Criminal Psychology by Hans Gross (best book recommendations .TXT) 📕

details without its help. Definite conditions may bring to light very great distinctions. A body close to the face or in the middle distance looks different according as one eye or both be used in examining it. This is an old story and explains the queer descriptions we receive of such objects as weapons and the like, which were suddenly held before the face of the deponent. In cases of murderous assault it is certain that most uncanny stories are told, later explained by fear or total confusion or intentional dishonesty, but really to be explained by nothing more than actual optical processes.

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 Quatrem<e’>re-Disjonval, was able so accurately to observe the spiders in his cell as to make the observation the basis for his famous “Aran<e’>ologie.”

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 <p 204>

eye, perhaps, changes in some degree for just this purpose. But a prolonged use of the visual mechanism tends to hypertrophy—

or atrophy, as the eyes of deep-sea fishes show. It is well, in any event, to be careful about contradicting the testimonies of patients who have long lived in the dark, concerning what they have seen.

The power to see in the dark is so various that without examination, much injustice may be done. Some people see almost nothing at twilight, others see at night as well as cats. And in court these differences must be established and experimentally verified.

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.

Section 38. (2) Color Vision.

Concerning color vision only a few facts will be mentioned: 1.

It will be worth while, first of all, to consider whether color exists.

Liebmann holds that if all the people were blind to red, red would not exist; red, i. e., is some cervical phantasy. So are light, sound, warmth, taste, etc. With other senses we have another world.

According to Helmholtz, it is senseless to ask whether cinnabar is red as we see it or is only so as an optical illusion. “The sensation of red is the normal reaction of normally constructed eyes to light reflected from cinnabar. A person blind to red, will see cinnabar as black, or a dark grayish yellow, and this is the correct reaction <p 205>

for these abnormal eyes. But he needs to know that his eyes are different from those of other people. In itself the sensation is neither more correct nor less correct than any other even though those who can see red are in the great majority. The red color of cinnabar exists as such only in so far as there are eyes which are similar to those of the majority of mankind. As such light reflected from cinnabar may not properly be called red; it is red only for especial kinds of eyes.” This is so unconditionally incorrect that an impartial judge of photography says[1] that everything that normal eyes call violet and blue, is very bright, and everything they call green and red is very dark. The red-blind person will see as equal certain natural reds, greens and gray-yellows, both in intensity and shadow. But on the photograph he will be able to distinguish the differences in brightness caused by these three otherwise identical colors. We may, therefore, assume that colors possess *objective differences, and that these objective differences are perceived even by persons of normal vision. But whether I am able to sense the same effect in red that another senses, and whether I should not call red blue, if I had the color-vision of another, is as impossible to discover as it is useless. When the question of color is raised, therefore, we will try to discover only whether the person in question has normal color-vision, or what the nature and degree of his abnormality may be.

[1] W. Heinrich: <U:>bersicht der Methoden bei Untersuchung der Farbenwahr.

nehmungen. Krakau 1900.

2. It is not unimportant to know whether single tints are recognizable in the distance. There have been several examinations of this fact. Aubert[2] constructed double squares of ten millimeters and determined the angle of vision at which the color as such could be seen. His results were:

COLOR OF THE WHITE BLACK

SQUARE BACKGROUND

White 39”

Red 1’ 43” 59”

Light Green 1’ 54” 1’ 49”

Dirty Red 3’ 27” 1’ 23”

Blue 5’ 43” 4’ 17”

Brown 4’ 55” 1’ 23”

Light Blue 2’ 17” 1’ 23”

Orange 1’ 8” 0’ 39”

Gray 4’ 17” 1’ 23”

Rose 2’ 18” 3’ 99”

Yellow 3’ 27” 0’ 39”

[2] Physiologie der Netzha.ut. Breslau 1865.

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It is interesting to notice that the angle for blue on a white background is almost nine times that for white, orange, or yellow on a black background. In cases where colors are of importance, therefore, it will be necessary to discover the color and the nature of its background before the accuracy of the witness can be established.

3. It is well known that in the diminution of brightnesses red disappears before blue, and that at night, when all colors have disappeared, the blue of heaven is still visible. So if anybody asserts that he has been able to see the blue of a man’s coat but not his red-brown trousers, his statement is possibly true, while the converse would be untrue. But there are no reliable or consonant accounts of the order in which colors disappear in increasing darkness. The knowledge of this order would help a great deal in the administration of criminal justice.

4. The retina will not see red at the periphery, because there are no red rods there. A stick of red sealing wax drawn across the eye from right to left, appears at the periphery of the visual field to be black. If, then, a witness has not looked right at a definitely red object, and has seen it askance, he has certainly not observed its color. The experiment may be made by anybody.

5. According to Quantz[1] objects in less refractable colors (red, orange, yellow, and purple) look 0.2 to 3.6% bigger against white, while blue, blue-green, and violet objects appear from 0.2 to 2.2%

smaller. Dark and long-lined objects seem longer; bright and horizontal seem wider. And these facts are significant when witnesses judge of size.

[1] J. O. Quantz: The Influence of the Color of Surfaces on our Estimation of their Magnitudes. Am. Journal of Psychology VII, 95.

6. If colors are observed through small openings, especially through very small holes, the nuances become essentially different and green may even seem colorless.

7. According to Aubert, sparkle consists of the fact that one point in a body is very bright while the brightness diminishes almost absolutely from that point; e. g., a glancing wire has a very narrow bright line with deep shadows on each side; a ball of mercury in a thermometer, a shining point and then deep shadow. When we see this we say it sparkles because we unite it with a number of similar observations. It is therefore conceivable that at a great distance, under conditions of sharp or accidental illuminations, etc., we are likely to see things as sparkling which do not do so in the least. With the concept “sparkling,” moreover, we tend to unite, <p 207>

at least under certain circumstances, definite images, and hence “glancing weapons” are often seen in places where there were only quite harmless dull objects. So also coins are seen to sparkle where really there are none.

Section 39. (3) The Blind Spot.

Everybody knows what the blind spot is, and every psychology and physiology textbook talks about it. But as a rule it is identified only with the little point and the tiny cross pictured in the textbooks, and it is supposed that it does not much matter if the little cross, under certain circumstances, can not be seen. But it must not be forgotten that the size of the blind spot increases with the distance so that at a fairly great distance, possibly half the length of a room, the blind spot becomes so great that a man’s head may disappear from the field of vision. According to Helmholtz: “The effect of the blind spot is very significant. If we make a little cross on a piece of paper and then a spot the size of a pea two inches to the right, and if we look at the cross with the left