How Does the Eye See?
A quick internet search might claim that “seeing is such a big part of everyday life that it requires about half of the brain to get involved” (“Eyes,” n.d.). But is that entirely true? An image provided by the Encyclopedia Britannica, Inc. shows the specific area dedicated to vision in the brain, looks like less than twenty five percent including the primary and secondary visual area. The greater argument to make is not to prove an exact scientific percentage of the brain’s use, but rather to point out that the brain is a very active part in the process of vision. Although the visual sections of the brain are defined in the diagram, it takes more involvement from other sensory areas of the brain as well. For instance,
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First of all, it has three layers; the Sclera, Choroid and Retina. The muscles attached to the Sclera control eye movements (“Anatomy and function of the eye,” 2011). Other parts of the eye, iris, cornea, pupil, lens and optic nerve play essential roles in the function of sight. The iris is the colored area of the eye. It is the muscle that regulates the size of the pupil which allows light to enter. The cornea, the clear layer over the front of the eye, is responsible for refracting that light. The lens is behind the pupil. It helps to focus, but the cornea that does the most to focus the light. There is also the aqueous humor, which is another clear layer is made of gel that nourishes the cornea. The retina is the tissue containing cells that convert light into color, sending them to the optic nerve where the brain receives the information and interprets the image ("How We See", …show more content…
The retina is the eye’s sensor. The purpose of the retina is to receive light focused from the lens, convert the light into nerve signals, and then to send these signals on to the brain (“Retina”). The retina processes the light through light-sensitive cells called rods and cones converting the signals into colors for the brain. Rods, in which there are many of one kind, are used for low-light (night vision) and do not sense color. Cones, however, have three different kinds corresponding to red, green and blue. The different light frequencies activate the appropriate colored cell or cells to interpret infinite numbers of colors. The photoreceptors converge on the optic nerve. Images are actually perceived by the brain, not seen by the eye. It can be compared to a camera as the image is seen with film or a memory card (Richards, 2014). Additionally, the image is reflected upside down, but the brain inverts it to be right-side up. This can also be compared to the function of the camera.
Vision is often taken for granted and often over-looked for its marvelous intricacies. The brain processes the information it is given very quickly with immense synchrony. MIT graduate student, Bhavin R. Sheth relates a fine illustraton. “Mr. Sheth compares vision to an orchestra, where clusters of cells in different parts of the brain cooperate to process different
The ultimate goal for a system of visual perception is representing visual scenes. It is generally assumed that this requires an initial ‘break-down’ of complex visual stimuli into some kind of “discrete subunits” (De Valois & De Valois, 1980, p.316) which can then be passed on and further processed by the brain. The task thus arises of identifying these subunits as well as the means by which the visual system interprets and processes sensory input. An approach to visual scene analysis that prevailed for many years was that of individual cortical cells being ‘feature detectors’ with particular response-criteria. Though not self-proclaimed, Hubel and Wiesel’s theory of a hierarchical visual system employs a form of such feature detectors. I will here discuss: the origins of the feature detection theory; Hubel and Wiesel’s hierarchical theory of visual perception; criticism of the hierarchical nature of the theory; an alternative theory of receptive-field cells as spatial frequency detectors; and the possibility of reconciling these two theories with reference to parallel processing.
Another speaker, Margaret Livingstone delves into the visual aspect of our senses. Livingstone mentions how artists recognize things about vision that neuroscientists are not privy to until years later. Livingstone discussed the differentiation between color and lightness, and how the two contribute differently to a work of art. Color is thought of as “comparing activity” whereas light is thought of as “summing them.” Livingstone indicates that the visual system is subdivided into a ventral system and a dorsal system.
The pupil is where light can enter the eye. The iris is in control of the amount of light that actually goes through. The light reaches the lens, which alters the shape of it so the eye can focus on it. Light reaches the retina, which consists of cones and rods. Colors are saw differently based on their implied meanings, which to various psychological functions. The cones are responsible for color. The color red would have such an effect on people’s perception of others based on their production of affect, behavior and cognition. A sociocultural theorist would explain this effect by indicating that the associations with the color red are normal. When a student sees a plethora of red marks on their paper, they automatically think they failed the assignment. Biological theorist would best explain this theory by saying the color red helps them survive or reproduce. A man may be attracted to a woman more because she is wearing red. This attractiveness could cause him to find his mate and eventually reproduce. A behavioral theorist would explain this effect by saying the color red provokes pleasure and avoids pain. A person can associate red with romance and
The eye is an important sensory organ for vision which houses a sensitive optical apparatus in a relatively isolated tissue compartment. Eye is essentially made of three layers: (1) sclera, (2) uveal tract, and (3) retina with each of these layers performing intricate duties which ensure proper functioning of the eye.
Processing capacity is a very broad and flexible category according to many researchers. In fact, the quote above mentioned suggests that we often fail to notice things that happen just in front of us (unexpected events that are often salient) either because we were completely absorbed by something else or because we had so many things to do at the same time that we couldn’t pay attention to it. We have all at least once failed to see a friend who was waving at us while eating in the cafeteria or walking in a crowded street. The primary question that we should ask ourselves is: how many things can we attend at the same time? The truth is that we didn’t perceive this friend because of a phenomenon called “inattentional blindness”. The problem is that the richness of our visual experience leads us to believe that our visual representation will include and preserve the same amount of detail (Levin et al 2000). In this paper we’ll see the different theories of inattentional blindness, and the classical theories demonstrating this paradigm.
