Cinema-goers are fed up with trailers that give away a movie's plot-line or are better than the film itself, researchers have said.
A new study, based on responses to a 2013 trailer for The Hobbit: The Desolation Of Smaug, found that audiences want trailers which excite, tease and leave them emotionally engaged, without revealing excessive narrative.
The research by the University of East Anglia's (UEA) school of art, media and American studies, found that more than 80 per cent of people were left disappointed with a film after seeing its trailer.
In some cases the promos create expectations that feature films are unable to deliver on and are often considered better than the full film, the researchers added.
And many viewers were frustrated at spoilers contained within the trailers.
Lead researcher Keith M 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 enjoyable despite the expectations that a marketing campaign might set up.
"The key message to trailer producers, however, is that audiences want to be excited and teased about forthcoming films, to be emotionally engaged without feeling pummelled by excessive narrative revelation."
The findings are part of an ongoing research project about audience attitudes and reactions to film trailers.