Reading Activity Week #11 (Due Monday)

Near the beginning of the chapter there was a section I found interesting that discussed interaural time difference, ITD. This was interesting because it never occurred to me how the location of the sound that we hear. However, almost immediately I accurately turn my head in the direction of the sound that I hear. If I would have thought about it, the idea that we can tell the direction is perplexing because we hear in both ears. This is where ITD comes into play, basically the sound comes to the ear closest first then travels to the other ear. This enables an individual to detect the location of sound fairly accurately. There is a term used to describe the locations called azimuth. The text showed an imaginary circle or the area around us, azimuth describes the locations on this imaginary circle by measuring the location in degrees to which ear the sound will reach first. Although it gets very complex it was interesting to see how this function works in detail.

The text went on to discuss cones of confusion. The text describes it as the regions of positions in space where all sounds produce the same time and level differences. Previously ITD states that I am able to tell the location of the sound by where it is located and will generally physically turn that way correctly most of the time. Cone of confusion is those times when I am either wrong or unsure of the direction from which the sound is located. The text also refers to cones of confusion as perceptual phenomena. People move their heads fairly frequently and as so as this occurs, the ITD and the ILD (Interaural level of difference) shifts. Because of the movement this is one reason why the cones of confusion do not become a major issue with locating the source of sound.

The third section I found interesting was the section on auditory scene analysis. This section discussed how most of the time there are many sounds occurring at once in any given situation. With our sight we have the ability to avert our eyes to keep from seeing all the things around us at a given time. This is not as easily done with sound, because as the text states no matter how we turn our heads we still hear the sounds around us. As I sit hear studying, I can hear the noise of the keyboards, the people talking in the next room, my chair squeaking, and the music I am listening to at the moment. The setion went on to discuss the different strategies the auditory system uses to separate sound sources. The first is spatial separation between sounds. This is that a sound that seems to move in space is easily separated from background sounds that seem to stay the same. This enables us to distinguish and to sort sounds from each other. I found this interesting because as I thought about what I hear it seems that it should be terribly hard to function and it is amazing that our brains have these abilities to counteract the situation.

The part that I found least interesting was the section that went on to discuss distinguishing sounds by timbre or tones and grouping by onset. I think these were interesting but because they get more technical it gets kind of boring at least for me. The interesting part was how the Rolling stones used the grouping by onset to create a unique sound for their band. However I have been at some elementary band concerts that also used this method although not intentionally and definitely not with the same results.

I think the section that discussed how we differentiate sounds in situations will be most helpful. The reason being that it is important to understand how with all of the noise bombarding us how the brain is able to assist in helping us section the sounds off and categorize them to enable us to make sense of the sound around us.
This chapter builds on the previous in that chapter 9 discussed the biology and mechanics of the ear. While chapter 10 then builds on the mechanics of hearing and goes into how those mechanics are used and how the brain aids us in organizing hearing.

I think I would like to learn more about interaual time difference. It seems like it is pretty complex but I found it very interesting. This is a topic that I think I might try to find a video that shows how this works.
As I read the chapter I had a hard time focusing on the text because I kept noticing the different sounds around me. I kept thinking about the tones and how they affected me how accurately I could distinguish where they came from.

Terms: interaural time difference, azimuth, cones of confusion, sound, hear, interaural level of difference, auditory scene analysis, auditory system, spaital separation, timbre

1A) The interaural time difference
1B) I was surprised and interested to learn that the time difference between a sound coming to the left ear first and then the right allows us to know the position of the sound to within one degree. This is especially interesting since the experience of separate sounds coming from different places are interpreted based upon the size of the head. For a baby,with a growing head, his sound localization abilities decline as his head grows.
2A) Pinnae and sound frequecies
2B) The shape of the pinna in a person’s ear is complex with nooks and crannies. These pinnae funnel sound energy into the ear canal, but funnel some frequencies more efficiently than other, based upon the shapes of the pinnae. The size and shape of the upper torso also affects which frequencies enter the ear most easily. These two variables give us another cue as the location of the sound source.
3A) Timbre quality
3B) A listener can judge that two sounds with the same loudness and pitch are in fact dissimilar depending on harmonics and other high frequencies. In the same way that perception of color relates to levels of energy at different wavelengths, perception of timbre relates ot the energy of acoustic spectral components. This is what allows us to distinguish between the same note from two different musical instruments and between different vowel sounds.
4A) Auditory Distance Perception
4B) Judging the distance between a lister and the sound source depends upon the relative intensity of the sound. Intensity decreases with distance – an obvious concept. Because the intensity measure decreases as distance increases, we must apply the inverse square law. This doesn’t seem all that interesting to me at the moment. It could become interesting if this was able to help determine where a gunshot came from.
5) Auditory Scene Analysis is important to an understanding of perception because the ability to segregate the sources of multiple sounds in the environment is essential to an understanding of elements that are stationary as opposed to elements that are moving, elements that are dangerous as opposed to the ordinary.
6) Chapter 10’s explanations of the use of sound source information builds on the physical characteristics of the ear in Chapter 9, bringing the sensation of hearing to everyday life and helping to explain why location and timbre are important to understanding our social environment.
7A) Sound localization
7B) I am curious about how our ears and brains are able to distinguish the source of sound in a reliable way.
8) As I read this chapter, I was aware of the silence in the house around me, broken by the sound of the keyboard and the occasional birdsong outside. I thought about becoming more aware of sound in the environment and its impact on concentration and focus.
9) Terms: interaural time difference, sound localization, pinnae, frequency, auditory scene analysis, perception, timbre, sound segregation, auditory distance perception, intensity

