Katie Morgan's Weblog

Final Blog Entry 4/27/08

morgankb — Sun, 27 Apr 2008 18:13:39 +0000

The most interesting things I learned this semester were details about our sense that I can apply to my life. We spent so much time learning about our visual systems that I was able to apply a lot of what I learned to my own vision or the vision of someone I know. Learning about our smooth eye movements taught me why I have a difficult time tracking the ball while watch golf. Our brain integrates sensory information from neurons that code the direction and speed of moving objects with the observer’s expectations about the object’s motion to attempt to continuously watch a moving object. The brain matches our eye movements with the object’s movement to keep the image of the object stationary on the retina. At higher speeds of movement, like golf balls, our eye movements can be slower than the moving object. Our eyes have to guess where the moving object would be next and jump ahead to regain focus. I really enjoyed learning about color blindness because I have a good friend who is color blind. He has red green colorblindness so he has difficulty seeing the difference between red and green in certain situations. I was interested to learn about the absence of different types of cones that cause forms of color blindness. A fun website to see how the three types of color blind see the colors you see is http://gmazzocato.altervista.org/colorwheel/wheel.php. When we discussed the anatomy of the eye and how light hits the retina, I learned that I am a hyperope. I am slightly farsighted and wear glasses when I read because I often get headaches if I read for long amounts of time or I read at night. I also have trouble focusing my eyes because my left eye is not as strong as my right eye. My rectus muscles in my left eye are not be as strong at my rectus muscles in my right eye. I lose focus on objects with my left eye as they get closer to my face, while trying to focus with both of my eyes. I have worn contact lenses before so I was interested to know how they worked after we talked about them in class. I learned that contact lens bend the light to hit the retina in the correct way. Light converges on the retina too soon in people with myopia and converges on the retina too late in people with hyperopia. A contact lens is thinner at the center than at the edges to correct vision in myopes. This type of lens is convex in order to spread the light more so that it hits the retina further back in the eye. A contact lens is thicker at the center than at the edges to correct vision in hyperopes. This type of lens is concave to converge the light to hit the retina sooner. Contacts modify the light to converge correctly for each individual. The strength of the lens is in diopters, based on how much the lens bends the light. This website is helpful for explaining how contacts work: http://health.howstuffworks.com/contact-lens.htm. I enjoyed learning that I am a supertaster by counting 37 papillae on my tongue. It explains why I am a very picky eater and do not enjoy spicy foods. I am glad that we discussed how our sense of smell if often overlooked. Smells often trigger my memory to think about people or places that are important to me. I associate many memories with smell. The smell of a certain cologne or perfume can immediately divert my mind to think about a friend or family member. I also really enjoyed the paper assignments because I learned first hand to appreciate my senses. Having my sense of touch impaired cause me to appreciate how sensitive our sense of touch is. Simple things like putting on make up and making breakfast were more difficult to perform without the complete unaltered use of my hands. When wearing the ear plugs, I lost my sense of my surroundings without being able to hear normal background noise. Once I removed the ear plugs, I noticed background noise like the air vents that I never think about on a normal day. Experiencing the world with monocular vision was the most difficult task for me. I was uncomfortable the entire time. I did not have as good a depth perception and had to move my head much more than usual to see. The most interesting things that I learned this semester were things that I could apply to my life. I will remember those aspects more than anything else. I really enjoyed experiencing the senses individually and learning how they work together to form our perception of our environment.

