Humans

By Alexander McNamara
and Matt Hambly

In the city of Paris, 1794, French mathematician Sophie Germain swerved the École Polytechnique’s ban on women by assuming the identity of a male student who had left. She was able to conduct her studies by taking over his lecture notes and submitting work under his name, only to be rumbled when a professor demanded to meet this young scholar whose work had suddenly improved so dramatically. Luckily for her (and for mathematics), he was sufficiently enlightened to encourage her further, and in 1816 she became the first woman to win a prize from France’s Royal Academy of Sciences.
World Autism Awareness Day is recognised on 2 April
Megapress / Alamy
In 2007, to highlight the issues faced by autistic people around the world, the United Nations General Assembly signed a resolution that 2 April every year would be recognised as World Autism Awareness Day.
Autism is a condition that influences how people perceive the world, which can affect communication and understanding of social stimuli. However, understanding of autism has been skewed by an overly medical focus, says Anna Remington, head of the Centre for Research in Autism and Education at University College London, in a 2018 interview with New Scientist. Autism, says Remington, can bring extra abilities and the differences it produces could just represent diversity.

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Preserving snakes in brandy funded one scientist’s research

Naturalist and scientific illustrator Maria Sibylla Merian was well into her 50s when she set sail for South America, spending two years studying wildlife in Suriname. To recoup her costs, she preserved crocodiles, iguanas and snakes in brandy to sell to rich collectors. She was a meticulous observer, and during her trip she recorded the habits and life cycles of insects, devising a classification system still admired today. She has six plants, nine butterflies and two beetles named after her.
Triassic dinosaurs weren’t very big
Mohamad Haghani / Alamy
The Triassic period started 252 million years ago after the Permian-Triassic extinction event, and in the 50 million years before the next extinction event, huge reptiles evolved and ruled the planet. One particularly fearsome species known as the rauisuchians stretched 9 metres from nose to tail with teeth like steak knives. However, the dinosaurs that existed at the time were much smaller creatures, many not much bigger than a cow. Though they were lacking in stature, some had some unusual features, like Tanystropheus, with a neck twice as long as its body.
We can maintain relationships with only around 150 friends
Clare Jackson / Alamy
Although the number of friends on your Facebook profile might be a long way north of 500, there is a natural upper limit to the number of people you can maintain a stable social relationship with. This is known as Dunbar’s number, and it plays out in many more situations than you might realise. For example, historically it was the average size of English villages, the ideal size for church parishes, and the size of the basic military unit, the company.
There is also a correlation between primate brain size and the size of their social groups. Extrapolate this relationship to the size of a human brain and guess where that leads us? Yes,  around 150 social contacts.
Mount Everest’s summit would be 2 kilometres underwater at the ocean’s deepest spot
Alexmumu/Getty Images
At its deepest point, in an area known as the Challenger Deep, the Mariana trench plunges to a depth of 10,984 metres (36,037 feet) below sea level. This is roughly the same distance below the waves that commercial airliners fly above them, and if Mount Everest were to start at the ocean’s lowest point, at 8849 metres it would still be more than 2000 metres below the surface.

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By Chris Stokel-Walker

Empty stadiums still lead to a home advantage for football teamsStu Forster/Getty Images
Football teams appear to retain an advantage over opponents when playing at home despite there being no fans in the stadium – puzzling those who thought the home crowd helped player performance.
In European football leagues, historical analysis of games shows the home team wins around 50 per cent of matches, with the chance of a draw or home defeat both standing at around 25 per cent. The home advantage has been theorised to be caused by the roar from the crowd geeing up the home players – and possibly intimidating the referee in a way that encourages them to give decisions advantageous to the home team.

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The closure of sports stadiums to fans during the coronavirus pandemic gave Daniel Memmert and his colleagues at the German Sport University Cologne the chance to test these ideas. They looked at data from 40,000 men’s football matches before and after the banning of fans from sports events, including more than 1000 held behind closed doors across Europe.
The researchers found that the referee’s bias towards the home team disappeared in the games played during lockdown, with fewer yellow and red cards given to away teams than in games played in front of fans. But the proportion of away teams winning matches played without fans increased just 7 percentage points across Europe, which Memmert says falls below the level of statistical significance.

