Visual perception

“ The foregoing discussion of vision should indicate the complexity of the visual and mental activities involved in the discrimination, association, and interpretation of the data obtained through the eye. The psychology of visual perception is still a much controverted domain but it is believed that the glimpses of the process of vision which have been afforded are sufficient to enable the reader to understand many illusions and at least to appreciate more fully those whose explanations remain in doubt. ”

“ They say that it is just "highly probable" that the visual perceptions of two individuals have practically the same content when they look at the same object and are both in possession of sound eyes and optical nerves and brain centres. ”

“ This admission relieves the theory from the necessity of maintaining, that conceptions derived from touch are transmuted into the perceptions of sight. It attributes to the sight all that ever truly belongs to it, namely, the perception of colours out of one another; it provides the visual intuitions with an externality of their own—and the theory never demands that they should acquire any other ”

“ Visual Perceptions.—"Seeing" is very largely the mental interpretation of the primary sensations and the conditions under which they occur. For example, our ability to see objects in their natural positions when their images are inverted on the retina is explained by the fact that we are not conscious of the retinal image, but of the mind's interpretation of it through experience. Experience has also taught us to locate objects in the direction toward which it is necessary to turn the eyes in order to see them. ”

“ If it be not colours, then what is it that the touch compels us to associate with the eye? We answer that it is the abstract condition of impressions as the general law on which all seeing depends, but as quite distinct from the particular visual sensations apprehended in virtue of the observance of that law. ”

“ All those operations, therefore, which proceed from direct irritation of the nervous part of the visual organ, without the medium of the eye and of light, under the term subjective vision, are opposed to those phenomena produced by the media of eye and light, and known as objective vision. ”

“ Nor is it at all difficult to understand how this general condition comes to be associated with the eye, and how the particular visual sensations come to be associated with something distant from the eye: and further, how this association of the condition with one thing, and of the sensations with another thing, (an association established by the touch and not by the sight,) dissolves the primary synthesis of seeing and colours. ”

“ Experience points out the eye, and the eye alone, as the visual sensation essential to our apprehension of all our other sensations of vision, and we come at last to regard this sensation as the sense itself. Inveterate association leads us to regard the eye not merely as the organ, but actually as the sense of vision. We find from experience how much depends upon its possession, and we lay claim to it as a part of ourselves with an emphasis that will not be gainsaid. ”

“ Thus it is that the eye, without any conscious effort of the observer, is directed in succession to the various points of an object, and it is only by an effort of will in fixing the eyes upon one spot that one becomes aware of the blurred and confused forms of all the rest of the visual picture. ”

“ If the light, reflected from a single object touched by us, had produced not two merely, but two thousand separate images in our eyes, erect or inverted, or in any intermediate degree of inclination, the visual feeling, thus excited, however complex, would still have accompanied the touch of a single object ”

“ These senses provide the basis for all the arts—music and poetry are arts of sound; painting, sculpture, and architecture are arts of vision. And there are good reasons for their special fitness. Most cogent of all is the fact that vision and hearing are the natural media of expression; sounds, be they words or musical tones, convey thoughts and feelings; so do visual sensations—the facial expression or gesture seen communicates the inner life of the speaker; and even abstract colors and space-forms, like red and the circle, have independent feeling-tones. ”

“ The substitution of simultaneous retinal perception of form for successive perception has the effect of bringing together the terms of the relations of variety and contrast, unity and similarity, under what is approximately one act of attention. If we watch the movements of a painter's hand as he draws the outline of a human figure on a canvas, our eye may attain a rough perception of the successive directions and distances ”

“ The sense of sight has been wonderfully endowed with a duplicate power which we have come to call the mind's eye. With this visual faculty we produce some very important mental operations. We must first become conscious of this faculty and learn to use it intelligently and then to broaden its scope and increase its power to deal with details.
Visualization is the mind's eye reproduction of an impression made by the sense of sight. ”

“ So, on the authority of repeated experience, whatever is unsuitable is gradually excluded, and only those eye movements are retained which further the proper convergence of the two retinal images.”104 Of course, the power of vision is by no means completely developed at five months, though the technique of the function, so to speak, is by that time essentially perfected. Now begin the real tasks of visual practice: acquiring familiarity with external objects, imprinting the visual images on the mind, and widening the scope of association. ”

“ It will help you to become conscious of these mind's eye pictures if you will look away from the stranger's face for a moment and see both the face and name pictures in the visual impression which you have been forming. ”

“ We answer, by teaching us to associate vision in general, or the abstract condition regulating our visual impressions, with the presence of the small tangible body we call the eye, and vision in particular, or the individual sensations of vision, (i.e. colours,) with the presence of immeasurably larger bodies revealed to us by touch, and tangibly external to the tangible eye. Sight, as we have said, does not inform us that its sensations are situated in the eye: it does not inform us that we have an eye at all. Neither does touch inform us that our visual sensations are located in the eye. ”

“ It is not merely the outward mechanism and motion of the eyelids, nor the colour of the eyes, that constitutes their beauty; we have already said that the leading characteristic of the eye was expression. It is this expression which causes the eye to appear to speak, to fire up suddenly, to sparkle with flashes of light, to languish or conceal itself underneath its lashes, to raise itself with inspiration, or to pierce the abyss of thought, just according to the particular sentiment governing the mind at the moment. ”

