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Over six thousand fans watch ''Harry Potter And The Deathly Hallows: Part 2'' Croatian movie premiere at the Roman Amphitheatre in the northern Adriatic city of Pula, 270 km (167 miles) south-west from capital Zagreb, July 19, 2011. Picture taken July 19, 2011. Reuters

If you are angry that someone spoiled the plot of a movie or revealed the ending of a book, don't be.

A new study by researchers from the University of California at San Diego shows spoilers may enhance enjoyment, even for suspense-driven story lines and film plots.

After studying three types of stories -- ironic-twist, mystery and literary -- by authors such as John Updike, Roald Dahl and Agatha Christie, they found readers preferred versions with a spoiling paragraph written into the story.

"I was quite surprised by the results," researcher Nicholas Christenfeld said in an interview. "Like most people, I don't turn to the end of a book to see who dies or what happens."

For the study each story was read by up to 30 people and presented in two formats -- in the original version and with a spoiling paragraph inserted in the story.

Readers of all three story types preferred the spoiled versions of the stories more than the unspoiled originals.

"Plots are just excuses for great writing," Christenfeld explained. "Nonetheless, plots are important, like a skeleton or a coat hanger. You need it to display the things that are important but the plot itself isn't critical."

Christenfeld said in many cases a book or movie can be re-read or seen multiple times and still be enjoyable.

"As a film director, your job isn't really to come to the conclusion that the butler did it. A single line would do that," he said.

Once viewers know the ending of a film, they may want to view if again to see things that had meaning or didn't have meaning the first time they saw it.

The researchers said in the study, which will be published in the journal Psychological Science, they found that the success of entertainment does not rest on suspense alone.

"Stories are a universal element of human culture, the backbone of the billion-dollar entertainment industry, and the medium through which religion and societal values are transmitted," they wrote in the report.

Christenfeld and his co-author Jonathan Leavitt added that the findings could mean that commonly held perceptions about suspense may also be incorrect.

"Perhaps," they said in the study, "birthday presents are better when wrapped in cellophane and engagement rings are better when not concealed in chocolate mousse."