“We think territorial behaviour could be one factor for the home advantage,” says Memmert, comparing it to children being more dominant and outgoing in their own homes, and more reserved when visiting a friend’s house.
There were differences by country. In the English Premier League, the likelihood of home teams winning, losing or drawing barely changed, while in the German Bundesliga, home teams were 15 percentage points more likely to lose during the pandemic.
The findings are “striking”, says Joey O’Brien at the University of Limerick, Ireland. But he cautions against using them to draw firm conclusions. “The data used was in the later stages of most of these leagues,” he says: some games at this stage may be less competitive because the teams they feature are safe from relegation, but also not challenging for the league’s top spots.
Yet as sport carries on behind closed doors, the availability of almost an entire season of data without spectators will firm up the hypotheses, says O’Brien.
Journal reference: PLoS One, DOI: 10.1371/journal.pone.0248590

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Josie Ford
Lunar living
“Fancy buying a house on the Moon?”, an email that plops into Feedback’s inbox asks, continuing, before we have a chance to say, “Not particularly”, “It would cost you £234k a MONTH!”
“With Earth becoming increasingly populated and space technology advancing, it won’t be long before lunar living becomes the new normal,” this email, which appears to have come from a price comparison website, asserts. Yes, they were saying that back in ’69, too.
Mind you, recent revelations about lunar infrastructure developments such as kilometres-high concrete towers and fully operational sperm banks (20 March) might be enough to convince us this is an idea whose time has come.

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Alas, “Living on the moon is not as simple as life on Earth” – a statement Feedback would definitely describe as the under-variety. Building and transport costs, land licences and a property markup of 27.61 per cent, plus such boondoggles as solar panels, industrial-strength heaters and meteor-proof windows, mean we are looking at a surprisingly precise £44,525,536.42 for a first-time buy. Plus £1 billion for the nuclear-powered option.
What planet are they on, we can only ask. Although, considering the pre-pandemic prices of some of the real estate we see from our London penthouse stationery cupboard, the answer might well be Earth.
Lost in the post
In that pre-pandemic spirit of peering moodily into estate agents’ windows wondering who lives in a house like that, we find ourself moved to browse the Lunar Registry. This is the virtual shop window of the International Lunar Lands Authority, a body tasked – by itself, we presume – “with administering and allocating real property located on Luna, Earth’s Moon, and registering ownership claims to properties on the Moon on behalf of individuals and business entities around the world”.
Vast lava plains are very much in this season, we note, with land parcels on the hopefully named Mare Imbrium, or Sea of Rains, commanding an impressive $130.26 per acre at our time of looking (with a 35 per cent discount on 10 acres). Meanwhile, the going rate for an acre on the Sea of Tranquillity – the historic scene of the Apollo 11 landings – is just $52.61. Anticipation of just too many darn tourists blasting in and out and parking their moon buggies on the verges, we imagine.
Sad to read, though, that shipments of titles to lunar land outside the US may be subject to delays and restrictions owing to pandemic-related postal problems. Feedback considers this an unexcitingly 20th-century technology to rely on. Those in a hurry can download a PDF, but we are holding out for delivery on one of Elon Musk’s rockets, preferably one that doesn’t explode shortly after touchdown.
On second thoughts, we’ll wait for the post. Even this pandemic will be over before it’s time to assert our lunar land rights.
Coming out in the wash
We are as mystified as Ros Hancock by an ad for washing machine cleaning tablets that keeps popping up in her Facebook feed. “According to experts, the rate of bacteria counts exceeding the standard for household washing machines is as high as 81.3%,” it states.
We think it is trying to say that our assumption that washing machines are largely self-cleaning is invalid, perhaps by as much as 81.3 per cent. Whether we need a “triple Active Oxygen Decontamination Complex” to remove 99.9 per cent of bacteria and other pathogens lurking in the drum among our errant smalls is another matter. Another of our assumptions is that the remaining 0.1 per cent will soon reoccupy the vacated space.
Pray for a vaccine
Stuart Arnold was casting around for vaccination centres with available appointments near his home in south-west France when he happened upon one in Lourdes.
The tourism authorities might have wanted to keep that one quiet, he suggests – pilgrimages to the town for healing via other means being a thing. On the other hand, Stuart, if it works for you, how are we to tell whether it was the vaccine or St Bernadette?
Full of beans
Somehow it is always Feedback’s colleagues who are pressing the latest research on how caffeinated beverages improve productivity from their jittering hands into ours. We say “research”; we actually mean a PR puff dreamed up by someone with an interest in selling coffee and related products. An easy enough mistake to make in the early-morning brain fog.
As ever, though, it raises more questions than it answers. If an espresso boosts productivity by 80 per cent (an average of five standardised tasks done in an hour before drinking a shot, nine after), we are left wondering why latte drinkers could only manage two tasks in the same time frame before a caffeine infusion. Equally, we marvel at how the tip-top productivity of drinkers of Irish coffee was improved still further by a nip of the hard stuff. Well, it has been our saviour during lockdown.
Plain vanilla
Yes, that is Carolyn Beans you see writing about vanilla on page 46. Over and out.
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Humans need all the help they can get from their senses to stop them making mistakes with their varied diet. Let’s hear it for aroma and flavour that helped make them what they are, say Rob Dunn and Monica Sanchez in their fascinating book Delicious

