Reading Activity Week #6 (Due Monday)

1a &b) What did you find interesting?
One of the items in this chapter I found interesting was the three steps to color perception. First off, I would never look at color being perceived in just three steps. I would have thought it would have been more. The three steps are: 1) Detection: wavelengths must be detected. 2) Discrimination: we must be able to tell the difference between one wavelength and another. 3) Appearance: assign perceived colors to lights and surfaces in the world. I found the appearance section to be the most interesting out of the three. Because we have exactly three different types of cone photoreceptors, the light reaching any part of the retina will be translated into just three responses, one for each local population of cones. I have a degree in Graphic Design and have been in that market for over a decade. I am very familiar with the color spectrum. Most of my clients often request of “generic” names of colors and it is often hard to match what they have in their mind. There are virtually thousands of variations of the same color, and when that color is matched with a different (complimenting) color, they are more often than not worlds apart on how accurate they ‘think’ they really are. The fact is, more men than women are color blind, and most often, women are more accurate in the colors they want. Women are born with two X chromosomes and men only with one. That being said, if there is an abnormality in one X chromosome, women have a back-up chromosome with little chance of that one being abnormal.

2a & b) What did you find interesting?
The second item in this chapter I found interesting was the adaptation and afterimages section. Adaptations can be color specific as we can see in the phenomenon of an afterimage. An afterimage is a visual image seen after the stimulus has been removed. The textbook gave a couple of exercises to see what the effect looks like. The book showed a picture of negative afterimage of a man in standing in front of a castle. A negative afterimage is an afterimage whose polarity is the opposite of the original stimulus. Focusing our eyes on the black dot in the original picture allows our eyes to adjust for the optical illusion. This first opposite colored image is called the adapting stimulus. This illusion has become very popular in the TV show Brain Games. If you have never caught an episode of this, I recommend it. The show is on the NatGeo channel. There are usually 2 or 3 items that are related to this course. We are not attributing negative afterimages to just the cones or just one set of cone or color-opponent processes. Adaptation occurs at multiple sites in the nervous system.

3a & b) What did you find interesting?
The final item in this chapter I found interesting was the section about color vision in animals. Our ability to see/use wavelength information has gotten better for animals and humans through the course of evolution. I found it interesting the book states that there at least two realms of behavior where color vision is especially helpful: eating and sex. I could easily understand where color is important when seeking food. Imagine you cannot see colors at all and you are in the forest looking for food, if you cannot see colors, what’s to stop you from picking poisonous berries. I found it interesting bees can see short-wavelength (ultraviolet) light. Many wildflowers have dramatic patterns we can’t see because of the variations in the reflection of those short-wavelengths. Bees can see them, they have evolved to see them so pollination can occur. Color vision is accomplished in different ways, in different species. Humans are trichromats, with three different types of photoreceptors. Dogs dichromats, having two different types of photoreceptors. Chickens are tetrachromats, with four, although having more than three is often seen as not having any gain. Our S-, M-, and L-cones are different because they contain different photopigments. I found it interesting to read, many species use the color of their feathers or their fur to respond to sexual activity and mating potential.

4a & b) What one (1) thing did you find the least interesting?
One part of the chapter I found the least interesting was the section on color in the visual cortex. This section reminded me of the on/off center cells from Chapter 2. Without knowing how/why the opponent color theory is, it is hard to grasp the concepts being presented in that section. Single and Double opponent cells are cell types found in the visual cortex in which one is excited by and turned on or off depending on the level of stimulation presented. It was very confusing to read those terms along with the visual examples presented in the book. The only part of that section I understood was the achromatopsia, which is the inability to perceive colors, which is caused by damage to the central nervous system.

5) What did you read in the chapter that you think will be most useful to in understanding Sensation / Perception?
I think the most important part in this chapter to know was in the very beginning. Knowing that color is NOT a physical property, but it is related to physical property. The size of the wavelengths our nervous system can respond to will dictate how much color we perceive. Color is the result of the interaction of a physical stimulus with a particular nervous system. I think the introduction paragraph on the first page of this chapter was the most important concept to understand as a whole.

6) How, in what ways, does this chapter relate (build on) to the previous chapters?
This chapter relates to the previous chapters by reiterating some of the terms we have already used. It’s getting away from the structures more in this chapter, but it is getting more in depth of the nervous systems reaction to the world as a stimulus. I like how this chapter goes back to some of the more basic terms, and really dissect them in this chapter as a bigger and more complex issue.

