Some sounds are preferable to others. We enjoy the hypnotic roar of the ocean, or the voice of a favorite radio host, to the point that they can relax us in the midst of an otherwise stressful day. However, sounds can also drive us crazy, be it a baby crying next to us on a plane or the high-pitched whine of a dentist's drill. Hedonic and aversive responses to sound figure prominently in our lives. Unpleasant sounds warn us of air raids, fires, and approaching police cars, and are even used as coercive tools during interrogation procedures. Pleasant sounds are fundamental to music, our main sound-driven form of art, and the pleasantness of voices is important in evaluating members of the opposite sex.