Please
read chapter 4 (if you don't have a book yet, please let me know).
After reading chapter 4, please respond to the following questions:
What were three things from the chapter that you found interesting? Why were they interesting to you? Which one thing did you find the least interesting? Why? What did you read in the chapter that you think will be most useful to in understanding Sensation & Perception? Finally indicate two topics or concepts that you might like more information about.
Note:
Keep in mind that there are no scheduled exams. When you make you posts
make sure they are of sufficient caliber that the could be used as
notes in a test - since the posts are what we are doing in lieu of an
exam. Be sure to use the terms and
terminology in your posts.
While reading this section, the mid-level visual systems were interesting, and they provide another layer of visual analysis (identifying objects and backgrounds). However, the most interesting section to me was the higher level processing areas.
First, the specific pathways that are involved are interesting because 1) they diverge into two separate areas of the brain but 2) they arrive at areas that, in hindsight, seem fairly predictable. The "where" pathway travels through the parietal lobe and arrives near the motor cortex, which could be correlated as an area involved in spatial awareness. More interestingly, the "What" pathway travels through the temporal lobe, arriving near the temporal pole. This area is most known for its language processing, and its abundance of connections to the memory parts of the brain.
With the neurons of the pathways of the visual system becoming more specific and more complex, this implies an hierarchical structure of neural connectivity. Even though the higher tier neurons in the visual system hierarchy are less well known and more unpredictable, they still provide interesting insights into the overarching structure of the entire human brain.
Lastly, I had a spark of ingenuity while reading this chapter. If the higher tier visual neurons are connected to the limbic system, which is highly associated with memory, could retrieval of specific memories only stimulate the higher tier neurons, and not the entire hierarchy? Or put differently, by stimulating a specific neuron create the same result as the hierarchy creating a specific pattern of stimulations with this neuron being the final result?
As stated earlier, the mid-level visual systems are important for understanding the higher-level systems; however, they weren't as interesting to me as learning about the higher-level visual systems.
The last paragraph above is the most important information I obtained by reading this chapter.
I would like to learn more about the What & Where pathways.
Terms: mid-level/high-level visual systems, What and Where pathways, spatial awareness, hierarchical structure, etc.
Good points. I'm glad you are thinking about the possible implications for connections within neural pathways of the brain!
While reading chapter 4, I found many things interesting, but found a few things especially interesting. I enjoyed learning about contours because I think it is cool how the visual system can go beyond the information presented to it by the environment, and form edges around the object to identify what it is. The occasional lack of an edge on an object doesn’t hinder a person’s visual system. Sometimes it may actually be difficult to even see the gap in the edge. An Italian psychologist, Gaetano Kanizsa, investigated stimuli that were missing edges and how the visual system still perceived the object correctly. Edges that are perceived despite lack of physical evidence for them are called illusory contours. An Illusory contour is a contour that’s perceived, despite a lack of changes from one side of the contour to the other in the image.
This talent of the visual system posed a problem for structuralists like Wundt and Titchener. I also enjoyed reading about how an early group of perceptual psychologists studied how complex objects or perceptions could be understood by analysis of the components. I have learned about these early psychologists in other classes but didn’t know that they studied perceptions particularly related to the visual system. Structuralists argued that something like atoms of sensation (color, orientation, etc.), and that perceptions were the sum of these atoms. But overtime, examples like illusory contours, contributed to the disproving of this argument. Disproving examples led to the forming of the Gestalt school of thought.
I enjoyed reading about the Gestalt theory because I have learned about this theory in other classes, but refreshing is an effective learning tool, and I liked learning about it directly related to perception. Gestalt theory states that the perceptual whole was more than the sum of its sensory parts. A big contribution from this school of thought was the Gestalt grouping rules that guide the visual system in interpreting raw retinal images. This set of rules describes which elements in an image will appear to group together. The original list was assembled by members of the Gestalt school of thought. Lines of similar orientation have a tendency to be seen as part of the same contour. They “support” each other, in that two visible bits of an edge will actually make it easier to perceive a third collinear segment that lies between them, even if that middle segment isn’t visible. This principle is called good continuation, which means that two elements will tend to group together if they seem to lie on the same contour.
I found the concept of the Necker cube the least interesting to read about. The necker cube is an outline that is perceptually bistable, and unlike most stimuli, two interpretations continually battle for perceptual dominance. The middle vision committees of the visual system aren’t willing to consider any of the infinite number of other possible interpretations of the wire frame cube. This concept is related to the concept of ambiguous figures, which are a visual stimulus that gives rise to two or more interpretations of its identity or structure. I didn’t enjoy reading about the necker cube because I just didn’t find it very interesting.
I think the concept of good continuation will be important to my further understanding of sensation and perception, because it states that two elements will tend to group together if they seem to lie on the same contour. Lines of similar orientation have a tendency to be seen as part of the same contour. Two visible bits of an edge will actually make it easier to perceive a third collinear segment that lies between them, even if that middle segment isn’t visible. I also think that the Gestalt grouping rules are fundamental in understanding sensation and perception because they describe which elements in an image will appear to group together, and they help explain various aspects of texture segmentation and grouping. Texture segmentation is carving an image into regions of common texture properties.
I would like more information about middle vision, the concepts of parts and wholes, and segmentation because I enjoyed reading about them and would like further explanation on the topics.
Terms: contours, edges, visual system, illusory contours, structuralists, atoms, Gestalt, gestalt grouping rules, retinal images, good continuation, Necker Cube, middle vision committees, ambiguous figures, texture segmentation, middle vision, segmentation
Wow, you found lots of cool stuff! Good work. I tried an experiment to see if the Kanizsa (pac-men) shapes would produce not only illusory shapes, but produce a Visual Working memory benefit, the idea being the square should bind the different pac-men shapes together into a coherent object and allow the visual system to only have to store a single item instead of 4 (or 5 if you count the illusory shape). It didn't work out. Haha. Well, that's science, try something else.
