Screen time and kids’ brains: New Auckland University review warns of hidden harms – Cecilia Robinson

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OPINION: A University of Auckland review linked higher screen use to weaker focus skills.

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A new University of Auckland review has pulled together global longitudinal evidence on the longer-term effects of screen use on children’s executive function.

I was standing in our kitchen recently, doing what so many parents do at the end of a long day: negotiating screen time, homework, dinner and bedtime, all at once.

We are probably stricter than many families. Screens in our house mostly mean television. Our eldest does not have social media, and we have been operating as though a social media under-16 standard already exists. But still, screens creep in. Schoolwork. Homework. Entertainment.

That is the parenting guilt that comes with screens. It is not because we do not care. It is because we do care, we set the rules and still we can feel the line moving under our feet.

And now the evidence is becoming harder to ignore. A new University of Auckland review has pulled together global longitudinal evidence on the longer-term effects of screen use on children’s executive function. That sounds technical but it matters enormously.

Executive function is essentially the brain’s management system. It helps children plan, organise, pay attention, remember instructions, control impulses and regulate emotions.

These are the skills a child needs to sit in a classroom and focus. To start homework without melting down. To remember the steps in a maths problem. To lose a game without falling apart.

The review looked at 58 longitudinal studies involving children and young people up to the age of 18. Across the studies reviewed, 81% reported a negative longitudinal relationship between screen use and executive function. These are studies that followed children over time.

Perhaps most confronting were the brain imaging studies. All eight neuroimaging studies found differences over time in parts of the brain involved in executive function among children with higher or problematic screen use.

Some found smaller increases in brain volume. Others found weaker or less efficient connections between the parts of the brain that help children focus, plan, control impulses and regulate emotions.

That does not mean every child who uses screens will be harmed. But it does raise the stakes. This is not just about what we notice on the outside: a distracted child, a short attention span, a harder bedtime. The research is also detecting measurable differences in the developing brain itself.

There were other important findings too. Some studies suggested screen use and executive function difficulties can reinforce each other over time.

A child who already struggles with attention or emotional regulation may be more drawn to screens because they offer instant stimulation and reward.

But more screen use may then make it harder for that child to practise the very skills they are struggling with: waiting, focusing, calming down and managing frustration.

In other words, it can become a cycle. The more a child struggles to self-regulate, the more appealing screens become. The more time they spend on screens, the fewer opportunities they may have to build self-regulation.

I have a teenager, a 10-year-old and a 4-year-old, so I see the full spectrum of childhood and screens.

The preschooler who would happily watch something colourful on repeat.

The 10-year-old who needs a laptop for a school project but somehow becomes energised by it right before bed.

The teenager growing up in a world where not having a smartphone can feel like being left out of the conversation.

And then there is school.

For a time, both my son and daughter would come home and tell me that in one or two lessons a week, Minecraft had become part of learning time.

At first, I tried to be open-minded. Perhaps it was being used creatively. Perhaps there was a learning objective I was not seeing. But over time it became harder to understand, and my daughter eventually asked her teacher whether she was allowed to read a book instead.

That really stopped me. When a child is asking to swap screen time for reading during learning time, surely we have to ask whether we have lost the balance.

Schools are more aware, parents are asking better questions, and there is a more thoughtful conversation emerging about when technology genuinely helps learning and when it simply fills time.

But that experience stayed with me because it showed how easily screens can creep from being a tool into becoming the default. And that is the issue at the heart of this research. The question is not just what screens do to children. It is what they replace.

If screens are displacing sleep, movement, conversation, reading, imaginative play and real-world friendships, then children may be missing valuable opportunities to develop their executive function.

Screens are not neutral if they are taking up the space where children build the skills they need to thrive.

In the parliamentary education and workforce select committee’s inquiry into the harm young New Zealanders encounter online, one submission from an ECE (early childhood education) director and former secondary school teacher described a 2-year-old arriving at their centre unable to pick up food and place it in his mouth.

He had been fed pureed food from pouches while watching an iPad, was non-verbal and did not understand how to play or socialise.

The director wrote that within six months of removing screen exposure, his speech and development caught up to normal for his age.

That is an extreme example, but a powerful one. It reminds us that for young children, screen time is not only about what they are watching.

It can be about what they are not doing: touching, talking, chewing, climbing, waiting, playing and relating to the people around them.

Children’s brains are still developing. Executive function develops throughout childhood and into the mid-20s, which means children are especially sensitive to the environments we create around them.

A child who is constantly interrupted, stimulated and rewarded by a screen may find it harder to practise boredom, patience, attention and self-control. Yet those are precisely the muscles we need them to build.

As a parent, I have become increasingly aware that screen boundaries are about two things. Content matters deeply. So does displacement. What are children seeing, and what is the screen replacing?

Did it replace sleep? Reading? A conversation in the car? Being outside? The frustrating but important experience of figuring something out without an instant answer?

Other countries are starting to ask these questions. Sweden, long seen as a digital leader in education, is moving back towards books, handwriting, reading and arithmetic in the early years, has removed the requirement for digital learning tools in preschool and is moving towards mobile-free compulsory schools.

In that respect, Sweden is not ahead of New Zealand. It is catching up.

One of the first education changes made by the current Government was the “phones away for the day” policy, required in state and state-integrated schools from 2024.

It was sensible and important. But the next question is bigger than phones: when, why and how screens are being used during learning time.

Teachers are often the first to see changes in children’s attention, behaviour and stamina. Many have been raising these concerns for years. This is not about blaming teachers. It is about listening to what they are seeing and giving schools clearer support.

Nor is it about blaming parents, but we do have choices to make. We need to think twice before pulling out a screen because a sibling is bored on the sideline, a child is restless in a supermarket trolley, or we need a few minutes of quiet.

Those small moments add up. They are often where children practise waiting, watching, listening and managing frustration.

The burden cannot sit entirely with families. Policymakers have a responsibility to establish and enforce basic safety standards that technology companies must meet.

The Government has already shown leadership. Its commitment to under-16 social media legislation would make New Zealand an early follower globally, after Australia, in recognising that children should not be left to navigate these platforms alone.

But further questions are already here. What rules should apply to smart watches and other connected devices at school? Should screens be limited, or even removed, in early childhood settings? How do we make sure digital tools in primary school are used intentionally?

That does not mean rejecting technology. It means designing childhood with more care. When digital tools are used, schools should be able to explain why, what learning purpose they serve and what they are replacing.

The University of Auckland research should move us out of complacency.

Children do not need a screen-first childhood to be ready for the future. They need attention, resilience, curiosity, self-control, creativity and the ability to think deeply.

That is the real digital advantage. Not just knowing how to use technology, but knowing when not to.

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