Music has well established psychological effects, including the induction and modification of cognitive states, moods and emotions. Were it not so, then marches would be played as readily at bedtime as at the half time of football games, dirges would grace weddings, lullabies would be heard at parades and Gregorian chant would bombard our ears in supermarkets.

Many people think that psychology is one thing but physiology is another thing. There is the mind and there is the body. This common "dualist" assumption scores high on our own psychological "comfort meters". It is always nice when common sense matches scientific reality. When that happens, we feel that we have a good grasp of things and that an issue has been settled. Of course, the dualist position has a problem with the question of just how music affects our private mental lives. And just where is it that our private mental lives live anyway? But mind body dualism has been the dominant belief in the history of the world. Can so many people over so long a time be wrong? Certainly.

Yes, the mind is still mysterious. But it has proven impossible to toss away the brain and still keep the mind. By mind, I refer to our everyday mental experiences, not to the soul or similar formulations. I would not claim that science provides the only type of knowledge or understanding possible. Only that what we consider to be our normal, run of the mill, daily mental experiences necessarily are a product of our brain function. The evidence, quite overwhelming, cannot all be reviewed here. But a few examples. When our level of consciousness changes from waking to sleeping, the electrical activity of our brains changes as well. If one induces a sleeping pattern in the brain by drugs or other means, the behavior goes along. In fact, most drugs that alter our experiences, perceptions, moods, general state of pain, etc. do so by their physiological and chemical actions on the brain, including nicotine and alcohol. (Others, like local anesthetics, can block pain receptors on the body, preventing the brain from receiving messages that it interprets as pain.) Death is medically defined not as cessation of heart beat or respiration but rather by the absence of electrical activity of the brain, literally "brain dead". Finally, but more speculatively, if you exchanged brains with another person (really science fiction!!), where would your mind be ... with your brain or elsewhere?

So there is the mind and there is the body, including the rather important bodily organ of the brain. To begin to understand the power of music on our brains, and therefore on our minds, we need to consider some basic physiology.

The brain sends to and receives messages from the rest of the body ceaselessly, every minute, second and fraction of a second. As for the receiving side of things, the brain gets information from our senses vision, hearing, touch, taste, smell, etc. We can be constantly aware of these. But there is another major source of input to our brains, and thus ultimately to our mental lives ... our bodily hormones. These are secreted by our endocrine system and include sex hormones, like testosterone and estrogen, and a group usually called "stress" hormones, like ACTH, adrenaline and cortisol.

A capsule summary of the way stress hormones are released into the blood stream is that the brain, sensing stress, ultimately releases ACTH from the pituitary gland at the base of the brain, itself controlled by neural and hormonal messages from its link to the brain, the overlying hypothalamus. When ACTH reaches the adrenal glands, they release adrenaline and cortisol into the blood stream. These have many effects on target organs, including the release of stored glucose for energy, increasing blood flow to the muscles and increasing blood pressure, all as part of a constellation of bodily mobilization for possible action, defense or whatever. One effect of stress hormones is to dampen down the immune system, so that, unfortunately, continual stress can reduce the ability to fight disease. Although this counterintuitive effect of stress hormones is not fully understood, it should not be ignored.

While oversimplified, this sketch provides a basis for understanding how music affects the body. And of great interest, how the body then affects the brain. As noted above, the brain also receives the effects of the hormones which it has commanded glands (e.g., the adrenals) to release. So there is "feedback". In other words, our brains and our glands are in a continual pas de deux . Now a fascinating fact is that a major result of the release of adrenaline (also called epinephrine) is to affect the brain, particularly an almond shaped group of brain cells termed the amygdala. The amygdala can be thought of as a major emotional command center. When the amygdala is particularly active, it is believed emotions are experienced. There is another important effect when an experience causes adrenaline to be released and ultimately activate the amygdala (actually through the mediation of another hormone called noradrenaline), memories of the initiating experience are strengthened. That is, the body tells the brain how much adrenaline was released, which in turn modifies how strongly the brain stores the memory of the event which started the whole thing. In short, when we experience something very important, even traumatic, a lot of adrenaline is released which "instructs" the amygdala to help other parts of the brain store stronger memories.[1] So, as we come to the question of music and hormones, we must realize that hormones secreted in the body and affecting bodily processes, such as the cardiovascular, muscular and immune systems, also affect the brain.

There are now several studies, mainly within the last five years or so, that have addressed the issue of whether music itself actually changes the amount of release of our stress hormones. Most of these have concentrated on measuring levels of cortisol before and after various exposures to music.

We can start with attempts to reduce cortisol levels, or more specifically to prevent increased release of this stress hormone, in conjunction with invasive diagnostic and surgical procedures. Gastroscopy is one such diagnostic technique, involving the oral insertion of a probe into the stomach in the awake and aware patient. This is a highly stressful situation, so any approaches that would reduce stress would be helpful. Dr. Escher and coworkers allowed a group of patients undergoing gastroscopy to select and listen to the type of music they preferred, chosen in consultation with a music therapist. A control group heard no music. The control group showed a large increase in levels of cortisol, and also ACTH, in their blood. In contrast, the music group exhibited a significantly lower level of release of these hormones.[2] In a similar approach, in this case to surgery, MilukKolasa et al measured cortisol levels in patients in conjunction with informing them that they would have to undergo surgery the next day.[3] One group received an hour of music immediately following receipt of this unwelcome news, while another group of surgical patients received no treatment; a third non surgery group of patients served as additional controls. These workers found that the information about impending surgery produced a 50% rise in cortisol within 15 minutes in both surgical groups. Surgical patients who did not receive music exhibited a higher level of cortisol an hour later than the music group, which had returned to a baseline no different from the nonsurgical controls. Thus, music greatly reduced the duration of the cortisol response to stress. Both studies indicate that stress hormone levels can be reduced by exposure to music in a medical treatment setting.

