Ben Machell with his son, Thomas, two

Well, what is the harm? This is a question Adam Alter has spent more time than most parents contemplating. Alter is a psychologist and professor at New York University’s Stern School of Business. He is tall, thoughtful and looks like a slightly geeky Disney prince. He is 36 years old, comes from Australia and has a one-year-old son, Sam, plus a daughter due in a few months’ time. Already a New York Times bestselling author, he has just released a new book. Irresistible: Why We Can’t Stop Checking, Scrolling, Clicking and Watching is, as the title implies, an examination of why modern mobile technology – everything from social networking apps to games to email – is so compelling.

And the very short answer is that it’s designed to be. There are hundreds of incredibly clever, incredibly well-resourced people in Silicon Valley armed with a very detailed understanding of how the human mind works, and who have made it their business to make sure we cannot put down their apps or hardware. This has prompted a boom in what Alter terms “behavioural addictions”, which is to say, addictions fuelled not by the ingestion of a substance but rather by patterns of behaviour: the checking and scrolling and clicking and watching. He believes it’s possible that half of us now suffer from some form of behavioural addiction. And while this is bad news for adults who wish to escape their smartphone screens, it’s even worse news for children. Their impulse control is still a work in progress. They don’t think about the costs and benefits of their behaviour. If left to their own devices – literally, figuratively – kids do not stand a chance against such sophisticated technologies. Just ask Sparkly.

“It’s a very lopsided match-up,” says Alter. “The single biggest concern I came away with after writing this book is the relationship between children and these new forms of tech. It’s partly because self-control in young children is not fully developed; kids are not fully adapted to think about long-term consequences. So if you put something shiny and interesting in front of them, they will gravitate towards that even to their detriment.”

My son swiped once, thought it was the greatest thing that had ever happened and wanted to keep doing it

Alter remembers the moment his son first touched his phone. “There was a day when I was very busy and needed to check an email quickly. He was sitting on my lap and he reached forward and even though he was only a few months old, he started swiping at the phone. He was delighted that his swiping gesture actually had an effect and he wanted to keep doing it,” he says. “The world to a baby is pretty unpredictable, but these devices are so well crafted and intuitive that they deliver something to a baby that is reasonably predictable. It makes them feel like they have command over an environment that they generally don’t have much control over. He swiped once, thought it was the greatest thing that ever happened to him, and wanted to keep doing it.”

Every modern parent can remember a similar occasion: their child’s first encounter with digital technology. These moments often seem cute or at least entertainingly incongruous, but Alter found the episode troubling. Since then, he has made a point of never using his phone in front of his son– “I have to hide it from him” – and it’s the same deal with iPads. Verboten.

But if this approach sounds a little pious, Alter is at least in good company. “One thing that’s fascinating is that, when you hear people in the tech world talk about the way they use technology privately, it’s very different to how they describe it publicly. So Steve Jobs, talking about the iPad, said things like, ‘I think this is the best vehicle for consuming media.’ But a year later, when he was asked what his kids thought about it, he said, ‘The kids don’t use it. We don’t allow it in the home.’ ”

He cites a school in the Bay Area of San Francisco that is almost entirely tech-free. “It’s called the Waldorf School of the Peninsula and it doesn’t allow iPhones, iPads, computers, etc. And 75 per cent of the kids there have parents who are tech execs in Silicon Valley. So that gives you a sense of how the tech titans view these products.”

The problem with modern technology, he says, is not that it changes so quickly, but rather that it changes just slowly enough for us to not really notice the effect it’s having. “If you went back ten years and told people that we’d all be standing in elevators, sitting at dinner tables and walking down the street while staring at a small rectangular device, then that would sound dystopian. But it’s what we do now.”

To help us better see the wood for the trees, Alter quickly runs through some of the big changes that have happened in the decade since the iPhone was launched. So the first thing is portability. This sounds really obvious when you say it, but the fact is that children were unlikely to start demanding cartoons in the middle of a playground ten years ago because there was no way of watching cartoons in the middle of a playground ten years ago. But now there is. And once you start watching a cartoon or playing a game or whatever, the next problem you run into is that there is no natural getting-off point.

“The interesting thing with technology 20, 15, even 10 years ago was that there were built-in barriers to enjoyment,” he says. “You had to queue up to use the phone or the video console.” Or if you wanted to see a specific cartoon, you’d wait for it to come on TV. And once you’d watched it, you would drift off to do something else because then the news would come on, and the news was boring.

These natural breaks are called “stopping rules” and they have existed in most forms of leisure for ever. Only, these stopping rules are being deliberately, systematically destroyed by Zuckerberg and friends. Everything is now designed to be endless: if you start watching a box set on some streaming services, you can opt to have one instalment just roll into the next, a sort of auto-binge option that prevents you from having to make the decision to watch another. Similarly, there are three-hour Peppa Pig compilations on YouTube. A child can watch and watch, but the boring news never comes on.

