
Humans, in contrast, have a very puzzling four-year gap between sexual
maturity and prime reproductive age. Anthropologists disagree on when
the teenage phase first evolved, but pinpointing that date could
help define its purpose.
There are a variety of current explanations for the existence of
teenagers. Some believe that we need longer for our large brains
to develop. Other explanations suggest that a teenage phase allows
kids to learn about complex social behaviour and other
difficult skills, or that it is even required to develop coordinated
bipedal bodies adapted to travelling long distances.
Scientists once thought that the brain's internal structure was fixed
at the end of childhood, and teenage behaviour was blamed on raging
hormones and a lack of experience. Then researchers discovered that
the brain undergoes significant changes during adolescence.
According to many recent studies, teen brains really are unique (see
interactive graphic). Though many brain areas mature during childhood,
others mature later - such as the frontal and parietal lobes,
responsible for planning and self-control.
Other studies have shown that teens fail to see the consequences
of their actions, and that sudden increases in nerve connectivity
in teen brains may make it difficult for teenagers to read social
situations and other people's emotions.
One study in 2004 showed that teens have less brain activity in areas
responsible for motivation and risk assessment, perhaps explaining
why they are more likely to take part in risky activities such as
abusing drugs and alcohol, develop a hard-to-kick smoking
habit or indulge in under-age sex.
Teenage pregnancies and rising rates of sexually transmitted diseases
among teens are big problems - especially because today's teen
generation is the biggest the world has seen: a 2003 UN report
revealed that 1 in 5 people were between 10 and 19, a total of 1.2
But not everyone agrees on the best way to tackle the problem. Some
believe that comprehensive sex education is the key, while others
argue for abstinence only education courses.
John Pickrell, 3 March 2004
Adolescence unique to modern humans
* 12:25 06 December 2001
* Claire Ainsworth
The uniquely human habit of taking 18 years or so to mature is a
recent development in our evolutionary history. Growth patterns of
fossil teeth have shown that a prolonged growing-up period evolved
long after our ancestors started walking upright and making tools.
Our great ape relatives, the chimpanzees and gorillas, take about 11
years to reach adulthood. Scientists speculate that delaying this
process allows children to absorb our complex languages, culture and
What's more, we need extra time for our large brains to grow - they
are half as big again as those of the earliest humans, Homo erectus,
who appeared some 2 million years ago.
Christopher Dean of University College London and his team studied
teeth from H. erectus, our Australopithecus human-like ancestors such
as the famous "Lucy", and Proconsul nyanzae, an ape ancestor. The rate
of tooth development is tightly linked to how long it takes to become
Teeth grow by adding on enamel in small increments, leaving striations
rather like shell ridges or tree rings. By studying these rings, the
team could work out how fast the teeth grew.
They found that H. erectus's teeth grew at almost the same rate as
those of both modern and fossil apes and Australopithecus - suggesting
a shorter growing-up period.
This was surprising, as H. erectus walked upright, was about the same
size as us and made simple tools - all traits associated with being
human, says Dean. But it fits with the fact that H. erectus's brain
was much smaller.
By comparing the growth rate of the back and front teeth, the team
estimated that H. erectus children produced their first permanent
molars at around 4.5 years, and their second at 7.5 years. This
compares with 6 and 12 years in modern humans and 3 and 5 years for
modern apes, indicating that H. erectus was starting down the road of
modern dental development.
Journal reference: Nature (vol 414, p 628)
* Old bones may be earliest human ancestor
* 11 July 2001
* A 3.5 million year-old skull unearthed in Kenya may force a
re-examination of the evolution of modern humans
* 21 March 2001
* The most ancient human-like remains are unearthed in Kenya
* 5 December 2000
* Human Origins
* Evolutionary Anatomy Unit, UCL
Teen angst rooted in busy brain
* 19:00 16 October 2002
* Duncan Graham-Rowe
Scientists believe they have found a cause of adolescent angst. Nerve
activity in the teenaged brain is so intense that they find it hard to
process basic information, researchers say, rendering the teenagers
emotionally and socially inept.
Robert McGivern and his team of neuroscientists at San Diego State
University, US, found that as children enter puberty, their ability to
quickly recognise other people's emotions plummets. What is more, this
ability does not return to normal until they are around 18 years old.
McGivern reckons this goes some way towards explaining why teenagers
tend to find life so unfair, because they cannot read social
situations as efficiently as others.
Previous studies have shown that puberty is marked by sudden increases
in the connectivity of nerves in parts of the brain. In particular,
there is a lot of nerve activity in the prefrontal cortex. "This plays
an important role in the assessment of social relationships, as well
as planning and control of our social behaviour," says McGivern.
He and his team devised a study specifically to see whether the
prefrontal cortex's ability to function altered with age. Nearly 300
people aged between 10 and 22 were shown images containing faces or
words, or a combination of the two. The researchers asked them to
describe the emotion expressed, such as angry, happy, sad or neutral.
The team found the speed at which people could identify emotions
dropped by up to 20 per cent at the age of 11. Reaction time gradually
improved for each subsequent year, but only returned to normal at 18.