Reading Blog
Throughout chapter four I found a lot of interesting stuff and a few confusing topics. In relation to this I understood and enjoyed many of the diagrams and mini experiments but a few were also a little tough to conceptualize what they were trying to display. I really enjoyed the page about perceptual grouping and camouflage. This is such a strange phenomenon. Our brain seems so desperate to create groups and I think it’s really fascinating how nature has taken advantage of this, sometimes flaw/sometimes helpful, process of the brain.
In addition to this information comes the idea that, “an image has no meaning whatsoever until the middle- and high-level visual processes dig into them,” which I thought was the most important part of the chapter for me to add to my list of things that really help me understand sensation and perception. Learning this statement and then adding the grouping process helps me to understand why this is true. If nothing has any meaning until your brain creates meaning then the brain must spend all of its time creating meaning from the environment. It is interesting how simple of a statement this is, yet so complex and so hard to comprehend. If you take the example of a picture, it is made up of faces, patterns, colors, etc and this really has no meaning until the brain breaks it down and gives it meaning. It’s just mind boggling that your brain has to do this with EVERYTHING and then memorize it so that it doesn’t have to do it again.
An example that I liked of how our brain does this can be seen through figure 4.25. I read the example and then looked at the picture and could not figure out what I was missing or why I did not understand the example, until I looked closer and just as the experiment was showing It did take me extra time to find the lower case letters because your brain is so set on the fact that it found a pattern that it doesn’t really bother trying to find another one. A similar example comes with the naïve template theory and relates to the grouping example above. Our brain sees a few letter A’s and then can process anything that looks similar to an A as an A, once again, such a simple everyday process that we take for granted but is actually a really cool and practical part of what our brain and eyes are doing for us.
I had a difficult time understanding the necker cube example that links up with ambiguous figures and would like to know more about how that process works. The ideas on page 86 and 87 were difficult for me to understand. Therefore I did not really like reading about this topic.
Terms: perceptual grouping, camouflage, image, middle level, high level, visual process, naïve templates theory, necker cube, and ambiguous figure.
What is amazing is that you have organisms that are camoflagued based on the environment they live in, but also based on the fact that predators will not be able to discern figure from ground when the prey blends with the background. This means at some point the colors/textures of the organism evolved in response to the predator's visual system not being able to resolve this and based on the environment in which it lives (chameleons, snow leopards, etc). Glad you enjoyed the material, good post.
When first reading the book, I quickly found that middle vision to be a rather interesting thing. Middle vision being a loosely defined stage of visual processing that comes after basic features have been extracted from the image (early vision) and before object recognition and scene understanding (high-level vision). The goal of middle vision being to organize of a visual scene into groups that we can then recognize as objects so basically why its interesting is that its so basic to her vision while be so instantaneous. Another thing I found particularly interesting is that edges, or when there in fact a lack of edge, it actually doesn't bother our vision. Rather interesting that such a simple thing as an edge be so important and so unimportant at the same time. In this chapter, running across the term Gestalt wasn't the first time. Gestalt means 'form'. A school of thought that stressing that the perceptual whole could be greater than the apparent sum of the part. In my art class in high school was the first time I heard of gestalt, I found it interesting how it applies there while in this class as well.
The least interesting topic was the Necker cube. An outline that is perceptually bi-stable, unlike the situation with most stimuli, two interpretations continually battle for perceptual dominance. I found the definition in itself to be a bit of a snore feast so it was difficult to conceptually understand it.
Probably something that I see being a helpful concept with sensation and perceptions is the object recognition. Object recognition is one of the key tasks of visual perception. Two ways that this is happens is through naive template theory. The proposal that the visual system recognizes objects by matching the neural representation of the image with a store representation of the same "shape" in the brain. The other being structural description, a specification of an object in term of its parts and the relationships between the parts.
Object Recognition: Multidirectional Pathways and Middle Vision: Figure Ground are some things I'd like to go over
Terms: middle vision, gestalt, object recognition, naive template theory, structural description, necker cube, edges,
Snore feast or fest? haha. I think the cool thing is that with some of these stimuli you can have two distinct perceptions of its form, HOWEVER, not simultaneously. This means our visual system can only resolve one perception of form and make us conscious of said form at a single moment. Glad you thought the other stuff was cool, though. I think the necker cube tells you that the world can be viewed in a variety of ways and that sometimes there are multiple ways of viewing, understanding, interpreting, and judging the external events that occur around us. Cheers.
Middle vision was a concept that I found to be really interesting. Essentially, middle visions goal is to organize the elements of a visual scene into groups or formations that can then be in turn recognized as objects or things. Something that I found to be really cool is back when we talked about blind spots and how our brain just fills in what we think is in place of the blind spot by using past informational cues and other present information gathered. The same can be said about edges and lines. Our visual systems fill in missing gaps in lines.
I also found the parts about the perceptual committees that were talked about in the middle vision section very interesting as well. When looking at a visual scene, perceptual committees decide what should be seen. It is pretty well summarized in the book as “Middle vision behaves like a collection of specialists, each with a specific area of expertise and individual opinions about what the input might mean. The goal is to have a single answer emerge out of this diversity of opinions.” The ideas of similarity, proximity, parallelism, and symmetry also help explain the middle vision process really well. They all play a vital role in the processing of an image.
The inability to recognize faces or prosopagnosia was an interesting part towards the end of the chapter. We were introduced to this topic in the video we watched last Tuesday. Although someone that is unable to recognize faces, they may still be able to correctly identify objects. According to Wikipedia (http://en.wikipedia.org/wiki/Prosopagnosia), the specific part of the brain that is affected by prosopagnosia is the fusiform gyrus. As far as therapy goes, there have been very few successful therapy techniques. People with this problem have to use something called “piecemeal” or “feature by feature” strategies to be able to identify people. I feel as though I may use this as my subject for my topical blog so I do not want to go too in depth here.
