One of the things mentioned in The Perfect Mess was “Stochastic Resonance“. The essense of this is the idea that additional random noise can actually help us in deciphering messages than without it. You can read the wikipedia entry for a more indepth response.
This idea is interesting when coupled with the idea that humans perceive changes in their environment. This explains how we adapt to the rotten smell of a place and suddenly don’t smell anything, or how a pool feels very cold when we first get in, but eventually feels normal (even warm). By creating random changes in our environment, it can help us perceive things better.