| In the SELECTIVE HEARING
exhibit, two different recordings are played over two speakers,
placed on either side of the observer. The recordings can both be
played over both speakers or they can be played singly, each on
its own speaker. Visitors can attempt to listen to one or the other
or both of the recordings at once. Many people who try this notice
that when each recording is played over its own speaker, it is easier
to listen than when they are both played over both speakers.