I really didn’t find any topic in this chapter to be boring or uninteresting. This chapter did a great job in pushing the facts and ideals of middle vision across. They also summed up the subject of middle vision really well after talking about it for a few pages. I think that the most useful part of this chapter was the sections about middle vision. By understanding this, we can get a really good grasp on understanding how we perceive and recognize visual scenes.
TERMS: middle vision, blind spots, visual system, perceptual committees, similarity, proximity, parallelism, symmetry, prosopagnosia, fusiform gyrus
That's ok that you're fascinated by most of the stuff. I would say that is a good thing. Being honest about it is even better. Prosopagnosia is very interesting. Imagine being prosopagnosic. Can you? I am currently working with a neuropsychological patient who is a prosopagnosic and also has damage to her PPA/PHC (important for places, space, etc). Every time I go to her house for an experimental session to show her stimuli or have her run through tests I've created on a computer, she will answer the door knowing that I am coming over, knowing that I'm supposed to be there, but when she answers it's as if she is unsure of who she's opening the door for. Once I say, "hello" she knows based on auditory input and semantic knowledge that it is "Dwight" who is a researcher at UNR and here to run some tests. However, she will say, "every time its like I'm meeting you for the first time because I can not recognize your face." I could tell you more stories, but I'll save those if I end up making it back to CF for a visit. Cheers.
I had heard of the Gestalt theory in past psychology classes, but I liked how it was explained in chapter 4. Gestalt theory basically states that the whole is greater than the sum of the individual parts. I interpret this as in order to understand the message, one must look at the whole picture. Gestalt comes into play in the early stages of visual perception. It is in close proximity to middle vision, which is one of the first stages of organizing simple angles and patterns into what the object will be classified as. To go more into detail, these angles are called illusory contours; the edge of an object. I think this fits nicely into Gestalt theory because when we perceive images, we do not focus solely on the contours of objects, but rather the object as a whole. If we were to focus on the illusory contours, then we would not see much of anything of value to us.
The Gestalt grouping rules is a new concept to me. These rules organize the lines and contours into the appropriate groups. Essentially, they group together objects that match. When objects appear to go together then it is assumed that they are along the same illusory contour, this is known as good continuation. Not everything can be grouped together, but those who support Gestalt have set rules clarifying which groups are said to be grouped with one another.
Going along with the Gestalt grouping rules, I enjoyed the specifics on how things are grouped. Aside from texture segmentation (separating alike textures), similarity and proximity are some of the main points for the Gestalt theorists. When two counters are found to have good clarification and they are similar, then they will typically be put into the same groups. This is similarity-when things are similar, they have a higher chance of being grouped together. Similarly, items that are close to one another are often grouped together; this is the process of proximity. I both am interested and am confused by this concept.
I do not understand exactly what the chapter is trying to say when it says the ‘like things are grouped together’. This seems like common sense to me. What happens when there are unique objects that aren’t similar to other objects, do those just go unseen? I also don’t understand what the difference between common fate and the grouping rules are. As I said I understand these concepts, but I feel that this needs clarifying.
This chapter is useful for clarifying concepts that I had heard before, but making them easier to understand.
Terms: Gestalt, Gestalt grouping rules, middle vision, illusory contours, texture segmentation, similarity, proximity.
Think about things like colored shapes. If they are the same color and/or shape, they will be naturally grouped together. Neurally, this means that the brain will not have to devote as many processing resources or metabolic energy to the processing of these stimuli, b/c the feature (color, shape, etc). becomes redundant and the brain can group them to avoid redundant inefficient processing of that information. The brain is constantly using energy and the processes of the brain are metabolically costly. So, Gestalt principles of grouping seem to be an efficient mechanism that our visual system at some point began to utilize to avoid redundant processing.
After reading chapter 4 I found the section on texture segmentation and grouping to be interesting. I found this section to be interesting because it is something our eyes and brains do automatically. I thought the examples in the chapter did a good job of illustrating similarity, proximity, parallelism, and symmetry. I found it interesting that we tend to automatically group objects and images together if they are similar to one another or grouped close to one another. I also found it interesting that we automatically pick images out that are parallel to one another or symmetrical to one another.
Another idea I found to be interesting was the entry level category. This was interesting to me because it was the easiest thing for the brain to do. A subordinate level would be to recognize something more precise and specific. An entry level category is something quick for our brains to recognize because the images or objects are stored in our memory. It takes our brains more time to recognize objects that are subordinate or superordinate because they are not stored as closely as entry level in our brain.
I also found the information about the inferotemprol (IT) cortex to be interesting. I found the IT cortex to be interesting because it is stimulated and fires when there are more complex images unlike the striate cortex. This was mainly interesting to me because the IT cortex if important in face recognition. The IT cortex may also have to do with the grandmother cell (what makes us identify our grandmother’s face when we see it). It is fascinating to me that the IT cortex helps us recognize faces that are familiar to us.
I found the information on templates and structural descriptions to be uninteresting. The main idea I found to be uninteresting was the geons. I didn’t exactly grasp why the geons were so important and I found this information to be confusing and hard to understand. I also found the structural description theories to be a bit hard to understand and grasp.
I believe it is most important to understand middle vision in sensation and perception. I believe this concept is important because it gives us the simple steps to how our eyes and brains perceive objects and images. We need to understand middle vision to understand everything else.
I would like to know more about prosopagnosia and the IT cortex. I find face recognition to be very interesting and both of these concepts deal with face recognition and that is why I would like to know more about them.
Terms: texture segmentation and grouping, similarity, proximity, parallelism, symmetry, entry level, subordinate level, superordinate level, inferotemprol (IT) cortex, striate cortex, face recognition, grandmother cell, templates, structural descriptions, middle vision, prosopagnosia
So, if you like the IT cortex, then you should know about an area called the fusiform face area in the fusiform gyrus of the IT cortex. Nancy Kanwisher's lab is the authority on this area (she's at MIT). Also, you can check out some work by Gauthier, Tarr, and Curran. They have some ERP research on the FFA. There's a bunch of stuff out there about modular processing for faces. There's also some work by Kim Curby about the configural processing of faces, which is pretty interesting. When I worked with Otto, we did a lot of psychophysics research and face recognition research with same and other race faces to measure our perception and memory for these categories of faces. Don't hesitate to ask Otto for more to read or see if any grad-students are doing any research with him that you could pair up with to learn more.
