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Screen Time

5 Research Articles

The National Institute of Health estimates that children spend an average of five to nine hours a day using screens for entertainment, which is equal to or greater than the total time spent in the classroom.

This has increased two-and-a-half-hours a day from just 10 years ago, and smartphone ownership crossed the 50 percent threshold in late 2012 – right when teen depression and suicide began to increase. 

Social reward is processed in the same subcortical network as drug addiction. In internet/gaming addiction, multiple studies have shown atrophy (shrinkage or loss of tissue volume) in gray matter areas where processing occurs. Areas affected included the important frontal lobe, which governs executive functions such as planning, prioritizing, organizing, and impulse control (getting stuff done).

Volume loss was also seen in the striatum, which is involved in reward pathways and the suppression of socially unacceptable impulses. A finding of particular concern was damage to an area known as the insula, which is involved in our capacity to develop empathy and compassion for others and our ability to integrate physical signals with emotion.

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THE POWER OF THE LIKE IN ADOLESCENCE: Effects of Peer Influence on Neural and Behavioral Responses to Social Media     

Association for Psychological Science

So why do we have such a hard time controlling the amount of time we’re on our phones?

Scientists at the University of California refer to the “Power of the Like” to describe bursts of activity in the reward processing regions of the brain when adolescent test subjects viewed photos with many (compared to few) likes on Instagram. Even something as basic as an everyday social interaction is processed by the brain’s reward system — and smartphones are very capable of reproducing a whole range of those on a screen.



There are indeed several empirical studies which support this hypothesis and indicate that social reward is processed in the same subcortical network as non-social reward and drug addiction.

In October, Time reported that “Between 2010 and 2016, the number of adolescents who experienced at least one major depressive episode leaped by 60%.” About 77 percent of Americans have a smartphone, up from 35 percent in 2011. Among teenagers, 73 percent had access to a smartphone as of 2015…[Americans'] smartphone ownership crossed the 50 percent threshold in late 2012 – right when teen depression and suicide began to increase.”


In two nationally representative surveys of U.S. adolescents in grades 8 through 12 (N = 506,820) and national statistics on suicide deaths for those ages 13 to 18, adolescents’ depressive symptoms, suicide-related outcomes, and suicide rates increased between 2010 and 2015, especially among females. Adolescents who spent more time on new media (including social media and electronic devices such as smartphones) were more likely to report mental health issues, and adolescents who spent more time on nonscreen activities (in-person social interaction, sports/exercise, homework, print media, and attending religious services) were less likely. Since 2010, iGen adolescents have spent more time on new media screen activities and less time on nonscreen activities, which may account for the increases in depression and suicide.


This 2018 study provides some of the first causal estimates of the negative effects of smartphone use on academic performance analyzing data from 696 first-year university students in Belgium. A negative relationship was found such that heavy smartphone use was not only associated with lower exam marks, but also found to be causing lower marks.

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