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Section 40. (c) The Sense of Hearing.

We have two problems with regard to sound—whether the witnesses have heard correctly, and whether we hear them correctly. Between both witnesses and ourselves there are again other factors. Correct comprehension, faithful memory, the activity of the imagination, the variety of influences, the degree of personal integrity; but most important is the consideration, whether the witness has heard correctly. As a general thing we must deny in most cases completely accurate reproduction of what witnesses have heard. In this connection dealing with questions of honor is instructive. If the question is the recall of slander the terms of it will be as various as the number of witnesses. We discover that the sense, the tendency of slander is not easily mistaken. At least if it is, I have not observed it. The witness, e. g., will confuse the words "scamp," "cheat," "swindler," etc., and again the words: "ox," "donkey," "numbskull," etc. But he will not say that he has heard "scamp" where what was said was "donkey." He simply has observed that A has insulted B with an epithet of moral turpitude or of stupidity and under examination he inserts an appropriate term. Often people hear only according to meanings and hence the difficulty of getting them to reproduce verbally and directly something said by a third person. They always engage upon indirect narration because they have heard only the meaning, not the words. Memory has nothing to do with this matter, for when in examination, a witness is requested to reproduce directly what he has just heard, he will reproduce no more than the sense, not the words. Not to do so requires an unusual degree of intelligence and training.

Now if the witnesses only reproduced the actual meaning of what they heard, no harm would be done, but they tell us only what they suppose to be the meaning, and hence we get a good many mistakes. It does seem as if uneducated and half-educated people are able to shut their ears to all things they do not understand. Even purely sensory perception is organized according to intelligent capacity.

If this is kept in mind it will be possible correctly to interpret testimonies in those difficult instances in which one man narrates

what he has heard from another concerning his own statement, and where it might be quite impossible to judge the nature and culture of this third person. There are a few other conditions to consider besides.

If we have to discover a person's hearing power or his hearing power under definite conditions, it is best never to depend, in even slightly important cases, on vocal tests merely. The examination must be made by experts, and if the case is really subtle it must be made under the same circumstances of place and condition, and with the same people as in the original situation. Otherwise nothing certain can be learned.

The determination of auditory power is, however, insufficient, for this power varies with the degree any individual can distinguish a single definite tone among many, hear it alone, and retain it. And this varies not only with the individual but also with the time, the place, the voice, etc. In my bed-room, e. g., and in three neighboring rooms I have wall-clocks each of which is running. The doors of the room are open right and left. At night when everything is quiet, I can sometimes hear the ticking of each one of these clocks; immediately isolate one completely and listen to that so that the ticking of the other three completely disappears. Then again I may kindly command myself not to hear this ticking, but to hear one of the other three, and I do so, though I fail to hear two clocks together at just the same instant. On another day under similar circumstances I completely fail in this attempt. Either I hear none of the clocks in particular, or only for a short time, which results in the ticking's being again lost in the general noise; or I do hear the ticking of one clock, but never of that which I have chosen to hear.

This incident is variously explicable and the experiment may be repeated with various persons. It indicates that auditory capacity is exceedingly differentiated and that there is no justification for aprioristic doubt of especial powers. It is, however, admittedly difficult to say how experiments can be made under control.

There are still a few more marvels. It is repeatedly asserted, e. g., by Tyndall, that a comparatively large number of people do not hear high tones like the chirping of crickets, although the normal hearing of such people is acute. Others again easily sense deep tones but distinguish them with difficulty because they retain only a roll or roar, but do not hear the individual tones.[1] And generally,

almost all people have difficulty in making a correct valuation of the direction of sound. Wundt says that we locate powerful sounds in front of us and are generally better able to judge right and left than before and behind.[2] These data, which are for us quite important, have been subjected to many tests. Wundt's statement has been confirmed by various experiments which have shown that sound to the right and the left are best distinguished, and sounds in front and below, in front to the right and to the left, and below, to the right and to the left, are least easily distinguished. Among the experimenters were Preyer, Arnheim, Kries, Münsterberg.