During adolescence, social interactions become the dominant influence
on our behaviour, says McGivern. But at just the time teenagers are
being exposed to a greater variety of social situations, their brains
are going through a temporary "remodelling", he says. As a result,
they can find emotional situations more confusing, leading to the
petulant, huffy behaviour for which adolescents are notorious.
But this may only be true for Western cultures. Adolescents often play
a less significant role in these societies, and many have priorities
very different from their parents', leading to antagonism between
them. This creates more opportunity for confusion. "One would expect
to observe a great deal more emotional turmoil in such kids," he says.
Journal reference: Brain and Cognition (vol 50, p 173)
* Brain expression response linked to personality
* 20 June 2002
* Angry outbursts linked to brain dysfunction
* 27 May 2002
* Physical changes may be responsible for 'feeling' emotions
* 19 September 2000
* Psychology, San Diego State University
* Early Experience and Brain Development research
* Brain and Cognition
Movie smoking encourages kids to light up
* 13:14 10 June 2003
* Shaoni Bhattacharya
Watching movie stars light up on screen is the biggest single factor
in influencing teenagers to smoke, suggests a new US study.
Adolescents who had never smoked were almost three times more likely
to then take up the habit if they had watched films packed with
smoking scenes, compared to their peers who had seen films with the
least amount of on-screen smoking.
"There was a tremendous impact," says research leader Madeline Dalton,
at Dartmouth Medical School in Hanover, New Hampshire. "Movies were
the strongest predictor of who would go on to smoke - stronger than
peers smoking, family smoking, or the personality of the child."
"We know from past studies it's very rare for smoking to be portrayed
in a negative light. Smokers [in movies] tend to be tough guys or
sexy, rebellious women - which appeal to adolescents," she told New
Dalton's colleague Michael Beach adds: "Our data indicate that 52 per
cent of smoking initiation among adolescents in this study can be
attributed to movie smoking exposure."
"The effect is stronger than the effect of traditional cigarette
advertising and promotion, which accounts for 'only' 34 per cent of
new experimentation," notes Stanton Glantz, at the Center for Tobacco
Control Research and Education, in an editorial accompanying the study
published online in The Lancet.
The study began by recruiting over 2600 US schoolchildren aged 10 to
14 who had never smoked. Each child was then asked if they had watched
any of 50 movies randomly selected from 601 box office hits released
between 1988 and 1999. The number of occurrences of smoking in each
film was recorded by trained coders.
When followed up one to two years later, 10 per cent of the children
had tried smoking. Those in the top quarter of exposure to movie
smoking were 2.7 times more likely to have tried a cigarette than
those in the lowest quarter of exposure. This effect was independent
of other factors that might influence the child's smoking behaviour,
such as friends or family smoking.
"It's more evidence that movies have a strong impact on adolescents,"
says Dalton. "Previous studies have suggested that smoking in movies
influences adolescent smoking behaviour, but this is the first study
to show that viewing smoking in movies predicts who will start smoking
in the future."
Dalton, an expert in cancer risk behaviour in children, says a
previous study by the team showed that children were more likely to
smoke if their favourite actor smoked.
Movies which depict smoking should be given an adult rating or "R
rating" in the US, suggests Glantz, which would mean that children
under 17 could not see the film without a parent. "An R rating for
smoking in movies would prevent about 330 adolescents [in the US] from
starting to smoke and ultimately extend 170 lives every day," he
Journal reference: The Lancet (vol 361, no 9373, early online
* Controversy over passive smoking danger
* 16 May 2003
* Violent song lyrics increase aggression
* 4 May 2003
* Public smoking ban slashes heart attacks
* 1 April 2003
* Dartmouth Medical School
* Center for Tobacco Control Research and Education
* Action on Smoking and Health, UK
* The Lancet
Bedtimes could pinpoint the end of adolescence
* 08 January 2005
* Andy Coghlan
AT WHAT point does adolescence end? Perhaps at the point when we start
to go to bed progressively earlier rather than later and later.
The end of puberty, or sexual maturation, is well defined. It is the
point when bones stop growing, at around age 16 for girls and 17.5 for
boys. But for adolescence, the transition from childhood to adulthood,
there is no clear endpoint.
"I don't know of any markers for it," says Till Roenneberg of the
Centre for Chronobiology at the University of Munich in Germany.
"Everyone talks about it but no one knows when adolescence ends. It is
seen as a mixed bag of physical, psychological and sociological
His suggestion is based on a study of the sleep habits of 25,000
individuals of all ages in Switzerland and Germany. The study looked
at when people go to sleep during vacations, when they are free to
sleep any time. It reveals a distinct peak of night-owlishness at
around age 20. Women reach this peak at 19.5 years old on average, and
men at 20.9 years. After that, individuals gradually return to earlier
and earlier sleeping patterns, until things go haywire in old age.
Roenneberg, whose findings appear in Current Biology (vol 14, p
R1038), thinks that the peak in lateness is the first plausible
biological marker for the end of adolescence.
