How does music change shopping habits?
The constant background of pop music is something most shops and malls have in common.
But some of Britain's shopping centres may be about to become a lot quieter.
Hammerson, which runs a number of shopping malls across Britain, is thinking of phasing out music because of the effect it has on shoppers.
To find out the impact that sound might have, it has been carrying out some experiments.
The BBC's media correspondent, David Sillito, went to the Bullring shopping centre in Birmingham to find out more.