Too much annoyance prevents the body from simmering down after stimulation. According to Dr. Etienne Grandjean of Zurich's Federal Institute of Technology, interference with the body's recovery processes is the main reason underlying subjective annoyance. From this point of view, annoyance must be considered a biological protective mechanism helping man to avoid noise and to secure needed recovery. The biological meaning of annoyance is therefore comparable to other feelings of discomfort like hunger, fatigue, cold or heat—all of which are life-protecting warnings.
Some doctors regard noise-induced annoyance as potentially harmful. Doctors associated with the German Medical Information Service recognize that circumstances dictate whether or not a given noise annoyance is a mere nuisance or a health problem.
Noise annoyance can be a health problem if:
1. The victim is a night worker who must sleep days;
2. The victim is doing mental or creative work;
3. The victim is ill, or convalescing.
To be dismissed as merely an innocent irritant, noise must be brief, not too loud, occur only during normal daytime periods, and be of a specific quality and type. However, what may be mildly or non-irritating to most, may be annoying to the sick or the convalescent. Psycho-physical distractions due to noise may be cause for legal redress where work is primarily mental and creative.
If noise stress activates the biological organism to seek quiet, what happens when that need cannot be met? A person can do something about hunger, thirst, and fatigue. But what happens if he can't avoid noise?
Perhaps the unmet urge for escape is responsible for the acts of violence triggered by noise. Extreme hunger and thirst have forced men to behave irrationally. Is it not conceivable that unrelenting noise may also produce acts of violence?
Most noise victims, however, do not give vent to their anger. And since they usually have no rights against the noise source, they turn their rage inward. Or, even if there is no conscious awareness of the irritation, the organism is tensed.
One result of unreleased tension may be headaches. The modern incidence of headaches is associated with industrialization. Some experts believe New York has the highest headache rate in the United States. Dr. Arnold P. Friedman, a psychiatrist-neurologist who runs the headache unit at Montefiore Hospital, New York City, believes that tension, or "nerves," accounts for 70 per cent of the headaches which are so severe they annually send 24 million Americans to doctors for help.
A sudden rise in blood pressure may cause a headache.
Noise causes a sudden rise in blood pressure.
Headache pain may be caused by contraction of the head and neck muscles in response to stress.
Noise causes stress.
Many headaches occur when the blood vessels around the brain swell and impinge on a sensitive nerve, or when the blood supply to the brain is choked off by tense neck muscles. The muscle tension constricts the arteries, and the subsequent dilating phase is the painful phase.
Noise tenses muscles.
Migraine headaches are most often triggered by emotional factors in persons whose blood vessels are predisposed to painful changes in diameter.
Noise changes the diameter of the blood vessels.
Can noise cause headaches? No one knows, but it seems plausible that a dose of quiet could hurt aspirin sales.
It should not be surprising that the repeated acoustic shocks of appliances and transportation produce tension. It is as if the response to each unexpected signal were that of a total alert, with the body responding with maximum preparation for the unexpected.
This is how Dr. Welch describes the reaction of the brain to sudden sound: "Your ears register the sound and you whirl about, eyes seeking the cause...That brief moment in which you heard, turned, and saw launched a whirlwind of activity. 'Messages' flashed over a complicated nerve net to and from the brain. Chemicals in the brain flowed and changed. Simultaneously the other events around you triggered similar developments in the brain."
It would also seem that noise produces tension because it violates the "zones of sensory experience" described by anthropologist Dr. Edward T. Hall. Certainly noise is a trespass of the "social zone" four to ten feet from the body, and a trespass of the "personal zone" a little more than arm's length. But it seems to me that what makes noise so unendurable is that it also violates the "intimate zone," the one associated with lovemaking, comforting, and protecting.
Given all of this, there is good reason to suspect that in addition to chemical and physical reactions, noise plays havoc with our minds and our emotions. It is difficult to believe that noise which irritates, disturbs sleep, and constantly jars our nerves, just goes in one ear and out the other.
Until recently doctors have resisted the idea that emotions can play a role in all diseases, including infections, cancer, and heart ailments. Now the medical profession is receiving a flow of research reports that establish a relationship between emotions and disease. Emotional disturbance was reported to influence the common cold, attacks of asthma, and even the state of one's gums. (Yes, dentists are being urged to include some psychology as part of their treatment.) Other medical researchers have suggested a link between emotional states and the ability to ward off disease states, or get well once an illness has developed.