1a) The first interesting item I came across from chapter 10 was the section on interaural time differences. This is the sound difference in time between a sound arriving at one ear versus the other. If the source of the sound is to the left ear, the sound will reach the left ear first. This can even be used to locate the angle of a sound source which is called azimuth.

1b) This was interesting because I always took knowing where something was according to the sound for granted. I never really thought of the mechanics behind this ability, and know that I do I find it rather fascinating.

2a) The next part I found interesting was on the second cue to sound localization called interaural level difference. This is the difference in level intensity between a sound arriving at one are versus the other. Sounds are more intense at the are closer to the sound source. The ILD is largest at 90 and -90 degrees and it is nonexistent at 0 and 180 degrees (directly in front or behind you).

2b) This was interesting because once you put these two interaural differences together then it makes very easy to tell where a sound is coming from, and how close it is to you. For animals in nature this is what helps them hunt or in the opposite case, what keeps them alive when detecting other nearby creatures.

3a) The next interesting section was on harmonics and more importantly timbre. Timbre is the psychological sensation by which a listener can judge that two sound with the same loudness and pitch are dissimilar. Timbre quality is conveyed by harmonics and other high frequencies.

3b) This was initially interesting to me because timbre is a common word used in music. I have taken music classes before so I already had a grasp on this subject so it was interesting to see a term that I had been familiar with before in this textbook.

4a) The least interesting part from chapter 10 was on attack and decay. Attack is the part os a sound during which amplitude increases (onset) and decay is the part of a sound during which amplitude decreases.

4b) This was not interesting just because it was a simple concept and they overcomplicated it by describe in too big of detail how they work. They could have summed it up in one paragraph.

5) This chapter was the most useful in understanding how we perceive how far away sounds are in our environment. It also did a good job of explaining how we differentiat between different items creating the sounds we hear and how we can recognize them from just listening.

6) In the previous chapter we learned about the inner ear workings and the small mechanics that take place in order to create a sound, now this chapter adds on to this by showing how our hearing helps us learn about the real world environment that is around us. We also saw similarities from this chapter with previous ones about sight and how they correlate with one another.

7a) This I might change my mind on further investigating, but as of right now I would like to know more about ILD.

7b) I was very interested when reading this portion of the chapter and I would like to know in what situation would this be disrupted (like hearing loss in one ear)

8) When reading about ILD I stopped and could hear my wind chime directly behind me. I could tell exactly where it was and related it to my current reading at the time. Also I listen closely to my cats playing and knew where they were because of how the sound traveled to my ears.

9) interaural time differences, attack, decay, interaural level difference, harmonics, timbre, frequency, source

1. a) The first topic that I found interesting was the cone of confusion.
b) The cone of confusion is a portion of space where all sounds produce the same differences between the intensity and time. That is to say, all sounds have the same interaural time differences (ITD) and the same interaural level differences. I find this interesting first and foremost because it is called the cone of confusion. Secondly, I think it is interesting that in these areas, two cues for the location of a sound are rendered useless. Luckily, turning our heads solves this minor problem.

2. a) The second topic that I found interesting was timbre.
b) Timbre is the psychological experience in people that enables us to detect a difference between sounds despite a similar pitch and intensity between the sounds. This difference is detected by such methods as harmonics. I find this interesting because I find it really cool that the human ear can pick up such detail in sounds. It shows how multidimensional sounds can be.

