Cinema-goers are fed up with trailers that give away a movie's plot-line or are better than the film itself.
A new study, based on responses to a 2013 trailer for The Hobbit: The Desolation Of Smaug, found audiences want trailers that excite, tease and leave them emotionally engaged without revealing too much.
The research, by the University of East Anglia's (UEA) school of art, media and American studies, found more than 80pc of people were left disappointed with a film after seeing its trailer.
In some cases the promos create expectations that films are unable to deliver on and are often considered better than the full film. And many viewers were frustrated at spoilers contained within the trailers.
Lead researcher Keith Johnston said: "Despite the enduring appeal and apparent popularity of these coming attractions, modern trailer releases arrive with a perceived popular stigma - the presumption that they actively mislead or deceive audiences.
"Our research confirms this complaint, but we also found that audiences are aware of those issues when they watch a trailer and find trailers enjoy- able despite the expectations that a marketing campaign might set up.
"The key message to trailer producers is that audiences want to be excited and teased, to be emotionally engaged without feeling pummelled by excessive narrative revelation."