Humans

Homo naledi coexisted with Homo sapiens, but had a smaller brainXinhua/Shutterstock
The much-publicised claim that a species of small-brained ancient human buried its dead and produced rock art is completely unfounded, according to a group of researchers.
“The evidence for burial and rock art is non-existent,” says Michael Petraglia at Griffith University in Nathan, Australia.
However, the researchers behind the original claim say they are hard at work gathering more evidence to build their case. They also contend that their studies are caught up in a wider debate over how scientific… More

Cannabis has complicated effects on memoryMarkusBeck/iStockphoto
The stereotype of a stoner – someone who uses copious amounts of cannabis – is that they are scatterbrained and absent-minded. But how cannabis affects memory is more complicated than this caricature lets on.
For starters, memory is a complex, multi-faceted process. There is long-term memory – the information we retain for months or years – and short-term memory, which lasts only a few minutes. Then there is working memory, which is where we hold information in mind and manipulate it. Working memory allows us to do… More

P.PLAILLY/E.DAYNES/SCIEN​CE PHOTO LIBRARY
IT ISN’T often that an esteemed professor sets out to investigate a scientific discovery made by a 15-year-old boy, but in 1938 Robert Broom made an exception. The British-born palaeontologist was keenly aware that 1930s South Africa was gaining a reputation for its exceptionally primitive-looking hominin fossils. So, when he heard that schoolchild Gert Terblanche had discovered fragments of a hominin skull in a cave there, he tracked him down immediately. Broom’s visit to the boy’s school paid off – he later recalled that the teenager was sauntering around with “four of what are perhaps the most valuable teeth in the world in his trouser pocket”.
Within months, Broom had finished analysing the fossils. Deciding they were unlike anything discovered before, he gave the ancient hominin a new name: Paranthropus.
But despite his confidence that the remains were valuable, Paranthropus never became famous. Perhaps that is because it was a misfit: it resembled one of our small-brained ancestors, but it was present on Earth long after other ape-like hominins had given way to big-brained humans. Even among palaeoanthropologists, Paranthropus is described as the “forgotten” hominin.
Perhaps not for much longer. Spurred on by the discovery of more fossils, researchers are finally reassessing this addition to our evolutionary tree – and their work suggests it was one of the oddest. Paranthropus may have been a skilled tool-maker, but it also potentially grazed grass like a cow and communicated with low rumbles like an elephant. The question now is, can the research bring us closer to understanding how the last of the ape-people survived in a world that was dominated… More

Dolmen of menga, a megalithic burial mound in SpainimageBROKER.com GmbH & Co. KG/Alamy
This is an extract from Our Human Story, our newsletter about the revolution in archaeology. Sign up to receive it in your inbox for free every month.
Stop me if you’ve heard this one before: ancient Greek statues weren’t always plain white marble. Many of these sculptures were actually painted in vivid colours. However, most of the pigments have either eroded away or been scraped off by overzealous museum curators, leaving us with just the underlying white stone.
For example,… More

Esteban De Armas/Alamy
IN HIS poem The Conundrum of the Workshops, Rudyard Kipling imagined an early human pausing to admire a drawing he had scratched in the dirt, only to hear a voice whispering: “It’s pretty, but is it Art?”
Archaeologists know a bit about scratching in the dirt, and when their excavations reveal a beautiful ancient object, they find themselves asking the very same question. They are motivated by a desire to step inside the minds of our prehistoric ancestors. In many cases, they want to understand if and when ancient hominins began to create art, as we explore in… More

Antonio Sortino
IF YOU have ever marvelled at the accomplishment of Stone Age cave artists, you are in good company. In 1940, on visiting Lascaux cave in southern France, Pablo Picasso supposedly said: “Since Lascaux, we have invented nothing.” Perspective, movement, impressionism, abstraction, pointillism – it is all there. And these artworks are some 17,000 years old.
Picasso’s remark may be apocryphal. It was certainly premature. In 1994, hundreds of paintings twice the age of those at Lascaux were discovered at Chauvet cave, also in France. The Chauvet paintings are, quite simply, stunning: prowling lions and galloping horses are captured so vividly that the remote Stone Age world becomes almost tangible. Even more astonishingly, this art was created shortly after the dawn of the “cultural explosion”, an event archaeologists have long recognised as marking a surge in creativity that seems to have come out of nowhere. How could these first artists have already been so good?
We now have an answer: the Chauvet artists weren’t the first. Discoveries in recent decades have shattered the assumption that art was invented by our species some 40,000 years ago. Instead, we have increasingly compelling evidence of artistry in other ancient hominins.
Needless to say, this challenges our beliefs about who invented art. But it does more besides. It offers an insight into our forerunners’ appreciation for aesthetics and the value they placed on objects that seem, at first glance, unnecessary for survival. In so doing, it also provides tantalising hints that art has been a vital component of hominin life for millions of years.
To say that humans are the only living artists… More

It may be older users who are driving the rise in cannabis use in the USVolha Shukaila/SOPA Images/Shutterstock
Cannabis is the most used illicit substance in the world, with an estimated 219 million people using it in 2021. Nowhere is it more popular than in the US and Canada.

In 2021, 52 million people aged 12 and older in the US used cannabis, roughly 1 in 5 people in this age group. Those figures have been inching upwards over the last few decades – a fact that isn’t that surprising given the expanded access to legal (or quasi-legal) cannabis and a shift in attitudes towards the drug.

The uptick in use, ease of access and increased social acceptability of the drug have some experts – and parents – worried, particularly about increased use among adolescents. That is with good reason: a growing body of evidence suggests cannabis use during adolescence may affect brain development, potentially increasing the risk for developing various mental health conditions or substance use disorders.Advertisement
Yet so far, fears of a surge in adolescent cannabis use haven’t been borne out by the data. Results from the National Survey on Drug Use and Health, an annual survey conducted by the Substance Abuse and Mental Health Services Administration, showed that rates of past-month cannabis use among teens aged 12 to 17 in the US have actually declined over the past 20 years: from 8.1 per cent in 2002 to 4.8 per cent in 2021.
Instead, the increase in cannabis use is being driven entirely by adults. The 12 to 17-year-old crowd now has the lowest rates of past-month cannabis.

Some health professionals are sceptical that we are seeing the full picture when it comes to teen use, however. “I cannot believe that that is true, that it has not gone up,” says clinical psychiatrist Ryan Sultan at Columbia University in New York. “Every other piece of information would suggest it should be going up.”
For instance, we know that more people now think of cannabis as a relatively benign substance. “In general, when perceptions of things move toward safety… that increases the likelihood” of use, says Sultan. Legalisation of recreational cannabis has also been linked to increased uptick in use of the drug.
Sultan isn’t ruling out the possibility that expanded legalisation has diminished the drug’s allure, or that kids are choosing to wait until they are older to use weed. If those things turn out to be true, it would be welcome news, he says. But he thinks it is more likely there is a missing piece to the puzzle, hidden by a lag in the data collection.

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This ancient skull shows signs of healing within the walls of fracture lines inflicted by a blunt force injuryQian Wang
A man who lived in what is now China 2700 years ago had a hole cut in his skull to treat a head injury and survived. This suggests that shamanic doctors in that era could do advanced brain surgery.
The Yanghai cemetery in Xinjiang, China, is a large, ancient burial ground containing the graves of a clan that practised shamanism, generally defined as a belief system using trance to communicate with the … More