Humans

A new book by neurologist Guy Leschziner looks at the astonishing ways some people’s brains interpret the world, offering insight into how we all experience reality

Humans

23 February 2022

By Carissa Wong

Tasting words is one possible outcome of crossed sensory wires in the brainShutterstock/Brian Mueller
The Man Who Tasted Words: Inside the strange and startling world of our senses
Guy Leschziner
Simon & Schuster UKAdvertisement

VALERIA was 14 years old when she realised that most people don’t see colours and feel textures when they listen to music. Now in her mid-20s, when she plays a piano, bright oranges, purples and yellows flow in and out of her sight, accompanied by fleeting feelings of warmth on her face, an ocean breeze or a sharp sensation around the spine.
Valeria has synaesthesia, a phenomenon in which stimulation of one sense generates sensations of another. People with synaesthesia can’t control how their senses join up and many can’t imagine living with any other form of perception.
In The Man Who Tasted Words, neurologist Guy Leschziner explores how the senses, and the neural circuits that underlie them, shape our view of the world. By introducing us to people with rare sensory capabilities such as Valeria, Leschziner highlights that there is no “normal” perception of reality because what we perceive as being “out there” in the world is entirely generated by activity in our brains.
The book title is inspired by James, another synaesthete, who associates words with flavours. In James’s world, a trip on the London Underground is an uncontrollable buffet of flavours. Holborn station tastes of burnt matches and Liverpool Street of liver and onions.
Leschziner alludes to the fact that synaesthesia tends to run in families, but stops short of a satisfying deep dive into the research on how synaesthesia is linked to genetically determined structural changes in the brain.
As well as chronicling the experiences of people like Valeria and James, who have experienced the world in unusual ways since birth, Leschziner explores cases of sensory alteration that have affected people following illness or injury. Each case reads like a short detective story, with puzzling symptoms pieced together from Leschziner’s perspective as their neurologist, supported by quotes from the individuals themselves.
We meet Alison, whose taste for trout while holidaying in Fiji led to a type of nervous system poisoning that reversed her sense of hot and cold. A sip of icy water now causes her lips to burn, while a warm shower feels freezing cold.
We encounter Nina, who lost almost all her sight after a bout of flu as a toddler caused damaging inflammation in her eyeballs. Starved of visual inputs from her eyes, her brain now hallucinates colourful shapes, cartoons and sometimes zombie faces. This is a condition called Charles Bonnet syndrome, which Nina finds distracting and sometimes upsetting, but is, she says, preferable to darkness.
“Each case of sensory alteration reads like a detective story, with puzzling symptoms pieced together”
Leschziner also meets Paul, who can’t feel pain due to a genetic mutation that affects his sensory nerves. He has had a lifetime of injuries caused by a low aversion to danger because he can’t feel the painful consequences of risky behaviour. This has led to so many bone and joint problems that his movement is restricted. Leschziner explores the emotional toll of the condition on Paul and his parents, who lost a 13-month-old daughter with the same condition after her sepsis went undetected because she wasn’t showing signs of distress.
This book is packed with examples of remarkable perception, but it doesn’t stop there. Leschziner also considers how our senses affect the way we all live our lives. Smell, for example, plays a role in our choice of partners in ways that have driven the evolution of our species. He also touches on more philosophical questions, such as how we know what the world is really like, given that we can’t say with any certainty that our experience of it is anything like that of other people.
Throughout the book, Leschziner makes it clear that every person’s reality is as valid as the next. There are, however, moments where he seemingly assumes that the reader experiences all five senses – and in the “normal” way. At other points, there is unnecessary repetition, which detracts from the message he is trying to get across.
Overall, though, Leschziner provides a thought-provoking journey through the fundamental role our senses play in our experience of life and punctures the illusion that our window on the world is the unflinching truth. The fact that it is anything but only makes it more magical.