Ashley Montagu develops an interesting hypothesis that the emotions of the mother are directly communicated to the unborn child. Her emotions increase the hormonal output in her bloodstream and this increase is transmitted to the child's bloodstream. Severe emotional upsets at a critical development period might, he believes, be harmful.
One of the more striking papers presented at the December 1969 meeting of the American Academy for the Advancement of Science was that by Lester W. Sontag, M.D. on noise as a threat to the fetus. Enough research has been done, reported Dr. Sontag, to indicate that the embryo is vulnerable to environmental stresses, including sound pollutants. He cautions that the unborn be protected from excessive noise exposure.
Research is needed comparing the number of still-births and congenital deformities among children of mothers living in noise-stressed sites, such as airport vicinities, and mothers living in quiet locales.
A new hypothesis of annoyance is suggested by the work of Jansen and Rosen. Annoyance could be the reaction of the body to momentary "dying" of essential organs and tissues temporarily deprived of their normal flow of blood by noise-induced vasoconstriction.
What does vasoconstriction mean?
During the period when the blood vessels constrict there is a diminution of blood in circulation. Constriction slows the flow of blood through the vessels and therefore less oxygen and other nutrients reach an area at any given moment. The "pins and needles" feeling in a finger around which a rubber band has been tightened is a good example of what happens when there is an interference with normal blood flow.
Dr. Lehmann has reported that exposure to loud noise in factories interferes with blood circulation, and that workers in a boiler factory suffered constantly from impaired circulation in the skin. Vasoconstriction and accompanying loss of oxygen and other nutrients may be a cause of destruction of the cells of hearing, as well as of cells in other organs of the body.
If vasoconstriction from acoustic insults could eventually lead to a chronic state of constriction, and the cells of the inner ear eventually succumb, why may it not be assumed that some kind of damage is being done to many tissues and organs of the body if they, too, suffer from repeated vasoconstriction?
This theory of choking of the vital organs of the body would establish a physiological basis for annoyance. It would also explain why there are variations in individual reaction. The choking-off of the organ varies in proportion to the intensity, duration, suddenness, and repetition of the stimulus. One incident of stimulus can be so mild it passes unnoticed; a little more choking, and the victim develops a mild sense of annoyance; repeated choking with acute blood and oxygen stoppage, and the discomfiture increases and rises to intolerable levels. Choke an internal organ long enough, or severely enough, and it dies, as seems to have been demonstrated with the cells in the inner ear. Is it not possible that the subjective feeling of annoyance is, at least in part, caused by the "choking" of the various organs and tissues of the body by depriving them of a normal supply of blood?
Research is needed, such as that suggested by Dr. Rosen, which would attempt to correlate noise, vasoconstriction, and the subjective feeling of annoyance. This vasoconstriction theory raises the concept of annoyance to a level at which applied research would seem possible and fruitful. There may be a discernible biological and physiological basis for annoyance.
How often does one hear this statement: "At first the noise bothered me, but I got used to it."
But what the speaker means is only that his conscious awareness was reduced or disappeared altogether. One does not get used to noise. Somewhere in the human body, that sound is being absorbed—at an as yet unknown price. This is the law of the conservation of energy. Energy does not just disappear.
Whether or not noise annoyance is a health problem depends, to some degree, on the price to the human organism of "adapting," of making the necessary adjustments to an abnormal situation.
In 1966, Karl D. Kryter, who does research for NASA and the FAA at the Stanford Research Institute, reported: "There is evidence that following an initial adjustment to and learning the nature and meaning of one's noise environment people become less, rather than more, tolerant of continued exposure to aircraft noise."
In examining the question of adaptation, some researchers distinguish between exposure to meaningful and meaningless sounds. Meaningful noise is the noise that contains information. To Dr. Jansen for example, "It seems that man gets accustomed to most of the meaningful auditory stimuli if they are repeated often." Even then, he cautions, "scientific research now is not yet able to give all the criteria needed to determine the point at which health is endangered by a meaningful noise." According to Dr. Jansen, the personality of the listener, his individual physiological and psychological makeup, and his life experiences, all determine how well he becomes accustomed to meaningful noises. This is evident in the varying responses one gets when a group of people are exposed to construction noise. Some are more capable of tolerating it than others. But this does not necessarily mean they are not reacting to some component of that noise.