7a & b) What topic would you like to learn more about?
I would really like to know more about the abnormalities people can have or be born with when it comes to our perception of color. The small section of color blindness being more prevalent in men was interesting. I would also like to know more about how genes play a role on how we perceive color and our sensations in the visual department.

8) What ideas related to what you were reading (what did you think about) did you have while reading the chapter?
See above answer. I didn’t really think about anything but this chapter while I was reading it. My kids were distracting me enough, and the parts of this chapter I cared about and was easy to read, I read it a couple of times to get a visual of the processes involved. I guess one thing I thought about was the animal section. I couldn’t get over evolution has weeded out a lot of species based on the fact they couldn’t survive just based on the colors they couldn’t perceive.

TERMS: color perception, detection, discrimination, appearance, cone photoreceptors, retina, color spectrum, cones, X chromosome, adaptation, afterimages, adapting stimulus, wavelength, short-wavelength (ultraviolet), color vision, trichromats, dichromats, S-cone, M-cone, L-cone, photopigments, photoreceptors, visual cortex, opponent color theory, single opponent cell, double opponent cell, achromatopsia, sensation, perception

1. I found the three steps to colour perception fascinating. The first step is detecting wavelengths with the combination of sensitivities of S-cones, M-cones, and L-cones; the second step is to tell the difference between wavelengths, which is a lot more complicated than it sounds. Last step to perceiving colours is to assign perceived colours to different situation, and maintain the colour we see even when the conditions change. Just like any other thing that is related to sensation and perception, we take colour perception for granted. No one thinks twice when the see colours (I probably will, after this chapter), but colour perception is such a complicated process that people can study about it and write pages of information about it in a boring textbook regarding sensation and perception. I was pleasantly surprised to read about the obstacles that need to be resolves when the eyes differentiate different wavelengths. It takes a few thousand words to describe the process, but colours are perceived instantly when the wavelength hits our visual system. That’s why I thought it was fascinating.
2. Opponent colour theory is another part I found interesting. I always knew blue and yellow makes green, but I never cared to find out why (again, taking sensation and perception for granted like most people do). Reading this chapter allowed me to corporate what I learned from the previous chapters and many real life experiences, and make more sense of my perception. Figure 5.14 helped me a lot in understanding the first two paragraphs about opponent colours, it shows just why blue and yellow makes red, and yellow and blue makes green. Before this class, I assumed that colours were on a continuum which starts with white and ends with black, with rainbow-like colours like in between. Opponent colour theory, however, takes black and white out of the picture and make those two colours another opponent pair. I didn’t think it make any sense before studying figure 5.14 more carefully, which then made me realize that neither black nor white fit in anywhere.
3. Lastly, colour constancy is also interesting. Though the paragraph was a little hard to digest as it discusses matters which requires some imagination, I still like it anyways. I thought colours change depending on the conditions, as in lighting or nearby colours, and I was partly right. Brown, because it is one of the related colours, and there is no independent light that is brown, the colour can only be explained with dark orange or yellow. The same concept can be applied to gray, which is essentially darker white. When seen in isolation, brown will appear yellow or orange, and gray will look white. In other words, the related colour changes depending on the conditions.
4. Colour in the visual cortex threw me off a little bit, it was a little bit hard to swallow but since I had a good grasp on the opponent colour theory, I was able to understand how the visual cortex see colour more clearly. I had to go back and forth between those pages to refresh my memory of opponent colour theory and the application of that theory on the visual cortex. It was challenging at first but I figured it all out eventually.
5. I believe the most crucial piece of information is knowing that colour is not universal. Colour perception depends upon the interaction of physical stimulus and the particular nervous system. Because we often mistake people who do not see the same colour as us “colour-blind,” but are they really blind? Maybe they just have a slightly different nervous system than us that perceive the physical stimuli differently. The same concept is applicable to other species, who see differently than us because the interaction between the physical stimuli and their nervous system is different.
6. This chapter builds on the previous chapters beautifully because the previous chapters allow us to understand the physical proponents of the visual system, which then makes it easier for us to understand that colours are not physical, but instead subjective interactions between the wavelengths and our visual cortex. By understanding how information is perceived through our eyes from the previous chapters, this chapter is easier to read as it only adds on the information that we have already learned.
7. I would like to do some more research on colour perception, and maybe focus on the second step just to narrow down my topic. It is so interesting to learn about things that we take for granted, I was fascinated by how much work goes on when we “see” colours. If I come across some information about colour-blindness, I will put in some effort to read up on it as well.
8. I was thinking about my dog the whole time I was reading the chapter, and when I got to the animal section, I was full of joy. People say dogs are colour-blind, but after reading this chapter, I know for a fact that they are not “blind” to colours, they simply just have another visual system that interact with the external physical stimuli differently than us. My friend often mentions that my dogs loves yellow – because his favourite toy is yellow and he likes my yellow pillow. I corrected him a few times and explained that it is probably coincidence that his two favourite things (besides me) are yellow, as dogs do not generally care about colour and they use their nose more often to navigate around the world.
TERMS: colour-blind, colour-blindness, visual cortex, opponent colour theory, perception, sensation, interaction, physical stimuli, nervous system, colour constancy, colour perception.

