Political Science

ndrea Russell assignment two 12

Andrea Russell.

Assignment two.


1: Describe the process of perception as a series of steps, beginning with the environmental stimulus and culminating in the behavioral responses of perceiving, recognizing, and acting.

Perception is a cognitive process, the processing that takes place; information is then sent to the senses which is then relayed towards our brain for further analysis. Perception is a sensory experience. Recognizing environmental stimuli; is the actions that are a direct response to the perceptual process. This is where we come to understand different properties, elements that pertain to our survival, the information here is critical to how we respond to Stimuli. Our brains organize, identify, and interpret different stimuli depending on our environment; that is how we can potentially perceive. At a music festival, it may seem that we are over loaded with sensory: First I will locate a spot and take my place; here I will lay a blanket down or put chairs down to mark my spot. One where I can observe all the things around me a long with my friends. To my left I can see bright colored stands full of band shirts and bohemian jewelry. To the right of me I see more vendors but they are all for food and beverages. I can smell this with including being able to actually see them working their stalls. In the center of my view is the stage, where musicians are performing, with this comes a crowd of people all enjoying the countless things taking place at once.

All of this together is what defines environmental stimulus. Perception, are these electrical signals that pass through the brain. This is then processed as an experience; like seeing a hula hoop twirl on a dancer’s waist. When we recognize, it means that we are able to successfully place an item in a category. For instance, I can tell that the instrument being played is a guitar; I know this because I can see the musician and I can categorize him and the instrument he’s playing. Acting; this is our physical response. An example would be the reaction our bodies have when we hear music. Our bodies swaying back and forth is a motor activity that is done in response to the perception process.

2: Because the long axons of neurons look like electrical wires, and both neurons and electrical wires conduct electricity, is tempting to equate the two. Compare and contrast the functioning of axons and electrical wires in terms of their structure and the nature of the electrical signals they conduct.

Neurons are nerve cells; neurons are messengers. These messengers are passed through the brain from a receptor through an electrical signal. Axons are what transmits information or nerve impulses from one cell to another. Like an electrical wire; when an axon is torn the nerve impulse will not end up being transmitted, like electrical wires axons have an outer coating that gives it insulation. Especially when it is being damaged by force. This leads to problems being noticed in the nerve cell, despite the possibility that the axon may be torn.

A physical example of comparison is a cord to an appliance like for instance a vacuum cleaner. Often times, I know I can rush the brushing process and on occasion have gotten the cord caught on the blades. When damage is caused to the exterior of the cord the vacuum will continue to properly function despite the fraying of insulation, which then exposes bare wire. When we touch it with our bare hands after the rubber protection has melted off, almost if not instantaneously I will feel a shock. Basically the insulation from the electricity is no longer there and is now exposed. Our skin is our insulation, like the rubber is to the vacuum wire. The same is the electrical signal sent from axons sent to one cell to another the electrical signals connection, the axon is a wire that is so long that that if you attached it from one end to the other there would be enough wire to reach from the moon and back (Neurons and Circuits). Our brain is composed of different subsystems it is these signals that are in charge of sending information that is far, or long distanced. Our brain processes so much information, it is these connections that work together to figure out the over 10,000 connections. Wires connect signals at the speed of light while the signals in our brains are slower in transporting signal.

3: What are the two answers (one “simple” and the other “profound”) to the question, “Why is our perception of colors and details worse in the dim illumination than in bright illumination?”

Our retinas perform important work, amongst these things is the adaption to different light intensity. How we see a sunny day at the park is not the same way we see while driving at night in the dark, light intensity differs. The nervous system has a limited range in response. Our retinas solve issues by adapting slowly. The ambient level of illumination is a system that compensates for deficiencies. When the light changes gradually the change can be immediate. However when the light changes a lot, that is if the level is constantly changing it will take a very long time adjust. We may be able to see in dimly lit areas but to be able to detail crisp color. Wave lengths of light or lack of light determine hues, and the colors we perceive. The ability to see color decreases the darker it gets. Our cones produce a response that is needed. Cones simply reach a point where they may no longer have the ability to pick up traces of light in order to have a response.

