DS is 18 months. We realised recently tv was creeping in to more and more of the day - we had meant to limit it to until 8am and after 6pm but it was often on more like until 9 and after 5 and sometimes in between. For the past week we have not put it on until 6.20pm (in the night garden) and the change in DS has been quite scarily remarkable - previously he would come home from nursery, tv would go on and we would often have a few hours of fractious whining, not settling to anything, and generally quite a stressful evening routine. Without the tv on he has been playing well and concentrating brilliantly, on drawing, books, jigsaws etc - like a different child at times! It does make me wonder how much of a distracting effect the constant background noise and colours of the tv has. I have to admit like other posters here I like background noise and always tend to have tv and radio on in the background so the silence has been a bit unnerving for me but the difference is massive and positive. We have also noticed that when the tv does go on now he will sit down and watch it for the 20 or so minutes before bath whereas before when it was on constantly he would glance at it and maybe stand in front of the tv for a minute at a time, but now he will sit on my knee and really focus and chat through what he is seeing.
I don't want to sound sanctimonious or anti-tv as I'm not at all, he still has it on for an hour or more in the mornings, am just amazed at the effect it seemed to be having which I hadn't been aware of. DS has never been great at concentrating at the best of times so I guess it makes sense that the distraction of the tv in the background isn't helpful when we are encouraging him to read or draw etc...