When light pass through your lens and hits the back of your eye (retina) where you can have rods and cones that type of cells are responsible for peripheral vision. Because of all this research I know now why I can only see to a certain point when I look with the side of my eyes. Its cause your eyes need to practice more to see more like the color to a certain point and shape. You practice you will learn that your eyes will see more and long as you keep your eyes healthy.
The four main components of the eye that are responsible for producing an image are the cornea, lens, ciliary muscles and retina. Incoming light rays first encounter the cornea. The bulging shape of the cornea causes it to refract light similar to a convex lens. Because of the great difference in optical density between the air and the corneal material and because of the shape of the cornea, most of the refraction to incoming light rays takes place here. Light rays then pass through the pupil, and then onto the lens. A small amount of additional refraction takes place here as the light rays are "fine tuned" so that they focus on the retina.
Massaro, D. W. & Warner, D. S. (1977). Dividing attention between auditory and visual perception. Attention, Perception & Psychophysics, 21(6): 569-574.
and the iris which is the colored part of the eye, it regulates the amount of light
An inspection of the modern animal phyla will reveal that eyes are just as diverse as they are complex. Some organisms like the rag worm have pigmented cup eyes while other like he box jellyfish have two lens eyes and two pairs of pigment pit eyes. To account for the diversity in eye structure, we must first examine the eye ‘prototype’, the original structure that was acted upon by evolution. The simplest organ that can be considered an eye is composed of a single photoreceptor cell and a single pigment cell, without any lens or other refractive body (Arendt, 2003). Such organs are know as eyespots, and...
Well, let's take a look at the brain. From being in class, my awareness about what I'm doing, what I'm seeing, what I'm hearing, what I'm thinking has come to reflect upon not just what, but how is it all being done by my brain. This morning I woke up, my eyes opened, I looked out my window, I saw the sun rising, it was this beautifully deep yellow/orange color. I thought, "How beautiful" and I smiled with a sense and feeling of wonderment. It could be said that I experienced nothing out of the ordinary this morning. Yet, if I could narrate these few activities in terms of the networking of neurons resulting in my eyes opening, my sight of the sun, my ability to perceive its color, my inner acknowledgment of its beauty and the emotions that sight evoked in me, you would be reading for a very long time and what I did this morning would indeed present itself in quite an extraordinary light. It is in recognition of this, with respect to the brain's aptitudes, that Howard Hughes in his paper, "Seeing, Hearing and Smelling the World" quoted May Pines in expressing, "We can recognize a friend instantly-full face, in profile, or even by the back of his head. We can distinguish hundreds of colors and possibly as many as 10,000 smells. We can feel a feather as it brushes our skin, hear the faint rustle of a leaf. It all seems so effortless: we open our eyes or ears and let the world stream in. Yet anything we see, hear, feel, smell, or taste requires billions of nerve cells to flash urgent messages along linked pathways and feedback loops in our brains, performing intricate calculations that scientists have only begun to decipher"(1).
Perception is defined as the process of organizing, interpreting, and selectively extracting sensory information . Visual perception is left to the individual person to make up their own mind. Perceptual organisation occurs when one groups the basic elements of the sensory world into the coherant objects that one perceives. Perception is therefore a process through which the brain makes sense of incoming stimuli.
Blakslee, S. (1993, August 31). The New York Times. Retrieved May 2, 2014, from www.nytimes.com: http://www.nytimes.com/1993/08/31/science/seeing-and-imagining-clues-to-the-workings-of-the-mind-s-eye.html
The incredible thing about the human eye is that it can see objects to as far as 2 miles long.That’s almost 35 football fields! Let’s consider the mechanics of the eye. The eye is a clear ball with water-like fluids in there.You have the front of the eyeball which is translucent called the cornea. It’s extremely thin and its job is to protect the eye by refracting light that comes through. The next part of the eye is the pupil, which mostly everyone knows about.It is the black portion in your eye. Did you know that it gets its color from when light entering the eye is absorbed and it doesn’t leave the eye. You may also notice that when you’re looking at the pupil, you can see a different colored circle in them. This is called the iris, and it varies among everyone. Your actual eye color is determined by a pigment in the iris.The genes from your parents set a human’s eye color. The iris’s job is to widen or close depending on how bright or dark it is. If its bright and the sun is basically beaming down on you, the iris will adjust so your pupil will get smaller to only let a certain amount of light in. If you’re in the dark, your iris adjusts so your pupil will get bigger so a greater...
As further protection, the eyelids automatically close when an object suddenly moves close to the eye.Parts Of the EyeThe eye is made of 3 coats, or tunics. The outermost coat consists of the cornea and the sclera. The middle coat contains the main blood supply to the eye and consists of the choroid, the ciliary body, and the Iris. The innermost layer is the retina.Cornea and ScleraThe Sclera, or the white of the eye, is composed of tough fibrous tissue. On the exposed area of the eye the scleral surface is covered with a mucous membrane called the conjunctiva.