Tricky cards
With the article “How to Make Better Choices” you presented the Wason task (5 May, p 38). You showed four cards bearing D, A, 2, and 5, and the caption: “Each of these cards has a letter on one side and a number on the other. Which two cards should you turn over to allow you to decide if the following statement is true: If there is a D on one side, there is a 5 on the other?”
The article says that 75 per cent of the subjects asked this question choose the wrong answer. The correct answer, however, is that no two cards can prove the hypothesis. Indeed, turning all four cards would not prove it nor be guaranteed to disprove it.
This is a classic case of a poorly formed question. A correct formulation would be along the lines of “which two cards should be turned over to maximise your chance of falsifying the hypothesis?” If the researchers had asked that question they might have got different results. As it is their result is simply a reflection of the confusion among the subjects when presented with a nonsense question.
The editor responds:
It all depends on the size of your universe. The question (and correct answer) make sense if they apply only to the four cards, but are ambiguous if you hypothesise a general statement about all cards bearing letters or digits.
Plastic problem
Michael Reilly describes recent advances in plastic recycling technology but only touches on the problem of collecting and separating plastic waste items (12 May, p 28). There are about five main types of plastic in common use, and up to 20 more in less common use, and all require different treatments. There is no way that most people can separate them.
It is hard to see how we can achieve significant advances in recycling rate unless the packaging industry standardises by using only one or two clearly marked types. And what is so wrong with land-fill if done properly? Plastics are composed mainly of carbon 鈥� so land-fill is a convenient way of sequestering this.
From David Stevenson
You describe technologies for sorting polyethylene terephthalate (PET) from other plastic waste and cleaning it. Rather than spend money doing this 鈥� and shipping waste long distances 鈥� would it not make more environmental sense to use plastics (apart from PVC) for fuel for power generation to reduce the demand for costly oil which could instead be diverted to the manufacture of replacement virgin plastics? This would avoid stages in the cycle and the associated waste.
Newbury, Berkshire, UK
For the record
鈥� In reviewing Animals in Space by Colin Burgess (14 April, p 49), Mick O’Hare wrote that “Laika… hit the world’s headlines in June 1957 when the Soviet Union launched her into space aboard Sputnik 2”. The news actually broke on 3 November 1957.
Head on your knees
Feedback’s insurance friend is on a wind-up mission (19 May). Airlines recommend the brace position not to make dental identification easier, but because it significantly reduces injuries to limbs by reducing their tendency to flail about on impact. In the 1989 crash at Kegworth in Leicestershire many who survived but did not adopt the brace position suffered leg fractures.
On the other hand, I suspect the effect of a life jacket in enhancing your chances of survival floating in the North Sea or the North Atlantic for any length of time would indeed be minimal. It could help you to keep your head above water while you get to a life raft and relative safety.
Lifesaving options
In the article on making better choices you say that more people go for the “safe” option, described as a sure chance of saving 200 people out of 600 at risk, than for a sure chance of losing 400 (5 May, p 41).
Maybe they appreciated that the former does not exclude the possibility that more than 200 will be saved, and that the latter does not prohibit, simply by the wording, fewer than 200 being saved.
The editor writes:
鈥� This was indeed explored in subsequent research, such as that by Anton K眉hberger and David Mandel, who found that the effect disappeared if the outcomes were completely spelled out, for example by specifying “400 will die and 200 people will not die”.
Authors' rights
Reporting the Encyclopedia of Life project, you mention “documents published prior to 1923 鈥� and therefore not subject to copyright restrictions” (12 May, p 14).
That applies only to the US. In the UK, the rest of the European Union and most of the rest of the world, works go out of copyright 70 years after the death of the author.
Vile bodies
I am repeatedly struck by the complexities of media censorship (21 April, p 5 and p 33). Particularly in the US-dominated world of Australian television, there seem to be few, if any, limits on the extent of violence that can be shown on free-to-air television. On the other hand, the heavy-handed censorship of any sexual material suggests that there are parts of human bodies that will cause the collapse of society if they are seen by the masses.
This seems odd considering that all children have access to at least one naked body (their own). Despite this, they do not become morally bankrupt perverts as children.
Clearly there must be an age where nudity becomes a heinous sin 鈥� as shown by the hysteria that followed Janet Jackson’s “wardrobe malfunction” while entertaining the audience of the 2004 Super Bowl, an American Football game. Any material representing the reproductive process is guarded even more closely because of the danger that this unnatural act poses to society.
This attitude fosters the mindset that while killing and injuring people is a normal part of life, a body without clothes on it is an obscenity, and sex is a threat to national security. Why?
Train strain
You say that “in transport we need hybrid vehicles, biofuels and a concerted effort to move traffic from road to rail” (12 May, p 3). Transferring demand to rail will only reduce greenhouse emissions if rail is more efficient than the alternatives.
The 18th report of the Royal Commission on Environmental Pollution in 1994 identified the road coach as the most energy-efficient option for long-distance personal travel. The small car emerged as more efficient than suburban electric rail.
At that time, the commission felt that rail should be the preferred mode, despite its relative inefficiency, because it might be able to use hydrocarbon-free electrical power before this would be possible for other types of transport. The emergence of fuel cells and vegetable hydrocarbons suggests that rail may get no such advantage from using electricity.
Lobby groups purporting to show that cars and coaches are less efficient than rail do not compare like with like when they use the overall consumption figures produced by governments for different modes of travel. The mix of individual journeys served by each mode differs so grossly that it is meaningless to compare the averages.
