Topic I. OF SENSE-PERCEPTION. Criminal Psychology: a manual for judges, practitioners, and students | ||
(b) The Sense of Sight.
Section 37. (I) General Considerations.
Just as the sense of sight is the most dignified of all our senses, it is also the most important in the criminal court, for most witnesses testify as to what they have seen. If we compare sight with the hearing, which is next in the order of importance, we discover the well-known fact that what is seen is much more certain and trustworthy than what is heard. "It is better to see once than to hear ten times," says the universally-valid old maxim. No exposition, no description, no complication which the data of other senses offer, can present half as much as even a fleeting glance. Hence too, no sense can offer us such surprises as the sense of sight. If I imagine the thunder of Niagara, the voice of Lucca, the explosion of a thousand cartridges, etc., or anything else that I have not heard, my imagination is certainly incorrect, but it will differ from reality only in degree. It is quite different with visual imagination. We need not adduce examples of magnificence like the appearance of the pyramids, a tropical light; of a famous work of art, a storm at sea, etc. The most insignificant thing ever seen but variously pictured in imagination will be greeted at first sight with the words: "But I imagined it quite different!" Hence the tremendous importance of every local and material characteristic which the criminal court deals with. Every one of us knows how differently he has, as a rule, imagined the place of the crime to be; how difficult it is to arrive at an understanding with the witness concerning some unseen, local characteristic, and how many mistakes false images of the unseen have caused. Whenever I ciceroned anybody through the Graz Criminal Museum, I was continually assailed with "Does this or that look so? But I thought it looked quite different!" And the things which evoke these exclamations are such as the astonished visitors have spoken and written about hundreds of times and often passed judgments upon. The same situation occurs when witnesses narrate some observation. When the question involves the sense of hearing some misunderstanding may be popularly assumed. But the people know little of optical illusions and false visual perceptions, though they are aware that incorrect auditions are frequent matters of fact. Moreover, to the heard object
In this, again, is the basis for the distrust with which we meet testimony concerning hearsay. For we feel uncertain in the mere absence of the person whose conversation is reported, since his value can not be determined. But a part of the mistrust lies in the fact that it is not vision but the perennially half-doubted hearing that is in issue. Lies are assigned mainly to words; but there are lies which are visual (deceptions, maskings, illusions, etc.). Visual lies are, however, a diminishing minority in comparison with the lies that are heard.
The certainty of the correctness of vision lies in its being tested with the sense of touch,—i. e. in the adaptation of our bodily sense to otherwise existing things. As Helmholtz says, "The agreement between our visual perceptions and the external world, rests, at least in the most important matters, on the same ground that all our knowledge of the actual world rests on, upon the experience and the lasting test of their correctness by means of experiments, i. e., of the movements of our bodies." This would almost make it seem that the supreme judge among the senses is the touch. But that is not intended; we know well enough to what illusions we are subject if we trust the sense of touch alone. At the same time we must suppose that the question here is one of the nature of the body, and this can be measured only by something similar, i.e., by our own physical characteristics, but always under the control of some other sense, especially the sense of sight.
The visual process itself consists, according to Fischer, "of a compounded series of results which succeed each other with extraordinary rapidity and are causally related. In this series the following elements may principally be distinguished.
(1) The physico-chemical process.
(2) The physiologico-sensory.
(3) The psychological.
(4) The physiologico-motor.
