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Lab: Smart-phoney data

WE ARE really bad at knowing how long we spend on social media, a study found. And this discrepancy could undermine claims about the effects of, for example, smartphones on our health because most studies rely on self- reported surveys.

Dr David Ellis and colleagues at Lancaster University looked at 10 widely used surveys for measuring screen time.

They compared 280 people’s responses against objective data gathered by Apple’s Screen Time, which accurately measures how much time a user spends on their iPhone. The researchers found the objective and self-reported data were largely unrelated.

The closest correlation scored 0.4 and the worst scored 0.13, where 1.0 is total correlation. This means how much someone tells you they use their phone bears little relation to how much they really do.

This doesn’t mean that self-reporting — on which almost all smartphone research is based — is completely useless, said Dr Ellis. But it does mean that grand, sweeping claims about the effects phones and social media have on mental health are probably not based on sound evidence.

For example, self-reported survey results have been used to back claims linking increasing smartphone use to more teenage suicide and a drop in sexual activity.

‘It’s good someone is checking this,’ said Dr Peter Etchells, of Bath Spa University, who studies the effects of video games.

Self-reporting is also of limited accuracy in other areas, such as measuring diet and exercise, but people tend to be less critical of claims that smartphones are affecting mental health because they tie into our own pet theories, said Dr Etchells.

When you are doing basic science, self-reporting can be useful, said Prof Andrew Przybylski, an experimental psychologist at the Oxford Internet Institute, whose own research often involves such data.

‘But if you’re out there saying stuff like “Don’t give teens mobile phones until they’re 15”, or if you’re the health secretary wanting to use age verification software to limit kids’ social media time on the basis of these estimates, that would be bad,’ he said

Dr Ellis agreed, saying: ‘If you’re making claims about how it ruins lives, or if you’re going to change policy or give advice to parents, you need to be sure your measurements are as good as they can be.’

And if self-reporting doesn’t accurately measure behaviour, what does it reflect, asked the University of Bath’s Brittany Davidson, another author of the study.

No sex in a bot brothel, please … but only if you are married

Sex machine: Robot brothels are in pipeline PICTURE: EPA

MARRIED people would be judged more harshly for visiting a robot brothel than single punters — perhaps because of fears it may interfere with their relationship.

A study exploring the moral maze of the future asked more than 300 people to judge the character and actions of people.

Mika Koverola at the University of Helsinki in Finland said researchers set their story in the year 2035, with a person, either male or female, single or married, deciding to visit a brothel.

Depending on the scenario a sign read either ‘You cannot tell our robots from real humans’ or ‘All our workers are real humans’. Participants were asked to judge the actions of the character on a scale of one to seven. They were significantly more likely to condemn a married person than a single person paying a visit.

People were also judged less harshly for paying for a sex robot than a human.

The researchers also asked participants about their personal sexual history and found those who said they have had more sexual partners were more permissive towards the idea of visiting a brothel, regardless of the nature of the sex worker. Women more harshly condemned the characters than men.

‘Relationships seem to drive how people morally judge the use of sex robots,’ said Thomas Arnold at Tufts University in Medford, Massachusetts.

‘The more you start thinking about it as something that could compete against or interfere with relationships, that seems to be what people morally object to.’

Sex robots — known as sexbots — are not likely to look or act like a human in the near future, but plans for robot brothels are already in the works. In Texas, a proposed robot brothel was blocked from opening by the local council. A similar facility is planned in California.

Attitudes towards sex robots may vary between cultures and the team plans to study differences, said Prof Koverola.

Cavemen ‘put their hands up to lose a finger’

Riddle: Image in Cosquer cave PICTURE: GETTY

STONE Age Europeans may have willingly had their fingers amputated during religious ceremonies.

The theory could explain why so many prehistoric images of hands are missing fingers, say researchers from Simon Fraser University in British Columbia.

Out of 49 such images in the Cosquer cave near Marseille, 28 have at least one finger segment missing. And after reviewing ethnographic studies conducted since the 17th century, the researchers found ritual amputation is far from unusual, with 121 societies known to have practised it.

Dr Mark Collard, who led the review, said it showed his theory about the cave paintings was plausible. But he admitted: ‘I couldn’t imagine signing up to do it myself.’

Dr Ian Gilligan, of the University of Sydney, said it was more likely that the paintings showed fingers lost to frostbite.

‘Sound fence’ cuts animal road deaths

Roadkill risk: Warning to motorists PICTURE: ALAMY

HUNDREDS of animals have been saved from being run over thanks to a warning system that lets wildlife know when cars are approaching.

Tasmania — which has one of the highest rates of roadkill in the world — tested a ‘virtual fence’ along a three-mile stretch of highway near the state’s north-west coast.

Alarms placed on posts at 80ft intervals emitted loud sounds and flashing lights when triggered by vehicle headlights, scaring animals away from the road. ‘The alarms go off in a wave ahead of the car as it travels,’ said Dr Samantha Fox, from Tasmania’s wildlife management department, who led the project.

Over the three-year trial, 102 animals were killed while 408 died in an adjacent five-mile stretch not protected by the sound fence. Endangered Tasmanian devils were among those spared.

The trial may now go on to be repeated in other parts of Australia.

Stars in their eyes… Astronomers spot biggest black hole collision yet

A BLACK HOLE collision detected by astronomers is the largest to be observed so far. The LIGO observatory, based in the US, received gravitational wave signals from the merger of two black holes about 34 times and 50 times the mass of the sun. LIGO’s Nelson Christensen said the size was curious because ‘it is at the limit of what you might expect from stellar evolution’. The team said three other interstellar collisions had been found in the data from earlier observations.

We missed the party… 10bn years too late to see stars at their peak

STAR formation peaked 10billion years ago. An international team has mapped the history of stars using a gamma ray telescope.

Starlight blocks gamma rays, so measuring how many rays reach Earth and factoring in distance led them to calculate how many active stars there were at one point in history. They found the climax came less than 4billion years after the big bang. ‘We kind of missed the party,’ said Dr Kári Helgason of the University of Iceland.

Also in New Scientist this week:

■ The first gene-edited babies

■ How to beat climate change

■ Interview with Alan Moore, Watchmen author

Based on stories in the latest issue of New Scientist, which is available in the shops now. For more cool science and technology stories go to