Humans

New research reveals that miscarriage serves a critical role in human evolution – and in some instances, may even be associated with optimal fertility

Health 5 August 2020
By Alice Klein
WHEN I saw the positive result on my at-home pregnancy test, my mind raced ahead. I imagined how it would feel to hold my child for the first time, what we would call them. I thought of the bedtime stories we would read, pictured family camping holidays at the beach.
I never imagined that, just weeks later, while dancing at a friend’s wedding, a sharp twisting pain would signal that the pregnancy was over.
Like many women who have a miscarriage, I worried I had done something to trigger the loss. Had I exercised too hard? Slept too little? Around the world, studies show that many women experience shame and guilt after losing a pregnancy. One US survey found that 40 per cent of women who had a miscarriage believed it was because of something they did wrong. Though there is no evidence covid-19 increases miscarriage risk, the pandemic only exacerbates these worries. Society can add to the problem. In some countries, the culture of blame is so widespread that losing a pregnancy can land a woman in jail.
When I looked into the latest research, what I discovered not only challenged ideas that women are somehow responsible for their miscarriages, or experience them because something is wrong, but suggested that, surprisingly, they are usually associated with optimal maternal health. With advances in fertility medicine, we are finally starting to understand what happens in a miscarriage. This progress may offer solace when pregnancies don’t work out and help women struggling to become pregnant. It could even shed light on the role of miscarriage in our evolution. … More

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

Humans 5 August 2020

Josie Ford

Cursed crescent
One time, on a particularly cloudy holiday with friends, Feedback glanced up at the sky and noticed a dim ball of light floating not far above the horizon.
“Look at that,” we said, for want of anything more interesting to say. “It’s the day-moon.”
Readers, it was not the day-moon. It was, in fact, the sun.

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What this anecdote serves to illustrate is that if something has been askew in the heavens of late, Feedback would be among the last to notice.
So you can imagine our surprise at discovering that a coven of “baby witches” has hexed the moon. Or, at least, so says the internet.
It appears that in an occult corner of the social networking app TikTok – known as WitchTok to its friends – a group of young witches decided to cast a curse on the moon. This appears to have caused all sorts of turmoil within the witchcraft community, and no little amusement outside it.
For, after all, we people of science know that the moon cannot be hexed. The moon isn’t some primordial reservoir of arcane energy to be used in witchcraft. It is a symbol for mutually antagonistic countries to race towards in an attempt to prove the relative superiority of their way of life. Much more sensible.
Lean times
A worrying trend in the Feedback inbox of late is the amount of attention that nominative determinism spotters are devoting to New Scientist itself.

