Your ADHD child fidgets and squirms his way through school and homework, but seems laser-focused and motionless sitting in front of the TV watching an action thriller. Well, fret not, because new research shows lack of motivation or boredom with school isn’t to blame for the differing behavior. It turns out that symptoms of Attention Deficit Hyperactivity Disorder such as fidgeting, foot-tapping and chair-swiveling are triggered by cognitively demanding tasks – like school and homework. But movies and video games don’t typically require brain strain, so the excessive movement doesn’t manifest.