All these experiments indicate certain constant tendencies to definite mistakes. Sounds in front are often mistaken for sounds behind and felt to be higher than their natural head-level. Again, it is generally asserted that binaural hearing is of great importance for the recognition of the direction of sound. With one ear this recognition is much more difficult. This may be verified by the fact that we turn our heads here and there as though to compare directions whenever we want to make sure of the direction of sound. In this regard, too, a number of effective experiments have been made.

When it is necessary to determine whether the witness deposes correctly concerning the direction of sound, it is best to get the official physician to find out whether he hears with both ears, and whether he hears equally well with both. It is observed that persons who hear excellently with both ears are unfortunate in judging the direction of sound. Others again are very skilful in this matter, and may possibly get their skill from practice, sense of locality, etc. But in any case, certainty can be obtained only by experimentation.

With regard to the conduction of sound—it is to be noted that sound is carried astonishingly far by means of compact bodies. The distance at which the trotting of horses, the thunder of cannons, etc., may be heard by laying the ear close to the ground is a commonplace in fiction. Therefore, if a witness testifies to have heard something at a great distance in this way, or by having laid his ear to the wall, it is well not to set the evidence aside. Although it will be difficult in such cases to make determinative experiments, it is useful to do so because the limits of his capacity are then approximated.

Under certain circumstances it may be of importance to know what can be heard when the head, or at least the ear, is under water. The experiment may be made in the bath-room, by setting the back of the head under water so that the ears are completely covered

but the mouth and the eyes are free. The mouth must be kept closed so that there shall be no intrusion of sound through the Eustachian tube. In this condition practically no sound can be heard which must first pass through the air. If, therefore, anybody even immediately next to you, speaks ever so loud, you can hear only a minimum of what he says. On the other hand, noises that are conducted by compact bodies, i. e. the walls, the bath, and the water, can be heard with astonishing distinctness, especially if the bath is not detachable but is built into the wall. Then if some remote part of the building, e. g. some wall, is knocked, the noise is heard perfectly well, although somebody standing near the bath hears nothing whatever. This may be of importance in cases of accident, in certain attempts at drowning people, and in accidental eaves-dropping.

There are several things to note with regard to deaf persons, or such as have difficulty with their hearing. According to Fechner, deafness begins with the inability to hear high tones and ends with the inability to hear deep ones, so that it often happens that complainants are not believed because they still hear deep tones. Again, there are mistakes which rise from the fact that the deaf often learn a great deal from the movements of the lips, and the reading of these movements has become the basis of the so-called "audition" of deaf mutes. There are stories of deaf mutes who have perceived more in this way, and by means of their necessary and well-practised synthesis of impressions, than persons with good hearing power.

The differences that age makes in hearing are of importance. Bezold has examined a large number of human ears of different ages and indicates that after the fiftieth year there is not only a successive decrease in the number of the approximately normal-hearing, but there is a successively growing increase in the degree of auditory limitation which the ear experiences with increasing age. The results are more surprising than is supposed.

Not one of 100 people over fifty years of age could understand conversational speech at a distance of sixteen meters; 10.5% understood it at a distance of eight to sixteen meters. Of school children 46.5% (1918 of them) from seven to eighteen understood it at a distance of 20 meters plus, and 32.7% at a distance of from 16 to 8 meters. The percentage then is 10.5 for people over fifty as against 79.2 of people over seven and under 18. Old women can hear better than old men. At a distance of 4 to 16 meters the proportion of women to men who could hear was 34 to 17. The converse is

true of children, for at a distance of 20 meters and more the percentage of boys was 49.9 and girls 43.2. The reason for this inversion of the relation lies in the harmful influences of manual labor and other noisy occupations of men. These comparisons may be of importance when the question is raised as to how much more a witness may have heard than one of a different age.