"Watching television for more than 3.5 hours per day is associated with a dose-response decline in verbal memory over the following six years, independent of confounding variables."
associated
Not "caused".
It is still an interesting study, but this should be the first thing to recognize, whether it claims association or causation.
I also wonder if the type of programming matters : if watching quiz shows that jog memory and recall are different from watching soap opera, or sports, or learning programs for instance.
It might not be that simple. I think intellectual effort of these shows varies more within type than across. Tipping Point and Only Connect are both quiz shows but the first has questions like
How many degrees are there in a circle?
The latter has questions like; What can come fourth in this sequence?
All this happened more or less.
Sherlock Homes took his bottle from the corner...
There were four of us - George and William Samuel Harris...
associated
Not "caused".
It is still an interesting study, but this should be the first thing to recognize, whether it claims association or causation.