According to research done by Anne Blood and Robert Zatorre at Massachusetts General Hospital in 2001, music appeals primarily to the emotional centers of the brain. These researchers were able to measure the brain's activity in response to music. This effect, combined with the fact that many young people are controlled by their emotions to a much larger extent than are older adults, makes the teenage years a prime time of life for listening to and valuing music. Intense music, whether "positive" or "negative," functions as an intensifier of already intense adolescent experiences such as first loves, dealing with changing thoughts and physical realities, and moving away from parental authority.
More than any other age group, young people between the ages of 12 and 18 tend to function in groups. For reasons ranging from biological to social, this is a tribal time of life when individuals are defining their place within a group. Music is known for its group functions, reinforcing group solidarity and providing a shared experience. Intense music interacts with common young-adult activities such as seeking a mate, dancing, sharing personal information, drinking and staying up all night. Music often provides a "soundtrack" to these activities, triggering memories of them when it is heard again, and providing continuity over time.
Rhythm is an enjoyable aspect of music, but it is much more than that. Driving rhythms trigger physical reactions, such as foot-tapping, hand-clapping and dance. Rhythm often makes music lyrics much more accessible to listeners, and the listeners more suggestible. According to William Sargant, in his book "The Battle for the Mind," "...repetitive music with a repetitive beat...is very hypnotic and can generate an eyes-open altered state of consciousness in a high percentage of people. Once in an alpha state, people are at least 25 times as suggestible as they would be in full Beta consciousness." This is the potential danger of music lyrics with negative messages that glorify violence or anti-social behavior. The body responds to the sound and rhythm regardless of the message. The danger of rap music is not that it is bad music but that some of its lyrics are full of misogynist or violent messages. It is in fact very compelling music, which is obvious from its immense popularity, but some of it (a relatively small percentage) delivers an antisocial message.
In the late 1980s, the effect of music on teens became a highly publicized issue as Tipper Gore (wife of Vice President Al Gore) and the Parents Music Resource Group (PMRC) attempted to introduce warning labels on records that featured profanity and antisocial lyrics. Proponents of this measure claimed that young people were being adversely influenced, while opponents argued that, under First Amendment freedoms, musicians had the right to say whatever they want. The labels were introduced on some records, and opinions remain divided on what effect they had.
The controversy about the effect of music on teens is nothing new, as evidenced by books such as David Noebel's "Communism, Hypnotism, and the Beatles," published in 1965. Long before that, parents were decrying the immoral effects of jazz on young people in the 1920s. Adolf Hitler recognized the power of music when he outlawed jazz in Nazi Germany and in German-occupied Paris, attempting to replace its improvisational freedom with the regimented sounds of patriotic music. The fervor of controversies such as these tends to become muted with time, and then reappears in a somewhat different guise in the next decade.