“The bottomlessness of the news feeds on Facebook, Instagram and Snapchat today,” Alter goes on, “means that the stopping rule has been replaced by the default continuation rule. And it’s part of what makes these experiences so hard to manage.”

Alter believes that things get even more problematic as soon as a degree of interactivity is introduced. Games and apps that involve the acts of swiping, zapping, puzzling, etc, encourage a different level and intensity of engagement. “The biggest issue with interaction is that you get feedback. And feedback is the engine of addiction,” he says.

“Kids will do stuff all the time to get some feedback from the world. They’ll behave badly because they’re curious about whether their parents will respond. They’ll push all the buttons in an elevator because they’re curious about whether it will have an effect … But if you have a device that gives them instant feedback all the time, that means they don’t have to try very hard to get feedback from the world. They will just return to that device over and over again. And that’s not inherently a terrible thing. If you have young children that are learning through educational games, there may be some benefit there. But what you want to ensure you don’t do is make it too easy for them to turn these devices into a sort of mental crutch. They get bored? Turn to the device. They have half an hour to kill? Turn to the device. They’re unsure what to do next? Turn to the device. That’s when it starts becoming dangerous.”

Modern mobile technology affects children in other ways. Dr. Guy Meadows is clinical director of the Sleep School, a London-based organization with a particular interest in encouraging healthy sleep patterns in schoolchildren. He says that over the past ten years, the number of children admitted to the hospital for issues related to lack of sleep has trebled. That the iPhone was launched a decade ago is probably no coincidence, especially when you consider that the glow emitted by modern LCD screens is what’s known as “blue light”, which is effectively the same thing as sunlight and which has the same melatonin-blocking effect (melatonin being the sleep-inducing hormone). To help mitigate these effects there are ways such as specialized glasses from https://felixgray.com/collections/blue-light-glasses that can help block light emissions and protect the eyes.

“As part of their bedtime routines, many children are being placed in front of these mini-suns,” says Meadows. “One of the most challenging things that we are facing at the moment is how we manage our use of smart technology. As adults we’re really struggling with it, let alone children.”

I go to children’s birthday parties – I saw four kids the other day, all the same age, just sitting on their parents’ phones, not interacting

Like Alter, Meadows is a parent as well as an expert – “I’ve got two children myself, four and six” – and says that while he’ll allow his children screen time in moderation, he won’t allow any after dinner. And, like Alter, he worries that phones and tablets allow children to pass the time in a kind of mental holding pattern: not bored, but not engaged with the world around them either.

“I go to children’s birthday parties – I saw four kids the other day, all the same age, just sitting on their parents’ phones, not interacting with one another. I was so worried about the simple process of cultivating social skills,” he says. “But at the same time, I recognise that parenting is incredibly hard, and it’s really easy to just pass a device to them.”

But you can still influence the behaviour of your children even without passing a device to them. What’s increasingly clear is that parents are going to have to walk the walk if they’re going to talk the talk when it comes to the use of technology. “What children are saying is, ‘My parents sleep with their phones next to them,’ or, ‘They sit in bed on their iPads,’ ” says Meadows. “It’s important for parents to be role models when it comes to sleep behaviours.”

But there is a sad irony here. Raising young children is hard. The days are long. The nights are long. You can find yourself suddenly cut off from the wider world, cloistered from friends and colleagues or even just people who can speak in full sentences. And in these moments, social media can feel like a lifeline, or at least a way of projecting a version of yourself that isn’t tired and grumpy and covered in all the various things that come out of small infants. Before I had children, I would always roll my eyes at the regular Facebook updates made by all the new parents I knew. Now, I absolutely get it. You exist. I see you. But if you’re not careful – if I’m not careful – then you can find you keep instinctively reaching for your phone. And your kids see you doing this.

“Children will pay a lot of attention to your gaze,” says Alter. “And if your gaze is directed away from them and at a phone, they notice. There is evidence that a lot of kids come to mirror the way that their parents use phones.”

So however much I want to curse devious Silicon Valley developers for pushing addictive software on my kids, I’m the one slyly checking my work emails when I’m meant to be supervising the construction of a Lego Duplo fortress. I tell Alter this and he is sympathetic. “The business of being a devoted parent is exhausting. You’re hurried and overworked, so you try to be more efficient with your time. But I do think that changes how you interact with your kids. Even if you’re looking at a phone while you’re pushing a pram and trying to get your baby to sleep, they’re looking up at you and can’t see your face. I think it changes your relationship with your child in a very broad, abstract way.”

But not everyone is sure that parents need to get quite so hung up about screen time. Earlier this month, for instance, researchers in the US raised an intriguing question: are teenagers using fewer drugs in part because they are constantly stimulated by their screens? “People are carrying around a portable dopamine pump, and kids have basically been carrying it around for the past ten years,” argues David Greenfield, addiction expert and assistant clinical professor of psychiatry at the University of Connecticut School of Medicine.

Dr Andrew Przybylski is an experimental psychologist based at the Oxford Internet Institute. He is amiable, enthusiastic, and his job involves researching how and why young people use technology, and then assessing what the effects are.