(5) The process of perception." It is not our task to examine the first four elements. In order
In addition we often think that the clearness of an object represents its distance and suppose that the first alone determines the latter. But the distinctness of objects, i. e., the perceptibility of a light-impression, depends also upon the absolute brightness and the differences in brightness. The latter is more important than is supposed. Try to determine how far away you can see a key-hole when the wall containing the door is in the shadow, and when there is a window opposite the key-hole. A dark object of the size of a key-hole will not be visible at one hundredth of the distance at which the key-hole is perceived. Moreover, the difference in intensity is not alone in consideration; the intensity of the object with regard to its background has yet to be considered. Aubert has shown that the accuracy of the distinction is the same when a square of white paper is looked at from an angle of 18", and when conversely a square of black paper on white background is looked at from an angle of 85". "When we put a gray paper in the sunshine, it may become objectively brighter than white paper in shadow. But this does not prevent us from knowing one as gray and the other as pure white. We separate the color of the object from the intensity of the incident light." But this is not always so simple, inasmuch as
Differences of illumination reveal a number of phenomena difficult to explain. Fechner calls attention to the appearance of stars: "At night everybody sees the stars, in daylight not even Sirius or Jupiter is seen. Yet the absolute difference between those places in the heavens where the stars are and the environing places is just as great as in the night—there is only an increase in illumination." Of still greater importance to us is the circumstance noted but not explained by Bernstein. If, in daylight, we look into a basement room from outside, we can perceive nothing, almost; everything is dark, even the windows appear black. But in the evening, if the room is ever so slightly illuminated, and we look into it from outside, we can see even small articles distinctly. Yet there was much intenser light in the room in question during the day than the single illumination of the night could have provided. Hence, it is asserted, the difference in this case is a standard one. In open day the eye is accustomed to the dominating brightness of daylight, beside which the subdued illumination of the room seems relatively dark. But in the evening one is in the dark, and hence even the little light of a single candle is enough to enable one to see. That this explanation is untrue is shown by the fact that the phenomenon is not regulated even when the circumstances in question are made identical. If, for example, you approach the window in daylight with your eyes shut, lean your forehead against the pane and shut out the light on the sides with your hands, and then open your eyes, you see as little in the room as when you looked into it without performing this ceremony. So again, if during the night you gazed at some near-by gas lamp and then glanced into the room, there is only a few moments' indistinctness at most, after that the single candle is enough. The reason, then, must be different from the assigned one—but whatever it is, we need only to maintain that immediate judgment concerning numerous cases involving situations of this kind would be overhasty. It is often said that a witness was able to see this or that under such and such illumination, or that he was unable to see it, although he denies his ability or inability. The only solution of such contradictions is an experiment. The attempt must be made either by the judge or some reliable
As to what may be seen in the distance, experiment again, is the best judge. The human eye is so very different in each man that even the acute examination into what is known of the visual image of the Pleiades shows that the average visual capacity of classic periods is no different from our own, but still that there was great variety in visual capacity. What enormous visual power is attributed to half-civilized and barbarous peoples, especially Indians, Esquimos, etc.! Likewise among our own people there are hunters, mountain guides, etc., who can see so clearly in the distance that mere stories about it might be fables. In the Bosnian campaign of 1878 we had a soldier who in numerous cases of our great need to know the enemy's position in the distance could distinguish it with greater accuracy than we with our good field-glasses. He was the son of a coal-miner in the Styrian mountains, and rather a fool. Incidentally it may be added that he had an incredible, almost animal power of orientation.
As we know little concerning far-sightedness, so also we are unable to define what near-sighted people can see. Inasmuch as their vision does not carry, they are compelled to make intellectual supplementations. They observe the form, action, and clothes of people more accurately than sharp-eyed persons, and hence recognize acquaintances at a greater distance than the latter. Therefore, before an assertion of a short-sighted man is doubted an experiment should be made, or at least another trustworthy short-sighted person should be asked for his opinion.
The background of objects, their movement and form have decided effects on the difference in visual perception. It is an ancient observation that lengthy objects like poles, wires, etc., are visible at incomparably greater distances than, e. g., squares of the same length. In examination it has been shown that the boundary of accurate perception can hardly be determined. I know a place where under favorable illumination taut, white and very thin telephone wires may be seen at a distance of more than a kilometer. And this demands a very small angle of vision.
Humboldt calls attention to the large number of "optical fables." He assures us that it is certainly untrue that the stars may be seen in daylight from a deep well, from mines, or high mountains, although this has been repeatedly affirmed since Aristotle.
