Identifying and evaluating explanations

In each of the following five passages, an explanation is offered, or various different
explanations are considered, for a given fact or phenomenon. For each passage:
(a) identify the fact or phenomenon which is to be explained;
(b) find the explanation or explanations given in the passage;
(c) think of any other possible explanations which are not mentioned in the passage;
and
(d) either
i. say which explanation you think is the most plausible, and why; or
ii. suggest further evidence you would need in order to decide which explanation
is the most plausible.
This exercise could form the basis of a class discussion.
1 Girls doing well while boys feel neglected, study finds
Donald MacLeod
‘Boys are blamed for everything’, complained a 14-year-old, encapsulating the
jaundiced view of school that seems to be having such a bad effect on boys’ exam
results.
‘It was a myth that girls perform poorly at school’, said Michael Younger, whose
study of an East Anglian comprehensive elicited the 14-year-old boy’s comment.
Boys are the problem.
The boy also complained: ‘Girls are treated a lot better and get first choice of
equipment and task.’
Reflecting the national picture, the girls at this school have done consistently better
at GCSE than the boys, although the gap has narrowed.
Mr Younger said some schools should take credit for implementing equal opportunities
policies which had reduced discrimination against girls. They now had to tackle
boys’ under-achievement and disengagement, although Mr Younger admitted that it
was a complex problem to which he did not have any easy answers.
He and Molly Warrington, his fellow researcher at Homerton College, Cambridge,
found that boys felt they were unfairly treated or neglected in class, although
teachers and the majority of girls disagreed.
Staff said boys went to considerable lengths not to appear swotty – for instance,
denying to classmates they had done homework even when they had, or playing up
in class. They saw boys as unable to concentrate or organise themselves and lacking
in motivation.
Girls tended to be more focused, and study was not seen as bad for their image.
Parents and teachers agreed that girls did more homework, while boys saw it as a
necessary evil to be done as quickly as possible.
Seventy per cent of girls thought female teachers treated boys and girls equally; only
46 per cent of boys agreed.
A majority of all the pupils surveyed thought male teachers were biased towards
girls, however – accepting behaviour from girls which they punished in boys.
A fifth-form girl agreed that girls were treated more leniently by male teachers. ‘The
girls have a reputation for being well-behaved, so if, for example, they don’t do their
homework they won’t get told off as much.’
Boys from the same year complained that they got less attention from male teachers
than the girls did.
Girls appeared to have clearer goals, said Mr Younger, which led them to focus on
their work. Some boys had no idea what they wanted to do after GCSE and several
had no idea what later courses to take.
(Copyright Guardian News & Media Ltd 1995)
2 Number of road deaths at post-war record low
Fewer people were killed on Britain’s roads last year than in any year since 1926, but
a rise in the number of those seriously injured suggests that further improvements
are unlikely.
Preliminary figures released by the Department of Transport suggest that 3,651
people died on the roads, a fall of 4 per cent compared with 1993 when 3,814 died
– the previous post-war record low.
The fall in deaths, despite an increase in road traffic of 3 per cent, appears to be
explained by better paramedic treatment at the roadside and improved medical care,
since the figures for serious injuries have increased to 46,784, a rise of 4 per cent.
In fact the number of deaths is just about the only figure to have gone down between
1993 and 1994. Serious injuries for both car users and pedestrians also increased.
Indeed pedestrian casualties rose by 2 per cent overall from 1993 levels to 49,026
and while deaths fell by 7 per cent to 1,148, serious injuries increased by 4 per cent
to 11,924.
While Britain generally has a good safety record on the roads compared with its
European neighbours, the number of child casualties is proportionally higher and
last year reinforced the trend, with child casualties going up by 6 per cent to 45,239.
The number of child pedestrians killed on the road went up from 135 to 173, a rise
of 28 per cent.
The increase in injuries means that the Government has virtually no chance of
meeting its target of reducing total roads casualties by one-third between the early
Eighties and 2000. However, it will easily achieve the target on deaths if present
trends continue.
Edmund King, campaigns manager of the RAC, said: ‘There are very worrying
features about these figures, particularly on child deaths. One thing that could be
done quite easily is to bring the clocks into line with the Continent so that children
would not have to go home from school in the dark.’
He says that the increase in serious injuries shows that the number of accidents is
rising and he feels many are caused by drivers feeling too insulated in their modern
cars. Mr King said; ‘They listen to the stereo, have the heater on and it’s almost as if
the outside world doesn’t exist. And then they fall asleep or make a mistake . . .’
Brigitte Chaudhry, national secretary of RoadPeace, an organisation for road accident
victims, said the figures on deaths may be misleading; ‘Deaths are only counted
as such if they occur within 30 days of the accident. Nowadays, many people are
kept alive for much longer thanks to modern medical techniques and die later than
that.’
She added that the main reason for the reduction in deaths over the last 30 years is a
decline in the number of vulnerable road users, such as pedestrians and cyclists,
using the roads: ‘As there are fewer pedestrians on the road and more are getting
hurt, it suggests that roads are more dangerous and not safer.’
3 Health check
It is not often that the heads of our prestigious medical colleges bandy about words
such as ‘terrifying’ and ‘time bomb’, but last week three of them came together in an
unprecedented move to issue a warning about the soaring numbers of overweight
and obese people in Britain. Two thirds of men and women are now classed as
overweight or obese. One in 10 children under four is obese, rising to one in six in
the five–15 age group. Obesity has doubled among children, trebled among women,
and nearly quadrupled among men over the last 20 years. . . .
In the same way that many people claim that their weight ‘just crept up over the
years’, so, too, has the experts’ realisation of the full extent of the obesity problem.