“ To a large extent we are misled by the impressive prominence of the visual data. In vision we are presented with a system of inter-related and simultaneously occurring sensations which we find by experience to be the sure and certain indicators of the potent obstructions which our activity encounters. For this reason we habitually make use of the visual sign as the guide and instrument of our exertional activity, and this habitual use leads us to regard the visual presentation as the essential form of Reality. ”

“ We learn, therefore, to react to a visual shape in a manner corresponding to how it would appear if it were in the centre of the field of vision, provided we do not immediately focus153 upon it, which is what we naturally do when anything visible interests us. ”

“ Whatever be the term, which we may use, however, there is, and must be, a sensation peculiar to touch, without regard to the extent or quantity of the surface impressed,—as there is, in colour, a sensation peculiar to vision, without regard to the extent of the portion of the retina on which the light may have fallen. ”

“ A visual image is modified not only by other sensations just previously experienced, but also by all those experienced simultaneously with it, and especially by such as proceed from contiguous portions of the retina. This is the phenomenon of simultaneous contrast. In this, as in successive contrast, both brightness and hue are involved. A bright object appears still brighter when its surroundings are darker than itself, and darker when they are brighter than itself. ”

“ A great part of the contents of our minds consists of sensuous (chiefly visual) images, and though we may imagine reflection to go on without further images supplied by vision or hearing, touch or taste or smell, yet we cannot well see how fresh experiences could be gained in such a state. ”

“ Whereas we maintain that the only eye that we have—the only eye we can form any conception of—is the visible eye that belongs to the visible body, as a part does to a whole; whether this eye be originally revealed to us by the touch, by the sight, by the reason, or by the imagination. ”

“ Visual Imagery When we speak of “images” in connection with Imagination and Recognition we do not refer merely to mental pictures of things seen. Mental images are representations of past mental experiences of any and every kind. They include past sensations of sound, taste, smell, feeling, pain, motion and the other senses, as well as sensations of sight. One may have a mental image of the voice of a friend, of the perfume of a flower, just as he may have mental images of their [Pg 10] appearance to the eye. ”

“ If we assume, on the other hand, that the movements and their feelings are alone possessed of the extensive quality, we make an unjustified hypothesis, for the phenomena compel us, it is true, to accord an influence to movement, but give us no right to call the retinal sensations indifferent, for there are no visual ideas without retinal sensations. ”

“ The reason is that subconsciously we accompany visual experiences with tone-sensations, and vice versa. Cases are even known of human beings in whom the secondary sensation occurs with such intensity as to equal the primary one. Such people say that they 'see' sounds and 'hear' colours. ”

“ Our subject, the sense of sight, is adapted to light and its modifications, colour and shade, and render to the perception the surface, form, and position of objects through the medium of light.
Sight and hearing seem to bear the most important characteristics, being employed on those objects which form the basis of human knowledge, viz., time and space. ”

“ Her beauty and glory, visible in her tints and hues, are in the brain of the observer,—a play of light reflected from the myriad objects upon which it breaks in infinite diversity of ethereal wavelet's. One may see colors which do not exist as undulations. For example, let one look fixedly at a brilliant red object for a while, and then close his eyes. He will behold an image of the same object of a green color. ”

“ When an object augments or diminishes to the eye or imagination from a comparison with others, the image and idea of the object are still the same, and are equally extended in the retina, and in the brain or organ of perception. The eyes refract the rays of light, and the optic nerves convey the images to the brain in the very same manner, whether a great or small object has preceded; nor does even the imagination alter the dimensions of its object on account of a comparison with others. ”

“ The visual image is continuous, notwithstanding the retinal stippling and the existence of the blind spot. When we lay our hands on a smooth table we fill in the interstices between the sensational points, and feel the surface as continuous. ”

“ Yet philosophy has ascertained that we derive nothing from the eye whatever but sensations of color.... How, then, is it that we receive accurate information, by the eye, of size and shape and distance? By association merely. ”

“ That many images of objects rove In many modes to every region round— So thin that easily the one with other, When once they meet, uniteth in mid-air, Like gossamer or gold-leaf. For, indeed, Far thinner are they in their fabric than Those images which take a hold on eyes And smite the vision, since through body's pores They penetrate, and inwardly stir up The subtle nature of mind and smite the sense. ”

“ Light comes into those open windows, the moving panorama of external nature passes before them, but distinct vision, which recognizes and individualizes objects, is something more than a mere passive, bodily sensation. ”

“ When we say that the eye sees, we use popular, but not strictly correct language; the eyes are the organs or instruments of vision—that is, for transmitting certain qualities of matter to the mind; it is not the image on the retina which the mind contemplates, for we are utterly unconscious that such an image exists—it is the object itself. ”

“ We may and usually do, for example, recognize a mirror as smooth without experiencing it as smooth—the image equivalent of the idea remains latent. Our ordinary experience with objects is too hasty and too intent on practical ends for images to develop. On the other hand, the leisurely attitude characteristic of the aesthetic experience is favorable to the recall of images; hence, just as in the aesthetic perception of objects we put our feelings into them, so equally we import into them the relevant images. ”

“ If there were such a medium, acting as a mirror to nature or life, and retaining the impression, it must be universal as the supposed æther of the scientist; and how could impressions on this medium intelligible to us be focussed as the vibrations of light are through the needlepoint of the eye to record a single view-point? In our visions of the memory of nature we see undistorted figures. If we could imagine the whole body to be sensitive to light, as is that single point in the brain on which the optic nerves converge, what kind of vision would we have? ”