1a) What did you find interesting?
The first thing I found interesting was the just the physical property of color and how we see it. Color itself isn’t a physical property but it is related. We see a narrow range of the electromagnetic spectrum between the wavelengths of about 400 and 700 nanometers. The color of the bit of the world is correlated with the wavelengths of the light rays reaching the eye from that bit of the world. But most of the light we see if reflected light. Typical light sources, like the sun or a lightbulb, emit a broad spectrum of wavelengths that hit surfaces in the world around us. Some wavelengths are absorbed by the surfaces they hit. The more light that is absorbed, the darker the surface will appear. Other wavelengths are reflected, and some of that reflect light reaches the eyes. The color of the surface depends on the mix of wavelengths that reach the eye from the surface. This is just generally all interesting to me because I knew that how we see had to with light reflecting but I had never gone into this much detail.
2a) What did you find interesting?
The second thing I found interesting was the different types of photoreceptors. There are three types of cone photoreceptors. These cones differ in the photopigment they carry and as a result they differ in their sensitivity to light of different wavelengths. The three different cone types are named for the location of the peak of their sensitivity on the spectrum. There are short-wavelength cones (s-cones), middle-wavelength cones (m-cones), and long-wavelength cones (l-cones). These cones only work at daylight (photopic) light levels. We have a different type of rod photoreceptor that works in dimmer light called the scotopic. Different types of wavelengths of light give rise to different experiences of color, and the varying responses of this photoreceptor to different wavelengths provide a basis for color vision. I thought this was all interesting because I never knew we had three different types of cones being used constantly.

3a) What did you find interesting?
The last thing I found interesting was adaption and afterimages. Adaption is one way of dealing with the vast range of light levels in the environment. Adaptation can be color-specific, as we see in the phenomenon of negative afterimages. If you look at a color for a few seconds, a subsequently viewed achromatic region will appear to take on a color opposite of the original color. The first stimulus in this is the adapting stimulus. The illusionary color we see afterwards is the negative afterimage. I thought this was interesting how we perceive afterimages and dealing with different light levels around us in general.
4a) What one (1) thing did you find the least interesting?
One thing I found the least interesting was the opponent color theory. This theory tried to describe the three basic colors of red, green, and blue. It described different color types competing with each other and how that worked. I think the theory made somewhat sense to me, but I just didn’t find it appealing at all. It was extremely complicated and very wordy. It was something that was hard for me to read and get anything out of the first time or want to skip over. I think it was empirical work in the field but just not my cup of tea.

5) What did you read in the chapter that you think will be most useful to in understanding Sensation / Perception?
I think the sections covering how we perceive color will help me understand more on sensation and perception. I had an idea of how light works with our eyes but I never knew the full out details. The whole chapter explained the process of the visual system and how it relates to the world. I think the section about color blindness will be helpful as well.
6) How, in what ways, does this chapter relate (build on) to the previous chapters?
I think this chapter relates to the other chapters by just expanding on the visual system. It goes into more detail rather than on the parts but how the outside world effects what we see. It uses the parts of the visual system we learned about and explained the role that color plays in it. I think a lot of the previous chapters we learned a lot of parts of the eye, this chapter talked about what those parts did in good detail.
7a) What topic would you like to learn more about?
I would like to learn more about how animals and the visual perception works. During my reading I haven’t really thought about animals at all. I thought this section was really interesting and how there are so many different animals with different visual systems. Plus there are a lot of different theories on the subject and how some animals can’t see in color and how some can. But these theories are constantly argued about. Which is why I’d like to expand more on the subject.
8) What ideas related to what you were reading (what did you think about) did you have while reading the chapter?
After reading about the animal vision I thought about my pets in general and what they may see. I also wondered about the tricks people teach dogs. There are some dogs that are taught to get the red object, which some are taught and get right every single time. But what if their red is just a darker shade of grey or something that they’ve accustomed to red? I guess just animal vision really interests me.
Terms: Physical property, color, electromagnetic spectrum, wavelengths, nanometers, light rays, reflected light, emit, absorbed, photoreceptors, cone, photopicment, short-wavelengths, medium-wavelength, long-wavelength, photopic, rod, scotopic, color vision, adaptation, afterimage, negative afterimages, achromatic region, stimulus, adapting stimulus, illusionary color, opponent color theory, color blindness, visual system.