Everyone – the doctors, the food industry, the Government and the obese – agrees
that the causes are complex and the solutions multi-factorial. It is not just about fat,
greedy people eating more than they need to and being too lazy to do something
about it. But a trip to the Bluewater [shopping centre] is a neat example of a lot of
the causes – and solutions.
The rise of these huge, out-of-town shopping centres has only added to the culture
of the car. Bluewater is not within walking distance of anywhere – everyone drives
to it. When they do get there, there are lifts from the car parks to the shops.
Escalators take you from one level to another. The distance that anyone has to move
under their own steam is minimal.
An interesting factor in the whole debate about obesity is that the average person
actually eats fewer calories and less fat per day than 30 years ago – but does far less
exercise. Parents drive their children 500 yards down the road to school, and then
carry on to their place of work. People drive to the park to walk their dog, or to the
newsagents to get a newspaper.
Children in particular suffer from this. They no longer cycle to the shops to get
sweets, or run down the road – they are driven there. The loss of playing fields,
combined with a (perhaps irrational) public perception that paedophiles and
murderers lurk at every corner, means that many youngsters don’t even know
how to ride a bike, let alone have the freedom to get on one and burn some
energy.
But back to Bluewater. A glance around the food court highlights another problem
– portion sizes. Order a McDonald’s burger, and the first thing you will be asked is
whether you want to ‘go large’. Bags of crisps come in maxi-sizes, chicken meals in
‘bargain buckets’.
(Extract from ‘Health Check’ by Maxine Frith, The Independent,
Monday, 16 February 2004)

4 Science debunks miracle of weeping madonna
The only weeping madonna officially accepted by the Roman Catholic Church
has been exposed as a fake by an Italian scientist who used the logic of Mr Spock,
the deductive reasoning of Sherlock Holmes and a knowledge of capillary
attraction.
There has been a sharp increase in the sightings of weeping madonnas, from Ireland
to Croatia, but the only one recognised by the Church is a statue of the Virgin Mary
in the town of Siracusa in Sicily. It first began weeping in 1953.
The ‘miracle’ of a statue that appears to weep has even been caught on film. But
Luigi Garlaschelli, a chemistry researcher at the University of Pavia, believes he has
an explanation.
Dr Garlaschelli has made his own weeping madonna which baffled onlookers into
believing the statue was able to shed tears without any mechanical or electronic aids
or the deployment of water-absorbing chemicals.
The secret, he revealed, is to use a hollow statue made of thin plaster. If it is coated
with an impermeable glazing and water poured into the hollow centre from a tiny
hole in the head, the statue behaves quite normally.
The plaster absorbs the liquid but the glazing prevents it from pouring out. But if
barely perceptible scratches are made in the glazing over the eyes, droplets of water
appear as if by divine intervention – rather than by capillary attraction, the movement
of water through sponge-like material.
Dr Garlaschelli said: ‘I notice that, among these weeping madonna miracles, the
only one accepted by the Catholic Church happened in Siracusa in 1953. This is
the best documented case, with many witnesses to an actual case of weeping, and
even a couple of amateur films showing watery tears appearing on the face out of the
blue.
‘Examination of a copy of this bas-relief from the same manufacturer as the original,
however, proved it to be made of glazed plaster and to possess a cavity behind the
face.’
Dr Garlaschelli said the actual madonna of Siracusa is kept behind a glass partition
and he is unable to inspect its glazing for himself. ‘I think permission won’t be
granted to examine it,’ he said. ‘Many of these relics are not allowed to be examined.’
5 Cars miss pollution target – and makers blame you
Carmakers will be more than a decade late in meeting their target to produce less
polluting vehicles because people are buying bigger, more powerful models, figures
suggest.
Sales of small cars fell to their lowest level for seven years last year while large
vehicles secured their highest share of the market yet. One in eight cars sold last year
was a 4×4 or people carrier, compared with one in eighteen a decade ago.
Average emissions of carbon dioxide for new cars fell by 1.2 per cent last year, well
short of the industry target of a 5 per cent decline. The fall was almost entirely due
to the rise in popularity of diesel vehicles.
The Society of Motor Manufacturers and Traders (SMMT) said that it was
disappointed by the slow progress towards the European target of reducing average
CO2 emissions for new cars to 140g/km by 2008. The British average last year was
169.4g/km and, on current trends, 140g/km will be reached only in 2021.
The SMMT said that drivers were partly to blame for demanding bigger cars with
faster acceleration and more gadgets. It said that falling prices of new cars and rising
incomes had encouraged millions of drivers to buy larger vehicles.
Features such as air-conditioning and electric windows, which add weight and consume
energy, have become almost ubiquitous. Safety systems such as air bags and
side-impact bars had added weight while rules on pedestrian-friendly bonnet design
had made cars less aerodynamic, it said. The SMMT report on the emissions of new
cars accused drivers of failing to reflect their concerns about global warming in their
choice of car.
‘Consumers say they support the environment, but act in a less sustainable way.
Consumers must also take an increased responsibility for the vehicles they purchase
and the journeys they make,’ it said.
But Friends of the Earth said that carmakers were to blame for the poor progress on
emissions because they spent more promoting gas guzzlers than low-emission cars. It
analysed advertising in national newspapers last September and found more than
half of advertisements were for cars in the two most polluting road tax bands. Only
3 per cent were for cars in the lowest bands. The campaign group added that the top
rate of road tax should increase from £215 to £600.
Sales of petrol–electric hybrids, such as the Toyota Prius, which produces only
104g/km accounted for only 0.3 [per cent] of the new car market.
Christopher Macgowan, the chief executive of the SMMT, said that the European
Commission was planning a scheme under which drivers would be able to claim up
to £400 towards the cost of a car with very low emissions. ‘It would be completely
unacceptable if we missed the target by a decade,’ he said.