I don't have kids, so I can answer that one.
I never had a television set in my room. But I did watch obscene amounts of tv from when I was able to click the "on" knob til grade 7. My test scores were significantly higher than most other kids. Maybe it helps that I played video games
But on the contrary, what would they suggest? They don't really say how we can improve, aside from maybe "don't watch tv". Sports? I know quite a number of kids who spend all their time playing sports. Their test scores aren't exactly stellar.
What about sports mixed with going out? For you Torontonians, just look at Metro Square on a friday night. Those thug-wannabe kids probably play basketball (or at least try
) and they spend time with friends playing foosball (maybe another sport if you want to call it that
). I bet none of them has even average test scores.
Long story short. I tend to not find studies like these too persuasive.