MIDTERM ESSAY
MIDTERM ESSAY
Assignment Instructions
For your Midterm essay exam, you will complete 10 essay questions which focus on the course readings. Midterm essay answers must be attached as a Word document to the appropriate assignment page, not typed into the assignment student comments boxes. In addition to writing a 300 word answer to each essay question with APA formatted citations and references (APA title page and reference page are required. Each question should be answered clearly and numbered) students will answer each question thoroughly and completely, providing examples where required.
Answer the questions below in your Midterm exam.
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.
2. Because the long axons of neurons look like electrical wires, and both neurons and electrical wires conduct electricity, it 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.
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 dim illumination than in bright illumination?”
4. What is color constancy? Describe three factors that help achieve color constancy. What is brightness constancy? Describe the factors that are responsible for brightness constancy. Lastly, compare and contrast color constancy with brightness constancy.
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 illuminate highways or parking lots, colors do seem to change. Why do you think color constancy would hold under some illuminations, but not others?
6. What is sensory adaptation? How does it occur within the various senses? What function does sensory adaptation serve? Provide a relevant example that illustrates your point.
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?
8. How does the eye transduce light energy into a neural message? What is the blind spot in the eye and how does it impact the transduction of light energy?
9. How is visual information processed in the brain? 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.
10. What theories contribute to our understanding of color vision? Discuss at least two relevant theories of color vision.
READING
WEEK-1
READING
Introduction
Topics to be covered include:
· Sensation and perception
· Sensory processing
· Physiology-perception relationship
· Neurons
What are sensation and perception? This lesson will walk through the process of sensory processing with an overview of the parts of the process you will explore in greater detail in later lessons. The sensation and perception process is a process that involves our physical senses reacting to a stimulus in the environment (like a bee), and moving that information to the brain for analysis based on our own unique bundle of experiences and knowledge. This makes perceptions unique to each person.
Visual processes will be introduced as they pertain to sensation and perception. Why is light important in visual processing? This lesson will answer that question and discuss the route sensory information takes in the visual processing systems. One of the main actors in this process is the neuron. By the end of this lesson, you will have a better understanding of what a neuron is and what it does as a messenger, conveying signals to and from the brain.
Sensation and Perception
A girl is out in a field enjoying the warm summer sunshine and beautiful flowers with a toddler. She hears a buzzing sound, and starts to look around to place the source. She is familiar with this sound, and looks for a bee. When she finds it, she realizes it is flying toward her and she begins to run. She has been stung by a bee before, and does not want to feel that pain again. The toddler that is with her, hears the same buzzing and sees the same bee, but does not run. As a matter of fact, the toddler is curious and stands watching until the girl picks him up and moves him to a new location.
Why did the toddler have a different reaction to the bee? It has to do with perception, and the cognitive processing that occurs as information from the senses is relayed to the brain for analysis. There is quite a lot of processing that occurs in between hearing the buzzing sound and looking for a bee, and seeing the bee, identifying what it is, and moving away from it.
PRIOR KNOWLEDGE CHANGES PERCEPTION
If the information relayed to the brain matches information previously stored through acquired knowledge and experience, the brain perceives this sensory information based on what is previously stored. The toddler did not have information stored on what bees do, so she was not afraid. The girl, on the other hand, has been stung before, and has previously stored knowledge about bees. Her knowledge led to her perception of the situation. This example shows the interaction of sensation and perception.
Sensation is the process of gathering and transmitting information from the five senses: sight, hearing, taste, smell and touch. Sensation acts as a conveyor of information, but does not process the information (Goldstein & Brockmole, 2017). The information from the senses is processed by the brain as it interprets the information based on knowledge previously stored. This cognitive process is called perception (Goldstein & Brockmole, 2017). In this example, sensation occurs as the girl hears a buzzing sound and sees the bee. The information is then sent to the brain, where it is compared to information already stored in memory systems to create perception.
Processing Sensory Information
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· Bottom-up and Top-down Processing
From the beginning, the girl heard a buzzing sound. This information was relayed to the brain. The brain prompted the visual senses to search for the sound. The eyes registered the bee and sent that information to the brain. This time the brain sent the command to move away from the area. The command was based on information stored in the girl’s memory, and experiences she had previously had with a bee. The information that was relayed from the senses to the brain is called bottom-up processing (Goldstein & Brockmole, 2017). The information relayed from the brain to the rest of the body, and the recognition and review of knowledge is called top-down processing (Goldstein & Brockmole, 2017). One easy way to remember this is to think about the location of the brain, and most of the senses. Most of the senses are below the brain, so sending information to the brain would be an uphill process. The brain sits at the top of the body, for the most part, so information used by the brain would be top-down.
Vision
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The sense most people tend to rely on first is vision. The brain interprets the wavelength of light and interprets it as color. Different wavelengths of visible light represent different colors (Griggs, 2016). Shorter wavelengths appearing as blueish colors, mid-length waves appear greenish, and longer waves appear as red, orange and yellow hues (Goldstein & Brockmole, 2017). The wavelength determines color and the amplitude determines the intensity (Griggs, 2016). The wavelength is measured as the distance between wave crests and amplitude is measured by the height of each crest (Griggs, 2016). The number of waves that pass in one second in the frequency.
Visible light is the range of electromagnetic radiation that humans can see, from about 400 to 700 nanometers of wavelengths. The rest of the electromagnetic spectrum is invisible to the human eye (Goldstein & Brockmole, 2017).
Neurons
· MESSAGE TRANSPORTERS
· PARTS OF A NEURON
· SPECIALIZATION OF NEURONS
· HOW A MESSAGE TRAVELS
Let us look at how the message travels through a neuron. The dendrites receive the message from other neurons. They then send the information to the soma. The soma receives the messages from the other neurons and moves them to the axon. The axon carries a message from the soma to the terminal branches that will move the message on to the next neuron in the communication network. The message moves down the axon through an electrical current. The message moving through the axon is called the action potential (Goldstein & Brockmole, 2017).
Action Potential
When a message travels through a neuron it is based on an electrical charge. When an axon is at rest, meaning a message is not traveling through it, the electric charge inside the axon is more negative than positive. This is called resting potential. When a signal for a new message occurs, the charge inside the axon reverses to a positive electrical charge. This signal and the change in electrical charge is the action potential. Once the signal passes the axon and moves to the terminal branches, the charge inside the axon returns to a negative status and as long as a new signal is not coming through, the axon returns to resting potential (Goldstein & Brockmole, 2017). An action potential response is an all or nothing response. Once it begins it does not stop until the message signal has moved through the axon.
The electrical charge of the signal would remain the same size throughout its passage in the axon). This is called a propagated response. There is a limit to how many responses can move…