The study confirms that 20-year-olds sleep any time except in the
evening, says Malcolm von Schantz of the Surrey Sleep Research Centre
at the University of Surrey, UK. "Don't I know it - they're in my
The suggestion that this peak in sleep habits marks the end of
adolescence is intriguing, he says, but more research will be needed
to prove these behavioural changes are a result of physiological
changes, rather than lifestyle. "A lot of things happen to you around
this age," von Schantz points out.
If it is a physiological effect, forcing teenagers to get to school
for, say, 8 am, could be a mistake, Roenneberg says. They probably
take nothing in for the first two lessons because they are still in
biological "sleep time", and end up with a horrendous sleep deficit by
Letters: Growth spurts
* 01 May 1993
* TIM BROMAGE
Barry Bogin has written a marvellous explanation about why we go
through the adolescent growth spurt ('Why must I be a teenager at
all?', 6 March). We can equally marvel at another spurt not often
mentioned by biologists and anthropologists, namely the mid-childhood
spurt occurring between ages six and eight. It varies in magnitude and
shows itself as a mere blip on Bogin's growth rate curve, but it has a
very interesting history.
First, it is an opportunity for body growth to get its due after so
many years of devoting unequal resources to growing a large brain.
Every parent will attest to the struggle of dressing children and the
seeming incoherence of a clothing industry that makes pullovers to fit
little bodies that have to pull them over a brain which is nearly 95
per cent of its adult size at 6 years of age.
Second, this spurt is related to the adolescent spurt in developed
nations. Puberty is not only the time of accelerated growth, it marks
the beginning of the end of growth too. In order for adolescents to
reach the normal height for their population they must be so far along
by the time puberty hits them. Thus for children with relatively short
pre-pubertal growth periods, an extra push is needed early on (the
mid-childhood spurt) to get them to their right preadolescent height
before the pubertal growth spurt.
Children of populations with puberty closer to 16 years of age, such
as those of some underdeveloped nations, do not experience the
mid-childhood spurt because they have more prepubertal time to grow
Tim Bromage City University of New York
Spotty genes - News
* 21 December 2002
HERE'S something else grumpy teenagers can blame their parents for -
In a study of identical and non-identical twins, Veronique Bataille of
St Thomas' Hospital in London and her team have shown that acne is 80
per cent genetic. Environmental factors, such as eating the wrong
foods or wearing greasy make-up, are relatively unimportant. They will
report their results in The Journal of Investigative Dermatology.
Finding the genes involved could clarify what triggers acne, and
possibly lead to cheaper, more effective treatments. Worldwide,
prescription drugs for acne cost about $4 billion each year.
Fine young slobs?: Kids who spend hours hunched in front of television or
computer screens may look as healthy as their active brothers and sisters. But
are they storing up trouble? Helen Saul reports
* 23 April 1994
* HELEN SAUL
A teenage computer games addict sits engrossed in front of a screen,
hardly moving for hours on end. A parent, worried about strangers and
excessive traffic on the roads, insists on driving the children to
school. Increasing pressure on children to perform well in academic
subjects relegates physical exercise to the bottom of the priority
list at school.
It all seems like a recipe for weak bodies and illness. But are
today's children and adolescents really as sedentary and unfit as
popular images would have us believe? And if they are, what should be
done to persuade them to be more active?
On the face of it, the facts are hardly encouraging. The Broadcasting
Audience Research Board's figures for 1993 show that in Britain
children between the ages of four and 15 watch an average of between
two and three hours of TV each day. The National Curriculum for
schools allocates an average of only one hour a week for physical
education, and in practice less than 10 per cent of this time is spent
exercising. Moreover, as many as one in three children do less than
the equivalent of a 10-minute walk each day, according to Neil
Armstrong and his research team at the University of Exeter.
Yet just as politicians in Britain want to see a return to
competitive, team-oriented sport in schools, experts are stressing the
need for exercise regimes geared for individuals which require a
minimum of formal training. Researchers, meanwhile, are busy
questioning the underlying assumptions that today's young couch
potatoes are physically weaker than their supposedly more active
For children, it may be a mistake to equate physical inactivity with
low physical fitness, says Armstrong. He and his colleagues have spent
the past nine years monitoring the links between exercise and fitness
in some 700 children, aged between 9 and 16. Part of this endeavour
has involved measuring how the hearts and lungs of some of these
children perform during strenuous exercise. The result is surprising:
the hearts and lungs of inactive children perform just as well as
those of habitually active children - and just as well as those of
children of previous generations. 'There's no scientific evidence to
show that children are less fit than they used to be,' says Armstrong
So childhood laziness is no bad thing? Not quite. Physical fitness is
clearly influenced by a myriad factors other than exercise, including
genetics and diet. It also means different things to different people:
a long-distance runner and a weightlifter are both physically fit, but
in different ways and because of different exercise regimes. The way
hearts and lungs respond to aerobic activity is certainly one measure
of physical fitness. But the strength and stamina of skeletal muscles
may be just as important. Exactly how important is unclear, for few
long-term studies of the effects of exercise on children have
attempted to examine all these factors.