1. The first topic that I found interesting was the concept of the problem of univariance. I found this interesting because I had always wondered why we can see more colors in the light than in the dark. It makes sense that it is because while cones (daytime photoreceptors) come in different types that are tripped by different wavelengths of light, rods (nighttime photoreceptors) only come in one type. This effectively decreases the range of colors visible in low-light situations.

2. The next topic I found interesting was metamers. This is the name for when different wavelengths of light look identical to each other because they cause the same cone reaction. This means that even though two wavelengths, or combination of wavelengths are different from each other, if they create the same cone output, the color seen will be the same. I find this incredibly interesting because I like colors in general and it is enlightening to learn way colors can mix to form another.

3. The third subject I found interesting was colorblindness. I find this interesting because I cannot help but wonder how the colorblind see. I would like very much to put goggles on and see the world through their eyes. It is interesting also that there seems to be many types of colorblindness. One could be deuteranope (no M-cones), a protanope (no L-cones), a tritanope (no S-cones), a color-anamalous (2 cone types so similar they cause similar cone responses), a cone monochromat (only 1 type of cone), or a rod monochromat (no cones). The fact that there are so many types of colorblindness really makes me wonder how the world can be viewed so differently from how I see it.

4. The topic I found least interesting was the actual wavelengths. They simply did not spark my interest. They have little to do with what makes me curious. It only reminded me of math, which accomplishes nothing except making me anxious.

5. I believe the part of the chapter explaining how rods and cones work is most useful. By understanding the basics of how the eye processes the colors we see acts as a major building block to understand sensation and perception.

6. In previous chapters, we only talked about spatial vision and recognizing what we see. We never talked about how the image itself gains its life and color. Exploring the method to seeing actual images we see gives us a corner stone upon which to bring the rest together, in my opinion.

7. I would like to learn more about colorblindness. This is because it is such a broad topic that I could learn a great deal of information. I also want to learn about it because one of my most cherished senses is sight. Having that sense damaged in anyway would be sad for me. This also causes me to want to learn more about how it works and how people cope/live with it.

8. Apart from what I mentioned in the previous answer, I thought a lot about metamers. I thought about what colors we may be missing from our lives because we don’t have more cones with different sensitivities. It makes me mildly upset to find that there are more colors I will never comprehend because I don’t have a wider assortment of cones. I also do want to reiterate the desire for “color-blindness goggles.”

Terms: Univariance; cones; rods; daytime photoreceptors; nighttime photoreceptors; metamers; colorblindness; deuteranope; protanope; tritanope; color-anamalous; monchromat; rod monochromat; wavelengths

1. One thing that I found interesting from chapter 5 was the idea that everyone may or may not see colors the same way. How do you know if you see the same colors as everyone else around you? How do you prove that everyone sees the same colors? The answer is you can’t really. I find this interesting because we go through our entire life thinking that our eyes are completely normal and we are seeing everything that everyone else is seeing but we don’t know if we actually are. This concept is astonishing to me because the answer is so unclear and there isn’t a way right now to figure out and give a clear answer. Putting aside visual systems that can see most colors clear and concise, there are disorders of the eye such as color blindness. There are a couple different types that the book talks about those being deuteranope, protanope, tritanope, and color-anomalous. I didn’t know that there were different types of color blindness. I figured you either were color blind or you weren’t. It was interesting to learn a little more about each of these disorders because one could have this but not ever know it because they think their visual system is completely normal.

