Teenagers now spend an average of 4.5 hours on their phones! UCSD’s Dr. Kara Bagot is an investigator on that $300 million NIH study. Her team is scanning teenager's brains as they follow Instagram. Based on her data and the results from other studies, Dr. Bagot is among scientists who believe screen time stimulates the release of the brain chemical dopamine, which has a pivotal role in cravings and desire.
Jean Twenge is a psychology professor at San Diego State University. The iPhone was introduced in 2007. Smartphones gained widespread usage among young people by 2012. Jean Twenge says she was startled to find that in the four years that followed, the percentage of teens who reported drinking or having sex fell. But the percentage who said they were lonely or depressed spiked. It's possible other factors may have played a role, but Twenge says she wasn't able to identify any that correlated as closely as the growing popularity of the smartphone and social media.
Jean Twenge: It's not just the loneliness and depression from these surveys. It's also that ER visits for self-harm like cutting have tripled among girls age 10 to 14.