Written by Claudia Belliveau, Ph.D. Candidate McGill University

*You can listen to the audio version of this blog post on the Curious Neuron Podcast (Season 3, episode 38)

The American Academy of Pediatrics recommends NO screen time younger than 18 months and very little screen time (<1hr/day) from 18-24 months unless it’s video-chatting with family members. Have you ever wondered why?

To start, we need to lay out that not every screen is the same, and not every interaction with a screen is the same. First, television is usually a stationary object that is viewed from a few feet away, usually, this is seen as a one-way interaction where a child absorbs (or not) what is going on. Viewing an age-appropriate show (think Sesame Street) is different than watching an adult show (think Bachelorette); in fact, research shows that adult television blends in with background noises for children and can actually disrupt playtime. Second, a tablet/phone is a portable device that can be viewed from a distance or right up close to the face. Usually, tablets/phones have touch screens that allow for 2-way interaction. Third, both watching television and playing/watching on a tablet can be supervised by a parent or not. All these situations are different and research studies focus on a few aspects at a time.

Can kids under 2 learn from a TV show or an app?

A 2021 study showed that toddlers could interact intentionally with a tablet (playing an age-appropriate game), they understood with multiple trials that they had to drag a toy into the matching hole. This study also showed that toddlers were able to recognize parts of an e-book more than they recognized from the paper version of the same book.
However, there are multiple studies that show television in the background is not actively absorbed, and that it is very difficult for children under 2 to learn new vocabulary only from a television set - there needs to be a ton of repetition and it needs to be age-appropriate. It seems that preschool-aged children can more easily learn from age-appropriate television shows.

Does screentime negatively impacts development?

A 2020 meta-analysis (the gold standard of making conclusions from research) that looked at over 80 studies - found that excessive screen use (>1hr/day for toddlers) was correlated with obesity and less sleep time duration (Li 2020). Another 2020 meta-analysis also correlates evening screen time with poorer sleep outcomes in toddlers under 2 years old, but not preschoolers (Janssen 2020). Decreased sleep time can leave your toddler feeling cranky and dysregulated which can lead to more developmental issues down the line if this stays consistent.
Studies have suggested that screen time during early development leads to executive functioning issues (learning to adapt, prioritize, understand) and emotional regulation problems. In fact, a 2021 study that examined 14 different countries found that more time spent watching TV was associated with increased negative emotionality (moodiness), emotional reactivity (think tantrum), and aggression among ALL 14 countries! Interestingly, attention problems and decreased soothability (ability to calm) varied depending on the culture. Spain seemed to have fewer issues of soothability while the Netherlands had more pronounced negative effects - this could be because Spanish families watched shows together, while in the Netherlands children had more alone screen time (Desmarais 2021).
Many people claim that can impact language development - this seems to be true when kids under the age of 2 watch too much television unsupervised (Alroqi 2022). However, even though co-watching and interacting with a child during screen time is better than leaving them unsupervised, when it comes to language development, it is still even better to read aloud with your toddlers (Hanson 2021 and Li 2020).

Does screen time disrupt sleep?

Many studies show that increased screen time reduces sleep time and sometimes quality (Chindamo 2019). We’ve known for a long time that blue light disrupts melatonin release (West 1985) which delays sleep onset. Melatonin is a hormone that your brain produces in response to darkness (it regulates a 24-hour schedule that repeats itself called the circadian rhythm). Early in life, this rhythm is highly influenced by the outside world, so blue light from screens can dysregulate this rhythm more permanently than in adults. This might explain why we see more drastic sleep issues in younger children associated to screen time (Janssen 2020).
On another note, more screen time means less time for activities during the day, and sleep at night. We only have 24 hours in a day. If we factor in 12-13h of sleep for toddlers, that leaves 11-12h of awake time. Factor in 2-3h for naps and we’re already at 8-9h of play, physical activity, eating, discovering outdoors, bathing and reading. If we add in screen time, we have to remove other very important interactions that are necessary for toddlers.

If you have to use screen time how do you do it safely?

Engage with your child while using the screen together - talk about how the characters are feeling “wow, Timothy looks sad, I can understand why”, narrate what you see “did you see that, she jumped so high!”. Children, especially those under 2 years old, really need repetition and active engagement to learn new words from television.
Find age-appropriate media for your child to consume - I like Common Sense Media
Use the “night shift/ blue light blocker” setting on your tablet/phone in the evening - research shows that this is still not enough to leave melatonin on its regular schedule, but it does help a bit (Calvo-Sanz 2020). Blue-light glasses also do an okay job at allowing melatonin to stay on its regular schedule (Leung 2017). Reminder, these studies were done on adults, there doesn’t seem to be much research on toddlers and blue light

The final verdict

In summary, screen time for children under 2 years old should be avoided. This doesn’t mean that viewing TV once in a while is “dangerous”, these studies simply remind us that with children under the age of 2, we need to be mindful of their screen time. Co-watching and making it an active experience is a great way to mediate the negative effects of screen time.