2. The next concept that really stood out to me in this chapter was the section about color vision in animals. In the animal kingdom, two specific factors are especially useful when looking at two realms of behavior: eating and sex. When an animal searches for food, the food being brighter and aesthetically pleasing, it makes it easier for the animal to recognize the food. An example in the book explained that flowers are made of colors to attract bees. The reason behind this is because the tradeoff of food for sex. The bees give the flower pollination and in return the flower gives the bees food to survive. Another factor that was talked about was the idea that the ability to notice colors in other animals results in successful mating and strong offspring. This makes more sense to me now that the males in the species are the ones to be decorated in bright, beautiful colors. If females were unable to distinguish the fit males from the unfit males, certain species would be in a lot of danger. I find this interesting because I am an animal lover and I have always wanted to look further into the mystery of the colors animals see in comparison to the colors that human beings see.

3. A third thing that I found interesting in this chapter was the two terms unrelated colors and related colors. Unrelated colors are colors that can be experienced in isolation. Related colors are colors that can only be seen in relation to other colors. Colors such as brown and gray can only be experienced depending on the other colors around them. An example used in the book is the idea that a gray patch will appear white when it is surrounded by complete darkness. Brown will appear only if it accompanied by other lighter colors otherwise it will appear as dark orange or dark yellow (depending on the brown). I find this interesting because now it makes me think that the color I think I am seeing is not necessarily the color that is right in front of me. The colors of other objects around it have a major effect on the color I perceive and in a way that kind of freaks me out. This concept kind of plays into the first concept that I was interested in of people seeing colors differently. We all perceive objects and colors differently and it is interesting to read all about the reasons why.

4. There were many concepts from chapter 5 that I found to be boring or I didn’t grasp the full concept. One of these was the history of the trichromatic theory. I didn’t find this theory to be that interesting to helpful in understanding more about sensation and perception but then having to read about the history of it made it that much more boring. I am not good with names and different ideas that different people come up with. I would rather learn about the theory and concepts relating to the theory rather than the people who came up with or contributed to that theory.

5. I think the part in the chapter that will be useful in understanding sensation and perception is in the beginning of chapter where it talks about people seeing the same colors. Understanding that there are different colors out there and that colors look different next to other colors have a huge effect on the way we perceive things. This section explains different components of the visual system and relates it to everyday life. Understanding the different colors and being aware of what we are actually seeing is key when trying to understand the visual system relating to sensation and perception.

6. Chapter 5 builds on all of the previous chapters because it continues to talk about our visual system but this chapter goes more into detail about our ability to perceive color. We have been talking about the visual system in the previous chapters and each chapter picks out different aspects of the visual system and chapter 5 is all about seeing colors. This chapter also brings up some terms that were used previously in the chapter and this also builds on our understanding of these terms. Many of these terms and concepts are very complex and these chapters do a nice job of explaining them and building off of each other which in the end makes it more interesting and easier to understand.

7. I would like to learn more about the abnormalities in people perceiving color such as the different types of color blindness. I find these interesting because there are different types causing different problems. Abnormalities in anything have always interested me and always causing me to ask questions of why and how.

8. While reading the chapter, I wasn’t really focusing on anything besides what I was reading. I did think a little bit about how my visual system and the colors that I see could be completely different than what other people see and I wouldn’t even know it. Little questions like this go through my head while reading these chapters. I always think I have something wrong with me but in all reality I am just psyching myself out.

Terms: Visual system, color blindness, deuteranope, protanope, tritanope, color-anomalous, unrelated colors, related colors, isolation, history of the trichromatic theory, sensation, perception.

1a) Achromatopsia

1b) This is a disorder in which the patient is unable to perceive colors. This is caused by damage to the central nervous system. I found this interesting because, like prosopagnosia, I cannot imagine a world where I could not distinguish colors. It seems like a fascinatingly confusing topic. The patients know where one color stops and another color begins, but they are unable to identify what colors they are.

2a) Color Blindness types

2b) I found these interesting because often people think of color blindness as being completely blind to color and only seeing the world in shades of gray. In reality this is only one type, cone monochromat. These individuals only have one cone type which truly makes them color blind. Others simply cannot see or have difficulty distinguishing certain colors.

3a) Anomia

3b) Similar to Achromatopsia, Anomia is the inability to distinguish objects even though they have the ability to see and recognize them. The book uses the example of a patient picking out a banana. They pick it out because it “looks right,” however they are unable to tell you that the banana is yellow. I found this interesting because it seems incredibly similar to Achromatopsia. I would like to know what they difference is between the two.

