Research has shown that playing music in a store can improve the moods of customers and increase the chances they make purchases. But what about the employees? New studies show that people tend to be more cooperative (and less self-interested) in a group setting when they’re listening to happy music. Note that the type of music matters. Happy music — songs with rhythm and warmth — encourage cooperation much more than “unhappy” music with arrhythmic song structures and screamed lyrics. This isn’t just applicable to the retail setting. Next time you need a group to work closely together — during a meeting or a brainstorming session — consider playing music. Not only will it break up the usual, often dreary, background silence in your office, but it could also improve your team’s performance.