One of the most important senses we as humans have is our sight. It is what allows us to understand and perceive the world around us. While all senses serve a purpose, and many senses will work over time when one is lacking. It is the visual acuity that allows us to distinguish details; this is what lets us have the ability to sit in a field of flowers and have the capability of detailing a singular flower petal, and its unique and beautiful characteristics. The sensation from light is a stimulation that is a process of vision, meaning that we perceive images, shapes, these become part of how we perceive sensory. Illumination plays a key role in our visual system it conserves light, detects color. The moon is an illuminated object. Brightness is perceived if the target region has higher luminance than the background (increment), whereas darkness is perceived if the target has lower luminance (decrement) (Brightness and Darkness as perceptual dimensions),

4: What is color consistency? Describe three factors that help achieve color consistency. What is lightness consistency? Describe the factors that are responsible for lightness consistency. Lastly, compare and contrast color consistency with lightness consistency.

Color consistency is the familiarity we have with how we perceive an object. Three factors that allow us to achieve this are; objects with familiar colors, may also be identified through their shape and size. Lightness consistency, perceiving the proportion of light that is relatively reflective despite where the object is. We will continue to view the object in the same color despite distance and reflection. Lighting plays a part in how images on our retina are seen. In this instance the color will not change despite change in lighting conditions. Factors responsible for lightness consistency, an example is a sheet of white paper, photographers often use this to “white balance” here we will test for color temperature, of a light source. This allows the detection of warmth and coolness. For instance we know that if the context or background is the same, then the color will remain however if we change the area, or surroundings then these images may change its perspective in our minds, meaning that the color could change. By comparing and contrasting color consistency with lightness consistency. A person’s vision matters here. It is that which allows us to not only judge the illuminants color but the level of color constancy or consistency. Dark colored objects tend to absorb light while white or lighter colored objects tend to reflect most of the light. Gray like objects are illuminated in between. The link between both lightness constancy and color constancy is their purpose. They both prove helpful in the ability of being able to see different perspectives of objects, shapes, and colors. Although the objects, shapes, and even colors stay the same, when areas are softly lit or bright, colors can appear different. Yet the color does not actually change what changes is our perception system; this is what helps us keep those colors constant despite the illuminating conditions.

5: When you walk from outside, which is illuminated by sunlight, to inside, which is illuminated by “tungsten” illumination, your perception of colors remains fairly constant. But under some illuminations, such as street lights called “sodium – vapor” lights that sometimes illuminates highways or parking lots, colors do seem to change. Why do you think color consistency would hold under some illuminations, but not others?

Tungsten is a thin wire, this is what has been a part of the traditional light bulb design since its initial invention by the man himself Thomas Jefferson. Electricity will run a current through, which will then glow brightly, these are artificial lights that can be found in our ceiling fixtures, and common lamps. By producing more heat, we will be encountering a warmer light, one with a reddish source. Street lights, range from very white lights to ones that produce a color rendition that is more yellow- orange in color when it glows. When we discuss why would color consistency hold up under some illuminations and not others. Some bulbs burn warmer than others, this could affect how we see color consistency. Those lights that produce a white color tend to have better color rendition that is, colors, objects and shapes will continue to be their true color. Yellow lights tend to obscure illumination; even producing the color to become different, this color tends to lean towards the gray scale. The image that comes to mind is one where we are driving in a car at night, at some point while driving we notice that the lights illuminating our view are not crisp, like that of a flash. Dimly lit streets can morph roads together especially for those who suffer from vision impairments. Light source plays an effect, surfaces may reflect light differently depending on the source which provides the illumination. Affects like that of changes from nearby surfaces are considered to be a reflected light change. Our surroundings and the conditions that are a part of the surroundings. Our visual system then ends up compensating; meaning scene illumination changes when our light source is changed by physical processes. It is important to take into consideration that the color constancy condition matters when proposing if the changes in stimulation are given to the natural or artificial nature of the illumination source.

6: What is sensory adaptation? How does it occur within the various senses? What function does sensory adaptation serve? Provide a relevant example which illustrates your point.