Humans

31 March 2021

By Simon Ings

Humans have long searched for complex flavours in our foodPublic Domain/The Metropolitan Museum of Art
Delicious: The evolution of flavor and how it made us human
Rob Dunn and Monica Sanchez

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Princeton University Press
HOW do we know what to eat? Dolphins need only hunger and a mental image of what food looks like. Their taste receptors broke long ago and they no longer detect anything but salty flavours, thriving on hunger and satisfaction alone.
Omnivores and herbivores, on the other hand, have a more varied diet – and more chance of getting things badly wrong. They are therefore guided by much more highly developed senses of flavour and aroma.
In Delicious, evolutionary biologist Rob Dunn and anthropologist Monica Sanchez weave together what chefs know about the experience of food, what ecologists know about the needs of animals and what evolutionary biologists know about how our senses evolved. Together, this knowledge tells the story of how we have been led by our noses through evolutionary history, turning from chimp-like primate precursors to modern, dinner-obsessed Homo sapiens.
Much of the research described here dovetails neatly with work described in biological anthropologist Richard Wrangham’s 2009 book Catching Fire: How cooking made us human. Wrangham argued that releasing the calories bound up in raw food by cooking it led to a cognitive explosion in H. sapiens around 1.9 million years ago.
As Dunn and Sanchez rightly point out, Wrangham’s book wasn’t short of a speculation or two: there is, after all, no clear evidence of fire-making this far back. Still, they incline very much towards Wrangham’s hypothesis.
“The loss of a bone that helped separate our mouth from our nose had consequences for human olfaction”
There is no firm evidence of hominins fermenting food at this time either – indeed, it is hard to imagine what such evidence would even look like. Nonetheless, the authors believe it took place. They make a convincing, closely argued case for their rather surprising contention that “fermenting a mastodon, mammoth, or a horse so that it remains edible and is not deadly appears to be less challenging than making fire”.
“Flavor is our new hammer,” the authors admit, “and so we are probably whacking some shiny things here that aren’t nails.” It would be all too easy, out of a surfeit of enthusiasm, for them to distort their readers’ impressions of a new and exciting field, tracing the evolution of flavour.
Happily, Dunn and Sanchez are scrupulous in the way they present their evidence and arguments. As primates, our experience of smell and flavour is unusual, in that we experience retronasal aromas – the smells that rise up from our mouths into the backs of our noses. This is because we have lost a long bone, called the transverse lamina, that helps to separate the mouth from the nose.
The loss had important consequences for olfaction, enabling humans to search out tastes and aromas so complex that we have to associate them with memories in order to individually categorise them all.
The story of how H. sapiens developed such a sophisticated palate is also, of course, the story of how it contributed to the extinction of hundreds of the largest, most unusual animals on the planet. Delicious is a charming book, but it does have its melancholy side.
To take one dizzying example, the Clovis people – direct ancestors of roughly 80 per cent of all living Indigenous populations in North and South America – definitely ate mammoths, mastodons, gomphotheres, bison and giant horses. They may also have eaten Jefferson’s ground sloths, giant camels, dire wolves, short-faced bears, flat-headed peccaries, long-nosed peccaries, some tapir species, giant llamas, giant bison, stag moose, shrub-oxen and Harlan’s muskoxen.
“The Clovis menu,” say the authors, “if written on a chalkboard, would be a tally of a lost world.”

