Extra screen time drags down teenagers' exam grades, study finds

No hard evidence yet: Scientists who followed 800 kids for a year for indicators on how different behaviours affect academic performace say it is possible that too much screen time negatively affected their grades.

LONDON: Teenagers who spend an extra hour a day surfing the Internet, watching TV or playing computer games risk performing two grades worse in exams than their peers who don't, according to research by British scientists. 

In a study of more than 800 students aged 14 and 15, researchers from Cambridge University also found that physical activity had no effect on academic performance.