There were plenty of things in this chapter I found extremely interesting however If I had to pin point just three of them, my top would be facial recognition amongst monkeys. The example that was given of the inferotemporal cortex and certain faces was very fascinating. The second item I found to be interesting was when the book talked about camouflage. I know we learned about camouflage ever since we were younger however I find this to be very cool. How a creature can either change it’s appearance to fit a certain environment or a certain way the creature was created. The third item I found to be interesting was the subject of geons. I’ve been studying a certain perceptual ability test for my graduate examine and on their it contains a number of geons. A geon is a specified as collections of non accidental features that our visual system should be able to recognize it accurately and quickly.
Honestly there was not one thing in this chapter; I truly enjoyed learning about everything because I love anything perceptual with complexity! In fact another thing I found to be interesting was multiple recognition and how it is not just a single act but that we recognize an object in multiple ways. There were many things in this chapter I found to be very useful with sensation and perception. Occlusions and the way we interrupt why a certain image stop if it had an edge on it. I don’t think you can read Chapter 4 and not realize that Gestalt had a pretty big impact on sensation and perception. Gestalt’s grouping rule starts that an image will appear to group together. I think two important topics that I would like more information about middle vision and also the multidirectional pathways for object recognition
Terms: Inferotemporal cortex, camouflage, geon, multiple recognition, occlusions, Gestalt, Gestalts Grouping Rule, middle vision, multidirectional pathways, object recognition.
Camo is cool for sure. IT cortex and the selectivity of face sensitive neurons of the macaque IT cortex is amazing too. The monkey neurophysiology is a very difficult type of research to do. You have to train monkeys for months, drop an electrode into the right spot of the brain, and then show them tons of trials of stimuli. Show them a face, show them a cartoon of a face, show them just eyes, show them mouths, show them an inverted outline of a face, show them all kinds of different stuff, and see how patterns of rate coding for that individual neuron change (i.e., how often it fires). There is a lot of monkey physio research out there on various regions of the brain implicated in various cognitive and visual processes. It is interesting stuff. Unfortunately, it takes a long time and the procedures are quite invasive for our closely genetically related monkey friends.
After reading chapter 4, I found numerous interesting topics about perceiving and recognizing objects. Texture segmentation and grouping was something that I enjoyed reading. Texture segmentation is all about our mind piecing images into regions of common texture. Similarity and proximity are two terms that help us determine what texture segmentation is. Similarity is the tendency of two features to group together which will increase the similarity between the two. Proximity is the tendency of two features to group together as the distance between them decreases. When you group them together the objects will look more together and the same. Another part of texture segmentation is parallelism and symmetry. Parallelism is the idea that parallel lines likely belong to the same figure and symmetrical regions are likely to be seen as a figure. Common region and connectedness are also two terms that say that features will likely group together in our visual system if they seem to be part of the same region or connected. I found this interesting because our mind always seems to mesh like things together and it’s hard to tell the difference.
Another topic I found interesting was Structural description. Structural description is the representation of the object we see in parts and the relationship between those parts. The book had a cool example about how we see different types of the letter A. At first scientists used native template theory which we interpret an image by matching it with a stored neural representation of it in our brain. This theory wasn’t possible because we don’t have enough brain power to do that for everything single thing we see. The way we decipher images is through structural description. We look at the lines and shapes that make the letter or whatever we are looking at and figure out what the image is.
One last thing I found interesting was infer temporal cortex. This is part of the cerebral cortex in the lower portion of the temporal lobe. This has great importance for object recognition. What I found interesting was the finds from Charlie Gross. The cells in the infer temporal cortex of a monkey were excited when a monkey’s face was shown. Some of these cells would also be excited for objects that resembled a monkey’s face. What they found was that we have cells that active when we see certain shapes and objects that we are familiar with.
I didn’t like reading about the necker cube. I really didn’t understand what the book was trying to explain about we interpret each image. I understand that everything we see can be ambiguous but I don’t get why some people see one thing and other people will see something else.
I think the concept that will benefit me most out of this chapter will be middle vision. It really explains what we do when we have an early vision of something and how we transition that image into something of high vision.
Two topics I would like to learn more about would be middle vision: edges and object recognition: Multidirectional pathways.
Terms: necker cube, infer temporal cortex, cerebral cortex, object recognition, Structural descriptions, native template theory, texture segmentation, similarity, proximity, parallelism and symmetry.
I think the cool thing is that with some of these stimuli you can have two distinct perceptions of its form, HOWEVER, not simultaneously. This means our visual system can only resolve one perception of form and make us conscious of said form at a single moment. Glad you thought the other stuff was cool, though. I think the necker cube tells you that the world can be viewed in a variety of ways and that sometimes there are multiple ways of viewing, understanding, interpreting, and judging the external events that occur around us. Cheers.
I would like to start this post by saying chapter four was a much better chapter to me that chapter three was! The three things that I found to be most interesting in chapter four were Figure and ground assignment, Prosopagnosia, and Parts and wholes.
Although figure ground assignment is a very basic concept, I found it interesting to read about some of the principles involved in the process. The list of things in this assignment range from the surrounding of regions to relative motion of a figure. It is interesting to think that all of these things work together to help one come to a single conclusion on what something is. Prospagnosia interested me because it is sort of a scary thing to think about. I’m sure that it would be really stressful to not be able to recognize faces. Not only would it be stressful, but it would also be sad. This made me think about the guy that we saw in the video we watched in class. He could not even recognize himself that was hard to see. Parts and wholes was another thing that was of interest to me. The main reason I was interest by the section on parts and wholes was because the global superiority effect is so true. The whole object definitely takes precent over the individual parts. When I looked at the figure it took me forever to break down the letters and find a U. its funny how our brains work
The section of the chapter that talked about Perceptual committees was really uninteresting to me. I did not really grasp what the section was saying. The little figure with the demons only made it more confusing. I hope that this is something that we are able to discuss in a little more detail in class.