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Almost 200 people died in the German floods of 2021 because experts couldn’t convince them of impending danger. We must rethink how to get through to the public, says hydrologist Hannah Cloke

Humans

| Comment

23 February 2022

By Hannah Cloke
Simone Rotella
IMAGINATION is one of those powerful human traits that sets us apart from other animals. By reading the word “circus”, your brain automatically conjures up a rich tableau of images and ideas. But you don’t need to be daydreaming of clowns to know that imagination plays a vital role in science.
The advancement of this domain intrinsically requires the birth of new ideas. Einstein famously claimed that imagination was more important than knowledge in the formulation of his theories. When researchers test ideas against reality, imagination is hardwired into the process: the point of science is that it allows you to see the future, to look round corners, to extend the capability of human insight. In that sense, imagination in science is alive and well.
But in another sense, it has an imagination problem. I recently gave evidence to two state-level inquiries in Germany into the July 2021 floods in the west of the country. Both inquiries are exploring why almost 200 people died there in a deluge that was forecast accurately several days in advance. It is a complicated question that will probably yield many answers. I believe a lack of imagination may be partly behind this.Advertisement
The scientists couldn’t imagine that their forecasts, delivered in good time and with accuracy, could be ignored. Municipal authorities couldn’t imagine that such dire forecasts might be correct. And many of the people living in harm’s way just couldn’t imagine what a 9-metre wall of water would do, or how badly they would be affected.
The best scientists use many of their human abilities – imagination and creativity, collaboration, communication and empathy – to make discoveries and reach new insights. Yet when it comes to telling people about them, we can turn into robots, unable to deliver important messages.
All of the most compelling ideas are those conveyed to us in ways that we can see and picture and feel. The big bang is a conceptual theory that no one needs to grasp to stay alive, yet it fundamentally changed the understanding of our existence. If physicists were able to describe it only to other physicists, humanity would be all the poorer.
Putting a human face on non-human phenomena can work too. There is good evidence that naming storms leads people to take action to protect themselves. In the UK, we have had plenty of exposure to this recently. The prospect of Corrie, Dudley or Eunice smashing into your home, as opposed to just seeing a generic warning of “gusts greater than 80mph”, engages your brain in a way that encourages a response.
If naming storms works, then how about naming floods? Would people be more or less likely to respond to a warning and move to higher ground if a rising river was renamed Flood Dave? Such a label may be less accurate to hydrologists, perhaps, than saying that a rise in river levels of 5 metres will lead to flooding with a return period of 20 years. But probably more useful to everybody else.
As with the comet-spotting astronomers in the film Don’t Look Up, or the real-life climate scientists that it is based on, it is a tragedy to see danger ahead when no-one acts to avoid it. The most advanced supercomputers running complex simulations are useless if nobody understands the risks that they foretell.
By ignoring imagination when we convey science, we are shirking our responsibility as scientists. If communicating our findings is important – and sometimes, lives depend on it – then we have a responsibility to undertake the task with as much flair, creativity and passion as we use when we do our research. Logic and reason is fine. But when we can’t move beyond the facts, people may die.

Hannah Cloke is a hydrologist at the University of Reading in the UK (@hancloke)

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A statistical tool borrowed from ecology suggests that there were originally 40,600 copies of stories about King Arthur and other western European heroes – but only 3648 survive

Humans

17 February 2022

By Chris Stokel-Walker
A scene from the Romance of Lancelot of the LakeThe Print Collector/Alamy
Nine in 10 medieval manuscripts telling tales of chivalry and heroism have been lost to time, according to a new estimate that uses ecological statistical models to understand the volume of literature produced.
Katarzyna Anna Kapitan and Daniel Sawyer at the University of Oxford and their colleagues from around Europe borrowed the ecological concept of the “unseen species model” to understand the volume of medieval literature in the genre of narrative fiction that once existed. These medieval texts include the famous stories of King Arthur and of Lancelot.
An unseen species model is a statistical tool that ecologists can use to estimate biological diversity after surveying an area. Chances are that the survey won’t uncover all of the species in the area, but the model can use the number of observed species and their abundances to estimate how many additional species are present.Advertisement
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“These models use the pattern of the observed evidence to estimate what we’re not seeing,” says Sawyer.
In the manuscript study, the researchers looked at the number of surviving copies of each manuscript – which is a little bit like the abundance of a biological species. Their model states that once all copies are missing, the manuscript is lost – a little like a species vanishing from the study area.
They gathered records of 3648 copies of 799 works written in Dutch, French, Icelandic, Irish, English and German. The model then suggested that these copies are part of a population that originally contained 40,614 copies of 1170 works.
“It’s very valuable for our research that we’re stepping beyond the case studies that dominate our field,” says Kapitan – in other words, it is important to engage with the manuscripts that have been lost as well as those that survive.

