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Let the people map out their own footpaths

Readers’ comments on highway design made me think of one of my little “soap box moments” (Letters, 22 February). I have seen many grassed areas across which architects have laid attractive-looking walkways, only for the public to ignore these and take more expedient routes across the grass, creating muddy tracks.

Would it not be better to simply grass the whole area, wait for people to decide which way to cross it and then lay down paths along those routes? These may not look the most attractive on paper, but they would be more efficient.

For the record – 21 March 2020

• There was some understanding of silver’s antibacterial action before work on flagella revealed a new mechanism (7 March, p 15).

Let's not use these below-average earnings figures

Why do you use mean salary in your annual survey of science earnings? Most employees will probably earn less than this average figure (29 February, p 22).

In 2019, the median income for full-time workers in the UK was £30,353 and mean earnings were £37,428 per year. A relatively small number of high earners skews these figures.

The median is the preferred measure: 50 per cent of salaries are less than it. In the UK, about two-thirds of full-time salaries are less than the mean.

Can we be sure that burial was by Neanderthals?

Michael Marshall reports that evidence at Shanidar cave in Iraq suggests a Neanderthal corpse, known as Shanidar 4, was buried in a grave (29 February, p 19). Can we rule out that the burial was conducted by a human, given that archaeologist Emma Pomeroy, who was part of the team behind the discovery, says humans were displaying such behaviour at the time?

I sometimes play hide-and-seek with curious spiders

You report on spiders’ intelligence extending beyond their bodies (8 February, p 42). I have often wondered about this when watching orb-web spiders spinning their webs: they seem to use a leg to “measure” the distance between strands.

I sometimes play hide-and-seek with black-headed jumping spiders – perhaps I have too much free time on my hands. I move my pointed finger slowly towards one until it backs away. Then I move my finger away, and the spider follows and touches it, showing what seems to me to be curiosity.

I want us to curb the internet of everything

A group of astronomers has called for legal action to stop the launch of vast numbers of satellites (8 February, p 14). They aren’t the only people who should be concerned. Thousands of low-orbit satellites are being launched annually to provide universal secure internet services.

But the carbon emissions of the rockets used to launch them, plus the energy required to run the “internet of everything”, guide our driverless transport systems and so on, will increase greenhouse emissions. It has been reported that on-demand video alone could produce a substantial proportion of global greenhouse emissions by 2025. Will the world at large voluntarily reduce its dependence on such technology?

Perfectly free choice could only be the throw of a die

Richard Webb notes a connection between “agency” and thorny concepts like free will (15 February, p 34). The problem of free will vanishes once it is accepted to be illusory.

Webb details his decision not to adopt a puppy, listing internal, external and historical considerations that influenced it. This is always the way: agency is contingent. Choices may be good or bad, but a perfectly free choice could only be random.

It would be like binding oneself to the outcome of a dice-throw, as in that dreadful old hound by Luke Rhinehart, in which a psychoanalyst stakes everything on the throw of a die.

Better bricks from bacteria must still breach barriers

Your report on living concrete made with bacteria suggests a product that is comparable to a mortar mix (25 January, p 18). The group claims to produce blocks at ambient temperatures, using desert sand as aggregate, with strengths at least equal to industry standard lightweight blocks.

Sadly, vital technologies such as these must first overcome the inertia of established concrete-devouring industries and of risk-averse people who specify construction materials.

Other university students with almost no brain

Jessica Hamzelou reports on a bright teenager with half a brain who plans to go to university (15 February, p 10). The late John Lorber, professor of paediatrics at the University of Sheffield, several more extreme cases.

The most striking was that of a young man whose hydrocephalus meant that he was missing almost his entire brain – yet he was studying mathematics at university.

Editor's pick – Flaws and a ray of hope in pandemic policy (1)

It seems very likely that, to slow the spread of covid-19, many people will be encouraged to self-isolate (29 February, p 7). This policy poses risks to local food banks and similar aid organisations. Hungry people may go to food banks and come into contact with others who could be in a poor state of health. At the time of writing, those on zero-hour contracts – whose employer has no obligation to provide minimum working hours – may have no money to buy necessities, even if they have a friend who can shop for them. They are well-represented among food-bank users.

