Actual Responses from Beav's PSYC 463 Exams, Exam 3
Holy crap, I was in rare form on this one. It was getting late in the semester, and to be exact I believe it was the Thursday before "Dead Week". Those of you who attend UNL know that the aforementioned weeks is when there is at least one exam and/or project due for every class you have, and it's generally something you should have been gradually working on all semester but haven't been. This is the time of the semester when college kids stop sleeping and start going insane. I got hopped up on caffeine and went off to take my test. This is what followed:
Q: Describe how we use the information from two eyes to provide depth information. (You should include a description of the horopter and the importance of feature detectors).
Me:
Well, that multiple choice section went a lot better than I expected. If you'd like to know my state of mind right now, I think I drank too much Mountain Dew, and my brain right now is like an electrical circuit that is drawing too much wattage. It'll go for a while, but then I keep having to trudge down to the basement and reset the switch to get my attention back. Also, you can thank the papal declaration for me making it to class today. I was up until 5:30 and crashed without setting an alarm. The continuous ringing of church bells and the howling of neighborhood dogs that followed woke me up. Also, isn't the plural of "retina" "retinae" and not "retinas"? I don't mean to nitpick...but that struck me.
Here we come to a question where you've selected a concept that I don't really grasp. How you discover a concept like the horopter frankly is beyond me. I think the term sounds more like a derogatory term for loose women than a perceptual concept. I think I might adopt it. Next time some scandalous female tries to lure me away from my woman I'll scream, "Leave me be, you horopter! I'm a taken man!!!" Failing that, if I ever start a service that offers helicopter rides to prositutes, I'll call it 'horopter'. Where was I? Oh yeah, taking a test.
Soooooo the way that we use binocular cues to determine depth is by doing a lot things, really. Firstly, some prior knowledge of the size of the object helps a lot in the top-down processes. From there, we can use the visual angle to get an idea (albeit a subconscious one) of how far that thing is away from us. The visual angle and the amount of "space" taken up on the retina let us know about how big something is, and where it might be. Big angle, either big thing, close thing, or both. Small angle, small thing, far thing, or both. Along with that, we can use the retinal disparity of the two images from our two eyes to get an idea of the position of this thing. If the images fall at precisely corresponding points on our retinae (sorry, I'm a grammer nazi), then it is said to fall on the "horopter", which is an imaginary arc somewhere out in front of my face consisting of points that are all equidistant from my aforementioned face. Evidently from the way I worded that sentence, the horopter exists in front of my face and no one else's. If the two images fall on different points, then the degress of retinal disparity tells us where that thing is. We also can use accommodation and convergence, the oculomotor cues, to get a sense for how close something is. We call it kinesthesis. It's science.
Her: Lots of good here but a few missed details...I thought everyone would take the first option on this one. Hope the Mt. Dew buzz has worn off....or maybe you're on the next wave
Q: What is Corollary Discharge Theory designed to explain? Briefly describe the components of Corollary Discharge Theory (i.e., MS, CDS, IMS, comparator). Give at least two examples of how Corollary Discharge signals and/or Image Movement signals would work to provide information about the presence or absence of motion.
Me:
Corrollary Discharge Theory, which at first might sound like a life-threatening heart condition, is actually a model to explain the process by which we distinguish between motion created by things that are actually moving (real motion) and the perception of motion that might be created by moving our visual field across stationary objects (illusory motion).
Basically, when I move my eyeballs, the model states that because my visual input is changing, there is a signal sent to my brain that some motion is taking place and the things in my visual field are changing. Since I moved my eyeballs, there is also a signal sent to my brain that says essentially "Hey, I moved the eyeballs." In the event of eyeball movement, a copy of the motor impulse, or "corrollary" is sent out...or something to that effect. I'll be durned if I can accurately recall the exact model. The upshot of the whole thing is that when both the motion signal and the corrollary arrive at the brain at the same time, the brain says, "Nope, no real movement, that was just the eyeballs moving." When only the motion signal reaches the brain, then movement across the visual field is perceived...I think. What I took away from all that was "Two signals at the same time, no real movement. One signal, real movement."
Q: What is perceptual integration? What is perceptual dominance? Describe the relationship between equivalence, integration and dominance.
Me:
Side note: Both these proctor girls are pretty cute. I don't need these distractions. I hate this testing center and the ADD nightmare it creates for me. One of the proctors has a t-shirt that says "I Like Dirty Boys With No Money". If that's true, I bet she'd LOVE me. I'm broke.