What's more, even if childhood laziness does not erode physical
fitness immediately, children who fail to form the 'exercise habit'
are likely to regret it later in life. Studies of adults show that a
sedentary lifestyle is as likely to cause heart disease as high blood
pressure, smoking or high cholesterol levels. People who fail to take
physical exercise are thought to be twice as likely contracting
coronary heart disease. They also run higher-than-average risks of
developing breast cancer, diabetes and osteoporosis. In the US alone,
physical inactivity is estimated to cause 250 000 deaths a year.
Adults who don't exercise also perform badly on tests of heart and
lung fitness. Put them on a treadmill or cycle ergometer and measure
their aerobic fitness by monitoring oxygen uptake, heart rate and
carbon dioxide exhaled and you will find that their lungs can't take
up as much oxygen as their active counterparts. Armstrong and his
colleagues wanted to find out if the same was true for children. So
they tested 420 children, measuring their oxygen uptake as they
exercised on treadmills or cycle ergometers. The tests supported the
results of similar tests carried out some fifty years ago in Chicago.
The study also shows that, in contrast to adults, active children
perform no better in tests of aerobic fitness than children who don't.
Studies in other parts of the world show a similar trend, says
Steven Blair, director of epidemiology at the Cooper Institute for
Aerobics Research in Dallas, believes that one in five children in the
US is physically unfit. But he agrees with Armstrong that the limited
data available suggest there has been no major change in physical
fitness among young Americans over the past few decades. 'It's very
popular in the States for people to dash about saying 'It's terrible.
It's getting worse. More and more children are getting more and more
unfit.' But how do they know that?'
The links between exercise and fitness in children have always been
uncertain. It is doubtful that studies based on any one measure of
fitness can resolve the main questions. This is certainly true of
tests based on oxygen uptake. For one thing, oxygen uptake varies from
child to child because of genetic differences that influence muscle
growth, strength of the heart and so on. It could be that peak oxygen
uptake is too crude a measure to pick up a slight deterioration in
lung and heart fitness. Moreover, even if the hearts and lungs of
children do not weaken with lack of exercise, that does not
necessarily mean that inactive children are physically fit in a
Yet there are other signs that exercise may not be as important to the
fitness of children as it is to adults. In adults, for instance, there
is a clear link between physical exercise and blood levels of high
density lipoprotein, or 'good' cholesterol. This substance acts to
prevent the clogging up of arteries that is caused by high levels of
'bad' cholesterol, or low-density lipo-protein. The more exercise
people take, the higher their HDL levels and the more favourable the
ratio between HDL and LDL, which remains constant. But there is no
evidence that the same is true in children.
This, however, may be no reason to celebrate. If children can't feel
the physical benefits of exercise, won't it prove harder to persuade
them of its value? 'There's no way you can convince 15-year-olds that
by being more active today, they'll be less likely to get coronary
heart disease when they're 50,' says Oded Bar-Or, professor of
exercise sciences at McMaster University in Hamilton, Ontario.
The problem is compounded by the fact that inactivity often goes hand
in hand with eating too many fatty or sugary foods. More than two in
five children in Britain have total cholesterol levels (combined LDL
and HDL levels) above the American Health Foundation's safety limit.
This is calculated from the cholesterol level in adults that is known
to increase the risk of heart disease, taking into account the fact
that cholesterol levels increase gradually with age.
All the signs are that most children are not active enough to form the
kind of exercise habit that could protect them from ill health later
in life. As part of the Exeter study, for instance, researchers used
portable heart monitors to capture the heart rates of some 266
children from 9.00 am until 9.00 pm. The portable devices used a small
transmitter on the chest to send the heart rate data to a receiver on
a wrist band. Previously, the researchers had established that, on
average, the heart rate of children walking on a treadmill at 6
kilometres per hour is 140 beats per minute. From this, it was
possible to calculate that a third of the boys and half of the girls
do not even do the equivalent of a brisk 10-minute walk a day.
But not everyone is pessimistic. Drawing on data reported in 43
different epidemiological studies, Blair concludes that children and
adults alike can reduce the risk of heart disease later in life by
burning off just three kilocalories per kilogram of body weight per
day. For a child weighing 40 kilograms, this amounts to 120 kcal a day
- equivalent to the energy contained in an average biscuit. In a study
of 1800 boys and girls aged between 10 and 18 years, Blair found that
the most met this standard.
That said, most researchers see no harm in encouraging all children to
be more active. 'It's all pluses,' says Armstrong. The biggest plus of
all is that having developed an exercise habit, a child may be more
likely to retain it throughout adulthood. But do active children
necessarily become active adults?
What little evidence there is suggests the answer is yes. In 1990,
researchers in Britain questioned more than 4000 adults on their
behaviour, attitudes and beliefs about activity and fitness as part of
the Allied Dunbar National Fitness Survey. A quarter of those who said
that they were active as teenagers also said that they were active as
adults. Only two per cent of those who said that they were inactive at
the younger age said that they were active as adults.
