Music and the Brain
In Macedonian hills, the music of Orpheus was said to possess certain magical qualities, having powers strong enough to alter the very behavior of people and animals. Among its abilities, the notes of Orpheus' lyre were said to calm the guard-dog of Hades (1), to cause the evil Furies to cry, and to tame the deadly voices of the Sirens (2). Was this power simply a divine and magical gift with no other explanation, or can we explain more specifically the connections between music and behavior?
Sound is an important input affecting the nervous system. The brain reacts to sound input because information signals are able to travel from the outside environment, across action potentials and through the neural network into the brain. Such signals, electrical in nature, can be detected by the electroencephalogram, or EEG, which measures the electrical activity of the brain (3). Such electrical activity has been shown to correspond to different states of consciousness within an individual, as the EEG reveals different brain activity depending upon the mental state and the actions of the person being observed. Four different types of brain waves are defined—beta, alpha, theta, and delta—and each corresponds to a different state of activity and consciousness. Beta waves, vibrating at a frequency of 13-50 hertz, are those that are experienced during the normal and alert waking state; alpha waves at 8-13 Hz occur during relaxation; theta waves (4-7 Hz) in the "halfway" moments between waking and sleeping; and delta waves, the slowest at 0.5-4 Hz, during sleep. Interestingly, the brain has been shown to emit the slower theta waves even when in the waking state, when in the undergoing such activities as chant and meditation (4).
For thousands of years, music has been regarded as possessing unique powers in affecting the human experience. Specifically, music has been associated with healing abilities, and has been used for such purposes throughout history. Traditionally, the types of sound responsible for healing are characterized by distinct rhythms, and by specific emphasis on repetition that stems from those rhythms. The existence of repetitive beat seems to aid in the achievement of meditative state. Shamans are well known for their use of drum beats to access healing powers both within themselves and for the people they wish to treat (5).
It has been suggested that in the meditative state—a state of extreme awareness and internal mental calmness—the two hemispheres of the brain become synchronized in brain wave production, rather than generating signals of varying frequencies and amplitudes. It would thus make sense that the repetitive nature of chant, and the underlying beat of music, is central in the unifying and rhythmic effect that such practices have on the brain. Specifically, we find the underlying repetitive drone, a constantly held baseline tone, in numerous types of spiritual chant, including the Hebrew,...