Over the past decade, smartphone use among teenagers has increased dramatically. One study conducted by the Journal of American Medical Association found that teens spend an average of five hours on smartphones each day, almost two of which are spent on social media. If so much of teens’ daily lives is spent on a screen, what effect could this have on their brains?
Around 10 years old, brains begin to make developmental changes that increase sensitivity to social rewards, causing them to feel significantly more satisfying. This occurs because receptors for oxytocin and dopamine (the hormones responsible for happiness) multiply in the part of the brain called the ventral striatum. This makes pre-teens and teenagers more sensitive to social feedback (positive and negative) from peers.
Social media activity is closely tied to the ventral striatum, meaning that social media causes a rush of dopamine and oxytocin.
Social media leads to the activation in the brain’s reward system for adults as well as children, however, adults are less vulnerable to the effects due to two factors: 1) adults have a fixed and assured sense of self separated from praise or criticism from their peers and 2) adults have a prefrontal cortex that is more developed, which allows them to regulate emotional responses to social rewards (and social media) more effectively.
Aside from social media specifically, pediatric neurologists warn that excessive screen time can overall have long-term negative effects on developing brains.
Jane Tavyev Asher, MD, director of the Division of Pediatric Neurology at Cedars-Sinai Guerin Children’s, reported in a conversation with the Cedars-Sinai Newsroom that when a young brain is exposed to too much screen time, it overstimulates the visual cortex (the part of the brain that processes images), limiting the use of the auditory cortex (develops social skills and language). This is partly why it is heavily important to be screen-free for early development (toddlers and young children).
Pediatrician Michael Rich, director of the Center on Media and Child Health at Boston Children’s Hospital, associate professor of pediatrics at HMS and associate professor of social and behavioral sciences at the Harvard T.H. Chan School of Public Health, emphasizes how screen time can also negatively impact creativity and sleep in teenagers.
Rich describes how, as the human brain grows, neural connections are built and lost depending on which are used more often. Screens are an active part of that process; many screen-based activities offer “impoverished” stimulation that do not compare to real-world experiences. With stimulation available for growing brains at each moment, unstructured time where kids can just be bored is limited. Without boredom, there is not as much space for creativity and imagination.
In addition to creativity and imagination, studies show that using blue light-emitting devices before going to sleep can disrupt sleep patterns by suppressing melatonin production (the hormone that helps sleep). Staying up late on a screen not only makes the time spent sleeping shorter, but also makes the quality of sleep weaker.
As screens and social media become more popular and we learn more about the impact that they have on our behavior and brain development, it is critical to approach them thoughtfully in order to set healthy boundaries and use them in the most effective way, minimizing harm.