Whooo, you picked a doozy here, didn't you? Oooooookay, perception integration. What you have when you have perceptual integration is the use of multiple senses combined in some proportion to create an overall perceptual experience. For example, when I walk into the kitchen of our house, I combine the visual input of its general filthy state, the smell of wet dog (even though we don't have a dog...ewwwwww), the temperature of the air, the sound of the creaking floorboards...and perhaps the taste of a glass of orange juice that I get from the fridge to form my experiece of our kitchen. Then I think "Wow, I should really clean. Nah, I'm always the one who cleans, and I'm moving out in May. Let it be Dave's problem." But I digress.
Perceptual dominence, then, is the tendency for one sense to play a greater role in a given perceptual experience than others. Usually it's vision, but not always. Let's say I'm eating a steak. While the appearance of the steak is important to me, as is the temperature and texture of it, the most important aspect is going to be my sense of smell. Why? Because as we know, you can't taste much without smell, and the taste of that steak is what I care the most about. This may not be universally true, but it is for me and my steak, you can count on that.
You have a real penchant for asking questions that could be multi-page essays, and "Describe the relationship between equivalence, integration and dominance." is no exception. I'll explain equivalence by giving the example of me going skiing. This is an activity that, at least in my opinion, requires me to balance two critical senses: Touch and Vision. I must be able to see where I'm going, and I also must have a good sense for being able to feel the terrain, the consistency of the snow, the slope of the mountain, etc. so that I can respond correctly and not fall. I will go ahead and say I could not ski without either of these senses and I think they're pretty equivalent in the overall perception of me skiing.
The relationship, I guess, is that in virtually any situation, integration and dominance are happening, and in many equivalence is also happening. It is the overall proportionality that creates the precise pereptual experience in the moment. They are crucial to the overall perceptual experience because in case you didn't know, it is not a passive fidelity system.
Her: yeah...I knew that...here's the deal....dominance occurs when there's a failure of integration...the info coming in from the two senses can't be combined to form a unitary representation, so one modality dominates the representation that is formed by the senses...usually vision
Q: What is figure-ground segregation and how does it relate to the perception of objects? Describe some of the characteristics distinguishing figure from ground. What do we know about when figure-ground segregation occurs in the perceptual process, and what does that suggest about the nature of perception?
Me:
Well well well, looks like I jumped the gun on the ol' "what does that suggest about the nature of perception?" question. I was afraid we weren't gonna see it.
Figure-ground segregation is the process by which we pick out objects (figures) in the environment and separate them from everything else (backGROUND). It relates to the perception of objects because if you have vision, you're pretty much always doing it. Perceiving something visual? Figure-groud segration. Go ahead, try to think of a good, practical, real-world scenario where you're not figure-ground segregating while looking at something...I dare you. If you can't, I get an A+ for the semester and don't have to do the final. Deal?
The figure generally tends to overlap the ground. Take for example catching a football. If I'm watching for the ball, then I segregate the ol' pigskin (figure) from the sky (ground) because I can clearly see that the ball is overlapping the sky behind it. I also perceive the edges separating ball from sky as belonging to the ball, and not to the sky. Often the figure will have characteristics that differ from the background, such as the example of a K-State fan at a Husker game. The purple stands out against the background of red.
I don't really know what you're hinting at with the "what do we know about when figure-ground segregation occurs in the perceptual process", but I'd just be willing to bet that it means that we use top-down processes and that it all means that peception is (gets out tape recorder, hits play) "AN ACTIVE, ORGANIZATIONAL PROCESS."
Her: I can't think of one, but your A+ depends on what you CAN do, not what I can't do....(but good try)...perceptual process--go back to the loop...does it always happen 'in order'?
Q: (Shows a big picture of some cars on a highway near some mountains)
(a) List and briefly describe the information provided by at least 5 pictorial cues available in the picture.
Me: Ugh. Ok, we've got overlap. I know that the car is in front of that pine tree because it overlaps the tree.
We've got...ehm...linear...I want to say convergence but I know that isn't right...because the lines of the road get closer together as the road gets farther away.
We've got relative size. The tree in the background must be farther away than the tree in the foreground because it seems smaller.
We've got some texture gradient. The shubs, etc. seem closer together as they get farther away.
We've got storms moving in over the pass. Expect delays. If you can, avoid travel through this area, as blizzard conditions are possible.
We'd have that phenomenon with the horizon...if I could figure out where the horizon is in this picture. My Art History Major ex-girlfriend would be disgusted with me right now. That's okay, she often was. I'm not bitter. Moving on....
Q:
b) List and briefly describe at least 3 depth cues that would be available to you if you were actually sitting in the moving car from which the photo was taken (as opposed to merely looking at the photo, as you just did).
