By: Andie E. Stallman, M.A.

Did you know that the brain is about 95% of its adult volume by age 6? That’s pretty impressive! But then you might ask: why does a 6-year-old behave so differently than a 30-year-old? Well, even though the brain grows rapidly, it continues developing in other ways. In fact, the frontal lobe, which helps with decision-making and self-control, isn’t fully ‘up and running’ until your mid-20s. The key is an important  process called “synaptic pruning.”

What is Synaptic Pruning?

Synaptic pruning is the brain’s way of fine-tuning itself by eliminating unused or unnecessary connections. This is crucial for children because it helps their brains become more efficient. Think of it like decluttering—keeping only what’s necessary for emotional regulation, language, and other important skills, and letting go of the things you don’t need. That’s why it feels harder to learn a new language as an adult than it was when you were a child. Languages use different pathways that become weaker as time passes without using them.

How Does Screen Time Affect This Process?

Just as practicing a language strengthens certain brain pathways, screen use influences which pathways the brain uses regularly. Research shows that excessive screen exposure can impact cognitive, emotional, and behavioral functioning in kids and teens. It can even contribute to brain degeneration in adults, particularly with conditions like dementia. Think of it like this: if you break your right foot and have to use crutches for six months, by the time you start walking again, the muscles in your right leg will have weakened due to underuse. Technology can have a similar impact. This is why it’s so important to teach our children how to protect their developing brains from the effects of too much screen time.

Technology: A Double-Edged Sword

Now, don’t panic and throw out all your devices—technology is not the enemy.  There is still a lot to learn more about the effects of screen-time and research is happening around the world. Technology has also been shown to have numerous benefits. It can help us stay connected to friends and family, support learning, and even boost certain brain functions. At the end of the day, it comes down to balance.

Moderation is Key: A Cake Analogy

I’ll be the first to say cake is delicious. But eating it for every meal of every day would not be good for anyone in the long run. The same goes for technology. So, just like we tell our kids to eat their broccoli before they can have dessert, encouraging healthy habits and screen-free time will help keep our brains healthy and maintain those important brain connections for generations to come.

What’s Next in the Digital Dementia Series?

In the next post, we’ll dive deeper into how excessive screen time can lead to social isolation and a sedentary lifestyle, and how these things can impact mental, physical, and cognitive health. Don’t worry—I won’t ask you to run marathons (unless that’s your thing!). In the meantime, check out the first blog ‘DIGITAL DEMENTIA: How Screen Time Affects Kids’ Brains — And What We Can Do About It’ in this series for a more detailed introduction to “Digital Dementia.”

Disclaimer: If you have concerns about your memory or cognitive health, please consult a physician. If you have any mental health concerns, talk to a trusted confidant and seek professional support.

References

• Adams, C., Kubin, L., & Humphrey, J. (2023). Screen technology exposure and infant cognitive development: A scoping review. Journal of Pediatric Nursing, 69, e97–e104. https://doi.org/10.1016/j.pedn.2022.12.013
• Grigorenko, E. L. (2017). Brain Development: The Effect of Interventions on Children and Adolescents. In D. A. P. Bundy et al. (Eds.), Child and Adolescent Health and Development (3rd ed.). The International Bank for Reconstruction and Development / The World Bank.
• Manwell, L. A., Tadros, M., Ciccarelli, T. M., & Eikelboom, R. (2022). Digital dementia in the internet generation: Excessive screen time during brain development will increase the risk of Alzheimer’s disease and related dementias in adulthood. Journal of Integrative Neuroscience, 21(1), Article 1. https://doi.org/10.31083/j.jin2101028
• Small, G. W., et al. (2020). Brain health consequences of digital technology use. Dialogues in Clinical Neuroscience, 22(2), 179–187. https://doi.org/10.31887/DCNS.2020.22.2/gsmall
• Tierney, A. L., & Nelson, C. A. (2009). Brain Development and the Role of Experience in the Early Years. Zero to Three, 30(2), 9–13.

About the Author

Andie Stallman, M.A., graduated magna cum laude from Tufts University in 2022 with dual degrees in clinical psychology (B.S.) and child studies and human development (B.A.). She also holds an M.A. in child studies and human development from Tufts University. Andie has worked with youth diagnosed with various psychiatric conditions and currently contributes to research at McLean Hospital on adolescent mental health. She’s passionate about promoting resilience and long-term psychological well-being in children.