3. a) The third topic that I found interesting was auditory stream segregation.
b) Auditory stream segregation is the organization of sounds from a particular source. The brain separates sounds from different sources into different auditory streams. Each stream comes from a different source and is detected by methods like pitch and other qualities. After this, the auditory streams are further processed as separate items. I find this interesting because it shows how we can make sense of a bunch different sounds coming in at the same time. This really shows how well the brain is able to process a world with so many complex inputs of information.

4. a) The topic I did not find very interesting was the inverse square law.
b) The inverse square law is a law that states that the intensity has an initial decrease which is much faster than the distance increasing. This gives rise to a formula, which states that the increase of distance squared is equal to the decrease in intensity. I did not find this interesting because it is simply not a subject that interests me. It is a relatively simple concept to grasp, so I did not put much effort into caring about it.

5. What I read in the chapter that was most useful for understanding sensation and perception was what auditory localization was, and why it was important. Auditory localization is basically the process our body goes through in order to determine the location of the source of a particular sound. This is helpful in understanding sensation and perception because this process is essentially a method of perception, specifically for the locale of a sound. This subject is actually the topic of the entirety of chapter 10. Therefore, knowing the basic definition is necessary for understanding the chapter as a whole.

6. The chapter builds on the previous chapter because while chapter 9 was about the basics of the ear and hearing, chapter 10 was about a specific function of the system. Basically, chapter 9 was the intro course to the ear. Chapter 10 was a more specific subject matter.

7. The topic I want to learn more about is disorders. I want to find a disorder with sound localization because the text did not really mention any. It makes me curious as to whether there are any disorders with this area. Such a thing would seem unlikely, so I would like to find out if there are any or not.

8. All I really thought about in the chapter was that the cone of confusion was a scientific term and phenomenon. The phrase seems more like a remnant from a cartoon show I watched as a child. I find it incredibly odd that such a term is used to describe something scientific. However, if the shoe fits…

Terms: Cone of confusion; interaural time difference; interaural level difference; timbre; pitch; intensity; harmonics; auditory stream segregation; auditory streams; inputs; inverse square law; auditory localization; perception; sensation

1a. The first concept from chapter ten that I found interesting was interaural time difference. This is the idea that the ear closest to environmental noise is able to hear the noise before the other ear can perceive it. As an example, if a garbage can located on the left side of your body falls over your left ear will pick up the resulting noise first and perceive it before the right ear has a chance to. This ability allows us to determine what direction a sound is coming from and is vitally important for survival skills and natural selection.
b. I found this interesting because it is a very important concept based off of evolutionary principles and is crucial for surviving as both predator and prey. For a predator to catch food for survival they need to be able to perceive the noise the prey is making as well as determine where the noise is coming from. If a predator experienced a deficit in this facet of hearing they would likely die out as a result of an inability to locate food. Additionally, it is important that prey can identify where a predator is so that they can survive and thrive. Without the ability to sense a predator is coming and the direction from which they will attack, the prey would likely be killed off.
2a. The second concept from chapter ten that I found interesting was the medial superior olive (MSO) located in the brain. This lateralized part of the brain receives input from both ears and is responsible for interpreting and perceiving interaural time differences. The medial superior olive is the first place in the auditory system where inputs from both ears converge. Researchers have located MSO neurons in this area of the brain whose firing rates increase in response to time differences in inputs from the two ears.
b. I found this interesting because it is a part of the brain that specializes in interpreting sound from both ears. I like to learn about various parts of the brain and their specific functions. I also thought it was interesting that there are specific neurons and receptors in this area of the brain that fire only when the brain receives feedback from both ears.
3a. The third concept from chapter ten that I found interesting was interaural level difference (ILD). This is another cue to sound localization that depends on sound intensity. It specifically calculates the difference in level intensity between a sound arriving at one ear versus the other ear. Obviously, sounds are more intense at the ear closer to the sound source. This results because the head partially blocks the sound pressure wave from reaching the opposite ear.
b.I found this topic interesting because it is discussing our brains ability to perceive the intensity of noise that surrounds us which is important because preserves our ability to avoid noises that are too intense with the possibility to damaging hearing.
4ab. I did not find the sections on timbre and grouping timbre to be outwardly interesting. I think it was a dry section of the text and held some vocabulary that is still not readily available to me which resulted in a small amount of confusion. I generally prefer to read about brain structures associated with activity or clinical implications that occur when there is a deficit in an area of the brain.
5. I believe the sections on interaural time difference and interaural level difference will be very helpful knowledge to have while continuing sensation and perception. They are important concepts related to hearing that I will need to know for later concepts and chapters that expand on the auditory system. I think it is very important to be aware of critical parts of hearing and the environment considering all of our sensing and perceiving takes place in the environment.
6. This chapter specifically builds on the previous chapter that focused on the physiology of the auditory system. It goes into further detail of the auditory system and the vital parts that allow s to hear and perceive our environments. It uses previous vocabulary and concepts to introduce new concepts, like the interaural level difference, to ensure that it is easy to understand.
7ab. I would like to learn more about the section that covered when sounds become familiar. It is very interesting that we can become familiar with a sound and then recognize it in a split second when we hear it after our initial exposure. I want to learn about how this occurs and what parts of the brain are active when we actively remember a sound.
8. While reading chapter ten I thought about the evolutionary benefits that hearing has for living things. The ability to hear allows us to detect a predator/prey as well as where they are located and how close to us they are. I also thought about parts of the brain that become active when we recognize random noises. I am very interested in learning more about these aspects of the auditory system and their effect on survival.
Terms: interaural time difference, perception, auditory system, sense, natural selection, evolutionary perspective, medial superior olive, interaural level difference, timbre, grouping timbre,