4a) Trichromatic Theory of Color Vision

4b) This topic was difficult to get through for me. I had to read the definition quite a few times before I completely understood its meaning.

5) I feel that the most important thing that I read in this chapter would be the section on the different cones (s-cone, m-cone, l-cone). This was helpful in this chapter to be able to put a name to the parts that were affected by the disorders we were learning about.

6) This chapter built off of chapter 4 by talking more about recognition. Instead of looking at objects and people this chapter went into more specifically colors and pigments.

7a) Achromatopsia vs Anomia

7b) I would like to know what the difference is between the two disorders.

8) I thought about prosopagnosia especially when dealing with Achromatopsia. The inability to distinguish colors reminded me a lot of the inability to recognize faces. Something that is so common to all of us is so difficult to the people who suffer from this.

9) Key Terms: Achromatopsia, perceive, colors, central nervous system, prosopagnosia, color blindness, blind, cone monochromat, anomia, Trichromatic Theory of Color Vision, cones, s-cone, m-cone, l-cone

Color is not a physical property of things in the world, but it is related to a physical property. Objects in our world appear to be certain colors because of our particular visual systems. As we have learned, the human visual system sees a small range of the electromagnetic spectrum between the wavelengths of 400 and 700 nm. The “color” we see is correlated with the wavelengths of the light rays reaching the eye from the object the light is being reflected from. Most of the light we see is actually reflected light. Light sources can range from the sun to light bulbs, and they emit a broad spectrum of wavelengths that hit surfaces in the world around us. Some wavelengths are absorbed, making the object appear darker; while some are reflected and some of those reach the eyes. Color is the result of the interaction of a physical stimulus with a specific nervous system. I think this is a cool concept, interesting how we perceive the world around us.

Trichromacy brought me back to chapter two, more specifically about rods and cones. The two kinds of photoreceptors in the retina are rods and cones. Rods are sensitive to scotopic light levels; these are dim light levels at or below the level of bright moonlight. There are three types of cones named for their position on the spectrum of the height of their sensitivity. S-cones are sensitive to short wavelengths, M-cones are sensitive to middle wavelengths, and L-cones are sensitive to long wavelengths, easy to remember because each type has the letter that corresponds to the length of the wavelength each is sensitive to. After reading about the univariance problem, I learned that you can make any wavelength look like any other just by adjusting the intensity of the light. This doesn’t work in the three-cone world of our color vision as humans. With humans a specific light produces a specific set of responses from the three cone types. The idea that the color of any light is defined in our visual system by the relationships among three numbers is known as trichromacy, or the trichromatic theory of color vision. I liked relating it back to what I previously read, like to tie things together.

Concept of color space was also interesting; I have a friend who is big on photography and art so it’s all he talks about. The range of our experience of color can be described by reference to a three-dimensional color space. The useful terms used for defining color space in regard to color space are hue, saturation, and brightness. A hue is the chromatic aspect of a light, each point on the spectrum defines a different hue. The saturation dimension corresponds to the amount of hue present in a light. For example, white light has zero saturation. Brightness is the perceptual consequence of the physical intensity of a light. The sun’s light is physically more intense than the moon’s intensity. I thought it was interesting that there are nonspectral hues that can only result from light mixtures that are not present in the spectrum. I really enjoyed reading about color space, because I love how beautiful colors make our world but haven’t taken the time to really investigate the concept.

I found the concept of lateral geniculate nucleus to be the least interesting thing from the chapter, didn’t like learning about it in chapter 3 and reviewing did not make it more interesting. The lateral geniculate nucleus is a relay on the pathway from the retina to the visual cortex. It is a structure in the thalamus of the brain that receives input from the retinal ganglion cells and has input and output connections to the visual cortex. I know that this is an important part of the visual system, as is every part, but I just don’t find it very interesting to read about.

I think that the concepts of trichromacy and the problem of univariance will be very important to further understanding sensation and perception. The problem of univariance is the fact that an infinite set of different wavelenfth-intensity combinations can elicit exactly the same response from a single type of photoreceptor. One photoreceptor type cannot make color discriminations based on wavelength. Trichromacy is the theory that the color of any light is defined in our visual system by the relationships between a set of three numbers, the outputs of three receptor types now known to be the three cones. I did not understand the complexities of how our eyes/brains perceive wavelengths and light spectrums before reading this chapter. I overall it’s an interesting concept/process. Things are not actually the color we see, just how we perceive them.