A self-isolation policy assumes that people have both the financial and the social capital to survive for two weeks. Many visitors to the food bank with which I am involved have neither.

Scooters should announce their approach to be safe

Donna Lu concludes that though e-scooters are a disaster for cities, we must embrace them as a lesser evil than cars (29 February, p 25). I suggest they should be manufactured to emit a sound, such as a buzzing or whistling noise, when moving, so pedestrians know there is one coming up behind them.

Their quietness is so dangerous. People who move unexpectedly on the pavement to look in a shop window and forget to look behind them first could be injured.

We have to set net-zero carbon targets at scale

Graham Lawton draws attention to some of the subtleties of meeting targets for net-zero carbon emissions (8 February, p 24). Another arises when a relatively small area – that of a district council, say – sets such a goal. Too often, this means exporting surplus solar electricity during the day to offset usage at night. If many neighbouring areas do that, it doesn’t scale: there is no one nearby to export to.

The benefits of sorting stuff in alphabetical order (2)

The principal benefit of traditional alphabetical order is felt in reference material. Although the corpus of reference texts available and searchable electronically grows ever larger, many of us find that the text we want isn’t available, or is very expensive compared with a paper copy. In these cases, the index – and sometimes the body of the work – is arranged by the traditional alphabet, which anyone who wishes to find information in such a text must know.

The benefits of sorting stuff in alphabetical order (1)

Why not change the order in which we teach the alphabet to the QWERTY keyboard layout, Linda Phillips asks (Letters, 29 February). Well, not every language that uses the Latin alphabet uses that keyboard arrangement. As someone who touch-types, I frequently put spellcheckers to the test when visiting customers in France and Germany, where some keys aren’t where my fingers expect them.

The sequence of the letters has never been relevant to learning to write by hand. Its utility doesn’t disappear even if people mostly type. An agreed order is critical for sorting – allowing us to retrieve information efficiently. The ABC sequence is also useful because it maps onto other character sets, such as Greek and Cyrillic.

We aren't smiling at this work on expressions (2)

Young’s discussion of facial expressions was fascinating, not least for reporting research where subjects were asked to match the “right” emotion to images of posed facial expressions. But how good were the posers?

I wonder, too, how our reading of facial expressions is affected by the phenomena of “selfie faces” and by what I call “TV-reaction faces” that people put on to display an expression as if they were characters in a soap opera.

We aren't smiling at this work on expressions (1)

Emma Young’s article on facial expressions was very interesting (15 February, p 44). I was particularly taken with – though not surprised by – the implication that the FBI, other agencies and even commercial operations may be funding, and drawing conclusions from, questionable practices. These include programmes designed to train agents to spot signs of fear, stress and deception in people’s faces and body movements.

Sadly, some law-enforcement agencies have form in this. Such organisations spend vast sums on polygraph “lie-detector” machines and on people who claim they can decipher their output objectively, despite the overwhelming evidence that false positives are common and false negatives are easy to induce (25 May 2019, p 18). They present probabilistic DNA and fingerprint evidence as incontrovertible fact, and so on.

I have no doubt that innocent people have been incarcerated – or in certain jurisdictions worse – as a result of legal professionals and juries taking this so-called expert testimony at face value, and that there are offenders at large because they were discounted using the same reasoning.

Editor's pick – Flaws and a ray of hope in pandemic policy (3)

You report that, in some countries, many new covid-19 cases can’t be traced to their source of infection. A test exists for the virus itself, but is it also possible to deploy one for antibodies to the virus?

Such a test would help detect transmission chains by revealing those who have recovered from covid-19. It would also allow its morbidity and mortality rates to be more accurately determined, simply by randomly sampling the population of an infected area.

The editor writes:

We have since reported online that many labs are trying to develop tests for the antibodies (6 March, newscienti.st/NS-tests).

Editor's pick – Flaws and a ray of hope in pandemic policy (2)

The measures we are being encouraged to take to avoid covid-19 are equally effective against influenza. Will there be fewer cases of flu this year?