1) So far I’ve enjoyed the auditory reading more than the visual content of this textbook. I think being a musician provides a strong background for understanding a lot of the concepts from psychoacoustics and especially the parts from chapter ten about harmonics. Similar to the basis for all simple chord progressions, almost all sounds heard in real life are harmonic sounds. This means they are a collection of sine waves or pure tones waves of sound energy. The sound we hear is primarily the fundamental frequency, which is the sound wave that has the lowest frequency in the harmonic. The other waves are the second, third, fourth and so on harmonics. This grouping represents the frequency multiples above the fundamental frequency.
2) Building on number one, I was also interested to learn that we perceive the harmonic sound even when the fundamental frequency is not present. This occurs because the energy waves which form the harmonic integrate the same energy wave as the frequency wave. There are specialized neurons in the auditory nerve and cochlear nerve which are stimulated by very specific energy waves. When second or third harmonics pass through the auditory system, the energy waves (that contain the same energy waves as the first harmonic) will stimulate these neurons, as well as the ones for the second, third and fourth harmonics. I enjoyed learning about harmonic sound in chapter 10 because I am interested in music, voice, and perception. It would be interesting if the textbook had more information on the psychology behind some of these things, such as the difference between different types of harmonic sound (i.e., how they are perceived, impact on mood/emotion, etc.)
3) I liked how the last couple of pages focused on how auditory processing is combined with other input and context clues to produce our total perceptual experience. For the bulk of the chapter, I was wondering about the consciousness behind auditory processing and how all of it is combined in real life.

4) I kind of wish the chapter had included some kind of chart with similar localization cues and other aspects of auditory perception across senses. I felt like every cue had something similar regarding vision, and it would be nice if the book could help define those similarities better.

5) We spent eight chapters on vision, and I expect nothing less for hearing! I’m sure there will be more in the next chapter regarding higher processes, and hopefully some psychology related to perception.

6) In many aspects, this chapter is like some of the content we had for vision. Several auditory localization cues are similar to visual localization cues. Of course, chapter ten also builds on much of the anatomy of the inner ear taken from chapter nine, as well as the basics of psychoacoustics. Particularly, frequency, amplitude, pitch, and timbre were important in chapter ten.

7) I think the chapter left a couple of questions unanswered – specifically, page 292 says “somehow”, which I took to mean there is no simple answer to the question “how does the auditory system” separate sounds to form our perception?”. It might be interesting to read some of the studies done for the localization cues. For example, on page 282 I wondered if one could tell if the green frog in Figure 10.8(a) moved to the red frog’s position in Figure 10.8(b)… would we be able to detect it? Or would we assume the frog had only moved when we moved our head? Or, could it actually be two frogs but we misconstrue the existence of the red frog, and assume the green had moved? Obviously, research to date views the concept as a simple matter (there are two frogs), but the brief explanation left me with some questions.

8) When the chapter was discussing localization cues, I was thinking, I have never once consciously thought about how I can tell where a sound is coming from. Based on my personal experience, I can conclude this process occurs in a relatively low center of the brain. According to the chapter, the bulk of this knowledge does come from the pons. Realistically, we don’t wander around blindly guessing the source(s) of sound(s). Most of the time we have other cues that contribute to our conclusion about where a sound may be coming from. These may be visual, contextual, or memory-based. The chapter also mentioned how part of localization is learning-based, so we know that our hearing has been impacted by evolution. We can also assume it is to our benefit to combine visual clues with memory and knowledge and perhaps other sensory input to more accurately evaluate a given sensory experience. The textbook does address some of these questions towards the end of the chapter. Hopefully we’ll get more details in the coming chapters!