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By Alison George

Calcite crystals collected by humans more than 100,000 years agoJayne Wilkins
A cache of beautiful crystals collected 105,000 years ago in South Africa is shedding new light on the emergence of complex behaviours in our species.
A team led by Jayne Wilkins at Griffith University, Australia, discovered 22 distinctively shaped white calcite crystals at a site in the Kalahari desert called Ga-Mohana Hill North Rockshelter. “They are little rhomboids, really visually striking,” says Wilkins.

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These geometric crystals didn’t originate at the site and haven’t been modified, so seem to have been deliberately collected and brought to the rock shelter for ornamental purposes. “They don’t seem to have been used for everyday tasks,” she says.
The collection of beautiful items seems like a normal thing for humans to do today, but this so-called symbolic behaviour only emerged around 100,000 years ago. “Collecting these kinds of pretty objects for non-utilitarian reasons could have its roots in symbolism and arts and culture,”  says Wilkins.

Also found at the site were 42 fragments of burnt ostrich egg shell. The large egg shells may have been used by humans to store and transport water – offering more evidence of human innovation.
These discoveries in the Kalahari, 600 kilometres from the sea, are challenging the prevailing assumption that the emergence of complex behaviours like symbolism and technological innovation emerged at the coast, where humans had access to seafood containing nutrients thought to support brain growth.
Until now, the earliest evidence of symbolic behaviour was found at sites close to the sea, such as 100,000-year-old engraved ochre from Blombos cave and 60,000-year-old decorated ostrich egg shells from the Diepkloof rock shelter, both on the South African coast.
“In the Kalahari, which is really far from the coast, we are seeing the same kinds of behaviours, at the same time,” says Wilkins.
Journal reference: Nature, DOI: 10.1038/s41586-021-03419-0

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By Michael Marshall

Coarse pottery that was used to help extract salt from seawaterS.J. Sherlock
Stone Age Britons extracted salt from seawater using industrial-style processes more than 5500 years ago. The discovery means people in Great Britain were producing salt thousands of years earlier than thought, before the Bronze Age.The technology may have been brought by migrants arriving from mainland Europe.
“It changes how we think about Neolithic society,” says Stephen Sherlock, an independent archaeologist based in Redcar, UK.

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In mainland Europe, there is evidence of salt production from the heating of salty water as early as 6050 BC during the Neolithic: the last period of the Stone Age, before the invention of bronze. However, in Britain the earliest known evidence was from Brean Down in Somerset, where Bronze Age people were making salt around 1400 BC.
Sherlock has been excavating for many years at Street House, near the town of Loftus in north-east England. The site was occupied from the Neolithic, about 5700 years ago, into the later Bronze Age and the Iron Age that followed, and as recently as the 7th century AD in the Anglo-Saxon period of English history.

Geophysics revealed a buried structure about 200 metres from a Neolithic house, so Sherlock began digging.
“It was sealed by about a metre of clay,” says Sherlock. Beneath that was a distinctive pit measuring 2.8 metres by 2 metres, with a narrow trench leading into it. Three areas of the pit had been intensely burned, leaving charcoal deposits: Sherlock argues these were hearths. A hazelnut shell in the charcoal layer was radiocarbon dated to between 3766 and 3647 BC.
Similar structures are known from Iron Age deposits in Britain and are generally interpreted as “salterns” used for extracting salt from seawater. The water was placed in large ceramic pots, supported by stones over hot flames. The heat evaporated the water, leaving salt crystals. Sherlock found shards of pottery of a low quality characteristic of salt production.
“I showed these finds to salt-making experts,” says Sherlock. “They said you’d expect to find that in the Iron Age.”
Salt would have been the most valuable commodity in society, says Sherlock. It was hard to obtain and could be used to flavour or preserve food, for instance. “The people who controlled salt are going to be some of the richest.”
Journal reference: Antiquity, DOI: 10.15184/aqy.2021.25
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By Alexander McNamara
and Matt Hambly

