This doesn't come from any newspaper or sociological studies. In fact, that is just a hypothesis of mine, which I find would be interesting to discuss.
As I was watching the famous quizz programme on Japanese TV tonight, I was dismayed by the definitely low intelectual level of questions compared to the game in Europe (I can speak for the UK, France and Belgium at least). Tonight's questions were really averaging primary's school's level of knowledge. "What is the name of the princess with whom Alladin falls in love in Disney's animation ?" (the answer was of course "Jasmine", but the participant had to call the audience, of which only 66% got it right). That was a question for 1,5 million yen (the maximum being 10 million, 20x less than the UK's 1 million pound at current rate, which incidentally is disappointing for Tokyo, the world's most expensive city).
Another question, for which a previous participant failed, was : "If 5 people play hide-and-seek and 2 have already been found, how many remain to find ?" The guy answer 3, and the answer was obviously 2, as one is seeking... I don't even want to try to remember the very first questions for each participant, as they were disgustingly easy, even for me who isn't Japanese (as the game is culturally oriented).
In Europe, questions have seemed a little bit easier in the UK than in France or Belgium, but Japan really takes the biscuit. That matches perfectly with my opinion of the average Japanese "general knowledge". I have been appalled many times by hearing some of my (adult and well-paid, so supposedly well-educated) students, telling me such things as Argentina is part of Europe, New York the capital of the US, the US and the American continent the same thing (so many actually believe it, and confuse countries like Colombia or Canada with US States !), or even that Napoleon was a knight leading the crusades (I lie not !).
Just wondering, does "who wants to be a millionaire" exist in the US ?