Letters archive

In your Leader you appear to suggest some kind of equivalence between ecology and economics ( 21 November, p 5 ). Surely there is a hierarchical relationship here? Economic activity attempts to explain the exchange of goods within society, while society itself is embedded in and interconnected with the wider (natural) environment. The economic therefore …

I am not convinced treating killing as a disease will work ( 14 November, p 40 ). As Steven Pinker wrote in his book The Better Angels of Our Nature , for most of human history violence has been much more common than we now take for granted. What is remarkable isn't that some people …

To understand how a person can be made to overcome an aversion to killing others, look at military training and the inculcation of a belief system that justifies committing violence as being lawfully sanctioned. Distinguishing between "collateral damage" and "terrorism" requires looking at the objective facts through the prism of a belief system that sanctions …

Premeditated murder of all stripes is, at its deepest roots, made possible by the failure to suppress what dog trainers call a "prey drive". I see this as a primal reflex, held in check through social recognition, the most basic and essential form of associative learning. It is social recognition that allows us to see …

Higher prices for soft drinks will create a black market: seedy dealers will cut their product Mike Whitey is just one commenter sceptical about a UK proposal to raise sugar prices ( 5 December, p 7 ) .

There seems to me to be a paradox in all this discussion of expert computer systems replacing professionals ( 21 November, p 42 ). All the expert knowledge in these systems will have been derived from human "experts". But what happens after the human experts become redundant, and only the encapsulated knowledge remains? How will …

Chris Baraniuk discusses computer algorithms that de-select job applicants ( 31 October, p 20 ). Such programs now form a significant part of our lives. The measurements they purport to make and the actions they indicate are the subject of behavioural sciences. But where, for instance, is the science to justify how human resources departments …

So we now have computers that can spot liars ( 7 November, p 22 ). How can we be sure? We are told that algorithms picked out truth tellers 75 per cent of the time – but what they "correctly identified" were those found guilty by juries. Agreeing with a jury that someone is lying …

Your article asking whether food is getting less nutritious reports suspicions that the Chorleywood bread-making method could be a cause of the increase in bouts of irritable bowel syndrome ( 17 October, p 32 ). People with the condition often claim it is triggered by bread. I wonder whether the prevalence of the process might …

In your story "Consciousness theory rocked", you report that a proposed neural correlate to consciousness, the P3b EEG signal, can accompany unconscious as well as conscious brain processes ( 7 November, p 14 ). But this does not actually undermine global neuronal workspace theory. I'm not sure anyone expects to find a single neural correlate …

You report research linking schizophrenia to brain inflammation and more active immune cells in the brain ( 24 October, p 17 ). Could this high level of immune cell activity be linked to the Toxoplasma gondii parasite, commonly transmitted by cats? This has been linked to schizophrenia ( 30 May, p 42 ). I hypothesise …

I've worked with pseudoscorpions for much of my life and I found the snippet about these amazing arachnids using bats as transport most interesting ( 14 November, p 17 ). Hitch-hiking is common in several pseudoscorpion families. It can associate species with temporary or transient habitats, including nests, decaying trees, manure and compost heaps and …

Thank you for your report on pigeons diagnosing breast cancer ( 21 November, p 12 ). Much was made of employing pigeons to spot downed pilots in the ocean and at least one patent was granted, in 1981. I also recall reading about pigeons selecting faulty cigarettes. They are always good for a news item. …

You tracked the trajectory of a water molecule from a crashed comet to being printed on your magazine ( 14 November, p 30 ). As water is a molecule, not an element, when it is in liquid form, it can and does dissociate into OH- and H 3 O+ ions; then it swiftly reassociates, but …

You state that calculating the product of two numbers, each having n digits, requires about n 2 steps ( 21 November, p 11 ). But while this is true for basic multiplication, there are algorithms that for large numbers take on the order of n(log n)(log log n) steps. There are algorithms that are even …

• William Kirby's letter about siting nuclear plants by the sea should have referred to our being committed in 20 years' time to the risk of catastrophic sea level rises in a century or more ( 28 November ). • Watt's that? The energy used by a Google web search is 0.3 watt-hours or 1000 …