Buy-one-get-one-free promotions are now as influential as television advertising in getting consumers to try new products, research by IGD has revealed.
A survey of 1,000 shoppers found that 25% had tried a new product because it was on bogof, up from 19% in 2004.
This was now in line with television advertising, which also persuaded 25% to buy a product for the first time.
Other important factors were price reductions and multibuys, each of which received 16% of the votes.
However, the research also found that getting shoppers to try a product did not mean they would keep buying it.
Only 14% of those surveyed said they frequently carried on purchasing a new product after a promotion ended.
The findings come in the wake of comments made at this year's IGD Convention by Unilever UK chairman David Lewis, who said retailers' tendency to demand heavy investment at launch was endangering future innovation.
"If you sell a product at half price you don't build a sustainable brand and, in the attempt to promote innovation, we shorten the shelf life of the product," he said.
IGD said the growing influence of bogofs was attributable to a "bargain hunt" mentality.
"The research shows that we are promiscuous in our brand choices," said Michael Freedman, senior consumer analyst.