Drive me tame
In his article on taming wild animals, Henry Nicholls presents geneticist Dmitry Belyaev’s intriguing proposition that when our ancient ancestors approached a herd of animals, they identified the less skittish ones and took them home to breed (3 October, p 40). Although the article presents the trait being selected for as tameness rather than aggression, the important factor is most likely to be anxiety.
In fact, Cheryl Kassed andMiles Herkenham discovered several years ago that a strain of mice missing a gene subunit, the NF-kappaB p50 protein, seemed to have no sense of fear (). Unlike most lab mice that run for cover when a human approaches, these animals appeared friendly and curious, approaching people who entered the room. They would not be able to survive in the wild.
It may be that this was the first identification of a gene that affects behaviour. I presume the geneticists described in your story have heard of it.
Henry Nicholls reports on Soviet experiments into domesticating wild animals, such as the silver fox, the methodology for which was to select the tamest animals for breeding. The result was tame foxes that even wagged their tails. This is hardly revolutionary: the first animal that a farmer will cull from their herd is the angry one. This practice has probably existed for millennia, stemming from the fact that livestock with bad attitudes are dangerous.
Nicholls also reports the search for a species that humans can usefully domesticate from the wild by selecting those with the “tame” gene. I suggest deer, which are farmed directly from the wild. It would certainly save farmers the cost of erecting deer fences to prevent the animals fleeing in response to every scare they encounter.
Wadestown, Wellington, New Zealand
Henry Nicholls claims that cheetahs cannot be domesticated.
This puzzled me because, while in the Sahara in 1960, I spent the better part of a day with a perfectly tame, domesticated cheetah. It wandered around the courtyard and sat purring loudly at my feet. What’s more, the person who was with me, an ex-policeman from Kenya, had owned a cheetah. He told me that it travelled with him in the passenger seat of his MG.
Maybe Nicholls has a different definition of tame?
Broome, Western Australia
鈥� While many individual cheetahs have been tamed, attempts to breed them in captivity have failed. For more details, see Jared Diamond’s Guns Germs and Steel.
Future-proof farms
Your article on engineering pain-free farm animals (5 September, p 8) and the accompanying editorial “Pain-free but not guilt-free” (5 September, p 5), would have benefited from the input of people with experience in rearing domestic livestock.
Livestock producers already expend a lot of thought and investment endeavouring to keep livestock comfortable and pain-free, because creatures in constant pain don’t thrive and are, therefore, not cost-efficient. Even a factory farm has a big economic interest in making the animals comfortable enough to be willing eaters that do not waste metabolic energy on dealing with stress.
The real issue for consumers who object to factory farming is that the practices do not allow animals to exhibit their natural behaviours or eat a natural diet. They also feel that a great deal of pollution is caused by keeping animals in such large concentrations.
It is not difficult to do things differently. Raising a lot of livestock in a way that ensures them a healthy life 鈥� that is, providing them with room to exercise and the food they evolved to eat, such as grasses and clovers for grazing animals 鈥� is not expensive or hard. It is also beneficial to the environment, as animal manure and urine in reasonable amounts are the most sustainable fertiliser available. The grasses and clovers on which the animals graze help build soils and stop erosion. Such livestock can produce human food on the large amounts of land that can’t grow crops because it is too dry, rocky, or otherwise unfarmable.
Raising livestock under the conditions that fit the way the animals have evolved is the key to a truly sustainable agriculture, and to feeding the human population for the long run.
Design from data
W. Brian Arthur and Robert Cailliau both made the argument on your pages that technology progresses through evolutionary mechanisms (22 August, p 26 and 19 September, p 27, respectively).
However, it is part of the received wisdom in the field of reliability engineering that no new design is wholly revolutionary or wholly evolutionary. Rather, design is a mixture of original invention and subsequent improvement, based on the analysis of data from previous models.
The analysis part of the process is fundamental, and requires data from previous models to have been meticulously compiled; failure to do so results in the repetition of old mistakes. This is as far from the “trial and error” mentioned by Cailliau as Darwinian evolution is from selective breeding.
