Then they put half of each group together in a silent room, and the other half of each group in a different room equipped with earphones and a musical selection. Participants in both rooms were given a Fortran programming problem to work out from specification. To no one's surprise, participants in the two rooms performed about the same in speed and accuracy of programming. As any kid who does his arithmetic homework with the music on knows, the part of the brain required for arithmetic and related logic is unbothered by music—there's another brain center that listens to the music.
The Cornell experiment, however, contained a hidden wildcard. The specification required that an output data stream be formed through a series of manipulations on numbers in the input data stream. For example, participants had to shift each number two digits to the left and then divide by one hundred and so on, perhaps completing a dozen operations in total. Although the specification never said it, the net effect of all the operations was that each output number was necessarily equal to its input number. Some people realized this and others did not. Of those who figured it out, the overwhelming majority came from the quiet room.
Many of the everyday tasks performed by professional workers are done in the serial processing center of the left brain. Music will not interfere particularly with this work, since it's the brain's holistic right side that digests music. But not all of the work is centered in the left brain. There is that occasional breakthrough that makes you say "Ahah!" and steers you toward an ingenious bypass that may save months or years of work. The creative leap involves right-brain function. If the right brain, is busy listening to 1001 Strings on Muzak, the opportunity for a creative leap is lost.
The creativity penalty exacted by the environment is insidious. Since creativity is a sometime thing anyway, we often don't notice when there is less of it. People don't have a quota for creative thoughts. The effect of reduced creativity is cumulative over a long period. The organization is less effective, people grind out the work without a spark of excitement, and the best people leave."-Peopleware[http://www.amazon.com/Peopleware-Productive-Projects-Teams-S...]