depth and motion 4/18/08

morgankb — Fri, 18 Apr 2008 02:07:01 +0000

Pre-renaissance artists had trouble depicting depth in their pictures as shown through many paintings during that time period. The paintings lacked depth with the placement of people and objects in the pictures. People that were behind others were painted as the same size as those that were in front of them. Objects also appeared flat without any shading. At the beginning of the Renaissance, artists began to use techniques like shading and size differences to give depth to their paintings. Artists use differences in light and dark to show depth and orientation of objects. Clothing began to appear draped with folds in the fabric. Artists achieved this effect by coloring certain parts darker than others to show the reflection of light. Aspects of painting that show depth include linear perspective, occlusion, size, and shading. The aperture problem is that receptive fields can incorrectly identify the direction of a stimulus because the receptive field is too small to register the entire stimulus. For example, a large bar can move from left to right in more than one way but still be registered as the same motion by small receptive fields. If the bar is long enough vertically, it can shift from left to right and simultaneously move up or down without being registered as moving up or down. The same amount of the bar remains registered by the receptive field. Receptive fields cannot differentiate the different parts of the bar. Receptive fields only register that the same amount continues to be present in the field but moving left to right. Different areas of the brain process different types of motion information, which allows us to be experts at different types of motion and to be really good at detecting motion. The retina and the LGN have M cells that respond well to fast changes in intensity. They are able to convey this motion information to higher levels of processing in the cortex. Area VI contains directionally selective receptive fields that can detect local motion. Area MT works to detect motion of objects. Area MTS detects even more complex motion such as optic flow. Optic flow involves detecting when objects move toward or away from the observer in depth. It can also involve when an observer moves through an environment with many stimuli. Objects in front of or behind your point of fixation appear as two separate images because your eyes must act differently to perceive objects in front of your point of fixation than behind your point of fixation. Objects behind your point of fixation are in an area of uncrossed disparity so your eyes must diverge to see them. Objects in front of your point of fixation are in an area of crossed disparity so your eyes must converge to see them. These places appear as two separate images because they cannot be perceived simultaneously by your eyes.

it’s a colorful world out there 4/13/08

morgankb — Sun, 13 Apr 2008 23:35:34 +0000

John Keats laments Newton’s “unweaving of the rainbow” because he prefers to keep some things a mystery. Keats regrets when mysteries are analyzed and broken down by philosophers and scientists. I do not lament Newton’s “unweaving of the rainbow” because I am interested by his findings. I enjoy learning about the science behind the light that causes the rainbow from reflection. I like to know the reasons behind fun phenomenons such as rainbows. Newton breaking down the rainbow and different colors with his prism experiments have given us a great understanding of how color works so that we can manipulate color and understand how color is produced. The difference between adding and subtracting color is the difference between adding light and the absorption of wavelengths. Adding color involves adding light to create different colors. Subtractive color involves absorption of wavelengths to create different colors. Red, green, and blue are called primary colors because when they are all added together they make white light. When they are added in other combination they make different colors. For example, adding red and green light of equal intensities makes yellow. Subtractive color is more light when you add paint colors together to make different colors. When all colors are added together, they make black. Blue and yellow would make green. This occurs because the color of paint that you perceive is reflecting the color that you see. For example, red paint is absorbing all other wavelengths of light except for wavelengths that produce the color red. The condition of synesthesia tells us that “normal” sensory processing is all very closely linked between the senses. In people with this condition, one sense light hearing can trigger another sense like sight. This tells us that the sensory processing for hearing and vision are closely linked at some point in our bodies because one is able to trigger the other. I imagine it would be a very strange sensory experience to have a form of this condition. I would be very distracted if every time I heard a certain noise it caused me to see a certain color or feel a scratch on my arm. People with color blindness do not see the world in the same way that people with “normal” color vision do. They perceive the world in different colors than we do. Depending on the type of color blindness they have, they have trouble distinguishing between colors that have similar wavelengths. The most common type of color blindness is red green color blindness of which there are two types, protanopia and deuteranopia. These individuals have difficulty distinguishing between red and green in different conditions. They still see the same objects that we do but in different colors. Their perception of red and green are different from ours. We can test to see if someone’s visual world is similar to our own by giving them tests of gradations of color. People can line up colors in the order of similarity that they perceive them. If they line the colors up differently than us, we can assume that they perceive the world differently than we do. I have a good friend who is color blind. He showed me a website similar to examples we saw in class that showed how he sees the same colors that I see but in a different way. I found it very interesting to look at two examples of colors that look completely different to me but look exactly the same to him.

