A study following 1,323 children in Grades 3 to 5 and 210 college students has found that children who exceeded two hours per day of screen time (TV and video games) were 1.5 to two times more likely to be considered above average in attention problems by their teachers compared to children who met the guideline. A similar association between screen media time and attention problems (self-reported) was found for the college students. A study earlier this year found U.S. children aged eight to 18 devote an average of seven hours and 38 minutes per day to entertainment media (http://www.kff.org/entmedia/entmedia012010nr.cfm ).
Video games threaten kids' attention span
 Television and Video Game Exposure and the Development of Attention Problems. Pediatrics. peds.2009-1508 - peds.2009-1508.(2010).