TV’s magical powers magically screw up your kids
I can’t believe it’s not actual science! From Stuff:
It came after New Zealand research carried out by Otago University researchers, which found links between watching too much TV in childhood and developing problems later in life, including poor concentration, shorter attention span, smoking, high cholesterol and obesity.
Links! My god! Television sets must contain magical FuckUpYourLife rays which invade children’s minds and set them on paths to utter dysfunction!
Or … there could be something about the socioeconomic status of families where kids watch more TV. Certainly the ability of those families to have a stay-at-home parent so you don’t have two fulltime workers trying to juggle jobs and chores and children. Probably something about the education levels of the parents involved, their interest in reading, their high-falutin’ awareness of cognitive development, all that kind of stuff.
None of which, apparently, was controlled for in this very scary headline-making research. Nope, just one conclusion designed pretty much entirely to make poor uneducated families feel like automatic failures and terrify the comfortable middle classes that once again They Are Ruining Their Children’s Lives (next week: studies show reading too much to your child makes them illiterate!!!!)
In fact, the only vaguely-logical sounding “explanation” for the “links” between TV and BADSTUFF! is this:
But he said that after about two hours of sitting still, negative effects on health kicked in, which included increased long-term risks of obesity and heart problems.
What it’s important to note here is that, of course, two hours sitting still in front of those modern horrors, THE TELEVISION or THE COMPUTER, is completely physiologically distinct from the good old-fashioned sitting around we all used to do when reading, attending school, attending sports matches, listening to the wireless, etc. etc. It’s magical brain-destroying sitting.
Ideologically Impure 
Looking at the study done in Quebec, it does seem quite an oversight that socioeconomic status is not mentioned, it is an obvious confounder.
However, I also took a look at the study done in Dunedin, and they state that they do adjust for socioeconomic status. I am not sure you can read without paying (I only can because the library has a subscription), so I will try and upload the pdf for you to read.
http://www.freefilehosting.net/1-s20-s0140673604166750-main
(Do shout out if the link does not work, I’ll try again)