Psycology Module

Psychology Module For this essay, I have chosen the sense of sight. I personally think that our eyes are the most important sense we have in our bodies; obviously because they help us see. But how? What is the anatomy behind the magic of the eye? How is information transferred from the eye to the brain? What are the structures that help eyes perform their everyday functions? In this essay I will explain the answers to these questions and more, as we look at the anatomical and functional processes of the eye. Let me start off with the stimulus that makes it possible for the eye to even be useful. Light. Light is the electromagnetic radiation that shows properties of both waves and particles. The basic dimension of light is called the visible spectrum. The silver electromagnetic energies to with the eyes respond is made up of a narrow range of wavelengths of electromagnetic radiation. Visible light starts at short wavelengths of 400 nanometers which we send as purple or violet. Longer light waves produce blue, green, yellow, orange, and red. Which has a wavelength of 700 nanometers. All electromagnetic radiation is light, but we as humans can only see a small portion of this radiation (visible light). Cone-shaped cells in our eyes act as receptors tuned to the wavelengths in his narrow spectrum. All the other spectrums have wavelengths that are either too large or too small. Eyes have a lens to focus light rays on a light-sensitive surface at the back of an enclosed space. In the eye, it is a layer of photoreceptors (light sensitive cells) in the retina. Which is an area about the size and thickness of a postage stamp. Most focusing of the eye is done in the front by the cornea. A curved, transparent, protective layer that bends light inward. The lens, a clear structure behind the pupil that bends light toward the retina, makes some additional, small adjustments. There is a process called accommodation, where the focal point of your eye changes when muscles attached to the lens alter its shape. The eye has two types of photoreceptors. Rods and cones. There are 5 million cones in each eye and they work best in bright light. They also produce color sensations and fine details. On the flip side, there are about 120 million rods and they cannot detect colors. Pure rod vision is black and white and they are much more sensitive to light than cones. Rods therefore allow us to see in very dim light. Do you believe that the retina has a “hole” in it? Well it does! Each of our retina has a blind spot because there are no photoreceptors at the location where the optic nerve exits the eye to convey visual information to the brain. The blind spot shows us that vision depends greatly on the brain. The rods and cones also affect visual acuity or sharpness. The cones lie mainly at the center of the eye. The fovea, a tiny spot in the center of the retina, contains about 50,000 of them. These tightly packed cones produce the sharpest images. But what is the purpose of the rest of the retina? It doesn't just stay idol. Areas outside the fovea also get light. Creating a large region of peripheral vision (side vision). The rods are the most numerous, about 200 degrees from the center of the retina. A lot of our peripheral vision is rod vision. How do cones produce color sensations? The trichromatic theory of color vision hold that there are three types of cones, each most sensitive to either red, green, or blue. The opponent-process theory of color vision states that vision analyzes colors into “either-or” messages. So which theory is correct? Both of them! The first theory applies to the retina, in which three different types of cones have been found. Each contains a different type of iodopsin, a light sensitive pigment that breaks down when struck by light. This triggers action potentials and sends messages to the brain. The second theory better explains what happens further along in the retina, the optic pathways, and the brain after information leaves the cones. The moment light meets the retina, the process of sight begins. Light passes through the cornea and the lens, which combine to produce a clear visual image on photoreceptors. The image on the retina is reversed, and the information in the form of electrical signals is sent via the optic nerve. The optic nerve is a pair of cranial nerves that transmit impulses from the retina to the brain. The nerve will now transmit impulses from the retina to other parts of the brain which ultimately process the image and allow us to see. Visual information from the retina is relayed through the lateral geniculate nucleus of the thalamus of the primary visceral cortex; which is located in the occipital lobe at the back of the brain. Visuals are fed into at least three separate processing systems. One processes shape, another processes color, and another processes movement and location. How do these systems combine to produce the solid objects we perceive? The brain extracts biologically relevant information at each stage and associated firing patterns of neural populations with past experience. Finally, is overcompensation a myth? I know you may be thinking, what does overcompensation have to do with the sense of eyesight? Well, I have done some research and I have the answer for you. First of all, overcompensation means to have a strong want to be powerful, superior, and dominant. It can also be intertwined with want of self-esteem, self-devaluation. In relation to sensation and perception, overcompensation is the exertion of effort in excess that is needed to compensate for a physical or psychological characteristic or defect. Since we’re talking about eyesight, take blindness for example. When a person becomes blind, they need to use the rest of their senses (smell, taste, touch, hearing) to compensate, or fill in for the loss of eyesight. The same can go for the rest of the senses. When one is lost, the other four need to be used in place of it. This may cause the person to over use one specific sense, like smell or touch in the place of sight. If you can't see things, you only available option is to touch them. So no, overcompensation is not a myth. For some people it’s their reality.