Middle vision is what I believe will be the most useful concept to take from this chapter. This is important because this is when features become objects. What I take away from what I read about middle vision is that this is where the main connections are made so that we are able to understand what we perceive. Without middle vision what we see would be of no meaning.
I would like to learn more about good continuation and accidental viewpoint. If I would have said that I was interested in more that 3 things I would have written about these two also. There is nothing in particular that makes these things really stand out to me I guess I would just like to research them.
Key terms: middle vision, prosopagnosia, figure ground assignment, good continuation, accidental viewpoint, global superiority effect
If you like figure/ground stuff, read this article. Its a very cool piece about how attention can affect the responses our neurons have to figure and ground perception. http://www.journalofvision.org/content/9/11/18.full.pdf+html Cheers.
To begin, I really liked this chapter because I was able to relate a lot of it back when I used to take a lot of art classes in high school. Just this past Christmas my Grandparents took my family to a museum which was showing an artist that used the Gestalt rule of proximity(they never worded it that way). The pictures were every big and as you got closer you could start to identify the tiny pictures that went into making the big picture. They were really cool to look at from different distances. In art, it is possible that something you think is really good can end up as an ambiguous figure when other people give their critiques. Then again…giving bat creatures a re-boot so they don’t look like ‘rabid bunnies’ isn’t always a bad thing. The third thing I found interesting would be all the parts of the brain that go into sight; extrastriate cortex (visual processing), interotemporal (IT) cortex (object recognition), and the primary visual cortex. The brain is only so big and to think that it has all of these parts that go into the one function of sight is a little remarkable.
Just going back to how cells in the brain react when they recognize a picture or element of a picture. Just reminded me of the previous chapters. I know it’s important to perception but that still doesn’t make me a fan of biology.
What I think will be most useful is how the brain interprets images based on the Gestalt grouping rules. We do this all the time without even thinking about it and yet it has a big impact on how we see our world. These rules could be used to alter our perception and play with our mind. It would be like living in ‘Through the Looking Glass’. (A great book by the way.)
I think the book did a good job of breaking things down and explaining the material. But other conditions like prosopagnosia would be interesting to learn about. It’s sad that at this damage happens and people have to go through life not being able to recognize something as continues as their spouse’s face. But it does allow science a view into the brain’s functioning that it wouldn’t get otherwise. The other topic I would like more information about would be double dissociation. I think just being able to put it into another context would help me out a bit.
Terms: Gestalt grouping rules, proximity, ambiguous figure, extrastriate cortex, interotemporal (IT) cortex, primary visual cortex, prosopagnosia, and double dissociation.
If you like the grouping principles and "Through the looking glass." Try to see if the UNI library has the Vision Science book by Steven Palmer. Also, the "IS the visual world a grand illusion" (edited by Alva Noe at UC Berkeley I think). It (Palmer) is a massive book, but as we call it around UNR, it IS THE vision sciences and visual perception bible. Its got all of the stuff you guys have been talking about with respect to vision etc. plus more stuff. Also, with regards to visual cortex, they have these new techniques available with fMRI where they can map our your retinotopically organized visual cortex by showing you a rotating checkerboard, rotating/oscillating at a constant frequency and basically overlay a color-map of the various areas of visual cortex (V1, V2, etc.) by spreading out and flatting the MR images of the structure of your brain onto a 2-dimensional plane. So you could sit in the fMRI scanner and look at these stimuli for an hour or so and ultimately they would know where your specific V1, and other extrastriate areas of visual cortex were located within the MR image corresponding to the tissue of your brain. Cool, huh?
I really enjoyed the discussion of figure-ground assignment. A lot of these situations seem so intuitive that we do not bother to think about the reasons our brain would process features in a certain manner. As with most of this chapter, several processes/criteria work together (such as surroundedness, size, symmetry, etc.) to almost always come to a single perceptual conclusion. Some notable exceptions are optical tricks such as the Rubin vase or the Necker cube, which just go to show what happens when multiple interpretations fit these criteria equally.
This relates directly to the book's discussion of Gestalt theory. The principles behind this school of thought help to explain the natural inferences our visual system makes that go beyond that which is seen. These concepts help to give a concreteness to our ability to find an illusory contour where no physical edge would otherwise be seen to exist. I also believe these principles contribute a great deal to our capacity to recognize objects regardless of spatial orientation.
Another part of the chapter I liked that may speak to the Gestalt school was the section on facial recognition pertaining to Figure 4.34. When inverted, I could not notice the alteration to the face on the left. I think this speaks volumes about the hierarchical organization of our various perceptual committees. Because of its unusual orientation, the conclusion was that I was seeing a face with all its parts intact. While this was true, jumping immediately to a macroscopic view caused me to miss a minor detail that dramatically altered the perception of the face when turned right side up. The book attributes this to our facial recognition systems caring little about inversion - a function of inverted faces rarely appearing throughout our lifetimes. I'm not quite sure what I'm getting at, but I think it is important to remember that our visual systems can easily be fooled because they come to such quick conclusions based on visual evidence. These sorts of minor tricks can really help you to relate to people with visual disorders such as prosopagnosia.
The one section I did not enjoy was the part about naïve template theory. This is not to say that it should not have been included, it is just difficult to reconcile this sort of viewpoint with the infinite number of potential templates found in our world. This week I couldn't pick out a specific concept that I thought would be most useful because I found most of this chapter to be essential and interesting. I would like to learn more about the what and where pathways and anything that relates to object recognition.