Ken Fox, who lectures in physical exercise at the University of
Exeter, believes that what motivates people to do exercise shifts over
time. Overemphasising sports and team games is one reason why
adolescents drop out, he says. This is particularly true of girls
whose participation in exercise during adolescence falls off more
dramatically than that of boys. Groups of girls may not value
formalised activities such as competitive sport, he says. 'But
aerobics and dance may be more socially acceptable to some groups of
girls. And if they value these activities, they're more likely to make
the decision to take part.'
Bill Kohl, director of the division of childhood and adolescent
medicine at the Cooper Institute of Aerobic research, says: 'Fitness
and activity is for all kids, not just for those who are athletically
gifted. It's not necessary to run a marathon or be Sebastian Coe to
get health benefits from physical activity.
Helen Saul is a freelance writer specialising in health and medicine.
Teenagers special: Brain storm
* 05 March 2005
The prefrontal cortex is the home of "executive" functioning,
high-level cognitive processes that, among other things, allow us to
develop detailed plans, execute them, and block irrelevant actions.
This area undergoes a bulking up between the ages of 10 and 12,
followed by a dramatic decline in size that continues into the early
20s. This is probably due to a burst of neuronal growth followed by a
"pruning" stage in which pathways that are not needed are lost.
If the adolescent's brain is still bedding down its executive
functions, this might help explain why teenagers can sometimes seem so
disorganised and irrational.
Right ventral striatum
This area of the brain is thought to be involved in motivating
A study last year showed that teenagers had less activity than adults
in this part of the brain during a reward-based gambling game. The
researchers speculate that teens may be driven to risky but
potentially high-reward behaviours such as shoplifting and drug-taking
because this area is underactive.
The pineal gland produces the hormone melatonin, levels of which rise
in the evening, signalling to the body that it is time to sleep.
During adolescence melatonin peaks later in the day than in children
or adults. This could be why teenagers tend to be so fond of late
nights and morning lie-ins.
These are nerve fibres linking the left and right sides of the brain.
The parts thought to be involved in language learning undergo high
growth rates before and during puberty, but this growth then slows.
This might help explain why the ability to learn new languages
declines rapidly after the age of 12.
This part of the brain continues to grow until late adolescence. It
governs posture and movement, helping to maintain balance and ensure
that movements are smooth and directed. It influences other regions of
the brain responsible for motor activity and may also be involved in
language and other cognitive functions.
Teenagers special: Going all the way
* 05 March 2005
* Alison George
LYNSEY TULLIN was 15 when she became pregnant. The only contraception
she and her boyfriend had used was wishful thinking: "I didn't think
it would happen to me," she says. Tullin, who lives in Oldham in
northern England, decided to keep the baby, now aged 3, although as a
consequence her father has disowned her.
Tullin is not alone. In the UK nearly 3 per cent of females aged 15 to
19 became mothers in 2002, many of them unintentionally. And unplanned
pregnancies are not the only consequence of teenage sex - rates of
sexually transmitted diseases (STDs) are also rocketing in British
adolescents, both male and female.
The numerous and complex societal trends behind these statistics have
been endlessly debated without any easy solutions emerging. Policy
makers tend to focus on the direct approach, targeting young
adolescents in the classroom. In many western schools teenagers get
sex education classes giving explicit information about sex and
contraception. But recently there has been a resurgence of some
old-fashioned advice: just say no. The so-called abstinence movement
urges teens to take virginity pledges and cites condoms only to stress
their failure rate. It is sweeping the US, and is now being exported
to countries such as the UK and Australia.
Confusingly, both sides claim their strategy is the one that leads to
fewest pregnancies and STD cases. But a close look at the research
evidence should give both sides pause for thought. It is a morally
charged debate in which each camp holds entrenched views, and opinions
seem to be based less on facts than on ideology. "It's a field fraught
with subjective views," says Douglas Kirby, a sex education researcher
for the public-health consultancy ETR Associates in Scotts Valley,
For most of history, pregnancy in adolescence has been regarded not as
a problem but as something that is normal, so long as it happens
within marriage. Today some may still feel there is nothing unnatural
about older adolescents in particular becoming parents. But in
industrialised countries where extended education and careers for
women are becoming the norm, parenthood can be a distinct
disadvantage. Teenage mums are more likely to drop out of education,
to be unemployed and to have depression. Their children run a bigger
risk of being neglected or abused, growing up without a father,
failing at school and abusing drugs.
The US has by far the highest number of teenage pregnancies and births
in the west; 4.3 per cent of females aged between 15 and 19 gave birth
there in 2002. This is significantly higher than the rate in the UK
(2.8 per cent), which itself has the highest rate in western Europe
Another alarming statistic is the number of teenagers catching STDs.
In the UK the incidences of chlamydia, syphilis and gonorrhoea in
under-20s have all more than doubled since 1995. The biggest rise has
been in chlamydia infections in females under 20; cases have more than
tripled, up to 18,674 in 2003. Chlamydia often causes no symptoms for
many years but it can lead to infertility in women and painful
inflammation of the testicles in men.
