Amanda Baker in Scientific American:
Adolescence – the period extending from puberty to the point of independent stability – is often portrayed as a very dramatic time with a new emphasis placed on the importance of friendships and social input. Researchers have even found during this period that many adolescents value the input of their peers even over the input of their family. The current generation of teens are faced with the addition of social media and digital content to their lives, additions which seem to have pushed many age-driven differences in behavior into a new arena. There are even notable differences in the way the current generation of teens consumes media. While older adults watch ~47 hours per week of television on average, current teens are only watching about 19 hours. Instead, they are consuming vast amounts of online video – like Youtube, Vine, and vlogs. In traditional television or movies the stars and the plots are often mysterious people and ideas that cannot be touched by the outside world. In contrast, young vloggers and stars of Youtube and Vine often host Q&A sessions with their fans; integrate feedback into future content; and express their gratitude not to their fans, but to their “6 million friends.”
Move up just a few years to young adults and there is already a shift, with this group watching five times as much television as online video. At least some part of that difference can perhaps be accounted for with changes that occur in this period to the brain itself. One of the areas going through important structural changes in this period – with additions of gray matter and changes in shape – is the area that deals with “social emotions.” Social emotions are those that require you to consider what others might be thinking – like guilt or embarrassment – rather than your own emotional experience – like fear. When researchers ask adolescents and adults to explain certain emotions, both groups feel and describe them in the same way. But the activity that is happening in the brain, and the way that information is being processed, differs between the two groups.