development of vision 4/3/08

morgankb — Thu, 03 Apr 2008 18:20:04 +0000

The nature versus nurture debate comes into play in the development of a normal visual system when discussing how and why changes in vision occur. There is debate about whether behavioral changes in the visual system are caused only by biological changes caused by nature or whether they are influenced by experience and the environment as well. Research shows that normal visual experiences merely allow for the normal development of vision. Nurture does not significantly influence the path of nature. The behavioral consequences of an underdeveloped or abnormally developed visual system can include diminished vision or monocular vision. If cells do not fully develop in one eye, the other eye can take over higher level cells in the visual cortex. There can also be a loss in peak contrast sensitivity and peak spatial frequency with cell damage and cell loss in the visual system. I think there are so many areas of the cortex devoted to the processing of different types of visual information in order to better process visual information. Different areas of the cortex can analyze different parts of the visual field so that we can better perceive elements of our visual field. Each area of the cortex can contribute its own part to our understanding of the environment that we see. There are too many details and various components of objects for just one area of cortex to analyze.

visual experts 3/29/08

morgankb — Sat, 29 Mar 2008 05:28:50 +0000

Studies on facial recognition tell us about how we have object recognition for areas in which we have an expertise. Humans are experts in faces because we see many of them every day. We process faces as a whole, not by their individual components. This tells us that we processes objects as a whole when recognizing them. Studies that measure brain activity show that an area of the brain called the FFA is active in people doing face recognition tasks. The FFA is also active when people look at objects of their expertise, such as a car expert looking at different kinds of cars or a dog expert looking at different breeds of dogs. Facial recognition studies tell us about our object recognition of highly familiar objects. Gratings are such popular stimuli in studying visual perception because they allow researchers to manipulate spatial frequency, contrast, orientation, and spatial phase. Variations in these components allow researchers to understand how each of them contribute to our visual perception. Spatial frequency is the number of light and dark areas in an image. Contrast is the intensity difference between the light and dark areas in an image. Orientation is the axis of the gratings bars. Spatial phase is the grating’s position relative to a landmark. Researchers manipulate these components in different gratings to understand how each contributes to vision and affect each other. I have exhibited inattentional blindness when I have watched many movies. While watching a movie, I am focused on the action and the characters and have often missed changes in the setting. During one scene, a book is on a table in the background. When the camera goes back to that table the book is no longer there. Another example is when an actress’ hair can change from being down to be pulled up in the same scene because of an error when filming one scene at different times. One can extract different levels of detail at different spatial frequencies. High spatial frequency is many cycles within each degree of visual angle and has narrow bars in a grating. Low spatial frequency is few cycles within each degree of visual angle and has wide bars in a grating. Contrast is easier to see at levels of lower spatial frequency than high spatial frequency because the bars are wider and easier to discriminate dark from light bars.

complexity of vision 3/23/08

morgankb — Sun, 23 Mar 2008 11:47:52 +0000

Retinal processing of visual information is different from cortical processing of the same information in many ways. The LGN has center surround receptive fields just like the retina but the surround of an LGN receptive field has a stronger inhibitory effect than the surround of a retina ganglion cell receptive field. The center’s are more inhibited by the surrounds in the LGN than in retina ganglion cells so they must have a stronger excitatory response to have the same response, if their surrounds are also stimulated. Unlike retinal ganglion cells, cortical cells are orientation selective. Cortical cells have a preferred orientation of light that they respond to maximally. Cortical cells can be categorized into simple cells, complex cells, and hypercomplex cells based on their preferences for orientation and length of light. Cortical cells can also have receptive fields that are not circles. The consequences of the duplex solution of vision are differences in vision in light and in dark. Rods are sensitive to light and allow us to see in environments with very little light. Cones gives high resolution and are concentrated in the fovea, where the center of our visual field projects on the retina. Our cones allow us to see with high resolution and our cones allow us to see in environments with very little light. Rods and concentrated in the periphery of our retina so we do not see the periphery of our visual field as well as we see the center with our fovea and cones. In the dark, we can see better if we don’t look directly at something because we use our rods. Vision in low light environments is scotopic vision and in high light environments is photopic vision. We primarily use our cones in photopic vision and our rods in scotopic vision. We can use the oblique effect to study the stage of development in which organization of visual information occurs in our brains and possible reasons for this effect. Cortical magnification is that the center of the visual field is highly exaggerated in the brain. The center of the visual field is the fovea. A large part of the cortex represents the fovea which has the highest concentrations of cones and gives the highest visual acuity. This is a good thing because we are able to see and focus on what we see best in our visual field. We are able to concentrate on the center of our visual field without being distracted by everything in the periphery of our visual field. We are still able to see what is in our periphery and be aware of our periphery while still being able to focus best on where we are directly looking.