Terms: figure-ground assignment, surroundedness, size, symmetry, Rubin vase, Necker cube, Gestalt theory, illusory contour, facial recognition, perceptual, committee, prosopagnosia, naïve template theory, what and where pathway, object recognition
The brain is constantly using energy and the processes of the brain are metabolically costly. So, Gestalt principles of grouping seem to be an efficient mechanism that our visual system at some point began to utilize to avoid redundant processing. Good points in your post. Configural processing is interesting with respect to faces. Have you guys gone over the inversion effect and the Thatcher Illusion? I can send Otto a VB program I have to Thatcherize faces that you could use to see what your face looks like Thatcherized. We did some work when I was in his lab on some thatcherized same and other-race faces.
I thought that this chapter was very interesting because I think visual illusion stuff is very interesting. Ambiguous figures are very interesting to look at because they can be viewed in so many different ways. Another classic example of an ambiguous figure besides the necker cube is the one with all the stairs or the old lady or young lady pictures. These are classic works of art and are very interesting to look at. They can be interpreted differently depending on which parts of the photo you focus on. It may not be easy to see one parts of the image right away because you may distiguish different features of the image than other people. When I think of accidental viewpoint, I think of looking at a watch. Depending on which angle I look at my watch from, can alter the time it looks like it is. Another thing that I thought about while reading this chapter was army camouflage. Older army camouflage had rounded edges of greens and browns. Today's army camouflage has a more pixelated look to it when close up, but this has been proven to be a more effective form than the older version. I thought that all these topics were useful in understanding sensation and perception.
I didn't find the object recognition section very useful. We had previously talked about this in class that certain cells are specifically triggered by only certain objects. Personally, I think that there is more that needs to be discovered about why this happens and that this happens for certain reasons.
Terms: ambiguous figure, necker cube, accidental viewpoint, camouflage,
I think the idea behind the new camo is informed by what we know about the visual system. We can't really resolve the exact pixelated texture from distances far away, which is good for camo, b/c you have the basic variation of colors, etc. based on the environment that the soldiers are in (e.g., if its high desert, there will be mostly ground/sand colors with a little bit of sage green/gray, etc.). So, the pixelation is probably efficient and representative of the natural distribution of color variation in the particular environments they work in. Also, in an environment like that, any brush will be somewhat browish or greenish, but it will be vertical or branchlike so that probably explains the fine edges/pixelation as well. You should do some research and tell us what you find.
There were a few things I found interesting in this chapter. Middle vision, according to the text, is a loosely defined stage of visual processing that comes after basic features have been extracted from the image and before object recognition and scene understanding. I just thought it was kind of neat how it works where we organize elements to be able to group the object to be able to recognize it. Another thing I thought was interesting was agnosia, which is a failure to recognize objects in spite of the ability to see them. The reason I thought this was interesting is because I have never heard of the term before, and it just made me wanting to understand the difference between that and Alzheimer’s disease. Lastly I thought the naïve template theory was interesting as well. Naïve template theory is the proposal that the visual system recognizes objects by matching the neural representation of the image with a stared representation of the same shape in the brain. I just thought it was an interesting concept, and am easily amazed with some of the amazing things your brain can do, and how things are stored in your memory for you to pull up, as you need.
Unlike the previous chapters, I had a hard time naming something I found least interesting. I thought it was an interesting chapter that had a lot of good and valuable information. The thing from this chapter I found to be the most useful in the understanding of sensation and perception was the part I talked about earlier, middle vision. I think this is the most important stage of vision to understand how we do develop our vision of objects and how we recognize the objects as well.
Two topic I would like to know more about are agnosia, and the Necker cube.
Terms used- Middle vision, agnosia, and naïve template theory.
So with the agnosia, its not so much a memory deficit as it is a perception deficit. You can't use the perceptual info to recognize the object. With Alzheimers, the perception is intact (to a certain extent) and you could name some objects (e.g., phone, etc.), but you wouldn't remember that you used the phone moments ago. Agnosia is usually brought on by traumatic brain injury or stroke or something, but Alzheimers is based on a weakening of the neural tissue due to the formation of amyloid plauques that form and cause tissue to die off. So, we typically think of them as distinct based on the difference between a lack of knowledge about some perceptual stimulus (agnosia) and a lack of an ability to remember interactions or necessary future or past events with stimuli (including people, eating, medication, etc.) in the case of Alzheimers.
One of the more interesting pieces of information from chapter four was the concept of middle vision. There are varying amounts of level for vision, one of which was talked about earlier in the text as low-level vision. There is also a high-level vision as well. The term this chapter starts with consists of the between portion of these levels, the middle vision. Middle vision helps us to process and describe features because of a combination of previous exposure to the stimuli of a feature and before object recognition. This is why we are able to readily identify the various objects in our environment with knowledge of what they are. The starting block to identifying objects deals a great amount with how we find edges. The complicated part is identifying which edges belong to which objects. For example, you may view a tree in front of a car, but are able to distinguish the connecting lines and define them as two completely separate objects. Illusory contours are an example of further complications when trying to identify edges. Though nothing is changing from side to side in a visual aid, there appears to be a change, which ultimately becomes a false perception. Earlier psychologists even struggled to make sense of these contours. Structuralists are considered the perceptual psychologists. They included many notable individuals including Wilhelm Wundt and Edward Titchener. To further continue interest on the subject of contours I also really liked reading about the Gestalt school. Gestalt is a German word, which means form. The basic idea of Gestalt is that the whole is greater than the sum of its parts. Members of the school created rules to describe which elements appear to group together in an image. We have the tendency to places lines of similar orientation into the same contour. I find it interesting how we perceive certain things like edges so much with little thought when the reality of the situation is a complex idea that starts with neurons in the striate cortex. The figure and ground section also provided a lot of nice information that branch from the Gestalt school. The figure-ground theory includes depicting the figure itself and the area of the background as two distinct visuals. The reason I find this interesting was because of the vace/face image created by the Danish psychologist Edgar Rubin. I feel like the concept of middle vision will most likely continue to help me with my understanding of sensation and perception. Along with many other previously mentioned components to middle vision, there are also five principles to help summarize. These principles are: bring together that which should be brought together, split asunder that which should be split asunder, use what you know, avoid accidents, and seek consensus and avoid ambiguity. Middle vision is an important concept from the chapter that I was able to find interest in and helps relate to how I see things through sensation and perception. I also enjoyed the section about faces and because of that I would like to find more information related to the disorder of prosopagnosia. Prosopagnosia is the inability to identify faces. Along with that I would also like to learn more about double dissociation and how one of our functions, such as hearing, can be effected without harming our sight and vice versa.
