First off I just want to say this is my own ideals, thoughts and theories. Now I always thought that if we were to destroy all TVs then after a while we will be able to see images in our heads more clearly. But giving the fact that TV replaces our mental imaging capabilities then if we keep this going then sooner or later people that say that they can see images in their head will be sent to the mental hospital, and I say that only because we (society) call people crazy that are mentally way above us or mentally way below us. I, myself haven't set down and watched an hour of TV in like 6 years even though I'm only 22. Great topic and there's so many other problems that TV causes.
Kids these days spend many, many hours in front of the television. These hours are not being spent using their imagination and playing, so kids are developing their creative thinking skills less.
Even when reading a book a kid has to at least imagine what it looks like. But TV just gives it all to them.
I don't understand why some people are constantly condemning TV. No, it does not dull creativity, at least if you watch the right stuff. The site Fanfiction.Net alone features thousand of stories that were written by fans after being inspired by their favorite series. Over 25 thousand stories for Stargate SG-1, almost 50 thousand stories for Buffy, over 80 thousand for Supernatural... And I'm not even sure anyone could count the amount of TV-inspired fan art on a site like Tumblr, to begin with.
Furthermore, imagination is actually trained by TV and movies since these are visual media. As creativity is only recomposing concepts and objects we already know, TV is adding to the reservoir of what we once have seen. If I were simply reading a detailed description of the dinosaurs from Jurassic Park, my imagination would never be as detailed as having actually seen the movie.
Of course it all comes down to people's personalities whether they prefer books or TV shows (or neither), but hating on TV only because there are some lowbrow shows is as pointless as hating on reading because celebrity gossip magazines exist.
When a child watches too much tv when they are little (like my little half-brother) then yes, have like no creativity. All my little brother does is play with a tablet, sit on the computer, or watch tv. When I was his age all I did was play little games with my sister with my Barbies or I would write stories and songs or plays. He doesn't do that. All he does it rely on TV for entertainment. It's a shame. If that's not how you were raised though, then TV won't damage you.