Using the statistical data produced, the researchers were able to estimate that 62 per cent of copies of English romance and adventure tales have disappeared, compared with 19 per cent of copies of similar manuscripts in Irish, and 23 per cent in Icelandic.
Finding a way to quantify the missing literature is a “holy grail”, says Kathleen Kennedy at the University of Bristol, UK, because it fills the knowledge gaps medieval scholars have about the context of existing work. “Applying statistical models from ecology offers a tantalising workaround, and the team’s findings generally support existing scholarly assessments,” she adds.
However, Kennedy points out it is still just an estimate – even if it is one rooted in statistical rigour. “In the end, we cannot ever prove or disprove either traditional or statistical estimates of lost literary works, or the manuscripts containing them,” she says.
Journal reference: Science, DOI: 10.1126/science.abl7655

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Feedback is our weekly column of bizarre stories, implausible advertising claims, confusing instructions and more

Humans

16 February 2022

Josie Ford
Sleep, perchance to diet
That April is the cruellest month has yet to pass peer review, but there is little doubt February is the shortest. Feedback considers this just as well. Some of our more southerly readers may be sunning themselves on the beach, but in our pre-Arctic stationery cupboard hole, we are just waiting for the winter murk to clear.
It is at this time of year, when we are thinking about getting fit for the bikini season and doing nothing about it, that we want to read, and not question too deeply, headlines such as our own “Getting enough sleep may lower the amount of calories you eat”. The study in question, from a team at the University of Chicago Sleep Research Center, found that an extra hour’s sleep at night allowed participants to cut their energy intake by 270 calories a day – “the equivalent of around three chocolate digestive biscuits”, as the Press Association helpfully put it in its story on the research.
Why stop there? A comforting graph swims into our head of a rising line of hours not consuming calories, crossing over a falling line of calories consumed. The most effective weight-loss mechanism is surely to never get out of bed at all.Advertisement
Getting up the nose
As we take some horizontal exercise, a PR puff is popped our way by a svelte, overslept-looking colleague with a straw hanging from their nose. “To inspire those who struggle to reach their recommended daily intake of water, air up is a world first in food technology that utilises retronasal smell to provide a zero-calorie, zero sugar, zero additive way to drink 100% pure water which tastes flavoured,” we read.
Flavours “from Lime and Orange-Passionfruit to Cola and Iced Coffee” are created by using a special widget to inject bubbles of scented air into the previously 100 per cent blameless water. “We’ve revolutionised the way we drink water. You still have to use your mouth, but the taste has changed!” the company’s website continues. A welcome release for those of us who had been attempting to discover flavour by snorting our water.
Smell my cheese
We note merely in passing a press conference held on 7 February by New York City’s new mayor, Eric Adams, in which he claimed that people wouldn’t be able to tell the difference between “someone hooked on heroin” and “someone hooked on cheese”.
Entirely our experience too. Meanwhile, Adams’s own claim that he eats a vegan diet has been called into question after he was seen eating fish. Given that phylogenetically there is no such thing as a fish, we can’t rule out a plant-based variety. As to the cheese thing, as Twitter user Tyler Conway remarked, “let he who has not snorted grated parmesan off the countertop cast the first stone”.
Sperm waving
If not cheese, SpermTree – “a species-level database of sperm morphology spanning the animal tree of life”, recently described in the journal Scientific Data-promises some real, hard science.
What researchers get up to with descriptions of more than 4700 types of sperm, we hardly need to know. We are busy following an atavistic impulse by downloading the spreadsheet and reordering in descending order of sperm length.
Top of the list by some margin is the fruit fly Drosophila bifurca, with sperm over 5.8 centimetres in length when fully unfurled. This strikes us as a mite exhausting for an insect just a few millimetres long. We aren’t surprised to learn elsewhere that this limits its output to a few hundred cells in its lifetime, an apparent limitation on its reproductive chances that has been dubbed the “big sperm paradox”. This is clearly a sticky problem. Still, we are pleased to learn via a graph in the SpermTree paper that publications on sperm morphology are on the up and up.
Toast’s flip side
“Dear Professor Feedback,” Jonty Rix writes, warming the cockles of our heart. “As a social scientist,” he continues, chilling our blood again, “I am perplexed (and a little disappointed) by the failure of your discussions about the landing outcomes of ‘toast’ to fully consider socio-cultural or post-materialist understandings of the possibilities.”
We are beginning to regret reopening correspondence on the fate of falling buttered toast (8 January). But pray continue. “For example, the nature of upness seems a fundamental problem, as does a lack of a rich consideration of the numerous spaces in which toast is experienced, and of course our underlying definitions of toast and butter and the power relations inherent in their production and usage.”
We nod uneasily, wary of saying the wrong thing. We hope some opening into this whole new metalevel of debate is given by Toby Bateson. He disagrees with our assertion, backed up with references, that toast will always land butter-side down in any universe that supports intelligent bipeds (29 January). “By simply making the toast twice as long it will rotate at half the speed and so will land butter side up,” he writes. “The problem arises due to a fundamental flaw in the proportions of toast which can be adapted to solve the problem in any universe, regardless of table height and the intelligence of the bipeds who made the toast.”
We’re off to have a lie-down and burn some calories.
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Dan Bradica
Visit
A New Nature at White Cube Bermondsey in London spotlights the work of the late Isamu Noguchi, whose sculptures in galvanised steel and other industrial materials explore the fundamental structures of nature.
Chris Reardon/EPIX EntertainmentAdvertisement
Watch
From is a new sci-fi horror show made by the executive producers of Lost. It sees unfortunate travellers trapped in a small town in Middle America, terrorised by strange creatures that only come out at night. The series streams on Epix from 20 February.