Terms: Middle vision, illusory contours, structuralists, Gestalt, Gestalt grouping rules, striate cortex, figure ground assignment, prosopagnosia, double dissociation.
There are a lot of cool illusion type sites out there. Check them out sometime. They will give you an idea of how your perception is not always veridical.
This chapter was very interesting to me and I was excited to see that we were getting into the optical illusion parts and about how our eyes just make things up. It's amazing how our eyes just automatically group things together instead of seeing each thing individually. It's knid of lkie if you mix ltetres up in a wrod your eeys can sitll raed tihs ptrlfecey bcasuee the fsirt and lsat ltteer of the wrdos are the smae wichh is an eamxlpe of how our eyes gorup tnhgis tgoehter. That is also known as gestalt grouping rule. This specific example I believe is common region. This has always interested in me and it's interesting to learn about how our eyes just fill in the blanks or group things together without us even knowing, or meaning to. Accidental viewpoint is when a viewing position that produces some regularity in the visual image that is not present in the world. It's interesting that when we stick our hands out to the side of our head, it is fuzzy and not clear, but yet we are able to know that it is our hands. However, we don't see it clearly until it is out of our blindspot. Prosopagnosia is the inability to recognize faces, like the guy that was in the video that we had to watch in class when Dr. MacLin was skipping class. This would majorly
suck if you were unable to recognize faces, even your own face. Watching the video made me realize how greatful I am for being able to see objects and faces and colors and everything else that I can possibly see because I would miss out on a lot of things. Everything in this whole chapter were really interesting and kept my attention. There wasn' anything that I did not like and everything applied to sensation and perception.
Terms: Gestalt groupoing rules, common region, accidental viewpoint, blindspot, prosopagnosia
Haha. I'm sure Dr. M had a good reason for not being there. Prosopagnosia is definitely dehabilitating. Check out an earlier post I made on someone else's comment about this visual deficit.
I really enjoyed the part of the chapter that discussed how we interpret edges in every day life. I found it interesting that that our brains make up edges (illusory contours) sometimes to make sense of images. I thought it was interesting how the book went into the history of what they used to think these lines were made up of. The structuralists Wilhelm Wundt and Edward Bradford Titchner thought that there were atoms that ended up looking like little bits of color and that is why these illusory contours were perceived. This was later found to be false. A Gestalt school was formed that stressed that the perceptual whole could be greater than the apparent sum of the parts. People that were in this school were Max Wertheimer, Wolfgang Kohler, and Kurt Koffka. The people at the Gestalt School contributed a lot to what we know about perception. They came up with some concrete rules.
I thought the texture segmentation and grouping part of the chapter was very interesting. This was one of the rules that the people in the Gestalt school came up with. They came to find out that our visual system has rules about texture. The portion of the image with the coarser texture is separated from the rest of the image that part of the image is perceived differently. Our brain divides things out by similarity and proximity. Similarity means that the things that are closest to each other will be kind of grouped together in our brains. Proximity means that the closer together the items are the more likely they will be grouped together in our brains.
I also found Steve Palmer’s theories to be very interesting. These theories also had a lot to do with grouping things together in your mind. Palmer found that if features are found to be in the same region together they would be grouped together. This is called the Common Region. He also found that if two items were connected they would be grouped together in one’s mind. This is called connectedness.
I had trouble finding something I found uninteresting in this chapter so I am just going to talk about a 4th thing thing I found interesting. I thought the Template theory was interesting because we talked about it in my cognitive psychology class. It basically says that you have a certain template for each thing in your mind and the more something you see fits into that template the more likely you are to recognize it. Your brain has a structural definition of an A in your brain and when it can be matched with what you perceive you can recognize it as the letter A.
I think the most important thing to remember in this chapter when trying to understand sensation and perception would be the different theories about edges, and why we see things the way we do. How we group them together is also important in understanding perception.
I would like to hear more about template models and structural models in class.
Terms: Illusory contours, structuralists, Wilhelm Wundt, Edward Bradford Titchner, Gestalt School, Max Wertheimer, Wolfgang Kohler, Kurt Koffka, texture segmentation, similarity, proximity, Steve Palmer, common region, connectedness, Template theory, Structural definition, template models, structural models
Try to see if the UNI library has the Vision Science book by Steven Palmer. It (Palmer) is a massive book, but as we call it around UNR, it IS THE vision sciences and visual perception bible. Its got all of the stuff you guys have been talking about with respect to vision etc. plus more stuff. It's a great book to help understand vision science.
Gestalt Psychology has been a favorite of mine since taking Maclin's history and systems of psychology class. So, I was really excited to read more about them and the Gestalt school in this chapter. I thought the examples that Maclin gave in class and in his lecture on Tuesday of the illusory contour's was very interesting, and I was interested in the Gestalt grouping rules that goes along with it. One rule being the good continuation rule was interesting to know that humans have similar beliefs on what we think we see and what we don't think we see.
I also found it interesting when chapter four brought up similarity and proximity. I was interested in this because it is relatively easy to test on yourself. Along with the examples in the books, Dr. Maclin used a picture of two women. One woman was sitting close to the camera, while the other one was farther back. Based on the proximity of this picture, the women in the background looked obviously smaller than the one closer up. When Maclin photo shopped her to be at the same proximity as the women close to the camera, she looked sooo small! This was very interesting to me in relation to proximity.