looks can be deceiving 3/16/08

morgankb — Sun, 16 Mar 2008 10:15:56 +0000

Roger Carpenter’ s statement “The eye is at once the master and slave of vision” has many implications about the function of the eye in our vision. I believe that he meant that the eye is the master of vision in the sense that we cannot not see without our eyes. However, the eye is also the slave of vision because we cannot not see anything if there is nothing to see, even if we have eyes. The eye is crucial to our ability to see but is useless if there is nothing to see. An OFF center ganglion cell receptive field is a receptive field in which the center responds most to a decrease in light and the surround responds best to an increase in light. It is organized the way it is to allow the eye to detect edges and boundaries of light. The eye can detect the borders of light based on the response of these center-surround receptive fields. If the OFF center shows a decrease in activity with light exposure and the surround shows an increase in activity with light exposure, you can determine where the light begins and ends based on the response of the receptive field. If a bar of light shines on an OFF center receptive field and only hits the surround, the resting activity level of the center will not change and the activity level of the surround will increase. This tells the eye where the light is hitting according to where the activity levels change on the receptive field. The Transformers theme song talks about how there is more than meets the eye with the transformers. This relates to visual perception because what we see does not always give us enough information about an object to know it’s function. Looks can be deceiving and can trick us into thinking certain objects are different than what they really are. People often mistake fake fruit in bowl in my dining room for real apples. We gather clues about our environment from our visual perception of the world. However, our vision does not always provide us with the whole story. The transformers can change into different objects that you would not predict from just looking at them. Objects in our environment can also surprise us by doing things we would not predict or that we perceive differently. Optical illusions can trick our eyes into thinking that the pictures are moving even though they are stationary. We need to use our other senses to fully perceive the environment accurately in addition to our vision.

eyes wide open 3/9/08

morgankb — Sun, 09 Mar 2008 08:45:41 +0000

I learned in class that I am a hyperope which means I am slightly farsighted. I wear glasses when I read because I often get headaches if I read for long amounts of time or I read at night. Small printed words are especially frustrating. On top of everything, I also have trouble focusing my eyes. My optometrist told me that my left eye is not as strong as my right eye. From what we learned in class on Wednesday, I suspect that my rectus muscles in my left eye may not be as strong at my rectus muscles in my right eye. I lose focus on objects with my left eye as they get closer to my face, when I try to focus with both of my eyes. I cannot cross my eyes either. I tried to do the trick where you look at your nose and then look left but I cannot get my eyes to focus for a long enough time. While I was on spring break, I decided to test my friends reactions with their pupils because I did not get to see my parents. I told them that I had forgotten my passport in my room and that we would need to go back to get it. Sure enough my friends’ pupils widened as they reacted to this news. They were very surprised and frustrated until I told them that I was only joking. I researched how contacts work because I am curious to know. I learned that contact lens bend the light to hit the retina in the correct way. Light converges on the retina too soon in people with myopia and converges on the retina too late in people with hyperopia. A contact lens is thinner at the center than at the edges to correct vision in myopes. This type of lens is convex in order to spread the light more so that it hits the retina further back in the eye. A contact lens is thicker at the center than at the edges to correct vision in hyperopes. This type of lens is concave to converge the light to hit the retina sooner. Contacts modify the light to converge correctly for each individual. The strength of the lens is in diopters, based on how much the lens bends the light. This website is helpful for explaining how contacts work: http://health.howstuffworks.com/contact-lens.htm.

