People who like to write in cafes are onto something, it seems: A moderate level of noise—the equivalent of the background buzz of conversation -- prompts more-creative thought, according to a study.

Across several experiments involving more than 300 people, participants worked on a series of exercises demanding mental flexibility, including word-association games and practical problems. They brainstormed about how a mattress company might improve its product, for example, and devised as many uses as possible for a brick....