[00:01.01]Lesson 25
[00:03.22]Non-auditory effects of noise
[00:11.01]What conclusion does the author draw about noise and health in this piece?
[00:18.19]Many people in industry and the Services,
[00:21.21]who have practical experience of noise,
[00:23.99]regard any investigation of this question as a waste of time;
[00:28.67]they are not prepared even to admit the possibility that noise affects people.
[00:34.56]On the other hand,
[00:35.97]those who dislike noise will sometimes use most inadequate evidence
[00:40.50]to support their pleas for a quieter society.
[00:44.39]This is a pity, because noise abatement really is a good cause,
[00:50.12]and it is likely to be discredited if it gets to be associated with bad science.
[00:56.80]One allegation often made is that noise produces mental illness.
[01:02.85]A recent article in a weekly newspaper, for instance,
[01:06.37]was headed with a striking illustration of a lady in a state of considerable distress,
[01:12.20]with the caption 'She was yet another victim, reduced to a screaming wreck'.
[01:19.25]On turning eagerly to the text, one learns that the lady was a typist
[01:24.54]who found the sound of office typewriters worried her more and more
[01:28.84]until eventually she had to go into a mental hospital.
[01:33.69]Now the snag in this sort of anecdote is of course
[01:37.49]that one cannot distinguish cause and effect.
[01:41.41]Was the noise a cause of the illness,
[01:44.21]or were the complaints about noise merely a symptom?
[01:48.33]Another patient might equally well complain
[01:51.08]that her neighbours were combining to slander her and persecute her,
[01:55.23]and yet one might be cautious about believing this statement.
[01:59.87]What is needed in the case of noise
[02:02.22]is a study of large numbers of people living under noisy conditions,
[02:07.04]to discover whether they are mentally ill more often than other people are.
[02:12.39]Some time ago the United States Navy, for instance,
[02:15.93]examined a very large number of men working on aircraft carriers:
[02:20.91]the study was known as Project Anehin.
[02:24.65]It can be unpleasant to live even several miles from an aerodrome;
[02:29.62]if you think what it must be like
[02:31.43]to share the deck of a ship with several squadrons of jet aircraft,
[02:35.96]you will realize that a modern navy is a good place to study noise.
[02:41.52]But neither psychiatric interviews nor objective tests
[02:45.92]were able to show any effects upon these American sailors.
[02:50.67]This result merely confirms earlier American and British studies:
[02:55.97]if there is any effect of noise upon mental health,
[02:59.29]it must be so small that present methods of psychiatric diagnosis cannot find it.
[03:05.82]That does not prove that it does not exist; but it does mean
[03:10.57]that noise is less dangerous than, say being brought up in an orphanage
[03:15.45]-- which really is a mental health hazard.