"What too much screen time leads to is a variety of missed opportunities for learning and development", says Madigan. While giving children screen time so that parents can do other things is fine, if families want a truly holistic learning experience for their kids, they will need to physically be with them, regardless if its a non-screen or with screen activity.
"It is notable that screen time reduced both children's sleep even at this early age and reduced parents' reading to children, which we know is a strong predictor of positive child outcomes, such as higher IQ", said Gentile, who called the new study "strong" and "well-conducted".
Overall, mothers reported their children spent a mean 2.4 hours a day on screens at age 24 months, 3.6 hours a day at 36 months, and 1.6 hours a day at 60 months, they reported. They should also choose high-quality shows and watch them with their children to answer any questions and help them understand what they're viewing.
In the study, 2-year-olds spent about 17 hours a week in front of a screen.
Limitations included the research team's inability to account for screen time children experienced before age 2 and to distinguish between specific types of screen time, such as whether children were watching educational apps.
Researchers from the University of Waterloo, University of Calgary and Alberta Children's Hospital Research Institute said toddlers who spent more time watching a screen at 2 years old did worse on developmental markers than those who spent less time watching a screen.
That strongly supports expert guidelines that recommend limiting screen time for young children, when the brain is rapidly developing new connections and learning from every cue it receives.
As a next step the children were assessed for developmental targets in motor skills, social skills, problem solving skills and communication skills.
Too much screen time could affect kids' development in a couple of possible ways, although a cause-and-effect link hasn't been proven, she said.
The apparent explanation is simple: when a kid is in front of a screen, they're not talking, walking or playing, the activities during which basic skills are cultivated.
Results were as hypothesized, higher screen time predicted poorer outcomes in terms of developmental milestones and skills achieved.
"Excessive screen time can impinge on children's ability to develop optimally", they write.
The opposite association - poorer developmental progress leading to more screen time - was not observed. The way in which children are using TV or computers is also important.
Experts said parents should keep those statistics in mind while children are stuck in the house for most of the week due to unsafe winter weather.
Researchers recommend families prepare a media plan including rules for when devices can be used and for how long.
However, she added that parents shouldn't panic, since the field of research into screen time and its effects on development is in its infancy.
"The majority of children of all ages exceed the screen time recommendations, so parents have to be more strict setting healthy limits", Goldfield said by email. Children benefit when parents devote more attention to them rather than relying on devices to occupy or calm them down.