Music is sometimes called the "language of the emotions." If you ask people why they listen to music, they most often say it is for its emotional effects.

Some CDs are geared to particular emotions. I have one called "Classic Weepies," a selection of instrumental pieces without words. It raises two more questions: Why would someone want to listen to sad music? What is it about musical instrument sounds that can make someone sad, or happy, or whatever?

Before going on to your second question (about how the brain responds to music), let me mention two ideas about how musical emotions depend on cognition (how we perceive and remember).

Consider this case: You hear a song for the first time on a day when something very special happens. Very likely, you will remember that day whenever you hear that song again. That song and the events of the day are associated with one another in your memory.

Here is another idea about why music causes emotions. By listening to music, you develop expectations about what will happen next in the music you are listening to - even if you have never heard it before. The idea is that emotion is produced when the music violates your expectations. This can cause surprise, frustration, amusement, wonder, excitement, sadness - a wide range of emotions.

Finally, let us turn to the brain. Brain imaging techniques (especially fMRI, which stands for functional magnetic resonance imaging) are being used to discover which parts of the brain are responding when people listen to music.

We are finding that many of the brain areas for music are the same as those for hearing speech - although language areas tend to be stronger in the left hemisphere, whereas music areas tend to be stronger in the right.

And - back to music and expectation and emotion. I recently did an fMRI study looking for brain areas that respond to violations of musical expectations. I compared normal melodies with the same melodies changed to have some unexpected rhythms and notes. Areas in the secondary auditory cortex responded much more strongly to the changed melodies. This suggests that violations of musical expectations produce responses at early stages of processing in the brain.

I think we are now getting closer to answering your questions. Thanks for them!