Me: What? There's no file in my brain for this...
How about...motion parallax. The stuff near to me would appear to whoosh by in the opposite direction while the far-away stuff would seem to be slow and in the same direction. Because I'm familiar with that concept, I'd use it in a top-down manner to determine depth.
I'd have some convergence because not everything would be on a screen 2 feet in front of me.
I'd have some accommodation for the same reason.
I'd have some music playing, and I'd be singing, because that's what I do on road trips.
Her: a) thinking of atmospheric perspective & ht in the field of view b) NICE SAVE!
Q:
The following questions all relate to auditory localization:
(a) What is the cone of confusion, and which cue to auditory localization is it most closely related to? How can people overcome the cone of confusion?
Me: (This is my favorite of all the answers I gave all semester)
I don't know. I was gone that day and you didn't put that info into the powerpoints. It just says in red "Insert cone of confusion".
At this point, the cone of confusion is the metaphoric area in my brain where the understanding of this concept would go, but instead I don't know what it is.
Q:
(b) Considering both interaural time difference and interaural intensity difference, what combination(s) of frequency and location of sounds will be most difficult to localize?
Me:
Low frequencies that were off in the periphery I'd think. Really low frequencies from anywhere, but probably moreso in the periphery because while there is a difference in time, there won't be much in intensity. If it's right in front or behind, there won't be interaural time difference, you know it's right in front or behind. High soudns cast that intensity shadow because their frequency is so great...so they're easier to localize. That must be why whenever the thugs come a thuggin' down my street, I can hear the bass blasting out their Cadillac for a long time, but can't really tell where it comes from until they're pretty close. Darn thugs and their thuggin'.
Q:
(c) Again considering both time and intensity difference, what combination(s) of frequency and location of sounds will be easiest to localize?
Me: High pitches, straight on. Intensity shadow. I said most of this in the last question. That's probably why sonar uses a high pitches frequency, eh? Maybe that's also why a bat was attracted by the beeping of our basement smoke detector as it ran out of battery last year and got down there and became stuck on a glue trap and ultimately died and caused the basement to smell weird. Maybe not...
Her: c) so is it wet dog or dead bat...oh yeah the wet dog's in the kitchen. you've got the big pieces....cone of confusion is a cone-shaped area extending and expanding from the ear ....all sounds falling on the cone have equivalent interaural time difference; easiest to localize are NOT directly in front or behind because those are confusible and NOT on the cone of confusion...you've got all the frequency stuff right
Q: Describe how we use the information from two eyes to provide depth information. (You should include a description of the horopter and the importance of feature detectors).
Me:
Well, that multiple choice section went a lot better than I expected. If you'd like to know my state of mind right now, I think I drank too much Mountain Dew, and my brain right now is like an electrical circuit that is drawing too much wattage. It'll go for a while, but then I keep having to trudge down to the basement and reset the switch to get my attention back. Also, you can thank the papal declaration for me making it to class today. I was up until 5:30 and crashed without setting an alarm. The continuous ringing of church bells and the howling of neighborhood dogs that followed woke me up. Also, isn't the plural of "retina" "retinae" and not "retinas"? I don't mean to nitpick...but that struck me.
Here we come to a question where you've selected a concept that I don't really grasp. How you discover a concept like the horopter frankly is beyond me. I think the term sounds more like a derogatory term for loose women than a perceptual concept. I think I might adopt it. Next time some scandalous female tries to lure me away from my woman I'll scream, "Leave me be, you horopter! I'm a taken man!!!" Failing that, if I ever start a service that offers helicopter rides to prositutes, I'll call it 'horopter'. Where was I? Oh yeah, taking a test.
Soooooo the way that we use binocular cues to determine depth is by doing a lot things, really. Firstly, some prior knowledge of the size of the object helps a lot in the top-down processes. From there, we can use the visual angle to get an idea (albeit a subconscious one) of how far that thing is away from us. The visual angle and the amount of "space" taken up on the retina let us know about how big something is, and where it might be. Big angle, either big thing, close thing, or both. Small angle, small thing, far thing, or both. Along with that, we can use the retinal disparity of the two images from our two eyes to get an idea of the position of this thing. If the images fall at precisely corresponding points on our retinae (sorry, I'm a grammer nazi), then it is said to fall on the "horopter", which is an imaginary arc somewhere out in front of my face consisting of points that are all equidistant from my aforementioned face. Evidently from the way I worded that sentence, the horopter exists in front of my face and no one else's. If the two images fall on different points, then the degress of retinal disparity tells us where that thing is. We also can use accommodation and convergence, the oculomotor cues, to get a sense for how close something is. We call it kinesthesis. It's science.