No surprise, then, that teenage sex and pregnancy has become a
political issue. The UK government has set a target to halve the
country's teen pregnancy rate by 2010, and the US government has set
similar goals. But achieving these targets will not be easy. In an age
when adolescence has never been so sexualised, in most western
countries people often begin to have sex in their mid to late teens;
by the age of 17, between 50 and 60 per cent are no longer virgins.
Since the 1960s, UK schools have increasingly accepted that many
teenagers will end up having sex and have focused efforts on trying to
minimise any ensuing harm. Sex education typically involves describing
the mechanics of sex and explaining how various contraceptives work,
with particular emphasis on condoms because of the protection they
provide from many STDs.
The sex education strategy gained further support in the early 1990s
when policy makers looked to the Netherlands. There, teenage birth
rates have plummeted since the 1970s and are now among the lowest in
Europe, with about 0.8 per cent of females aged between 15 and 19
giving birth in 2002. No one knows why for sure, as Dutch culture
differs from that of the UK and America in several ways. But it is
generally attributed to frank sex education in schools and open
attitudes to sex. Dutch teenagers, says Roger Ingham, director of the
Centre for Sexual Health Research at the University of
Southampton,"have less casual sex and are older when they first have
sex compared with the UK".
But a new sexual revolution is under way. Spearheaded by the religious
right, the so-called abstinence movement is based on the premise that
sex outside marriage is morally wrong. "We're trying to say there's
another approach to your sexuality," says Jimmy Hester, co-founder of
one of the oldest pro-abstinence campaigns, True Love Waits, based in
Abstinence-based education got US government backing in 1981, when
Congress passed a law to fund sex education that promoted
self-restraint. More money was allocated through welfare laws passed
in 1996, which provided $50 million a year.
A key plank of the abstinence approach is to avoid giving advice on
contraception. The logic is that such information would give the
message that it's OK to have sex. "The moment we do that, we water
down the commitment," says Hester.
If contraception is mentioned at all, it is to highlight its failings
- often using inaccurate or distorted data. A report for the US House
of Representatives published last December found that 11 out of the 13
federally funded abstinence programmes studied contained false or
misleading information. Examples of inaccurate statements included:
"Pregnancy occurs one out of every seven times that couples use
condoms," and: "Condoms fail to prevent HIV 31 per cent of the time."
They also use some questionable logic regarding the success rate of
abstinence (see "Heads I win, tails you lose").
While some states advocate "abstinence-plus" programmes, providing a
level of advice on contraception alongside heavy promotion of
chastity, the hard-line "abstinence only" approach is in the ascendant
in the US. Around a third of US secondary schools have abstinence-only
programmes, and nearly 3 million young people have publicly pledged to
remain virgins until they marry.
And it is spreading. Last June an American group came to the UK to
promote the Silver Ring Thing, a Christian movement that encourages
teens to publicly pledge to remain virgins until marriage and to keep
their promise with the aid of a $12 ring. And True Love Waits has held
virginity rallies in Australia.
This trend comes amid claims that the UK's more liberal approach not
only does not work, but has the opposite effect. "Free pills and
condoms boost promiscuity" screamed the headline on the front page of
UK newspaper The Times last year (5 April 2004). It was prompted by
research by David Paton, an economist at the University of Nottingham,
UK, which found that in some areas that had increased access to family
planning services, teen pregnancy rates had remained the same and STD
rates had actually risen.
There are now increasing calls from conservative and religious groups
for schools in the UK to consider the abstinence option. A programme
called Love for Life is now operating in 60 per cent of schools in
Northern Ireland. It could be described as abstinence-plus that is
heavy on the abstinence. Its founder, Richard Barr, a GP from
Craigavon, County Armagh, says that focusing on contraception ignores
the bigger picture of human sexuality. "There's a massive need for a
more holistic approach, not just a damage-limitation approach."
And the UK mainland is home to a small but growing number of groups,
most of them with Christian roots, promoting abstinence-centred
education. The word abstinence is less in vogue than across the
Atlantic, however, and such groups are more likely to talk in terms of
delaying sex until young people are in a committed relationship.
But does the abstinence approach work? Do teenagers - a group not
renowned for their propensity to do what they are told - take any
notice when adults tell them not to have sex?
Proponents of abstinence claim research supports their strategy. But
the vast majority of studies that have been done in this area have
been small, short-term evaluations without control groups. "There have
only been three well-designed trials where an 'intervention' group is
compared with a control group and participants are tracked over time,"
One of these, published in 1997, looked at a five-session
abstinence-only initiative in California. The trial tracked 10,600
teenagers for 17 months (Family Planning Perspectives, vol 29, p 100).
The researchers found it had no impact on the sexual behaviour or
pregnancy rates of teenagers. The other two studies had similar
results. "None of them show that any abstinence-only programmes had
any impact on behaviour," says Kirby.
