the effects of excessive "screen time" (primarily meant to mean scrolling through social media, playing games on a mobile device (phone/tablet), not sitting at

the effects of excessive "screen time" (primarily meant to mean scrolling through social media, playing games on a mobile device (phone/tablet), not sitting at a computer doing work), may be harder to established in adults, but it's been pretty well established in teens by measuring the correlation between screen time and test scores, primarily stemming from high schoolers lack of ability to focus (short attention spans).