Mohamad Haghani / Alamy
The Triassic period started 252 million years ago after the Permian-Triassic extinction event, and in the 50 million years before the next extinction event, huge reptiles evolved and ruled the planet. One particularly fearsome species known as the rauisuchians stretched 9 metres from nose to tail with teeth like steak knives. However, the dinosaurs that existed at the time were much smaller creatures, many not much bigger than a cow. Though they were lacking in stature, some had some unusual features, like Tanystropheus, with a neck twice as long as its body.
We can maintain relationships with only around 150 friends
Clare Jackson / Alamy
Although the number of friends on your Facebook profile might be a long way north of 500, there is a natural upper limit to the number of people you can maintain a stable social relationship with. This is known as Dunbar’s number, and it plays out in many more situations than you might realise. For example, historically it was the average size of English villages, the ideal size for church parishes, and the size of the basic military unit, the company.

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There is also a correlation between primate brain size and the size of their social groups. Extrapolate this relationship to the size of a human brain and guess where that leads us? Yes,  around 150 social contacts.
Mount Everest’s summit would be 2 kilometres underwater at the ocean’s deepest spot
Alexmumu/Getty Images
At its deepest point, in an area known as the Challenger Deep, the Mariana trench plunges to a depth of 10,984 metres (36,037 feet) below sea level. This is roughly the same distance below the waves that commercial airliners fly above them, and if Mount Everest were to start at the ocean’s lowest point, at 8849 metres it would still be more than 2000 metres below the surface.

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By Karina Shah

A deed written on sheepskin parchment from 1499David Lee
Sheepskin was the most commonly used parchment for legal deeds over the past five centuries in Great Britain, even though it is quite fragile. This is most likely because fraud can be more easily detected on it than on vellum.
Sean Doherty at the University of Exeter in the UK and his colleagues analysed 645 pages from 477 legal deeds concerning property in England, Scotland and Wales dating from 1499 to 1969.

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They first cut a 2-square-millimetre sample of parchment from the edge of the documents. “We made sure to be well away from the text, any stamps and wax seals,” says Doherty.
The team then chemically treated the animal skin to isolate the protein collagen, which is made up of a mix of sub-units called peptides. “Each animal has a different set of peptides that make up collagen – it is species variable,” says Doherty. This let the researchers work out what type of parchment each deed was written on.
They found that 622 of the 645 pages were made from sheepskin, which was a surprise, as previous research suggested these types of documents were made with a variety of animal skin – most commonly vellum, which is made from calfskin.
“We expected to see a wide range of animals, but they pretty much all turned out to be from sheep,” he says.

Doherty and his team suspect that sheepskin was used for important deeds because it is difficult to alter without being noticed due to its high fat content.
When animal skin is first processed, it is submerged into an alkaline solution of chalk. This draws out the fat and removes any hair, leaving behind the dermis layer of the skin which is then stretched into parchment.
Sheepskin is between 30 to 50 per cent fat, compared to just 2 to 3 per cent in cattle and 3 to 10 per cent in goats. The removal of the fat causes sheepskin parchment to be very fragile. “The layers will detach because it has all these holes in it where the fat once was,” says Doherty.
As a result, you can see a visible mark where text has been altered on sheepskin more easily than other animal skins, which is useful for important documents.
“If someone intentionally tried to alter a word on a deed made of sheepskin, they would leave behind a telltale smudgy residue,” says Heather Wolfe at Folger Shakespeare Library in Washington DC, who wasn’t involved in the research.
Journal reference: Heritage Science, DOI: 10.1186/s40494-021-00503-6

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