Reading and the mind
Reading quantity may be related to IQ. That is, the more you read, the smarter you get. The relationship is somewhat complicated, and not the least bit controversial, but there is some evidence. For a good, although somewhat dated summary, check out this article.
I personally think that the quality of the reading material (aside from vocabulary level) is also important, and hence why the map below interested me. It is far harder to find evidence to support this, but generally the books that have more 'life on the page' as Ray Bradbury would say, have more themes - and themes give you more to think about. Being introduced to new themes makes you a better informed, deeper and more reflective person.
The map below shows the most read book by High School seniors in the USA. Firstly, great! Young people are reading! Second, they are reading some good material.
Now, there are good books, bad books and ugly books. The graph above adds an extra category - recently advertised books (i.e huge publicity push, usually with movie). I see some absolutely life changing books on the chart. Namely: Night, Animal Farm, Macbeth, and maybe Frankenstein (barely, but with great themes). It would be enlightening to see the top five most read books. It may be that those who read the Fault in our Stars also read all the others, but who knows.
The Fault in our Stars is neither ugly nor is it bad. One way to look at it is, does it play on the emotions of teenagers, or in contrast, expand their paradigms of human experience? In my opinion it definitely does the first, and perhaps the second a little. It's an okay book (IMHO), but clearly the teenagers love it. And why wouldn't they? It's carefully designed to appeal to them.
'Night' on the other hand is not. 'Night' is a recount by Elie Wiesel who was sent to the concentration camps in Nazi Germany when he was 14. You cannot read that book and not be changed. And yet, it is not designed for anyone, no market research went into it, it is simply a chunk of real life. If you read 'Fault in our Stars' you will 'feel' (loss, pain, anger, love) but you may not be changed.
Anyway, its great to see young people reading - and not all of them are falling for the commercialization of books and are reading material that is old but powerful, rather than new, glossy and popular. How much of these are required reading for school we don't know either. I suspect all the older ones are. However, any young person who gets through Animal Farm or Night is going to be an educated and interesting person.
Long live the book.