In a commercial setting, new designs are subject to a thorough analysis even before the first prototype is made. Many bright ideas fall at this hurdle when the inventor realises that they are not going to be marketable in their present form.
Hypnotic illusion
Nicola Jones reports her experience of hypnosis, during which unsuccessful attempts to make her experience paralysis and blindness are carried out (10 October, p 37). What she fails to mention is that similar attempts to replicate pathological behaviour with hypnosis date back 70 years at least, most notably to the work of psychiatrist Milton Erickson in the 1930s. I believe this type of investigation rests on a misinterpretation of hypnotic behaviour. In fact, one should question the reality of hypnosis, not endorse it upon the basis of the hypnotists’ catalogue of apocryphal tales.
Most of the thousands of people I, as a stage hypnotist over two decades, and others have hypnotised were not “faking it”, as Jones’s gross oversimplification has it, nor were they in a special state. I believe they were genuinely induced to fall for an illusion woven from subjective cognitive effects.
Jones reports researcher Amir Raz’s use of the Stroop test, where the names of a colour are written both in monochrome text and in fonts of different colours. Volunteers usually read out names on the monochrome list faster than they read the coloured fonts. The colour blue written in red ink, for example, forces the reader to deal with conflicting signals from the colour and the name. When I have applied the test, I have found that hypnosis leads to the subject deliberately reading the monochrome control list more slowly. This probably results from the experimenter bias effect, in anticipation of the expected test results.
A test which really exposes the absence of hypnotic state is the use of delayed auditory feedback (DAF) 鈥� where a subject’s voice is piped backed to them with a slight delay. This causes confusion and stumbling as they speak. Some hypnotised subjects insist they are deaf when suggested to become so 鈥� which means their confusion should disappear. However, in some studies, for example, that of Barber and Calverley (), they have been observed to respond to DAF exactly as someone with normal hearing would.
PET and fMRI scans have shown differences between those in hypnosis and non-hypnotised or simulating controls. It could be that such changes reflect the hypnotised subjects using cognitive strategies specific to the situation, rather like the selective cortical activations found in a musician playing an instrument. These are not brain states any more than the selective cortical activation that accompanies any focused activity is. Or should we now consider the pianist’s performance to be the manifestation of a state?
Put a lid on it
To get maximum efficiency on a hot day, (12 September, p 26) Stephen Hodges tell us that he uses a sprinkler to cool the solar cells that he has on the roof of his Jamaican home.
There are other forms of cooling that work just as well. For example, over 24 hours a “living roof” can smooth ambient roof temperatures from varying by 32 掳C to only 4 掳C, as demonstrated by Jeff Sonne of The Florida Solar Energy Center in his paper . The stabilisation afforded by living roofs is yet to be incorporated in measuring building energy performance in the UK, but could mitigate such issues as the urban heat island, weathering and rainwater surface run-off rates, while reducing the rate of biodiversity loss.
Stealthy power
Since reading about the decimation of bat populations around wind farms (12 May 2007, p 4), I’ve wanted to contribute the results of some deviant research I conducted as a boy in the UK.
My brother and I used to throw sticks at the bats fluttering outside our bedroom window, for obvious reasons. The fascinating thing was that rather than avoid the sticks, the bats would actually home in and follow them. This suggests to me that the bats dying around wind turbines could be doing the same thing. Perhaps they are following one blade when another comes up and clobbers them from behind.
So, to conclude my childhood research, I suggest the creation of stealth rotor blades invisible to bat sonar. Maybe they could be used to reduce at least one of the ecological problems attributed to these whirly beasts.
For the record
鈥� In our article “Don’t provoke the planet” (26 September, p 8) we stated: “A CCS facility at the Sleipner gas field in the North Sea, may have triggered a magnitude 4 earthquake in 2008.” This was incorrect: the earthquake was of magnitude 3.1 and was some 55 kilometres away from the Sleipner field. There is no evidence that it was caused by the CCS facility. Christian Klose, hazards researcher at Think Geohazards, who was referenced in the article, has asked us to clarify that he does not claim the CCS facility caused the earthquake.
鈥� We gave Saturn a new moon, but in fact Ganymede orbits Jupiter (17 October, p 43)