The explanation of our power to see very thin, long objects at
Helmholtz adds that weakly objective images disappear like a wet spot on warm tin, at the moment a single point is fixed, as does e. g., a landscape seen at night. This last acute observation is the basis of many a testimony concerning the sudden disappearance of an object at night. It has helped me in many an examination, and always to advantage.
In this connection the over-estimation of the moon's illuminating power is not to be forgotten. According to Helmholtz the power of the full moon is not more than that of a candle twelve feet away. And how much people claim to have seen by moonlight! Dr. Vincent[1] says that a man may be recognized during the first quarter at from two to six meters, at full moon at from seven to ten meters, and at the brightest full moon, an intimate may be recognized at from fifteen to sixteen meters. This is approximately correct and indicates how much moonlight is over-estimated.
In addition to the natural differences of sight there are also those artificially created. How much we may help ourselves by skilful distinctions, we can recognize in the well-known and frequently-mentioned business of reading a confused handwriting. We aim to weaken our sense-perception in favor of our imagination, i. e. so to reduce the clearness of the former as to be able to test upon it in some degree a larger number of images. We hold the MS. away from us, look at it askant, with contracted eyebrows, in different lights, and finally we read it. Again, the converse occurs. If we have seen something with a magnifying glass we later recognize
I do not believe that binocular vision is of much importance in the law; I know of no case in ordinary vision where it matters whether one or both eyes have been used. It is correct to assert that one side or the other of a vertically held hand will be clearer if, before looking at it with both eyes, you look at it with one or the other, but this makes little difference to our purpose. It must be maintained that a part of what we see is seen with one eye only,—if, e. g., I look at the sky and cover one eye with my hand, a certain portion of the heaven disappears, but I observe no alteration in the remaining portion. When I cover the other eye, other stars disappear. Therefore, in binocular vision certain things are seen with one eye only. This may be of importance when an effect has been observed first with both eyes, then with one; raising the question of the difference in observation—but such a question is rare.
There are two additional things to consider. The first is the problem of the influence of custom on increasing visual power in darkness. This power is as a rule undervalued. No animal, naturally, can see anything in complete darkness. But it is almost unbelievable how much can be seen with a very little light. Here again, prisoners tell numerous stories concerning their vision in subterranean prisons. One saw so well as to be able to throw seven needles about the cell and then to find them again. Another, the naturalist Quatre-mére-Disjonval, was able so accurately to observe the spiders in his cell as to make the observation the basis for his famous "Aranéologie." Aubert tells of his having had to stay in a room so dark as to make it necessary for others to feel their way, but nevertheless being able to read books without detection because the others could not see the books.
How quickly we get used to darkness and how much more we see after a while, is well known. It is also certain that the longer you are in darkness the more you see. You see more at the end of a day than after a few hours, and at the end of a year, still more. The
The second important element is the innervation of the muscles in consequence of movement merely seen. So Stricker points out, that the sight of a man carrying a heavy load made him feel tension in the muscles involved, and again, when he saw soldiers exercising, he almost was compelled openly to act as they. In every case the muscular innervation followed the visual stimulus.
This may sound improbable but, nevertheless, everybody to some degree does the identical things. And at law the fact may be of importance in cases of assault and battery. Since I learned it, I have repeatedly observed in such cases, from harmless assault to murder, that people, although they had not been seen to deal any blows, were often accused of complicity simply because they were making suspicious movements that led to the following inference: "They stuck their hands into their trousers pocket looking for a knife, clenched their fists, looked as if they were about to jump, swung their hands." In many such cases it appeared that the suspects were harmless spectators who were simply more obvious in their innervation of the muscles involved in the assault they were eagerly witnessing. This fact should be well kept in mind; it may relieve many an innocent.
Topic I. OF SENSE-PERCEPTION. Criminal Psychology: a manual for judges, practitioners, and students | ||