Prolonged exposures to various wavelength and stimulus, a process that makes changes, with sensitivity of sensory receptors. This is an occurrence that is a direct relation to the stimulus. Our bodies as humans have ways of adjusting to the constant stimuli we receive, our sensitivity to this stimuli adapts by matching those responses that are coming from the environment surrounding it. This process is said to affect all our senses to an extent we should be able to experience this depending, for instance smokers no longer realize the smell that lingers after having puffed on a cigarette. The same could be said about our taste buds, when we season food to much or use an incorrect measurement our taste senses are operating to the fullest. Our sight, also reacts to differences in illumination. By noticing reactions like a room starting to light up after you have walked into a room that is badly lit. Our brains become used to particular stimulus, meaning that because there is a constant stimulus being picked up by a number of senses that receptors inevitably change their ranges of sensitivity. Its purpose is to also reduce our awareness to a stimulus, by allowing our attention to be spread between more than one stimuli in the environment surrounding us at one time. Receptors have the ability to increase or decrease their ability to respond in certain environments. An instance that illustrates this; there is a scene in one of my favorite programs named Downton Abbey where one of the cooks in the home buys goods from an ex employ at a decent rate, this is a big deal since it is set in war world I. Sugar, and cocoa were definitely scarce as ingredients. They bake a magnificent looking cake, and as soon as they go to taste it they realize that they have been robbed immediately realizing the taste of the cake was wrong.

7: What are the characteristics of the energy that we see as visible light? Provide an example illustrating how these characteristics are expressed when someone sees a rainbow. What types of things (situations and/or objects) can interfere with these characteristics?

The light we see are waves of electromagnetic radiation, although what we see very little of this. The cones in our eyes act as a stimulus receiver. Light is basically the wavelengths that we as humans are able to see with our vision capability. Our eyes have specialized cells that are what act as the tuners which receive wavelengths. Wavelengths determine color, having a longer one may produce a red, reddish color. Depending on the spectrum may depend the visibility of color. It was Sir Isaac Newton who realized that when you have sunlight pass through a slit, plus a prism, color is then projected onto an object, for example a wall. These colors that are being projected are what we have now come to learn as the rainbow, this is caused by the refraction of light. These seven colors that we traditionally think of when we mention rainbow. Red, orange, yellow, green, blue, indigo, and violet, are really just reactions to light. When this happens in nature it is due to the light hitting the water, for instance droplets hitting the air and light from reflection. Situations that interfere with these characteristics can occur when more than one light source interferes with light waves. When waves are longer than one another they tend to spread themselves in much shorter waves. This is called diffraction, rays break a part, they do this by turning into light that us both dark and light colors within the spectrum. Another interference is the reciprocal action of light waves. Once two waves meet they can cancel each other out or even reinforce the waves. Diffraction can only be noticed when a light is passing via a narrow slit. Dispersion however is the white light that spreads into full spectrum wavelengths, this generally occurs when the direction of light changes the direction due to the wavelength.

8: How does the eye transfer light energy into a neural message? What is the blind spot in the eye and how does it impact the transference of light energy?

Our eye site comes from these cells that specialized, we call these cones it is with these cones that we see color. Our cones are at the center of the retina. It is for this reason that we tend to see objects, and their colors better when they are directly in front of us. The cones in our eyes are then turned into receivers that are being tuned to a wavelengths, this is known as a spectrum. Once the lens is in a position to reflect light back via rods and cones. First light, will enter our eye, this light is focused by the lens portion, it is when the particles hit or strike our retina it is then processed by ganglion cells, bipolar cells and these are what travels through our optic nerves which lead to the brain, thalamus and the visual cortex. Our retina is definitely the most important part to our vision. Sort of like the brain of our optical system. Our optic nerve sends information to the thalamus, this is where the optic nerve hits the retina and is often called the blind spot, this part of the retina does not give us any visual information hence why it is called the blind spot; the fibers here in the optic nerve are what carries different signals and messages to both our eyes and brain. Since we do not have photoreceptors here, that is rods and cones within what is called the optic disk, a small portion of each eye, the visual field positioned is the optic disk and without it we cannot detect images, this is what makes pictures for us. There are both natural and artificial blind spots, when an object blocks the light from reaching its photoreceptors. In situations, extreme bright lights cause a temporary blindness or a short absence of seeing, natural blind spots are presented in only a set amount of creatures not including human.

