Music can slow down and equalize brain waves. There are 4 kinds of waves that the brain has. Beta waves, Alpha waves, Theta waves, and Delta waves. All of these waves are measured in hertz. Beta waves range from 14-20 hertz, Alpha waves range from 9 to 13 hertz, Theta waves from 4 to 7 hertz, and Delta from .5-3 hertz. When we focus on daily activities, or experience emotions that are strong, that's when Beta waves occur. Calmness and having a heightened awareness are part of the Alpha waves, and if you're in meditation, sleeping, or in an inspiring mood where you're very creative, that's when you're using theta waves, and when you're in deep sleep, and deep meditation, that's when delta waves are used. The slower the brain waves, the more relaxed, contended, and peaceful we feel. Common household music, medium paced music, generally has a pulse of about 60 beats per minute, which in turn can shift from the beta waves to the alpha waves. This is in certain types of music like Baroque, and New Age type music. This will increase alertness and things of that sort. If you're listening to a Shamanic drumbeat, your waves may drop into the theta range, which would in turn, alert your state of consciousness. Because a Shamanic drumbeat alters your hearing, because it's so different than other types of music. Different types of music, alert different waves, which then react differently, which makes you react differently. “If you are daydreaming or find yourself in an emotional, unfocused mood, a little Mozart or Baroque music in the background for ten to fifteen minutes can help to steady your conscious awareness and increase your mental organization.” There isn't any bias or opposing viewpoints on this part, mainly because it's all proven fact. One can't argue with what has already been proven, because it's right. Scientists now know that the brain reacts differently to different types of music. (Campbell 65,66)