What of healthy individuals who are not in a medicallycompromised state? Mšckel and several coworkers at the Free University of Berlin undertook just such a study. They examined the effects of three types of music on several physiological measures. They employed a waltz by Johann Strauss because it had a regular rhythm. To contrast with this, a composition by the more contemporary composer W. H. Henze was used; the authors note that its rhythm was markedly irregular. The third piece was by Ravi Shankar, selected for it meditative nature without strong rhythmic characteristics. Levels of cortisol and also noradrenaline were reduced by one type of music, the Shankar piece.[4] Of course, the types of music differed in many ways in addition to rhythm, so the particular aspect of music that was responsible is unknown. Still hormonal control by music seems clear.

While these findings all seem to agree that music lowers levels of stress hormones, this is not a universal finding. For example, Brownley et al investigated how music affects cortisol in trained and untrained runners under three conditions: "sedative", "fast" and no music.[5] Following high intensity exercise, the authors observed increased levels of cortisol for fast music, compared to sedative and no music in the untrained runners only. So music can actually increase stress hormones. Indeed, in circumstances where the general stress reaction of bodily mobilization may be desirable, music might be a good way to promote this outcome. Such is the case when strenuous activity is required. The trained runners may already have conditioned their bodies to optimal levels of hormonal state, hence the absence of an effect of fast music.

Other studies also show that music can increase as well as decrease stress hormones. And this doesn't have to happen under conditions of high activity or athletic exercise. In one such study, college majors in music and in biology were exposed to two selections from Holst's The Planets Venus and Jupiter. The former was rated as peaceful and the latter as very lively. Hormones were altered by the music, but the effect was not so much due to the type of music (relaxing vs. energizing) as to the field of study of the subjects. The biology majors exhibited a decrease in cortisol, similar to that which might be expected from other studies of the effects of music. In contrast, the music students had significant increases in cortisol. When later interviewed, music students indicated that they were actively engaged in mental analysis of the music, some even "playing" their instruments mentally.[6] The same authors obtained similar findings in a follow up study in which unpleasant, even tragic, music was played to the two groups. [7]

Taken together, these findings indicate that there is no simple relationship between music and stress hormones. It is not only a matter of the type of music played, but also the cognitive and other mental activities that the individual brings to the situation. This seems to be a foundational consideration in understanding the interplay among music, hormones and the brain. Moreover, the longer term consequences of the music experience need to be kept in mind. As pointed out above, increased release of stress hormones can strengthen memories for events that occurred at that time or shortly before. Thus, in cases in which one wants to increase memory, music that produces transiently higher hormone levels might be employed, the "flip side" of musical sedation. Moreover, unlike the prescription for an antibiotic or similar therapeutic drug, a "prescription for music" has to be formulated with appropriate attention to and knowledge of the cognitive state, level of knowledge and likely mental response of the individual receiving the music treatment.

Healthy individuals already self select music but often without an understanding of how or why certain music affects them in a particular way. If a selection produces certain signs of arousal of the autonomic nervous system, like increased respiration and heart rate, the individual could be 11 self dosing" with increased levels of cortisol, adrenaline and other stress hormones. If done continually, chronic high levels of these hormones might be achieved. Whether this has serious health implications needs to be determined. Although one might not want to consider whether they are "overdosing" on cortisol, it might be prudent to give this some serious thought.

I McGaugh JL; Cahill L. (1997). Interaction of neuromodulatory systems in modulating memory storage. Behav. Brain Res. Feb, 83(1 2):31 8.

2 Escher, J., Hohmann, U., Anthemen, L., Dayer, E., Bosshard, C. and Gaillard, R.C. (1993). [Music during gastroscopy) [German]. Schweiz. Med. Wochenschrift, 123, 13541358.

3 Miluk Kolasa, B., Obminski, S., Stupnicki, R. and Golec, L. (1994). Effects of music treatment on salivary cortisol in patients exposed to pre surgical stress. Exper. and Clin. Endocrinol., 102,118 120.

4 Mockel, M., Ršbcker, L., Stšrk, T., Vollert, J., Danne, 0., EichstŠdt, H., Muller, R. and Hochrein, H. (1994). Immediate physiological responses of healthy volunteers to different types of music: cardiovascular, hormonal and mental changes. Eur J. Appl. Physiol., 68, 451 459.

5 Brownley, K.A., McMurray, R.G. and Hackney, A.C. (1995). Effects of music on physiological and affective responses to graded treadmill exercise in trained and untrained runners. International J. Psychophysiology, 19(3): 193 201.

6 VanderArk, S.D. and Ely, D. (1992). Biochemical and galvanic skin responses to music stimuli by college students in biology and music. Percept. Motor Skills 74, 1079 1090.

7 VanderArk, S.D. and Ely, D. (1993). Cortisol, biochemical, and galvanic skin responses to music stimuli of different preference values by college students in biology and music. Percept. Motor Skills 77, 227 234.