Experts have called for a rethink on guidelines around children's screen time, arguing that a smarter "family-centric" approach is more practical than blanket time limits.
One of the authors of a new evidence review, former chief science adviser Professor Sir Peter Gluckman, has also cautioned against heavy screen time under lockdown becoming a habit once restrictions lift.
Current Ministry of Health guidelines recommend zero recreational screen time for children under 2, less than an hour per day for kids aged 2 to 5, and fewer than two hours per day for those aged 5 to 17.
Yet, in our busy and tech-saturated world, ministry surveys find those guidelines are being exceeded by nearly 90 per cent of children younger than 14.
And spending too much time watching TV, playing video games and using social media is a problem that grows with age.
Around 60 per cent of 2 to 4-year-olds, 80 per cent of 5 to 9-year-olds, and more than 90 per cent of 10 to 14-year-olds are now gazing at screens for more than two hours a day, according to the most recent data.
That has prompted researchers at University of Auckland-based Koi Tū: The Centre for Informed Futures to assess the latest evidence on the effects of screen time on children's development - and whether official recommendations are adequate.
In their just-issued brief, the authors, Chloe Wilkinson, Dr Felicia Low and Gluckman, found the impacts of screen time on brains - outside that used for learning and studying - were complex and depended on a range of factors.
They included the precise type of screen activity, the level of engagement by caregivers, and whether the content they were watching was age-appropriate.
Still, they found that blanket screen limits didn't reflect contemporary family life.
Instead, they call for a fresh approach, where parents and caregivers aim to be more involved in their children's screen time by monitoring content, choosing interactive screen activities rather than passive watching, and balancing screen use with family time.
Low, whose work is supported by the Wright Family Foundation, said there was growing evidence that screen time could negatively affect children's ability to focus their attention and regulate their behaviour and emotions.
"The negative impacts are strongest when children use non-interactive, non-educational media instead of talking and playing with people and objects around them."
Studies of teenagers had already linked excessive social media and internet use with poor mental wellbeing, impaired cognition and sleep disturbances, she said.
"We don't know if this is a cause or consequence – if it's causing problems or if it's a symptom of teenagers with these problems using more social media and internet."
However, she said researchers generally agree on what was called the "Goldilocks effect".
"Just like finding the perfect temperature of porridge, not too little or not too much but a moderate amount is optimal for teenagers' mental wellbeing."
Gluckman acknowledged that during alert levels 3 and 4, it might be impossible for many families to adhere to the guidelines, as caregivers juggle caring for their children, homeschooling, and working remotely.
"What we need to focus on is not allowing the realities of lockdown to creep into everyday life and become the habits of the future."
But a new survey, released by NortonLifeLock this month, found that might already be the case.
New Zealanders have been averaging five hours of screen time a day on top of using devices for work and school since the Covid pandemic started last year, it showed.
About half of those surveyed found the amount of time they were in front of their screens had significantly increased outside the time they used it for work and school, and most used their smartphones to do it.
Five rules for screen time
• Avoid passive screen time for children under 2. Caregivers must be mindful of their own device use and whether it interrupts adult-child interaction.
• Choose educational content for preschool-aged children and join in with their viewing whenever possible.
• Monitor the content older children are exposed to, particularly with adult-rated movies and games, investigate parental controls on devices, and prioritise interactive screen time such as computers.
• Encourage a balance between screen time and other activities. Place limitations around screens where needed, for example, no screen use near bedtime and no devices in bedrooms.
• Discuss the pitfalls of social media with adolescents, such as the potential for cyberbullying and the unrealistic editing of images.
Recommended guidelines from researchers at the Koi Tū: The Centre for Informed Futures. Current ministry guidelines for young children can be found here.