At Selective Hearing, two separate recordings play at the same time, one coming from a speaker on the right, and the other from the left. Listening to one message makes the other seem to move into the background. Looking at one speaker will bring its message to the foreground. The exhibit highlights the process of listening to one conversation while excluding others at, for example, a cocktail party. The sorting out occurs in the brain, not in the ears themselves, but the mechanism is not entirely understood.