The first point he makes is that we need to be really careful when talking about “addiction” in the context of children using digital devices. Basically, just because a child enjoys doing something does not make it addictive. “It’s conflating the idea of enjoyment or gratification with something that’s destabilising or deregulating. You end up using the word ‘addiction’ to bridge between ‘popular and engaging’ and something that really is pathological.”

His second point is that, for all the anxiety surrounding the subject, “There is a real vacuum when it comes to good information about this.” Although he and his wife – also a scientist – have a three-year-old and a baby, he is opposed to the introduction of screen-time guidelines for children in the UK. In fact, he considers the whole concept of “screen time” to be practically useless. “It would be like talking about nutrition in terms of ‘food time’. You can spend food time eating healthily or at an all-you-can-eat Chinese buffet. You can be eating things with calories or things with no calories, things with sugar or things with no sugar. People don’t say, ‘Why aren’t I losing weight? I’m minimising my food time!’ And screen time as a concept is just as ridiculous. It’s crazy because all screens are not created equal and it’s crazy because it assumes all kids are created equal. And even if all five-year-olds were the same, all seven-year-olds are going to be different to the five-year-olds. To have one rule for all of them makes so little sense to me. And because I know the science is of relatively low quality, it strikes me as terribly unfair to parents.”

Besides, he continues, even if screen-time guidelines were based on years of incredibly high-quality research, it doesn’t mean that parents should feel bound by them, standing nervously over our children with a stopwatch. If you have a successful parenting style that doesn’t involve any access to iPads, then fair enough. Same if you have a successful style that’s pretty relaxed about access to tech. “You shouldn’t need a study for you to parent in line with your values,” he says brightly. “It might be nice if they line up, it might help you sleep at night, but it shouldn’t matter.”

Kids have basically been carrying around a portable dopamine pump for ten years

Finally, he says that we have to at least try to put the impact of excessive screen time into some kind of broader context when it comes to a child’s life. “Parenting is essentially a triage process,” he says. “You need to know where something like, ‘Oh God, screens!’ fits in with, ‘Oh God, traffic!’, or ‘Oh God, finish your breakfast!’ ” Earlier this year, Przybylski published a study that looked at the screen habits of 120,000 English 15-year-olds and the effect it had on their mental wellbeing. And one of the findings was that, even when a child would spend excessive amounts of time looking at screens, their mental wellbeing only suffered very slightly. “Even at exceptional levels, we’re talking about a very small impact.” When they tried to calculate the precise negative effect, they found it was considerably less bad – one fourth as bad, to be precise – as skipping breakfast or not getting eight hours’ sleep at night. In other words, if you had to pick just one battle with your 15-year-old, better to pick the one that ends with them eating breakfast.

“Just because technology is moving, people assume its impact is going to get bigger and bigger,” says Przybylski. “But smartphones are nothing compared with the invention of the electric lightbulb. We had 40,000 years of human culture. And then, one day, we had electric lightbulbs. And it completely changed the way we eat, sleep, work, live, reproduce and everything else. That was a real change. That beats iPads a thousand times over.”

And funnily enough, in some ways, Alter agrees. “I think there are certain changes around the corner that’ll make what we’re going through now seem like a curious ancient relic,” he says. “There’ll be a quaintness to the way we deal with tech now when you start to imagine what’ll happen when you look, say, ten years into the future.”

The prospect of easily accessible virtual-reality hardware is the next big concern. A friend of mine does a lot of work in VR. He has a son the same age as mine, and says he’s very cautious about the potential impact of this technology on his child’s development.

“The only reason kids live long enough to reach maturity is because we teach them, protect them and let them make the real-world mistakes to grow into intelligent humans. Fire hurts. Falling hurts. We cannot fly. Letting kids use VR too early will make them unable to differentiate the real world from the virtual,” he says. “You create hallucinations and a perception of something not present.”

Alter has his own concerns. “When all of us own a pair of virtual-reality goggles, what’s to keep us tethered to the real world? If human relationships suffer in the face of smartphones and tablets, how are they going to withstand the tide of immersive virtual-reality experiences?”

Although, somehow, I can’t see Alter or his children falling prey to it. Before our interview ends, he admits, a little bashfully and after some prodding, that he did once let his son look at an iPad. It was during a long flight from Sydney to New York when he was feeling tired, poorly and tearful. “I did feel concerned about it, but I told myself it was OK, because it was a really difficult moment. It was a low point as a parent. I’m sitting on a plane with lots of people who want peace and quiet more than anything, but my son is wailing because he’s in pain and not happy,” he says in a manner that suggests he has made his peace with it and knows he did the right thing. Then a pause. “It’s just that putting an iPad in front of him felt so wrong and inconsistent with everything I’d been telling people for so long.”

It’s OK, I tell him. I understand. We’ve all been there. Kids love screens. They love Peppa Pig on loop and toothbrushes they can befriend and swiping and swiping and swiping. Pretty soon, they’re probably going to love VR goggles. You can only do your best. There’s always going to be something.