We pass no judgement on this, but point ominously at a drawing of a snake eating its own tail while muttering about infinite recursion under our breath.
This week, for example, James Haigh writes in to comment on the name of an expert quoted in an article on public health policy regarding obesity.
“Michael Lean interviewed for the ‘Public health’s hard problem’ article??” asks James, making excellent use of the lesser-spotted (well, double-spotted, really) double question mark. “You couldn’t make this stuff up.”
Rumbling on
Some weeks ago, Feedback invited readers to send in the opening lines of limericks that we would do our humble best to complete.
Thank you to Ted Webber for throwing down the first gauntlet, based – in his words – on a New Scientist cover story. The opening line he wanted us to riff off was “If consciousness lies in our gut”. Well, Ted, here you go. Don’t say you didn’t ask for it.
If consciousness lies in our gut,
Then what is the role of the butt?
Neither Kant nor Foucault
Have pretended to know,
But to us it seems: open and shut.
Don’t be a square
Big news for geometry fans this week, as a German court has ruled that the Ritter Sport brand of chocolate can keep its trademark on square-shaped bars.
In its report, the BBC referred to the case as reinforcing Ritter’s “three-dimensional monopoly”, which – while being a charming phrase – perplexed Feedback. It goes without saying that the chocolates are three-dimensional: to our knowledge, no one has yet derived any pleasure from licking an atom-thick layer of chocolate spread off a graphene substrate.
But the trademark specifically covers square chocolate, not cubic chocolate. This, we are afraid, is a two-dimensional monopoly. And the reason we are afraid to say it is because the last time we checked, Hasbro had the trademark on that.
New chip on the block
While we are on the subject of chocology (chocolatey topology), Feedback was intrigued by a story this week about the quest to redesign the chocolate chip.
It turns out that the conventional tear-drop shaped chocolate chip, while effective in a brute force sort of way, lacks the geometrical finesse that chocolate chip cookie bakers wish it would have.
Namely, according to The Times, “it lacks a broad surface area to maximise taste and texture”. That is why Remy Labesque at Tesla – yes, electric car maker Tesla – has spent three years attempting a chocolatey redesign.
The new shape is a squashed diamond that tapers in three directions to maximise the textures it can achieve when melted. It is aesthetic, allegedly scientific and above all tasty. Feedback will be awaiting future updates with heavy and bated breath.
Good knights
There have been times of late, what with all this plague business going around, that the world has seemed to take on a distinctly medieval hue.
If you find this state of affairs discomfiting, then Feedback’s suggestion is that you stay well away from the Swedish island of Gotland. According to a report in The Times, the powers that be on Gotland have commissioned a troupe of knights on horseback to patrol the area around the ferry terminal, reminding people to socially distance.
The article is sadly lacking in detail about how exactly these reminders are to be enforced. At the point of a lance, perhaps? Or through several layers of PPE chainmail? Either way, the convergence of Sweden, medieval knights and global pandemic has a certain The Seventh Seal-iness about it that is making Feedback shiver.
Got a story for Feedback?
You can send stories to Feedback by email at feedback@newscientist.com. Please include your home address. This week’s and past Feedbacks can be seen on our website. More

Solving the Conway knot problem took mathematician Lisa Piccirillo on a journey into the fourth dimension. Here’s how she did it

Humans 5 August 2020
By Chelsea Whyte

Rocio Montoya

OVER the course of one week in 2018, Lisa Piccirillo cracked a mathematical problem that had gone unsolved for half a century. Posed by legendary mathematician John Conway in 1970, it concerns a complex geometrical object known as the Conway knot. While an ordinary overhand knot – the kind you would tie at the end of a thread – sees the string cross over itself three times, the Conway knot has 11 crossings. What Conway wanted to know is whether his knot can be formed by cutting a slice out of a more complex four-dimensional knot – or, as mathematicians put it, is it “slice”?
Piccirillo discovered that it isn’t. Her breakthrough came after finding a back door into the problem that could help mathematicians understand other four-dimensional objects. Currently a post-doctoral mathematician at Brandeis University in Waltham, Massachusetts, solving the Conway knot – along with her other research – has seen her offered a tenure-track position at the Massachusetts Institute of Technology. New Scientist spoke to her about the week she spent on the problem, her approach to mathematics and why it is time we stopped talking about geniuses.
Chelsea Whyte: How did you first become interested in mathematics?
Lisa Piccirillo: As a kid, I always liked maths and I was good at it in school. I’m from quite a rural area in Maine, and people said “if you like maths, you can become an engineer”. So I thought that’s what you do with maths, become an engineer. I went to a lot of day camps for engineering and made a lot of bridges out of popsicle sticks, and found out that … More

Hugging has benefits for our health that might make it worth doing despite coronavirus risks – here’s how to reduce the chance you’ll pass on the virus

Health 5 August 2020
By Linda Geddes
Hugs are less hazardous if they are brief and people wear face coverings
Jesus Merida/SOPA Images/SIPA USA/PA Images

IF THE pandemic has left you craving a cuddle, you aren’t alone. Some 60 per cent of people in the US reported feeling touch-deprived during the first month of lockdown, suggests a new study, even though only a fifth of those surveyed lived alone.
Tiffany Field at the University of Miami in Florida and her colleagues surveyed 260 adults and found that those reporting touch deprivation scored higher on scales measuring anxiety, depression, fatigue, sleep issues and post-traumatic stress.
Touch deprivation was more common in people living alone, but also affected those living with family or friends. “Only 33 per cent of people said they were touching their partner a lot, and as many as 37 per cent said they weren’t touching them at all,” says Field (Medical Research Archives, in press).