Although not a controlled trial, one of the largest studies of the
effect of abstinence pledges tracked the sex lives of 12,000 US
teenagers aged between 12 and 18 (American Journal of Sociology, vol
106, p 859). A group led by Peter Bearman, a sociologist at Columbia
University in New York, investigated whether taking a virginity pledge
affected the age when people first had sex. It did, with an average
delay of 18 months. The pledgers also got married earlier and had
fewer partners overall.
But when Bearman went back six years later and looked at the STD rates
in the same people, now aged between 18 and 24, he was in for a
surprise. In research presented at the National STD conference in
Philadelphia last year, he found that though pledgers had had fewer
sexual partners than non-pledgers, they were just as likely to have
had an STD. And the reason? "Pledgers use condoms less," says Bearman.
"It's difficult to simultaneously imagine not intending to have sex
and being contraceptively prepared."
Here lies the problem that many have with the idea of abstinence-only
education. While it may work for those kids who live up to the ideal,
those who don't are left without the knowledge to protect themselves
when they do have sex. "It's not rocket science," says Bearman.
But here's where proponents of the liberal approach can stop feeling
smug. Because despite many people's unquestioning assumption that
comprehensive sex education is the best way to reduce teenage
pregnancy, there is actually little good-quality evidence backing this
One of the problems in carrying out randomised controlled trials in
this area is the question of who should be used as the control group.
Most schools now have some form of sex education in place, however
rudimentary, and it would be unethical to take this away from some
children to create the control group. Instead researchers have tended
to compare standard sex education with new initiatives specially
designed to reduce pregnancy rates. But the results have been
unimpressive. A systematic review in 2002 of 26 such studies showed
that not one of them improved the use of birth control or reduced the
teenage pregnancy rate (British Medical Journal, vol 324, p 1426).
But in the past few years, a handful of randomised controlled trials
have been published showing that some carefully designed sex education
programmes do appear to work. One of the most effective is the Carrera
Adolescent Pregnancy Prevention Program, aimed at 13 to 15-year-olds
in a poor area of New York (Perspectives on Sexual and Reproductive
Health, vol 34, p 244). Abstinence is mentioned during the programme,
but most of the emphasis is on contraception. A three-year study
showed that the pregnancy rate of teenage girls who took the programme
was less than half the rate of those who didn't. Analysis showed this
was due to both greater condom use and delayed onset of sex.
Why should these programmes be any different? As well as lasting
longer, they were, says Kirby, "interactive and personalised, not just
abstract facts". The Carrera programme, for example, not only covered
sexual behaviour, it tackled the social disadvantages that lead to
teenage pregnancy. Along with information on and free access to
contraceptives, it involved intensive youth work such as sports, job
clubs and homework help.
Most UK sex education programmes seem half-hearted in comparison,
providing the bare biological facts, perhaps alongside a demonstration
of how to put a condom on a cucumber. "It's something I feel quite
angry about," says Michael Adler, a former STD physician at University
College London Hospital. In his job he saw many casualties of unsafe
sex. "We're failing young people right at the beginning," he says.
Unfortunately policy makers have recently lost a good source of
information about what works and what doesn't. The US Centers for
Disease Control and Prevention (CDC) in Atlanta, Georgia, commissioned
a panel of external experts to carry out a rigorous review of various
sex education programmes. The panel identified five strategies that
were successful in reducing the rate of teenage pregnancy, all based
on comprehensive sex education, and the details were posted on the
organisation's website. But in 2002 that information disappeared and
the CDC will no longer release it.
According to the CDC press office, the review programme is being
"re-evaluated". But sceptics fear it has been dumped because its
conclusions don't fit with the Bush's administration's views. "They
were inconsistent with the ideology to which this administration
adheres," says Bill Smith of the Sexuality Information and Education
Council of the United States, a liberal sex education advocacy group
based in New York.
What of the study that made the newspaper headlines in the UK last
year, showing that contraception provision is linked with higher STD
rates? Perhaps it should not really be taken as a damning indictment
of the liberal approach. The study looked at National Health Service
family planning clinics, not school-based comprehensive sex education.
Simply doling out condoms without tackling the wider issues is
unlikely to have much impact. Anyway, should the correlation between
sex clinics and STD levels really be so surprising? "Has it occurred
to [David Paton] that they put more services in areas with high
rates?" asks Roger Ingham.
In fact, amid all the scare stories, the average age when a person
first has sex now appears to be levelling out at around 17 in the US
and 16 in the UK. And although rates of STDs are on the increase in
the UK, teenage pregnancy and birth rates are on a downward trend, as
they have been in most developed countries for several years. A report
from the Alan Guttmacher Institute, a reproductive health research
group in New York, concludes this is due to factors such as the rise
of careers for women, and the increasing importance of education and
training (Family Planning Perspectives, vol 32, p 14). Perhaps it is
unsurprising, then, that it is among society's lowest income groups
that teen pregnancy rates are highest.
In the face of such complex societal forces, those who try to
influence teenagers' behaviour on a day-to-day basis undoubtedly have
a tough job on their hands. There may be no single solution. More
research is needed to produce detailed information on which kind of
sex education programmes work best, and in which contexts.