9) Psychoacoustic, harmonic sound, sine wave, pure tone, fundamental frequency, auditory nerve, cochlear nucleus, specialized neurons, frequency, amplitude, pitch, timbre,
visual cue, pons, localization cue

1a) The first topic that I found interesting was the section on the interaural time difference. The interaural time difference or ITD is the difference in time between a sound arriving at one ear versus the other. If a sound is heard to the left the left ear will be the first topic to hear the sound and just the opposite if the sound is to the right. This is the way that our brain is able to tell which way a sound is directly coming from. Azimuth is the angle of a sound source on the horizontal plane relative to a point in the center of the head between the ears.

1b) I found this section interesting because it has always been fascinating that once you hear a sound you automatically look towards the direction at which you have herd the sound come from. With this being said we are then able to know when things that may be dangerous may be approaching as we are able to hear what direction the sound is coming from and then we will be able to run in the opposite direction.

2a) The second section that I found interesting was the section about the physiology of the ITD. The medical superior olives MSO's are a relay station in the brain stem where inputs from both ears contribute to detection of the interaural time difference. According to the findings of Yin and Chan neurons were found in the MSOs whose firing rates increase in response to very brief time differences between inputs from the two ears of cats. The ITD connectors are able to form their connection within the first few months of life and developing the ability to use ITDs to localize sounds depends critically on having experience with separate sounds coming from different places.

2b) I found this to be interesting as I said before that ITDs interested me as we find out where a sound is coming from but it also made it more clear as to where the development of ITDs came from. It is fascinating that at as early as 2 months old we are already developing these skills that we will then be using for the rest of their lives and we don't even realize at that age how important that they truly are.

3a) The third thing that I found interesting was the section on auditory distance perception. This section talked about how far away a sound really is. The simplest cue for judging a sounds distance is relative intensity of the sound as the sound becomes less intense as the sound is further away. The inverse-square law is a principle that which states that as distance from a source increases, intensity initially decreases much faster than distance increases such that the decrease in intensity is equal to the increase in distance squared.

3b) I found this section interesting but also very confusing. I think that the part that I found most interesting was the first couple paragraphs as we spent a lot of time in the chapter talking about ITD, ILD, DTF but none of these really covers much distance than arm's length away from the body. It made me think about how we can hear sounds that are quite far away depending on the strength of our hearing but in reality it may sound closer but in fact its really quite a ways away.

4) The section that I found less interesting was most of the chapter as I have learned a lot of this information before but the least interesting is the part about complex sounds. I found this section of the book very hard for me to understand as there seemed to be a lot more information that it was harder for me to comprehend and I felt my self spending more time re-reading the information and got bored of it.

5.) This chapter is important to sensation and perception because it looks into sound localization and how and why we are able to hear the different things in our life's and to know where they are coming from. Our hearing is one of the senses that we often rely on most to assist us with different alerts that are going on in our life whether it be a fire, tornado, hurricane, or any other emergency even with having our hearing we are able to localize where this sound is coming from and be able to plan what to do next accordingly.

6.) This chapter builds on previous chapter because chapter 9 introduces us to the ear and it's functions chapter 10 goes into specific functions of the ear systems. With out the building on from chapter 9 I think that this chapter would have been much more confusing to the reader. It also has many different similarities from the previous chapters on eyes and how the eyes transmit information to the brain.

7.) I think something that I would like to research from this topic is looking to see if there are many disabilities that deal with sound localization. I think this would be interesting to be because I feel that the only type of disability that I personally know about is hearing loss. I know there are other disabilities out there but I lack knowledge about these topics and how they will effect someone's daily life even if it does not make them lose the sense of hearing as a whole.

8.) While reading this chapter it made me think a lot about how I have never really thought about how I am able to hear where a sound is coming from. I have noticed that I am able to hear sounds from different areas of a room but I have never really thought about how my brain is able to process the information. I also thought about how our brain and our senses are aligned and it made me think about our developmental period and how did the person who came up with all of this information first discover the difference from the senses and why did they call the different systems of the ear what they did. It has always been something that I have thought about no mater the topic of study but I had seem to think about it much more during this chapter and throughout this assignment. I feel that most people with hearing are not very thoughtful when it comes to their hearing as they have not thought about how much they rely on their hearing in their everyday life.