loud but not always clear 2/23/08

morgankb — Sat, 23 Feb 2008 10:05:10 +0000

I have experienced many mondegreens with song lyrics and faster talkers in my lifetime. A famous mondegreen comes from the song “Rock the Casbah” by The Clash. Many people, including myself, hear “lock the cash-box” instead of “rock the casbah”. We expect to hear words that we are familiar with, instead of words that we have never heard before. I had never heard the word casbah before listening to this song. I was not expecting to hear it so I thought I heard a different word that I know and that makes more sense to me. T Mobile made a commercial that involved a mondegreen from Def Leopard’s “Pour Some Sugar On Me”. A couple was in car listening to the song and the man thought the lyrics were “Pour Some Shook Up Ramen”. They called an information number to determine who was right about the lyrics. The commercial took advantage of the commonality of mondegreens. Most people have had disagreements about what was said in a song or in a conversation because of this common phenomenon. One can disambiguate between sounds by moving one’s head in different directions to hear the sounds in different ways. If you reposition your head, you can escape the “cones of confusion” and accurately locate sounds. The sounds must last for an extended amount of time for this to work. Moving your head to detect the location of a short clap will not help because the sound will have ended before you have time to adjust the position of your head. We are not always confused by a sound’s location because we are able to accurately identify the location of many sounds, depending on the sound’s location in reference to us. Sounds that are equidistant from each give are more difficult to locate then sounds that are close to one ear or the other. Various aphasias tell us that our language processing is very complex. There are multiple areas in the brain that contribute to language processing. If one of these areas is damaged, it can cause different problems in the steps of language processing. We learn more about the complexity of language processing by identifying the different functions of each area in the brain. Studying people with damage to different areas allows researchers to match patients symptoms with their brain damage and to identify the roles of various areas in the brain in language processing.

hearing our environment 2/16/08

morgankb — Sat, 16 Feb 2008 12:50:43 +0000

The best use for hearing is helping us to be aware of our surroundings in the environment. Hearing serves as an important sense that can give me clues about my surroundings when I am not able to see everything. There are times when I can hear danger approaching before I can see it. For example, when I cross the street, I can hear cars speeding toward me and honking, even when I am not looking. I can also hear people walking behind me on the sidewalk so that I know to move out of the way. People can get my attention by calling my name, when I am not able to see them in a crowd. Hearing complements seeing well for gathering information about my environment and reacting appropriately to situations. I do not completely agree with Helen Keller’s statement, “blindness cuts me off from things; deafness cuts me off from people.” I think that Helen Keller would have felt differently, if she had ever been able to hear or see. I would argue that blindness would cut me off from people and deafness would cut me off from the environment. Seeing people would be more important to me than hearing them for connecting and communicating. After being able to see, I cannot imagine a would in which I would not be able to see my family and friends. Hearing gives me clues about my environment and allows me to identify people before I see them by recognizing their voice. Hearing plays a huge role in my life. I am able to enjoy music and voices of friends. I am also able to sense my environment without needing to see everything. Deafness would take away my ability to fully enjoy and understand my surroundings. It is difficult to see everything at once. Hearing gives me clues about people and things that I am able to see and those that I cannot see. Seeing is more important to me for my relationships with people. However, hearing provides additional unique information about each individual. I think it is important that the acoustic reflex dampens one’s own voice so that one does not become deaf by one’s own voice. The dampening of one’s own voice also allows us to hear other people talking and other sounds, while we are talking. One might not speak loudly enough, if one was able to hear themselves at full volume. The acoustic reflex helps us to better communicate and interact with our environment by dampening our own voice and allowing us to hear multiple sounds at once.