If you are looking for a creative solution to a piece of work or a school assignment,don't lock yourself up in a quiet room. A new study suggests that moderate background noise is a better spur  to creative thinking than the sound of silence,Time magazine reported. A paper published in the Journal of Consumer Research says that the perfect working environment should buzz with a little noise. Researchers found that test subjects were at their most creative when background noise was measured at 70 decibels,the level one might find in a busy coffee shop. A nearly silent environment(50 decibels)was too quiet. Turning up the volume to 85 decibels (a jackhammer tearing up the pavement outside your building) was counterproductive-the noise became a distraction. The researchers asked 65 students at the University of British Columbia,Canada,to perform various creative tasks while noises recorded at a roadside restaurant were played in the background. In one experiment,scientists asked participants to brainstorm ideas for a new type of mattress . Test subjects had the most successful discussions when the noise in the background was noticeable but not too loud. While a quiet environment may make it easier to read a book. the authors of the study say that moderate background noise creates just enough of a distraction to force people to think more imaginatively, without breaking their focus so completely that they can't think at all. Should we all head for Starbucks to get creative? Not necessarily. Researchers found limited work time surrounded by the low-level noise of a coffeehouse is what really stimulates creativity. Equally, working in a care environment isn't good for everybody. The productivity boost was most obvious among those who were naturally creative to begin with. The recommended level of background noise is  _  .
50 decibels 65 decibels 70 decibels 85 decibels