Another distinction deserves to be made between the gift a subject receives after having completed a puzzle and the end of a book, besides the fact that the latter is not guaranteed to be pleasant.

It is not the case that these people skip to the end because of an inability to delay gratification -if that was all they were after, then their satisfaction being gratified there would be no reason to go back to the beginning and labor through 800 plus pages.

I have never read the end of a book first, but I do this sort of "cheating" on a small scale -glancing at the opposite page during a fight or search to see if doom is in fact imminent. It's simply because I can only regulate so much suspense.