http://www.wired.com/wiredscience/2011/08/spoilers-dont-spoil-anything/
"I’ve always assumed that this reading style is a perverse personal habit, a symptom of a flawed literary intelligence. It turns out, though, that I was just ahead of the curve, because spoilers don’t spoil anything. In fact, a new study [upcoming in _Psychological Science_] suggests that spoilers can actually *increase* our enjoyment of literature. Although we’ve long assumed that the suspense makes the story — we keep on reading because we don’t know what happens next — this new research suggests that the tension actually detracts from our enjoyment.
The experiment itself was simple: Nicholas Christenfeld and Jonathan Leavitt of UC San Diego gave several dozen undergraduates 12 different short stories. The stories came in three different flavors: ironic twist stories (such as Chekhov’s “The Bet”), straight up mysteries (“A Chess Problem” by Agatha Christie) and so-called “literary stories” by writers like Updike and Carver. Some subjects read the story as is, without a spoiler. Some read the story with a spoiler carefully embedded in the actual text, as if Chekhov himself had given away the end. And some read the story with a spoiler disclaimer in the preface.
...The first thing you probably noticed is that people don’t like literary stories. (And that’s a shame, because Updike’s “Plumbing” is a masterpiece of prose: “All around us, we are outlasted….”) But you might also have noticed that *almost every single story*, regardless of genre, was more pleasurable when prefaced with a spoiler. This suggests that I read fiction the right way, beginning with the end and working backwards. I like the story more because the suspense is contained."