I would like more information about the concept of metamers, because I understand that they are mixtures of different wavelengths that look identical but I would like further explanation on the subject to better understand it. I would also like more information about achromatopsia because I think it is interesting how a person could lose their color vision after damage to their brain/central nervous system. I like learning about how different areas of our brain serve specific functions, and how a person would have to adapt to not having a previously possessed ability like color vision after damage to that area of their brain. Ill most likely do my topic on it.

Terms: wavelengths, trichromacy, retina, rods, cones, scotopic, S-cones, M-cones, L-cones, univariance problem, trichromatic theory of color vision, spectrum, color space, hue, saturation, brightness, chromatic, nonspectral hues, lateral geniculate nucleus, visual cortex, thalamus, retinal ganglion cells, metamers, achromatopsia

1a) What did you find interesting?
i thought the 3 steps of color perception was pretty interesting.
1b) Why was it interesting to you?
i thought it was interesting because it had different types of wavelengths, different types of cones, photopic and even a scoptopic

2a) What did you find interesting?
another thing i thought was interesting was opponent color theory.
2b) Why was it interesting to you?
i thought the perception of this theory was pretty cool and it made it a bit more understanding, and it's something that i can somewhat relate to.

3a) What did you find interesting?
Color Constancy was somewhat also interesting to me as well.
3b) Why was it interesting to you?
i thought it was interesting because i was reading and wonder what would people without color constancy vision feel like, if they would see the same object as the ones who do but different background coloring since they wouldn't have color constancy .

4a) What one (1) thing did you find the least interesting?
i thought the chapter was nice and short and well explained, but my least favorite part would be the color vision in animals
4b) Why wasn't it interesting to you?
i think it was because i couldnt really relate to it, nor care well enough to try to since i don't have a pet animal and such.

5) What did you read in the chapter that you think will be most useful to in understanding Sensation / Perception?
i thought that the three different layers of color visions can be very useful in sensation and perception, also how the constancy background color help us have a vivid understanding of the actual image, how some people who cant see color can struggle but have ways of understanding colors somehow.

6) How, in what ways, does this chapter relate (build on) to the previous chapters?
this chapter related to the last chapter in many ways, the only difference is that this one is about the layers of colors and the last chapter was mainly about different layers of visual fields. i also thought that were very relative to the last chapter because it kind of reminded me of the rods and cones of visions in away.

7a) What topic would you like to learn more about?
i would like to do more research on color vision in animals.
7b) Why?
because i want to understand it more, and i want to know what intensity they have of color vision, whether their color visual system is the same or different with us.

8) What ideas related to what you were reading (what did you think about) did you have while reading the chapter?
when i was reading this chapter, i was wondering how hard it must be for people who are color blind to understand certain quality of things, to understand concept of colors, i was thinking if there is away those people to improve their color blindness and help them see from how people who in fact aren't color blind would, or maybe test some experiment and have a person who isn't color blind becomes color blind and see how that affects the things they do from that point on out.
TERMS: S.Cone, M.Cone, L.Cone, Rods and cones, visual fields, color visions in animals, photopic, scoptopic , opponent color theory, color constancy

Chapter 5
1A) afterimage.
1B) I find this interesting because it’s an optical illusion that we have all tried on some point. Where we look at something for a long period of time and the object gets taken away and we still see the image. It’s amazing of how our brain sees different things and how we preserve things.
2A) negative afterimage
2B) whenever there is a opposite reaction to a phenomenon its always interesting. Especially when it comes to the brain. The brain is a crazy part of the body one that we still don’t understand very well. We don’t even use 100% of the brain. Negative afterimage is interesting because we continue to see the image after the fact.
3A)agnosia
3B) this was in the other chapter and I find this interesting because brain damage is a huge ordeal. Many people have brain damage and you can have the same kind of brain damage and have a different reaction to it. I feel like I will deal with people with different brain damage in my future line of work.
4A) metamers
4B)I found this interesting but its sounds very confusing. For me anything that is more mathematical with physics is a little bit harder for me to understand. Metamers has two warning to it and its something that is just sitting with me very well so im not understanding it as well as I would like to.
5) After images goes a long way in this class because it has to do with sensation and perception. Sensation because it’s a wired sensation seeing something after its already gone. And perception because it a wired thing that our eyes and brain do.
6) this chapter has some of the same vocab as the previous chapter. And it goes into more detail of the brain. Each chapter goes into a little more depth the than the previous chapter. And then talks about a new topic. The great thing about this book is that it slowly brings you into the topic and gives your more information once you have the basic knowledge.
7A) I would like to learn more about agnoisa
7B) The last two chapters have talked about this so it must be pretty important. I think that I will deal with people with brain damage with my future career. I plan to be a law enforcement officer and having knowledge about people with brain damage.
8) this whole idea about learning about the brain is great and figuring out how we are understanding what we are seeing. It’s a great thing to know how we see so we can perhaps see better by knowing how our eyes play tricks on us.
9) sensation, perception, agnoisa, brain, eyes, eyesight, metamers, afterimage, negative afterimage.

