The UK will ban children under 16 from social media by early next year, replicating a policy that came into effect in Australia in 2025. The move is intended to put children’s well-being ahead of technology companies’ profits. But how will scientists study the effects of the measure and determine whether it is actually having a positive impact?

“We have no evidence either way,” says at Bath Spa University in the UK, who is working with the Australian government to analyse the effects of its own ban and is also advising the UK government. “It’s such new territory.”

Leading the way on research in the UK is the Wellcome Trust, which is already deep into the IRL Trial in Bradford. This has recruited about 4000 kids from 10 schools, aged 12 to 15, who installed an app on their phones to track their social media use. For half of those children, the app also limits access to social apps. The researchers expect to publish their first results in the middle of next year, after the newly announced ban has taken effect. However, at the Wellcome Trust says the findings should still help inform policy.

They will also improve upon existing research that tends to rely on self-reported measures, like asking children or their parents how much time they spend on social media, rather than using more objective metrics. What’s more, the few interventional studies that do exist . “If you’re talking about big changes here around mental health and those sorts of things, you’re not going to see changes in two weeks,” says Etchells.

Australia’s ban came into place in December, which is too recent to gauge its long-term effects. But once national bans like these are in place, it is impossible to do controlled studies, in which two groups of similar people are allocated access or not. What’s more, the results from larger studies on the wider population before and after the ban will be impossible to unpick from other social impacts.

For now, Sebastian is gearing up to run additional studies that hopefully generate at least some results soon after the ban. The UK government expects to bring legislation to Parliament before Christmas, with the policy coming into force in early 2027.

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The Wellcome Trust has invited 14 research teams to submit plans, some or all of which will be funded, into the effects of social media on young people’s well-being. These will take varying approaches to capture as much data as possible, with the goal of eventually synthesising the data into a conclusive result.

Some of these studies will follow existing cohorts and regularly interview them about their mental health and well-being over time, before and after the ban. Sebastian says these approaches can be insightful, but rigid. Other studies are proposing momentary assessments, where participants are sent text messages asking them to complete short surveys on the spur of the moment, capturing a different kind of data. Others may look to analyse data that is already being captured for some insight, such as the rate of hospital admissions or school absences.

With time against them, Sebastian hopes that some results could emerge relatively soon after the ban, but they are likely to be nuanced. For instance, a social media ban could have some positive impacts, but also disruptive ones in the short term, as online supportive networks are lost.

The effects of such bans are also likely to change over the years or decades, as today’s children and younger teenagers approach adulthood having never had access to social media. “It’s not that this is a done deal,” says Sebastian. “Policies could be continuing to change over the longer term, and it’s possible that the findings from our study and others will help to shape those policies iteratively.”

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For now, some are wary that the UK government is taking a reactive stance in the complex problem of poor youth mental health, without the appropriate data. at the University of Oxford told the Science Media Centre that a blanket age ban is a “blunt tool” and a stronger step than current evidence can support, but adds that the Wellcome research is an opportunity to learn whether these measures will “help, harm or neither”.

One thing that could hinder research – and undermine government policy – is the ability of users to skirt the bans. Early reports suggest that facial-recognition technology designed to verify ages online can be , and VPNs make it trivial to appear to websites as a user from another country where age checks aren’t mandated.

Surveys in Australia by the Molly Rose Foundation, a suicide-prevention charity, found that 61 per cent of 12-to-15-year-olds who had accounts on restricted platforms before the ban came into force . The organisation said that given the findings, it would be a “high-stakes gamble” for the UK to follow suit at this stage.

Need a listening ear? UK Samaritans: 116123 (samaritans.org); US Suicide & Crisis Lifeline: 988 (988lifeline.org). Visit bit.ly/SuicideHelplines for services in other countries.

Fully autonomous drones with no human oversight have killed soldiers on the battlefield for the first time. This is according to a senior figure in the Ukrainian defence industry, marking a watershed moment in warfare.

The one-off test involved 10 AI-controlled “Terminator” drones on the front line of the Ukraine war. Russian soldiers were killed.

“We tried it,” says drone-maker Alexander Kokhanovskyy, who supplied the technology and spoke to New Scientist at a press event hosted by the Ukrainian embassy. “It’s a test. We never implemented it [more widely].”

The test took place two years ago and involved quadcopter drones that were programmed to fly towards the front line, cover between 3 and 5 kilometres over around 10 minutes and then engage “Terminator mode”, in which an AI model searches for and intercepts targets.

“We just launch it and we know everything will be dead – everything that will be found there in this particular area will be dead,” says Kokhanovskyy. “There is no connection to the drone at all, you cannot see the video, nothing… Everything it sees will be killed.”

