The TV thing is very, very polluting. It goes right into 
the nervous system. The problem is how literate is 
your society, your family circle, your immediate 
circle? Your child is coming out in an intensely 
literate world, so he can take a fair amount of TV 
without too much harm. But to the ordinary kid 
without a lot of literacy, TV will just turn off any 
possibility of left hemisphere.

Maclean’s  , March 7, 1977, quoted in Letters of  
Marshall McLuhan,  (Toronto, 1987), p. 177.