Editor's pick: It's cats that are bending minds
The protozoan Toxoplasma gondii makes infected mammals more likely to take risks and also gives them a preference for the smell of cat urine, so infected rats and mice are easy prey for cats (30 May, p 42). Colin Barras didn’t, however, suggest any benefit to the protozoan in altering human behaviour.
What could that benefit be, since we aren’t usually cat prey? But this is to look at the problem from the protozoans’ viewpoint, when surely the whole system is for the benefit of cats. Cats spread the bug to infect rodents, which are then more easily caught, thus benefiting the cats.
The cats also spread the bug to humans who inexplicably take a liking to cats, despite the disdain they show for us. Why else would humans feed cats and look after them, unless their brains were deranged by toxoplasmosis?
West Launceston, Tasmania, Australia
Editor's pick: It's cats that are bending minds
I keep warning all my cat-owning friends about the parasite that makes them less risk-averse, but they just don’t seem to care.
Keyworth, Nottinghamshire, UK
Probing the proper purpose of pain
Barbara Findlay argues that the distress caused by pain has survival value because it elicits help from others (9 May, p 28). I offer an extension. It has been suggested that disgust is a disease avoidance mechanism: we feel revulsion towards cues associated with disease risk, such as bodily fluids and visible injuries, and that drives us to avoid the risk.
External signs of distress caused by pain must be strong enough to overcome this powerful avoidance tendency. In effect, there is a conflict between the desire to help elicited by evidence of suffering and the desire to avoid risk elicited by signs of disease.
We might feel pain more than other species because it is the way to get people to help us when they really want to get away from us. It’s not easy being a social animal.
Tongwynlais, Cardiff, UK
Probing the proper purpose of pain
It is good to see the function of pain explored using evolutionary concepts. But Barbara Finlay asserts that its obvious protective functions are insufficient to explain all pain. To fill the gap, she presents a circular argument: that we experience pain to obtain help, and need help because we are hurt. Pain is a complex event, and pain experience and pain behaviour differ with the social context. We don’t feel pain in order to get help; we need help because we are in pain.
London, UK
Probing the proper purpose of pain
Instead of prompting us to seek attention, the feeling of pain might simply serve to distract us. It would thereby ensure that, whether in labour or after exercise, we are less able to attend to thoughts or plans of action that might interfere with what our body has evolved to do in those circumstances to increase its chances of survival.
Cupar, Fife, UK
Does that mean the average antibanana emits 15 particles of matter?
tweets on our story on why there is more matter (23 May, p 28)
Skeletons do not show death rates
Rebecca Redfern and colleagues suggest that Romano-British urban dwellers were more likely to reach old age than their rural contemporaries (16 May, p 10). But all their data show is that the number of skeletons of various ages differs between sites. Death rates cannot be estimated because we cannot know the demographics of the live populations from which these skeletons came.
Paradoxically, if we constructed “life tables” from these data, giving the probability of death for each age group, it is likely that the mean age of death of the townies would be lower than that of the rural dwellers. Mean age of death is heavily weighted by the number of children dying; and there are more of these in the town sites than the rural.
London, UK
Empathy at the political poles
The issues that Darach Conneely raises in his letter on empathy and psychopathy have relevance to the politics of conservatism and socialism (2 May). Conneely notes that “strategies of populist politics… switch off our ability to feel empathy”. Conservatives regard the general population as selfish and stupid. They are un-empathetic to those considered “not of the tribe”.
Extreme conservatives, such as the Nazis, have exploited this in populist campaigns against minorities, and have defined minorities by pseudo-biology. For a conservative, the link between populism and oppression of outsiders is obvious.
Other conservatives share the same basic approach to the “natural” limits of empathy, but seek to mitigate rather than exploit their effects. This lies behind conservative support for tradition and religion, even if objectively illogical: they believe that these lessen tensions and encourage empathy.
Hence the deep conservative fear of the consequences if these are swept away. This fear also lies behind conservative respect for hierarchies 鈥� as a protection against the horrors of populism.