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A separate study of more than 1000 US adults found that those who frequently hugged, kissed or met up with friends and family in lockdown were 26 per cent less likely to report symptoms of depression and 28 per cent less likely to report loneliness, regardless of whether they were married or cohabiting. Regular video chats didn’t show the same benefits (medRxiv, doi.org/d5hf).
“We saw stronger mental health benefits from types of contact that involved touch, which aligns well with the benefits we know come from close touching, like decreased heart rate, higher levels of oxytocin and lower levels of cortisol,” says Molly Rosenberg at the Indiana School of Public Health in Bloomington, who led the work.
Given these benefits, is a quick hug out of the question? Rosenberg stresses the importance of limiting contact with non-household members to prevent the spread of the coronavirus, and most governments continue to advise people to maintain a distance of at least 1 metre from others.
But proximity isn’t the only factor. “Because most hugs are just a brief encounter – and the short time is really key here – I think there are ways to lower the risks to what is, to me, an acceptable level, especially given the benefits of hugging,” says Linsey Marr at Virginia Tech in Blacksburg.
Avoiding face-to-face contact is key. Marr recommends face coverings, pointing faces in opposite directions and not touching the other person’s face or clothing with your face. “This is not a spontaneous act: you have to plan, and you should ask consent,” she says.

“Most hugs are just a brief encounter, and there are ways to lower the risks”
“It would also be prudent to wash your hands before and after you hug, and maybe not exhale,” says Margaret Hosie at the University of Glasgow, UK.
Experts emphasise hugging isn’t risk free and shouldn’t be routine. It should also be avoided by those in high risk groups or showing any symptoms of illness. Even so, “I believe we are at a stage of the pandemic in which we should all be able to make our own risk assessment, based on what is now known about the virus and its transmission patterns, and then act accordingly”, says David Heymann at the London School of Hygiene & Tropical Medicine.
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By Michael Marshall
A hunting kit used by the San people and thought to be 150 years old
Marlize Lombard (with permission

Hunter-gatherers in Africa may have been using poison-tipped arrows for more than 70,000 years, according to a new analysis of ancient arrowheads.
This would be the oldest known use of poison arrows in the world, says Marlize Lombard of the University of Johannesburg in South Africa.
In southern Africa, Kalahari San people have used poison-tipped arrows to hunt for thousands of years. They often obtain poisons from the intestines of the larvae of Diamphidia leaf beetles. But it isn’t … More

By Jason Arunn Murugesu
Some early European farmers seem to have been much better off than others
Chelsea Budd/Umeå University

A wealth gap may have existed far earlier than we thought, providing insight into the lives of some of Europe’s earliest farmers.
Chelsea Budd at Umeå University in Sweden and her colleagues analysed the 6600-year-old grave sites of the Osłonki community in Poland, to try to determine whether wealth inequality existed in these ancient societies.
The team first found that a quarter of the population was buried with expensive copper beads, pendants and headbands. But this doesn’t necessarily mean that these people were richer during their lifetimes.

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“The items could simply have been a performance by the surviving family members,” says Budd. “It could be used to mitigate the processes surrounding death or even to promote their own social status.”
Budd and her colleagues therefore analysed the carbon and nitrogen isotopes in bones from the graves, which can give an insight into the quality of diet during life. “The human skeleton is an independent archive,” says Budd. “It can’t be influenced.”