9: How is visual information processed in the brain? But what are some things (situations and/or objects) which can impede visual information being processed in the brain. Please include a relevant example to illustrate your answer

Visual information from the retina is relayed through the lateral geniculate nucleus of the thalamus to the primary visual cortex — a thin sheet of tissue (less than one-tenth of an inch thick), a bit larger than a half-dollar, which is located in the occipital lobe in the back of the brain ( brainfacts). Information is then sent from the LGN or lateral geniculate nucleus, this structure can be found closer to the center of the brain. Which then has information sent to our primary visual cortex located in our occipital lobe and is found by the back of our brain. It is here that our brain begins to restore and reconstruct images. It is our brain that is in charge of processing images commonly thought to be our vision system alone, among the things we process visually are symbols, distance, and pictures. Those who suffer from this kind of disorder suffer from a visual processing. These disorders have some characteristics, like having some issues with being able to distinguish your left from your right. Normally we all have some issues learning how to decipher which is which but left and right confusion is generally associated with attention issues. Visual sequencing, is an issue where those suffering may present difficulties with being able to organize symbols, words, and images in a direct order. Children who suffer from this tend to misread letters, numbers, and words. Visual –motor processing issues is another example of a visual information process disorder, a characteristic is that feedback coming through our eyes have a difficulties trying to coordinate other movements, this includes the movement of other parts of the body. Children suffering from this disorder often have trouble writing on paper with margins as well issues with writing within the lines. Another symptom may include being overly clumsy and having comprehension issues when reading or copying from a book.

10: What theories contribute to our understanding of color vision? Discuss at least two relevant theories within the field of vision.

The two theories of color vision are known as the trichromatic theory also known as the Young-Helmholtz theory, and the opponent process theory. Both theories compliment one with the other their purpose is to explain the processes which operate at different levels of the visual system. The trichromatic theory was first experimented by you guessed it Young, and Helmholtz, these gentlemen tested out theories where they adjusted the relative intensity of several light sources that were measuring at different lengths. Their findings found that those who had fair or normal color vision needed at least three different wave lengths to the visibility spectrum. This finding is what led to a theory that would be consistent with what is now known as the trichromatic theory. Normal vision would be found to require at least three types of receptors, each of them would all have different kinds of peak sensitivity. These three balance activity cones are short, medium, and long wavelengths this is what determines color perception.

Opponent –process theory developed by a Ewald Hering, his theory links color pairs that have three opposing color pairs; this includes the color blue-yellow, red-green, and black-white. This theory, is based off of its consistency with the fact that two members of one of these pairs need to inhibit one another. However they cannot be paired at the same location, meaning we do not have vision that lets us see colors like bluish yellow or reddish green. Although the opponent process theory explains why there is “yellow”, the inhibitory connection between multiple cone types, even though there is no yellow cone. Excitatory and inhibitory connections are shared between these types of cones, stimulation of red is called L cones, and green M cones, are then summed together and this result is the color yellow or the perception of the color yellow.


Question 1: Environmental stimulus and perception, https://www.ics.uci.edu/~majumder/vispercep/chap1notes.pdf

Question 2: Neurons and Circuits, http://www.cs.utexas.edu/~dana/Ch3.pdf

Question 3: Brightness and Darkness as perceptual Dimensions, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2041963/

Question 4: Arend and Goldstein (1990)

L.E. Arend, R. GoldsteinLightness and brightness over spatial illumination gradients

Journal of the Optical Society of America A, 7 (1990), pp. 1929-1936

Question 5: Maloney and Wandell (1986)

L.T. Maloney, B.A. WandellColor constancy: A method for recovering surface spectral reflectance

Journal of the Optical Society of America A, 3 (1986), pp. 29-33

Question 6: https://psychologydictionary.org/sensory-adaptation/

Question 7: https://science.nasa.gov/ems/09_visiblelight

Question8: https://www.cs.princeton.edu/courses/archive/spring08/cos598B/Readings/Neuroscience_ch09.pdf

Question 9: https://www.churchillstl.org/learning-disability-resources/visual-processing-disorder/

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