The survey found that people who admit illegally downloading music spend an average of £77 a year on music. This compares with an average figure of £44 among those who do not download music illegally.
Think tank Demos commissioned the research from Ipsos Mori, in the week that the government confirmed it would go ahead with plans to block people who persistently download copyrighted material without paying for it from accessing the internet.
The research was carried out among 1,000 internet users aged between 16 and 50. One in 10 of them admitted to illegally downloading music. Among the illegal downloaders, eight out of 10 said they'd paid for CDs, vinyl or MP3s in the past year and nearly half said they liked to try things out before they decided whether to buy them.
Peter Bradwell, a researcher at Demos specialising in digital rights and consumer trends, said: "The latest approach from the government will not help to prop up an ailing music industry.
"Politicians and music companies need to recognise that the nature of music consumption has changed and consumers are demanding lower prices and easier access to music."
The findings, however, are likely to have little impact on those who are determined to clamp down on illegal downloads. They echo a ago by research company The Leading Question but the British Phonographic Industry has not shifted its policy. It estimates that copyright infringement costs the music industry £200m a year.
ISPs have criticised the "three strikes and you're out" policy of cutting off internet access to offenders, saying it is unworkable and that it puts the onus on them unfairly, when it is the entertainment industry that will benefit financially.
The government, however, says policy will act as a deterrent and that it does not envisage there being many people who fall foul of the law. The policy is due to come in to force next April, before the general election.