Read
A Little Book About the Big Bang by Tony Rothman, a former editor at Scientific American, explores arguably the most evidenced – and at the same time most mysterious – idea in modern cosmology.

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Petrov’s Flu is an ode to Russian sci-fi and absurdist artSergey Ponomarev/Sovereign Films
Petrov’s Flu
Kirill Serebrennikov
In UK cinemas nowAdvertisement
PETROV (Semyon Serzin) is riding a trolleybus home across the snowbound city of Yekaterinburg when a fellow passenger mutters that the rich deserve to be shot. Seconds later, the bus stops, Petrov is pulled onto the street and a rifle is pressed into his hands. Street executions follow. Then, he is back on the bus and it is unclear how much of that actually happened.
Petrov’s Flu is an ambitious, mischievous film, one that is rich in allusions to Russian history, literature and cinema. It is also a painfully precise, gut-wrenching depiction of what it is like to run a high fever. Seeing everything from Petrov’s sick, disjointed point of view, we find the real world sliding away again and again, often into violent absurdity.
Petrov’s fever gradually breaks over the course of the film, but it is a while before we can be confident about what is real and what isn’t: whether his friend, the drunken mischief-maker Igor (Yuri Kolokolnikov), is real and whether Sergey (Ivan Dorn), the struggling writer who browbeats poor Petrov on every point, is a figment of Petrov’s febrile imagination.
At the start, Petrov’s Flu is very much a sci-fi movie. The city is languishing under an epidemic that arrived accompanied by lights in the sky; Petrova (Chulpan Khamatova), Petrov’s estranged wife, is possessed by a demonic alien force during a library poetry reading; UFO-themed street graffiti comes to life and wiggles across the screen.
As reality and hallucination part company, however, it becomes something different: a film about parents and children; about creative work, pretension and ambition; and also, strongly, about Russia’s love of science fiction.
“Petrov’s fever gradually breaks, but it is a while before we can be confident about what is real and what isn’t”
At its birth, Western science fiction, and especially US science fiction, celebrated adventure and exploration. Russian sci-fi has always been more about finding and building homes in a hostile environment. It is also strongly religious in spirit, and was indeed for many years one of Russia’s very few outlets for spiritual expression.
The aliens in Russian science fiction invariably offer some form of redemption to a struggling humanity, and Petrov’s Flu is no exception. One of the most affecting scenes in the film is when Petrov, overcome with fear, dashes with his son to a local hospital, only for the pair to be intercepted by a kindly UFO.
Such are Petrov’s fever dreams, coloured by his space-loving childhood and his adult career drawing comic books. At one point, he remembers his mum and dad decorating a Christmas tree with festive plastic astronauts; at another, Petrova goes on a murderous rampage among the climbing-frame rockets and spaceships of a dilapidated playground.
Fans of Andrei Tarkovsky, director of 1970s science-fiction classics Solaris and Stalker, will enjoy the nods to key moments in those films. But it would be a mistake, I think, to watch this film for the sci-fi in-jokes. True, Petrov’s Flu is a shocking and funny contribution to Russia’s centuries-old tradition of absurdist art. But it is also a film about people, not to mention an extraordinary evocation of febrile delirium and its assault on the mind.
In the end, as fantasy and reality separate, what might have seemed to be a disconnected bag of bits (some tender, some shocking, all horribly entertaining) turns out to be a puzzle that, once complete, leaves us exhausted but satisfied. More