(1ab) I found interesting the different types of cone photoreceptors we have. I found this interesting because each cone differs in photopigment they carry and as a result they have different sensitivities to light of different wavelengths. For example, the S-cone, is preferentially sensitive to short wavelengths colloquially (but not entirely accurately) known as a “blue cone.” The M-cone, the middle wavelength cones also referred to as a “green cone.” Then there is the L-cone, which are the long wavelength cones, also known as the “red cone.” Those three cones are named for the location of the peak of their sensitivity on the spectrum. These cones also can only operate during day-light levels, which means photopic levels, meaning that these light intensities are bright enough to stimulate the cone receptors and bright enough to saturate the rod receptors.

(2ab) The three steps we go through in order to go from physical wavelengths to the perception of color also interested me. It was interesting to me because when you use your senses, you do not think about how complex the action is. The first step is detection, obviously the wavelengths have to be detected. The second step is discrimination, we go on to tell the difference between one wavelength, a mixture of wavelengths and so on. The third step relates to appearance, we assign perceived colors to lights and surfaces in the world. Our vision solves a problem by going through these three steps.

(3ab) Color blindness was the third topic of interest for me. Color blindness is a form of color vision deficiency found in 8% of males and 0.5% of females. Color blindness relates to the malfunction in one or more of the genes coding the three cone photopigments. There are numerous types of color blindness that affect a specific cone which is why it was so interesting to me. An individual could have no M-cones which makes them a deuteranope, or they could have no L-comes which would make them a protanope. Next there is the absence of S-cones which makes them a trianope. Color blindness has many more types, this just goes on to prove that everyone does not see colors the same way. Being a guy I am very disappointed that not as many women experience a color vision deficiency compared to guys. Everyone sees the world differently, put some color goggles on and see the worlds color in their shoes.

(4ab) The history of trichromatic theory didn’t interest me very much. This wasn’t interesting to me because I am just not attentive when reading about history, even though I do see the importance of Isaac Newton discovering that a prism would break up sunlight into a spectrum of hues. The concepts and theories relating to how we experience color are very interesting to me but the history is just kind of boring to me.

(5) Further developing my understanding of sensation and perception was achieved by realizing that color is not a physical property of things in the world, but rather it is a creation of the mind. Each individual person visualizes colors differently, we do not necessarily see colors the same way. Sensory information comes from a stimuli, we know that, but the way we process that into different perceptions ranges differently from person to person.

(6) This chapter continues to expand our understanding of the visual system. It describes how the visual system functions when percepting color. It uses parts of our visual system previously discussed to provide easier yet deeper understanding of the role perceiving color plays. It also provides the understanding that most of the topics related to sensation and perception are acquired and used by individuals the same way, but minds of different individuals create this sense differently.

(7ab) I would like to learn more about gender differences in color blindness and certain color deficits in the visual system. I would like to learn more about this topic because society constantly judges males and females. Researching this topic could provide me with credible information I could use when debating males and females. I also think my friends would appreciate credible facts and information presented to them.

(8) I thought about my buddy who cannot tell colors apart if his life depended on it. He is color blind, I go on each day with my color perception on point. I take for granted the things my body does autonomously until I read about it. I also thought about my dog because I have had plenty of people tell me that dogs are colorblind, this is not true. They just have a visual system that interacts differently with the stimuli they are presented.

(9) Terms : color perception, S-cone, M-cone, L-cone, photopic, color detection, color discrimination, color appearance, history of trichromatic theory, hue, saturation, brightness, dueteranope, protanope, tritanope