Her: Lots of good here but a few missed details...I thought everyone would take the first option on this one. Hope the Mt. Dew buzz has worn off....or maybe you're on the next wave
Q: What is Corollary Discharge Theory designed to explain? Briefly describe the components of Corollary Discharge Theory (i.e., MS, CDS, IMS, comparator). Give at least two examples of how Corollary Discharge signals and/or Image Movement signals would work to provide information about the presence or absence of motion.
Me:
Corrollary Discharge Theory, which at first might sound like a life-threatening heart condition, is actually a model to explain the process by which we distinguish between motion created by things that are actually moving (real motion) and the perception of motion that might be created by moving our visual field across stationary objects (illusory motion).
Basically, when I move my eyeballs, the model states that because my visual input is changing, there is a signal sent to my brain that some motion is taking place and the things in my visual field are changing. Since I moved my eyeballs, there is also a signal sent to my brain that says essentially "Hey, I moved the eyeballs." In the event of eyeball movement, a copy of the motor impulse, or "corrollary" is sent out...or something to that effect. I'll be durned if I can accurately recall the exact model. The upshot of the whole thing is that when both the motion signal and the corrollary arrive at the brain at the same time, the brain says, "Nope, no real movement, that was just the eyeballs moving." When only the motion signal reaches the brain, then movement across the visual field is perceived...I think. What I took away from all that was "Two signals at the same time, no real movement. One signal, real movement."
Q: What is perceptual integration? What is perceptual dominance? Describe the relationship between equivalence, integration and dominance.
Me:
Side note: Both these proctor girls are pretty cute. I don't need these distractions. I hate this testing center and the ADD nightmare it creates for me. One of the proctors has a t-shirt that says "I Like Dirty Boys With No Money". If that's true, I bet she'd LOVE me. I'm broke.
Whooo, you picked a doozy here, didn't you? Oooooookay, perception integration. What you have when you have perceptual integration is the use of multiple senses combined in some proportion to create an overall perceptual experience. For example, when I walk into the kitchen of our house, I combine the visual input of its general filthy state, the smell of wet dog (even though we don't have a dog...ewwwwww), the temperature of the air, the sound of the creaking floorboards...and perhaps the taste of a glass of orange juice that I get from the fridge to form my experiece of our kitchen. Then I think "Wow, I should really clean. Nah, I'm always the one who cleans, and I'm moving out in May. Let it be Dave's problem." But I digress.
Perceptual dominence, then, is the tendency for one sense to play a greater role in a given perceptual experience than others. Usually it's vision, but not always. Let's say I'm eating a steak. While the appearance of the steak is important to me, as is the temperature and texture of it, the most important aspect is going to be my sense of smell. Why? Because as we know, you can't taste much without smell, and the taste of that steak is what I care the most about. This may not be universally true, but it is for me and my steak, you can count on that.
You have a real penchant for asking questions that could be multi-page essays, and "Describe the relationship between equivalence, integration and dominance." is no exception. I'll explain equivalence by giving the example of me going skiing. This is an activity that, at least in my opinion, requires me to balance two critical senses: Touch and Vision. I must be able to see where I'm going, and I also must have a good sense for being able to feel the terrain, the consistency of the snow, the slope of the mountain, etc. so that I can respond correctly and not fall. I will go ahead and say I could not ski without either of these senses and I think they're pretty equivalent in the overall perception of me skiing.
The relationship, I guess, is that in virtually any situation, integration and dominance are happening, and in many equivalence is also happening. It is the overall proportionality that creates the precise pereptual experience in the moment. They are crucial to the overall perceptual experience because in case you didn't know, it is not a passive fidelity system.
Her: yeah...I knew that...here's the deal....dominance occurs when there's a failure of integration...the info coming in from the two senses can't be combined to form a unitary representation, so one modality dominates the representation that is formed by the senses...usually vision
Q: What is figure-ground segregation and how does it relate to the perception of objects? Describe some of the characteristics distinguishing figure from ground. What do we know about when figure-ground segregation occurs in the perceptual process, and what does that suggest about the nature of perception?
Me:
Well well well, looks like I jumped the gun on the ol' "what does that suggest about the nature of perception?" question. I was afraid we weren't gonna see it.
Figure-ground segregation is the process by which we pick out objects (figures) in the environment and separate them from everything else (backGROUND). It relates to the perception of objects because if you have vision, you're pretty much always doing it. Perceiving something visual? Figure-groud segration. Go ahead, try to think of a good, practical, real-world scenario where you're not figure-ground segregating while looking at something...I dare you. If you can't, I get an A+ for the semester and don't have to do the final. Deal?