By contrast, socialists see people as naturally communal, with communality embracing the whole human race. To them, narrow tribal identification is unnatural and the product of distortions of society.
Wantage, Oxfordshire, UK
Will artificial aliens show empathy?
Why would we want sentient life forms to inhabit a computer in a simulated reality (2 May, p 39)? One reason would be to find out whether it is possible for other evolved life forms to be genuinely altruistic. This would inform us of the stance to be taken if we encountered alien life.
Welwyn, Hertfordshire, UK
The ups and downs of meditation
Catherine Wikholm and Miguel Farias report that 7 per cent of people on meditation retreats experienced adverse effects, including panic and depression (16 May, p 28). But in the same issue Chloe Lambert mentions that 10 per cent of Americans aged 12 and over are estimated to be taking anti-depressants (p 35). If this means around 10 per cent of attendees on meditation courses have depression, for only 7 per cent to experience it while on the course seems an endorsement.
Hampton, Middlesex, UK
The ups and downs of meditation
The Buddha warned 2600 years ago that if new meditators sit too long, hallucinations may occur. People often believe that having more of something good, whether meditation or exercise, is better than having less. Just because some teachers charge big bucks for courses and retreats doesn’t make them better than others.
Wellington, New Zealand
The ups and downs of meditation
I have taught meditation (free of charge) as a Buddhist chaplain in a UK university for 13 years. I have never witnessed an adverse incident. But in recent years I have predicted a backlash against what goes under the name of “mindfulness”. The Buddha distinguishes between “right mindfulness” and “wrong mindfulness”. Mindfulness is only one of the Buddha’s eight factors. Crash courses are certainly not useful. Mindfulness, like any intervention, isn’t immediately suitable for some individuals with certain life traumas or illnesses 鈥� at least not without special support.
Woking, Surrey, UK
The ups and downs of meditation
The aim of Buddhist practitioners is to attain enlightenment, a state of egoless non-dual awareness, not emptiness, which is merely a tool to cut through ego, which doesn’t exist. Like the harms, the benefits of mediation are also underestimated in the West.
Oxford, UK
Animal experiment is under-inspected
Catherina Becker argues that animal research in the EU is highly regulated, illegal where alternatives exist and vital to medical progress (9 May, p 26). But though the UK boasts of its tight regulation of vivisection, in 2013 just 15.7 full time equivalent inspectors were responsible for policing around four million animal experiments. The disturbing incidents that occur in UK labs, as recorded by the government, such as animals chewing off their own feet or toes, are therefore hardly surprising.
Tonbridge, Kent, UK
Did the emperor see a meteor too?
I was surprised that in discussing meteors, St Paul and Christianity (25 April, p 8) you didn’t also mention the , whose conversion made Christianity the official religion of the Roman empire. If both Paul and Constantine saw meteorites, extra-terrestrial randomness could be responsible for the one-two punch of conversion and militarisation and the subsequent growth of this monotheistic faith.
Nanaimo, British Columbia, Canada
Can chirp clean cosmic echoes?
With Sarah Scoles’s report on radio bursts you show a graph of the delays between the first and last components of each to arrive, and these mysteriously appear in multiples of 187.5 (4 April, p 8). This looks to me like evidence of “stepped chirp” signals.
Radar designers, bats and whales all use “chirp” 鈥� varying the frequency of a signal during a pulse. This maximises the amount of information they can gain about the environment by looking at the reflections of many different frequencies instead.
A knowledge of the degree and nature of the dispersion can be used to de-chirp and thus increase sensitivity to reflected signals. So were the radio signals sent, with a chirp, by someone who hopes eventually to receive reflections?
Or do they result from a natural process, such as laser- or maser-like activity in the shells of old supernovae?
Northlew, Devon, UK
<b>For the record</b>
鈥� No way out: there wasn’t actually an exit for mice to swim to in our article on a pill to prevent stress; ketamine-dosed mice just swam around (30 May, p 14).