By Sam Wong
StockFood
WHEN cooking food, we need heat to diffuse from the outside to its centre. If we want food to be evenly cooked throughout, this can be a problem: by the time heat reaches the centre, the outside may be overcooked. But in some cases, we can use the slow diffusion of heat to our advantage, to create foods with a surprise in the middle.
One example is a molten chocolate cake, aka a chocolate fondant. Essentially, this is an undercooked cake. The key is to bake it just long enough so that the outside is firm while the centre … More

As sea levels rise due to climate change, heritage sites all around the African coast will come under increasing risk of flood damage – including Carthage and sites linked to the Ancient Egyptian civilisation

Humans

10 February 2022

By Michael Marshall
Sabratha, an ancient Roman town in what is now LibyaSklifas Steven/Alamy Stock Photo
Rising seas will more than triple the number of African heritage sites exposed to the risk of dangerous coastal floods.
By 2050, over 190 of these locations could be in peril. They include the ancient remains of Carthage in Tunisia – which was the capital of the powerful Carthaginian civilisation in the first millennium BC – and a region of the Egyptian Mediterranean coast rich in archaeological sites connected to the Ancient Egyptian civilisation as well as to the Greeks and Romans.
“Understanding climate risk to heritage is critical,” says Nicholas Simpson at the University of Cape Town in South Africa.Advertisement
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Simpson and his colleagues mapped 213 natural sites and 71 cultural sites on the African coast, which were recognised by the UNESCO World Heritage Centre or the Ramsar Convention on Wetlands of International Importance. “We didn’t know the spatial extent, the actual boundaries of most African heritage sites, believe it or not,” he says.
The team then combined this with a state-of-the-art model of sea level rise, which is one of the main consequences of climate change as warming seawater expands and ice sheets melt. Higher seas mean that major coastal floods, when they come, go higher and reach further inland.

At the moment, 56 of the 284 coastal heritage sites the team mapped would be in danger if a once-in-a-century flood struck. However, by 2050 that number will rise dramatically. Under a moderate emissions scenario, 191 will be at risk, and higher emissions will put 198 in danger.
The threatened sites also include Sabratha, a former Roman town in Libya with a spectacular open-air theatre that the Beatles considered as a venue for their final concert, and Kunta Kinteh Island in the Gambia, which has the remains of a fort used by British slave traders.
Elsewhere, up to 44 per cent of the area of the Curral Velho wetland in Cape Verde could be exposed by 2100, under a high-emissions scenario.
The obvious solution is “hard protection strategies” like concrete sea walls, but these may not be the best approach, says Simpson. In some cases, a better tactic would be “hybrid protections” that rely on wildlife, “so just restoring the broader ecology of the area, restoring salt marshes, seagrasses, mangroves”. Buffer zones around the heritage sites are also an option, he says, as is “recognising the local and indigenous knowledge systems that are there”.
It may not be possible to protect everything, says Simpson, but it is essential to try. “I believe there are solutions to climate change if we think hard enough and work hard enough.”
Journal reference: Nature Climate Change, DOI: 10.1038/s41558-022-01280-1

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