The figure generally tends to overlap the ground. Take for example catching a football. If I'm watching for the ball, then I segregate the ol' pigskin (figure) from the sky (ground) because I can clearly see that the ball is overlapping the sky behind it. I also perceive the edges separating ball from sky as belonging to the ball, and not to the sky. Often the figure will have characteristics that differ from the background, such as the example of a K-State fan at a Husker game. The purple stands out against the background of red.
I don't really know what you're hinting at with the "what do we know about when figure-ground segregation occurs in the perceptual process", but I'd just be willing to bet that it means that we use top-down processes and that it all means that peception is (gets out tape recorder, hits play) "AN ACTIVE, ORGANIZATIONAL PROCESS."
Her: I can't think of one, but your A+ depends on what you CAN do, not what I can't do....(but good try)...perceptual process--go back to the loop...does it always happen 'in order'?
Q: (Shows a big picture of some cars on a highway near some mountains)
(a) List and briefly describe the information provided by at least 5 pictorial cues available in the picture.
Me: Ugh. Ok, we've got overlap. I know that the car is in front of that pine tree because it overlaps the tree.
We've got...ehm...linear...I want to say convergence but I know that isn't right...because the lines of the road get closer together as the road gets farther away.
We've got relative size. The tree in the background must be farther away than the tree in the foreground because it seems smaller.
We've got some texture gradient. The shubs, etc. seem closer together as they get farther away.
We've got storms moving in over the pass. Expect delays. If you can, avoid travel through this area, as blizzard conditions are possible.
We'd have that phenomenon with the horizon...if I could figure out where the horizon is in this picture. My Art History Major ex-girlfriend would be disgusted with me right now. That's okay, she often was. I'm not bitter. Moving on....
Q:
b) List and briefly describe at least 3 depth cues that would be available to you if you were actually sitting in the moving car from which the photo was taken (as opposed to merely looking at the photo, as you just did).
Me: What? There's no file in my brain for this...
How about...motion parallax. The stuff near to me would appear to whoosh by in the opposite direction while the far-away stuff would seem to be slow and in the same direction. Because I'm familiar with that concept, I'd use it in a top-down manner to determine depth.
I'd have some convergence because not everything would be on a screen 2 feet in front of me.
I'd have some accommodation for the same reason.
I'd have some music playing, and I'd be singing, because that's what I do on road trips.
Her: a) thinking of atmospheric perspective & ht in the field of view b) NICE SAVE!
Q:
The following questions all relate to auditory localization:
(a) What is the cone of confusion, and which cue to auditory localization is it most closely related to? How can people overcome the cone of confusion?
Me: (This is my favorite of all the answers I gave all semester)
I don't know. I was gone that day and you didn't put that info into the powerpoints. It just says in red "Insert cone of confusion".
At this point, the cone of confusion is the metaphoric area in my brain where the understanding of this concept would go, but instead I don't know what it is.
Q:
(b) Considering both interaural time difference and interaural intensity difference, what combination(s) of frequency and location of sounds will be most difficult to localize?
Me:
Low frequencies that were off in the periphery I'd think. Really low frequencies from anywhere, but probably moreso in the periphery because while there is a difference in time, there won't be much in intensity. If it's right in front or behind, there won't be interaural time difference, you know it's right in front or behind. High soudns cast that intensity shadow because their frequency is so great...so they're easier to localize. That must be why whenever the thugs come a thuggin' down my street, I can hear the bass blasting out their Cadillac for a long time, but can't really tell where it comes from until they're pretty close. Darn thugs and their thuggin'.
Q:
(c) Again considering both time and intensity difference, what combination(s) of frequency and location of sounds will be easiest to localize?
Me: High pitches, straight on. Intensity shadow. I said most of this in the last question. That's probably why sonar uses a high pitches frequency, eh? Maybe that's also why a bat was attracted by the beeping of our basement smoke detector as it ran out of battery last year and got down there and became stuck on a glue trap and ultimately died and caused the basement to smell weird. Maybe not...
Her: c) so is it wet dog or dead bat...oh yeah the wet dog's in the kitchen. you've got the big pieces....cone of confusion is a cone-shaped area extending and expanding from the ear ....all sounds falling on the cone have equivalent interaural time difference; easiest to localize are NOT directly in front or behind because those are confusible and NOT on the cone of confusion...you've got all the frequency stuff right
posted by Beav at 3:53 PM
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