The team examined the bones of 30 people who lived within 200 years of each other, looking at 29 adults – aged between 18 and 45 – and one child. About 80 per cent of the bones found in the area belonged to cattle, and the group analysed those too.
Those buried with copper had a distinctive balance of carbon isotope ratios in their bones. The researchers found that this unusual balance was also seen in a subset of cattle bones found in the area, which suggests that the people buried with copper ate meat from these animals.
Budd’s team speculate that the cattle in question may have grazed on productive, brightly lit open pastures, because plants growing in such pastures would have similarly enriched carbon isotope values. This isotopic balance isn’t seen in plants that grow in less productive tree-shaded pastures. This suggests people buried with copper had access to lands and livestock that their counterparts didn’t.

Budd speculates that this could be linked to different levels of land ownership and wealth. Moreover, because these isotopic shifts were found in multiple generations and farming land is often inherited, Budd suggests the wealth gap may have been passed down.
“We’ve never found such inequalities in this period before,” she says.
“Rich graves do not necessarily mean rich people in any time period,” says Mark Pearce at the University of Nottingham, UK. “But this method provides an excellent proxy way of demonstrating the existence of social differences.”
Journal reference: Antiquity, DOI: 10.15184/aqy.2020.102
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By Jason Arunn Murugesu
The box was discovered in Lake Titicaca
Helder Hugo

This 500-year-old stone box of Inca offerings was found by divers in the Bolivian half of Lake Titicaca. It contains a miniature llama made from mollusc shell and a cylindrical gold foil thought to be a tiny version of an Incan bracelet.
Christophe Delaere at Free University of Brussels in Belgium and his colleagues think the box and its contents were part of a human sacrifice offering to the lake, as similar pairings of objects have been found in areas associated with Incan sacrifices. “This discovery extends the concept of ‘sacrality’ to the entire lake,” says Delaere.
The Incas ruled large parts of South America from the early 13th century until the Spanish invaded in the late 1500s. Underwater offerings were mentioned in books by Spanish colonisers, but no intact artefacts have been found until now.
Journal reference: Antiquity, DOI: 10.15184/aqy.2020.121
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By Donna Lu
We finally know where most of Stonehenge’s sarsen stones came from
Andre Pattenden (English Heritag

The origins of the giant boulders at Stonehenge have long been a mystery – but now we have uncovered where they came from.
David Nash at the University of Brighton in the UK and his colleagues have identified the source of 50 of the 52 large boulders, known as sarsens, that make up the monument’s iconic stone circle.
By analysing the stones’ chemical composition, the team has traced their origins to 25 kilometres away from the monument, in the West Woods in Wiltshire.

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The sarsens comprise Stonehenge’s outer circle as well as a horseshoe-shaped inner ring. Many are in trilithons: two vertical stones topped with a horizontal lintel.
Stonehenge also contains smaller rocks, known as bluestones, near its centre, the origins of which have previously been traced to Wales.
The researchers analysed the chemistry of the sarsens via a technique called portable X-ray fluorescence spectrometry, essentially a handheld X-ray gun. With this, they took five readings at different positions for each stone.

This revealed that 50 sarsens shared a common chemistry, containing more than 99 per cent silica, with trace elements including aluminium, calcium and iron.
“Two, much to our surprise, were different to that main cluster, but also different to each other,” says Nash. This suggests they have two separate origins.

Next, the researchers analysed a fragment of stone, taken from a collapsed sarsen when it was re-erected in 1958, to obtain a geochemical breakdown of the rock. They used this to sample areas of similar stone across southern Britain.
The site in the West Woods, one of six the team sampled in the Marlborough Downs, turned up with a match. “We didn’t expect we would ever find the original source area,” says Nash.
Identifying the origins of the sarsens opens up the possibility of future archaeological research into the routes they may have been transported to Stonehenge, says Nash.
The origins of the other two sarsens have yet to be identified.
Journal reference: Science Advances, DOI: 10.1126/sciadv.abc0133
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