"The most dangerous noise," states Jansen, "is noise we are accustomed to, that we do not `hear,' such as traffic noises. These are the noises that cause physiological responses because of their intensities or frequency-ranges. They do not lend themselves to adaptation." Jansen is quite concerned about the impact of this noise to which the person is accustomed but which does not convey information. Such a sound can be the constant roar of traffic that becomes, for some, an unnoticed part of the environment. Air conditioner noise is another example. Such meaningless noises starting at 70 decibels stimulate the vegetative nervous system, the stimulation increasing with intensity and other physical characteristics of the acoustic energy.
Jansen and Rosen observed that "white noise," noise without any predominantly strong tones, at 90 decibels, approximately the level found in some subways, caused the pupil of the eye to dilate, blood volume in the skin to be reduced because of vasoconstriction, a decrease in the stroke volume of the heart, and an increase of diastolic blood pressure. The increase in diastolic pressure, however, disappeared sometimes after several months of exposure.
In a classic study conducted over a three-year period with the same students of a pedagogic academy, Dr. Jansen was able to substantiate his evaluation of the adaptive process. Most of the students were exposed every day during their three years at the academy. Whether the noise burst was in milliseconds, or 90 minutes long, the subjects consistently reacted with vasoconstriction. The vasoconstrictive effect lasted as long as the stimulation; years of stimulus repetition failed to produce any signs of adaptation. "The noise-induced vegetative reaction," reports Dr. Jansen, "was always the same within the whole period."
Can this failure to adapt, which means that the body gets thrown on the alert with each noise burst, cause harm? Says Dr. Jansen, "These reactions caused by noise up to 95 dB must not be regarded as pathological when the noise is applied once or a few times; they might be pathological when a man is influenced for long years with intensities more than 95 dB (as investigations of industrial workers have proved). If there is an additional factor (psychic or somatic), it might be possible to endanger human health with less intensities and shorter time."
This last point is important. There is a tendency to dismiss noises found in the everyday environment as unimportant because they usually are below such intensities and in many cases are of short duration. There is also a tendency to evaluate noise exposure as if the person so exposed was in perfect health and not undergoing any other intense stresses. An organ forced to adapt to one set of abnormal conditions may have difficulty adapting to another set of abnormal conditions. Scientific research has not yet come up with an exact limit at which health becomes endangered.
Another view is presented by Dr. Bruce Welch, who specializes in investigations of stress and brain chemistry:
"It is often said that we 'adapt' to much stimuli, but this is simply not true if by 'adapt' one means to become just as well off as before. At the cognitive level, we come to be somewhat less surprised by loud noises after being subjected to them for a time. But we never cease to be startled. Instead of 'adapt,' a better word might be 'enured.' At the physiological level, we cease to recognize sounds of some intensities at all, and we cease to respond quite so violently to those which do affect us. This, however, as we have seen, simply reflects the fact that our nervous system is maintained at a higher level of activation, or adjusted to a higher balance-point in the interplay between activating and inhibitory neural systems all of the time."
I asked Dr. Welch if his view of adapting would apply to a sound stimulus from something like a STOLcraft, and he replied in the affirmative: "The addition of such intrusive sounds [helicopters and STOLcraft] to those with which the populace is already obliged to contend will weight the emotional and physiological balances further towards the extreme of sensory overloading and the debilitating effects which it may produce."
Most research has been done on the effects of industrial noise, not the variegated cacophony of today's civilized living. Is there periodicity or rhythm in the auto horn, the helicopter flyover, the jet flyover, the blender, the lawn mower, the garbage truck? All are sudden, unexpected. Adjustment does not seem possible.
If body tissue is penetrated by a needle with a given force, the pain decreases with repeated jabbing. Does the decline or even the absence of pain mean there is no tissue damage? Isn't the human nervous system being poked with the broad-band noise of an air conditioner, the sharp whine of a garbage truck, the staccato interjection of a jackhammer? To live with noise is not unlike living with electric shocks.
"Adapting" in any case to a continuing abnormal situation is like living with a bad marriage. Certainly a mismated couple scraping on each other's nerves can "adapt" and continue living together. What is the price of that adaptation, both to the partners and to the children of such a family, and to the community? What decibel formula measures adapting?