One more thing I found interesting in chapter four was the global superiority effect. I found this very interesting because it kind of summarizes how middle vision works. At first glance, it is easy for us to see the H C L in figure 4.32. But when asked to glance and find the little letters that make up those big letters, it takes our middle vision longer to find what we're looking at. Very well put, and illustrated to help understand middle vision!
One part I did not enjoy as much about chapter four was the Bayesian approach. It seemed interesting, but I just couldn't wrap my head around the idea. It was confusing and hard to understand.
The most useful thing in this chapter in understanding sensation and perception would have to be simply everything having to do with middle vision. Learning about middle vision in general is a great thing to know when learning about our perceptions of the world.
One topic I would like to learn more about would be Gestalt and more of their input on middle vision and what they did as a group to enhance the information we know now.
One more topic I would like to further research is different/specific cases where human beings were in a coma or something sort of medical problem, where they took advantage of the situation and did experiments on them to learn more about perception and middle vision.
Terms: Bayesian approach, similarity, proximity, texture segmentation, illusory contour, structuralism, gestalt, gestalt grouping rules, good continuation.
Bayesian stuff is math heavy and a lot of people don't understand it. It's mostly probability, but humans are pretty bad at probabilities anyway (e.g, the gambler's fallacy). Glad you liked the Gestalt stuff!
Chapter 4- Visual Cortex & Beyond
1. Brain damage and perception is very interesting in this chapter because I work with brain injury clients, and now I can understand more on their perceptions. The experiment was done with monkey brains, and one task was to remove food from a cylinder with a normal brain and the other task was to do the object discrimination again with a part of their brain removed. The monkeys did better when the brain was intact, and the monkeys had more difficulty with the object tasks with brain damage. This shows that brain damage effects perception. Landmark discrimination problem is the vocab word used to pick the food closer to the cylinder, and object discrimination was used to show a object and pick from two different ones.
2. The second topic I found interesting was the different qualities of perception in the separate brain areas. Once again the brain activity is interesting because of my job, and I was excited to learn more about perception and the parts of the brain used to determine objects. The rod and frame illusion is an experiment used on those asked to match stimulus to a task. This creates a perceptual visual illusion supports the idea that perception and action are served by different mechanisms.
3. The third topic I found interesting was the organization by left and right eye. The left and right hemispheres in the brain are bilateral structures that work together to perceive images. Only one eye is used to receive signals from the ipsilateral eye that is one the same side was the lateral geniculate nucleus and the contralateral eye is on the opposite side of the body from the LGN. Theres signals are sorted into layers to see one object, even when they are working separately, which I find to be very interesting.
One thing I found least interesting is about the double dissociation process. The experiment showed a person with temporal damage and a person with parietal damage. The two had opposite answers showing that there are two different functions from these brain areas. Person 1 could not name the object but knew the location. Person 2 knew the name of the object but not the location. I found this to be confusing but I would like to learn more about the different parts of the brain before I make further judgements.
I found the most useful information in this chapter was learning about brain damage effecting perception and the monkey study. It is interesting that they used monkeys brains to see brain damage, but is it ethical?
Two topics I want to learn more about is areas of the brain for faces,, places, and bodies. The second topic I want to know is perceiving attractiveness.
Chapter 4 is titled: Perceiving and Recognizing Objects. I had glanced through the book before starting this class and this was the chapter I was most excited about!
Illusory contours are super interesting to me. Basically your mind makes up lines and objects that aren't actually there but we perceive they exist anyway. The book also shows several examples of these contours in which I also fell into the perception that there are lines where there really aren't. One of them is an example of a "house" within black circles and lines, but the house isn't truly there. The alignment of the other objects is. I started thinking about this in my real life. The first thing I thought of was when young children see things in the clouds. Those shapes aren't actually there, nor are their lines for them, but we perceive that this object exists in the sky. This is a subject I would like to look more into and maybe even see more examples! I am going to make sure to do illusory contours for my topical blog!
Gestalt Psychology has always been a concept that I never really understood. I have heard about it in every single class and how it pertains to history, child development, etc. But never have I understood Gestalt Psychology as much as I did when it was pertained to perception. Gestalt started as a school and they believed that perception is even more powerful in your mind than what is real. Thinking about this, I know how true that concept really is. I thought about how I react to scary movies. Every little noise gets to me and I see things that aren't really there. My perception takes over my regular senses and causes me not to sleep very well at night. Within Gestalt Psychology in the book, I learned about the Gestalt grouping rules. This basically states that your mind will group together common objects in order for the image to make sense in your brain, even if it is just a perception of what truly is there. One of these grouping rules is good continuation which means that certain shapes will look like they come together just because they are on the same contour. This actually made sense to me! I really enjoyed the example given for good continuation because lines that cross are easy to determine which line is which by following it's course. I would like to look into this subject more as well and learn some more of the Gestalt rules and see if they make as much sense as good continuation.
I enjoyed the grouping set of the chapter because it explained why certain objects tend to group together in our perception. Some of my favorites were texture segmentation, proximity and symmetry. Texture segmentation is when objects of the same texture (or size) group together. Proximity made the most sense to me because object that are closer tend to group together more than those farther away. That makes sense because I wouldn't group something miles away with an image right next to me. Symmetry is very self-explanatory but it also makes a lot of sense because it is grouping objects that look exactly the same. Duh.
I really didn't find any parts of this chapter un-interesting so I decided to write about one more interesting thing I found in this chapter. I love figure-ground assignments! I never knew that was what they were called but they are so fun to figure out the different images perceived in one picture. The book uses the example of the vase and two faces. I always tend to see the vase first but then once I stare at it for long enough, I start to see the faces. It is so odd to me that my mind can just shift like that but it is awesome to know your mind changes thinking in that exact moment.
I feel like knowing each one of the examples of perception would be helpful for the rest of the book. Symmetry seems to pop up a lot in this chapter so that must mean its important!
Illusory contours, Gestalt, Gestalt grouping rules, good continuation, texture segmentation, proximity, symmetry, figure-ground assignment