Habitat at risk
Joseph Wright presented a false dichotomy in suggesting that climate change poses a greater risk to species survival than deforestation (12 May, p 43). Climate change likely represents for most species an ultimate rather than a proximate or direct cause of extinction and decline.
Hypothesised mechanisms by which climate change may threaten wildlife include raising the cloud base in high-altitude forests, reducing the area of suitable habitat, altering microclimates and thinning leaf litter that provides habitat for small terrestrial vertebrates and their invertebrate prey. All these are forms of habitat destruction qualitatively similar to the loss of primary forest. It seems bizarre to suppose that one represents a high risk while the others are negligible.
Surviving rainforest is most often found in regions unsuited to farming. Species found there may include refugees from destroyed systems, forced to survive in suboptimal conditions. If those conditions deteriorate further due to climate change, these are the species most likely to succumb.
Climate change is predicted to increase the incidence of fire in primary forests as they become drier, and this effect will be exacerbated in more open secondary forests. The consequences for wildlife within these systems are potentially drastic.
The popular media already seem in danger of forgetting the threat posed by habitat destruction, a message that has been lost in the clamour over global warming.
Compelling climate
Climate change sceptics such as Martin Durkin are guilty of a worrying non sequitur (19 May, p 26). Maybe there is an alternative explanation for the recent sharp increase in global temperature. But be the effect small or large, adding carbon dioxide to the atmosphere can only exacerbate the problem.
If the “sceptics” are right and the world is already warming from other causes we should be doubly determined to reduce man-made greenhouse gas emissions.
From Neil Fairweather
It seems to me that the environmental lobby has devoted far too much effort to making individuals feel guilty about their personal carbon footprints, in the expectation of curbing demand for high-emission activities. As an individual who cares about the threat of climate change, I don’t want to feel virtuous about my efficient lifestyle, I want to be given no choice.
Risley, Cheshire, UK
Punctuated Darwin
I am shocked that someone as knowledgeable as P. Z. Myers is promoting the age-old myth about “Charles Darwin’s belief that species evolved gradually” without periods of stasis (12 May, p 54). In On The Origin Of Species Darwin wrote: “Although each species must have passed through numerous transitional stages, it is probable that the periods, during which each underwent modification, though many and long as measured by years, have been short in comparison with the periods during which each remained in an unchanged condition. These causes, taken conjointly, will to a large extent explain why 鈥� though we do find many links 鈥� we do not find interminable varieties, connecting together all extinct and existing forms by the finest graduated steps.”
Darwin, quakes, rain
Laurent Bollinger says that in the Himalayas heavy rain appears to reduce seismic activity (5 May, p 20).
Charles Darwin in The Voyage of the Beagle says of (some) Chileans: “To their minds an earthquake foretold rain as surely as rain foretold abundant pasture. Certainly it did so happen that on the very day of the earthquake that shower of rain fell which I have described as in ten days’ time producing a thin sprinkling of grass. At other times rain has followed earthquakes at a period of the year when it is a far greater prodigy than the earthquake itself: this happened after the shock of November 1822, and again in 1829 at Valparaiso; also after that of September 1833, at Tacna.” So in the Himalayas rain prevents earthquakes, but in the Andes it appears to be produced by earthquakes.
Reporting suicide
The call by the president of the American Psychiatric Association for US media to avoid broadcasting footage of the Virginia Tech killer that might encourage copycat behaviour should have been unnecessary (12 May, p 22). There are plenty of guidelines on the topic in the US, and compelling evidence has been around for some time, notably in Suicidal Behaviour and the Media by Kathryn Williams and Keith Hawton, a global review of 90 studies from 20 countries going back over a century.
Building on their research and working with journalists and suicide prevention agencies, the MediaWise Trust has devised simple practical guidelines that are now in use around the world (see the suicide section of ).
The most important message for media professionals is that responsible coverage can save lives. By avoiding details of suicide methods and including helpline numbers in copy about suicide, journalists can offer a lifeline to those most vulnerable to suggestion.
The pity of it is that reporting suicide is rarely included in vocational training, so few journalists are aware of the potential consequences of insensitive coverage.
Food: the home front
Chris Pollock and Jules Pretty argue for a re-evaluation of sustainable food production in light of the effects of climate change and the end of oil (21 April, p 18). Now is the time to consider what constitutes sustainable agriculture.
Until recently it was assumed that organic farming was inherently sustainable. A recent report by the UK’s Department for Environment, Food and Rural Affairs questions that, presenting evidence that there is little difference in energy use between “conventional” and organic agriculture.
Organic farming may use less energy in the form of factory-produced fertilisers and pesticides, but it still relies heavily on oil. Making organic agriculture less oil-dependent would require huge labour inputs and a return to 19th-century farming methods, which would not produce enough food for today’s population.
Real change requires a complete reappraisal of the way food is produced and distributed. Supermarkets’ centralised buying and distribution networks forestall any chance of a real move away from factory farming in the short term. Local initiatives like farmers’ markets are making some impact, but they tend to be small-scale and intermittent.
One way to a more sustainable food economy would be to produce food on land that is closer to towns and cities. There has recently been a debate about using spaces in cities like Milton Keynes for growing food. This would drastically reduce the “food miles”, yet without a local distribution and marketing system it would surely fail. Elsewhere roof gardens are used to produce fresh food very close to the point of consumption, such as the hydroponic food garden on Singapore’s 800-bed Changi General Hospital.