One approach is to involve older teenagers, on the premise that
14-year-olds may be more likely to listen to 18-year-olds than people
of their parents' generation. Since having her son, Lynsey Tullin has
started working for Brook, a young people's sexual health charity, to
ensure that today's teenagers are more savvy about sex. "We talk the
same language," she says.
A tactic that she finds hits home is to describe new parenthood in all
its gory details - the nappies, the lack of sleep, a social life in
tatters. "We run workshops about being parents, telling them what we
went through," she says. "It's a shock."
Different approaches to teenage sexuality
Comprehensive sex education
Provides explicit information about contraception, sexuality and
Teaches that the only place for sex is within marriage, and the only
certain way to avoid pregnancy and STDs is abstinence. Does not teach
Promotes abstinence as the best choice, but provides varying degrees
of information on contraception in case teens do become sexually
Heads I win, tails you lose
LOOK at any abstinence-only literature, and you'll read that this is
the only certain way to prevent pregnancy and avoid catching a
sexually transmitted disease (STD). "Abstinence. Failure rate 0 per
cent," is the claim on one pro-abstinence website.
But does this make sense? The most important measure of any method of
preventing pregnancy and STDs is not its ideal effectiveness, but its
"use effectiveness" - how successful it is in the real, sometimes
messy, world of sex. Condoms, for instance, have a 97 per cent success
rate at preventing pregnancy if used correctly, but have an estimated
use-effectiveness of 86 per cent, due to problems such as tearing or
slipping. If people who intend to use condoms but never get as far as
opening the pack are included, some studies suggest the
use-effectiveness of condoms could be as low as 30 per cent - the sort
of figure abstinence fans shout from the rooftops.
What about applying the same real-world rules to abstinence?
Unfortunately there are no studies detailing the use-effectiveness of
abstinence in preventing pregnancy, but it is highly unlikely to be
100 per cent, as commonly claimed by its proponents. Their reasoning
goes like this: individuals who set out to remain abstinent but
succumb to temptation and have sex are no longer seen as abstinence
"users". And those who become pregnant may even be marked up as a
failure for the contraception strategy if, say, they attempted to use
a condom but bungled it.
Abstinence campaigners are very vocal about the failings of
contraception. But is it perhaps time to own up about the failure rate
Teenagers special: Bully boys
* 05 March 2005
* Clare Wilson
LAST year the UK pop music station BBC Radio 1 mounted a "Beat
Bullying" campaign, and over six weeks it was flooded with more than 1
million requests for its free "Beat Bullying" wristbands. As it
struggled to meet demand, a thriving market opened up on eBay for
these blue plastic bracelets. Bullying, it seems, struck a nerve -
which is hardly surprising, given that an estimated 1 in 5 secondary
schoolchildren in the UK has been bullied.
Most efforts to tackle the problem involve working with the
perpetrators as well as their victims. Teachers may be urged to help
bullies recognise and modify their behaviour.
Bullies, it is commonly believed, often come from unaffectionate or
violent families, and may have poor social skills and low self-esteem.
"Particularly in America, the traditional view is that [bullies] are
malfunctioning," says Peter Smith, a psychologist at Goldsmiths
College, University of London, who has advised the UK government on
how best to tackle bullying.
But could this view be wrong? Far from being the result of a damaged
psyche, could bullying be a successful social strategy - albeit one
that is very unpleasant for people on the receiving end? Over the past
few years, some psychologists, including Smith, have started to think
so. They believe that at least some kinds of bullying boost the status
of the bully among his or her peers.
Several studies by Anthony Pellegrini, an evolutionary developmental
psychologist at the University of Minnesota, support this theory. In
one study published in 2003, he asked a group of 138 schoolchildren
aged between 12 and 14 to say how aggressive their classmates were,
both physically and psychologically. On a separate scale, they had to
say which members of the opposite sex they would ask to a party
(Journal of Experimental Child Psychology, vol 85, p 257).
Those most likely to get an invite were boys who were physically
aggressive and girls who were psychologically so. "Boys have high
status with their male peers if they're bullies, and girls like them,"
If it turns out to be true that bullying raises the perpetrator's
social status, trying to change bullies' behaviour by boosting social
skills and self-esteem may not work. "Some bullies, at least, are
socially skilled," says Smith. "These skills have a function, which is
to enhance your status in a competitive peer group."
Teenagers special: Live now, pay later
* 05 March 2005
In the west, some of the biggest threats to teenagers long-term health
stem from bad habits such as eating unhealthily and smoking. Policy
makers are also paying growing attention to adolescents' mental
Fewer than 20 per cent of 13-to-15-year-olds in England eat the
recommended five portions of fruit and vegetables a day
American teenagers spend an average of 3 to 4 hours a day watching TV
In Australia, 20 to 25 per cent of under-17-year-olds are overweight
Almost a quarter of 15 and 16-year-olds in the UK smoke regularly
Some estimates suggest that up to 1 in 5 adolescents have some form of
psychological problem, ranging from eating disorders to depression or
In England 11 per cent of 11-to-15-year-olds have used drugs in the
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