New research shows too much screen time could contribute to higher levels of inattention and hyperactivity in preschoolers.
For four-year-old Eleanor and six-year-old Eira, TV time is a treat. Mum Rebecca Evans tries to limit it to half an hour but says it's a challenge.
"Managing screen time is a big issue in our family, I guess it's the same with a lot of other families. It's there, the kids are always asking for it."
And if they get too much screen time?
"Then you will live with the consequences, they can be real devils afterwards," says Evans.
Auckland University's Growing Up in New Zealand study looked at the prevalence of preschoolers' screen time.
Two-thirds of mums reported their two-year-olds had an hour or less of screen time per day, which is in line with Ministry of Health guidelines, but 12 percent of two-year-olds spent three hours or more on screens.
University of Auckland doctoral researcher in the School of Psychology, Maria Corkin, says increased screen time could impact the development of what are known as executive functions.
"They're a set of processes or skills that help children to manage their behaviour, manage their impulses, manage their everyday activities effectively," says Corkin.
The study found a heavy TV environment at two years old, which includes the television being on in the background and eating meals in front of the TV, is associated with poorer executive functions when they reach four-and-a-half. This could result in inattention and hyperactivity.
But it's not the screen time per se that's the problem, more what children are missing out on.
"Watching the television or having their attention drawn to it is displacing other activities that might be more beneficial to their development, such as interacting with other people," says Corkin.
Researchers recommend parental co-viewing to keep screen time low, not eating meals in front of the TV and minimising the amount of time the TV is on in the background.
