The tremendous ability that music has to affect and manipulate emotions and the brain is undeniable, and yet largely inexplicable. Very little serious research had gone into the mechanism behind music's ability to physically influence the brain until relatively recently, and even now very little is known about the neurological effects of music. The fields of music and biology are generally seen as mutually exclusive, and to find a Neurobiologist also proficient in music is not very common. However, some do exist, and partly as a result of their research some questions about the biology of music have been answered. I will attempt to summarize some of the research that has been done on music and the brain in recent years. I will focus in particular on music's ability to produce emotional responses in the brain.


One great problem that arises in trying to study music's emotional power is that the emotional content of music is very subjective. A piece of music may be undeniably emotionally powerful, and at the same time be experienced in very different ways by each person who hears it. The emotion created by a piece of music may be affected by memories associated with the piece, by the environment it is being played in, by the mood of the person listening and their personality, by the culture they were brought up in: by any number of factors both impossible to control and impossible to quantify. Under such circumstances, it is extremely difficult to deduce what intrinsic quality of the music, if any, created a specific emotional response in the listener. Even when such seemingly intrinsic qualities are found, they are often found to be at least partially culturally dependant.


Several characteristics have been suggested that might influence the emotion of music. For example, according to one study, major keys and rapid tempos cause happiness, whereas minor keys and slow tempos cause sadness, and rapid tempos together with dissonance cause fear. There is also a theory that dissonance sounds unpleasant to listeners across all cultures. Dissonance is to a certain degree culture-dependent, but also appears to be partly intrinsic to the music. Studies have shown that infants as young as 4 months old show negative reactions to dissonance.