With no way to tell what the automated drones had seen or targeted, human-piloted drones were sent into the area after the test to manually check results. Victims included “a couple of soldiers, one truck”, says Kokhanovskyy. While there is no recording of the automated drones attacking these targets, it was concluded that the drones had killed them.

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Kokhanovskyy says that he was not at the test personally but that it was carried out by an unnamed military unit near the cities of Bakhmut and Chasiv Yar as part of a Ukrainian counteroffensive push. The Ukrainian Ministry of Defence did not respond to questions about the test or the current legal position on the use of fully autonomous weapons.

The use of AI is common in militaries around the world, helping to pick targets among overwhelming piles of intelligence data and automating certain functions of weapons, but humans are always in the loop at some point. Kokhanovskyy’s admission is the most categorical evidence yet that a death has occurred in battle solely at the hands of AI.

The Ukrainian government currently bans the use of AI at the final stage of intercepting targets, according to defence company sources speaking at the embassy press conference, although AI is used for many parts of the process by many devices up to that point. Kokhanovskyy says that the government is aware of the growing capabilities of AI and that it is in talks with defence companies about whether or not rules should be made more lenient.

Reports in 2023 suggested that Ukrainian attack drones equipped with artificial intelligence were finding and attacking targets without human assistance – but were being deployed against vehicles such as tanks, rather than infantry. At the time, no human casualties were confirmed.

While there is no official international ban on autonomous weapons that can kill without human intervention, United Nations Secretary-General António Guterres has called for one, saying that “there is no place for lethal autonomous weapon systems in our world”.

The UN has said that there are concerns that such weapons could violate international humanitarian and human rights laws by removing human judgement from warfare. There is also a risk that autonomous systems could make mistakes, either attacking soldiers or equipment from the same side or striking civilians.

Most militaries are developing devices that automate at least some part of the process of attacking targets. The US has software that accumulates and analyses vast amounts of disparate data and selects targets on the battlefield that can then be struck by drones, but, in theory, this requires human confirmation. There have been claims that the US is also developing so-called Goalkeeper flying drones and Whiplash naval drones, which are capable of finding their own targets and taking them out.

A UN report from 2021 even suggested that a Kargu-2 quadcopter produced by a Turkish firm may have been used to autonomously attack humans the previous year. The gave no specific detail on the source of the claims or whether any humans had been injured or killed, but suggested that Libya’s Government of National Accord (GNA) had used the drones against retreating Haftar forces.

Major Danylo Polozhukhno, a senior figure in Ukraine’s 21st Separate Unmanned Systems Regiment of the 3rd Army Corps who was not aware of or involved with the test, told New Scientist that his soldiers use semi-autonomous control systems but that there is always a human in the loop.

“These drone systems and platforms are capable of automatically acquiring and tracking targets, as well as autonomously guiding themselves during the final metres of the approach, which helps simplify the operators’ work. However, we do not use fully autonomous drone systems that independently select and engage targets without any operator involvement,” says Polozhukhno. “Ukraine adheres to international humanitarian law and takes seriously its responsibility to uphold the rights of all combatants. It also exercises great care in decision-making in order to prevent civilian casualties.”

at the University of Oxford says killing with AI steals the dignity of the soldier, removes responsibility from the attacker and must be banned. “It’s not just problematic, it’s horrendous,” she says. “Do we want to be the society who kills other people, who allows their government to kill other people, without humans being involved?”

at the University of Exeter, UK, says that though fully autonomous attacks without humans in the loop are technologically possible, they may be less of a decisive tool than many think.

“It is certainly possible governments would allow this if it gave them any military advantage,” he says. “However, the fact remains that very few if any of the millions of drones which have been used in the Ukrainian war by Russian and Ukrainian forces have been [fully] autonomous.”

“So it’s not just that it’s ethically right to keep humans in the loop, at this point, it’s more militarily effective,” says King.

Kokhanovskyy says that the Terminator project has not progressed since the test because of Ukraine’s rules. He is now CEO of drone-maker Aero Center, which he says was not involved in the test as it had not been created at the time, a Ukranian firm working on autonomous interceptor drones. These are designed to target incoming Russian Shahed kamikaze drones and take them out before they can reach towns and cities full of civilians or important infrastructure.

The company’s ALITA system will consist of 16 launch pads, equipped with 64 drones. It will be ready by October and capable of watching for incoming drones, automatically launching and travelling towards the target at 450 kilometres per hour before taking out everything from small drones to helicopters.

But Ukraine’s current rules will forbid fully autonomous operation and demand humans verify targets in the final stages of interception. Even in that mode, the entire battery of 64 drones will require just two human operators, meaning it will dramatically reduce personnel.

“Every step of this one can be either manual or automatic. We’re not allowed to do the final stage automatically,” says Kokhanovskyy, who believes that the rules should change. “I would love to,” he says.