Researchers from the University of California in San Diego asked 30 people to rate 12 short stories, some of which had been altered to include a spoiler that revealed the story’s ending. The results showed that those subjects who were told of the plot twist ahead of time took more enjoyment out of reading the story than those who weren’t.
I was queuing up outside the cinema one late evening in north London circa 1999. It was a very long queue too. The film had been advertised as having this great unbelievable twist to the ending. People waiting with bated breath and anticipation wondering if the film was as good as the reviews said or was it just spin and hype. Got to my seat, smirking away, watching the place fill up quickly. Had a terrible urge to shout, “Look, people, spoiler alert… the twist is …. he’s dead!” Impatience had got the better of me and I had read the synopsis to Sixth Sense in Sight and Sound which gave the ending away. My partner who is much more patient than me kept telling me not to tell him (case of sticking fingers in his ears shouting, “La la la…not listening”…). So I would pretend to break the news to him by saying, “Twist to the film is that…..Bruce Willis must have taken acting classes as he aint bad”…
But then that’s me. Fortunately, reasearch shows that spoiling the ending doesn’t really matter. Hurrah! I can carry on reading the film synopses in Sight and Sound. Apologies too I should have flagged up spoiler alert as they do on Internet Movie Database (an utter must for any sad lonely film geek) when I announced the ending to Sixth Sense. Ah, c’mon, you must have seen it…. apparently it won’t spoil your enjoyment.
So maybe it’s better that you know that Verbal is Keyser Soze. That Soylent Green is made of people. Rosebud is the name of the sled. Donnie dies. Norman Bates is the killer – in drag. 42 is the answer. Deckard is a replicant (or is he?). Tyler Durden isn’t real. Bruce Willis is actually a ghost. Vader is Luke’s father. Neo is the one (whoa). Dil is a man. And that it was Earth all along – because it will improve your enjoyment of the movie.
Though in saying that I didn’t find out the twisty ending to The Others nor Memento until I watched it. Made a change. Though it is hard when you are telling someone how good/bad/indifferent a film is without revealing the ending, kinda slips out with the shriek of “Don’t tell me”!!. Movie industry desperately tries to keep blockbuster films that have cost a whole lotta money under wraps (new Batman film). Incidentally, when Hitchcock’s Psycho was released newspaper advertisements would say “By the way, after you see the film, please do not give away the ending. It’s the only one we have”. Rather ingenious, though audiences were not used to the infamous shower scene and made some sick.
By the way, I know, 30 people in this sample, not very impressive nor much of a cross-section sample but hey, backs me up…. 
Ha this is interesting – I wonder how a film is seen as “spoiled” relative to how detailed the spoil is, for example is a film “spoiled” if you know there is a twist somewhere, or only if you know the exact details and timing of where the twist is revealed.
Either way, I feel vindicated in consulting IMDB before watching a film
Some movies depend on “dramatic irony” to keep you hooked. EG, Double Indemnity or Sunset Boulevard where it’s not the “what” happened, but the “how”.