9.)Terms: Interaural time difference, ITD, Medical superior olives, brain stem, auditory distance perception, inverse-square law,

1. The first thing I found interesting from chapter 10 was auditory localization, or sound localization. Auditory localization is a listener’s ability to identify the location or origin of a detected sound. There was a good example from the chapter that helped me understand the concept a little better. The example was focused on an owl hooting at night. Although you cannot see the owl, you can usually figure out where the owl is by following the sound. I find this interesting because I’m sure we use this mechanism a lot more than one would think. We hear sound after sound after sound and for me, it is easy to detect the location of that sound but I have never actually thought about it in this way. Even when the sound is not in our visual field, we rely on our ears to help find that noise. I think I find this so interesting because we use this mechanism on a day to day basis but we don’t ever really stop to think about how this is yet another amazing thing our body can do.

2. Another concept from chapter 10 that I found to be interesting was the section on interaural level of difference. According to the book, this is the differences in level (intensity) between a sound arriving at one ear versus the other ear. I figured that sounds would be more intense in the ear that is closest to the sound but this section clarified even more for me. The book said that the reason behind this is actually our head. Our head blocks part of the sound pressure wave from reaching the other ear. I found this interesting because the book added to my knowledge about this subject. I enjoy learning even more details about the concepts I already know a little about.

3. A third concept from this chapter that I found to be interesting was the idea of sound familiarity. This idea basically entails that the more you hear a sound, the more familiar you are with it and it is easier to pick it out of a group of sounds. An example from the book was very useful and helped me further understand this concept. The example was a person saying your name out loud. Because you have heard your name so many times in your life, that sound is very familiar to you therefore you are going to be able to pick it out in a loud crowd. This can go for any word really that you are familiar with. Maybe you have a job as a waitress and a bell goes off when your table’s food is ready. You would become very familiar with that sound and it would be normal for you to be able to pick that sound out even in a crowded, loud space. I find this interesting because this is another concept that I knew a little bit about but this book helped further answer some of the questions I had about it. I found it interesting about our name. Sometimes I find myself answering to people who didn’t even say Abby; I just thought I heard my name and instantly responded... How embarrassing!

4. I didn’t find the two sections on timbre and grouping timbre to be that exciting. Part of this was due to the different terms and the meaning behind the terms. I did not catch on with these meanings as promptly as I usually do and that made me less interested in it. I was a little confused reading these sections and compared to most of the other sections of this chapter that I found interesting, this section did not keep me entertained.

5. I believe the most useful section in this chapter to help understand sensation and perception was the concept of sound localization as well as everything related to this in this chapter. Our senses and how we perceive things are relied on in our day to day lives and without them we would struggle to survive. Without vision and sound everything is so much harder and we don’t always realize how much we rely on these two senses to help us in our lives. We also don’t realize how much our bodies do to help us with these two senses as well as the other three.

6. This chapter builds on to the previous chapters because it is still focusing on our senses such as our visual system and auditory system. We already have a lot of information on these two large concepts but the chapters continue to teach us more information about the ideas involved as well as teach us new information that relates to it. When we have information to compare the new information to it makes it a lot easier to understand and apply to our lives.

7. I want to learn more about auditory scene analysis and the process that is involved in separating different sounds and knowing the difference between the sounds that need attention and the sounds that don’t. I understood this concept but there are more questions that I want answered. There are also other topics related to this that I would also find interesting and I would enjoy learning more about.

8. While reading this chapter, I kept thinking about white noise and sound localization and how they almost relate. White noise is the background noise that you always hear and sound localization knows where the sounds you hear are coming from. I know that I am always hearing different sounds but it is interesting that sometimes I will pick out different sounds and I want to know where they are coming from. After reading these chapters, it has come to my attention that the body does so much more than one could ever imagine.

9. Terms: Sensation, perception, auditory system, visual system, ILD, interaural level of difference, timbre, grouping timbre, sense, familiarity, white noise, sound localization, auditory scene analysis.

The first thing I found interesting was interaural level difference (ILD). Interaural level difference is the difference in level intensity between a sound arriving at one ear versus the other. Sounds are more intense at the ear closer to the sound source because the head partially blocks the sound pressure wave from reaching the opposite ear. The properties of the ILD relevant for auditory localization are similar to those of the ITD. Sounds are more intense at the ear that is closer to the source, and less intense at the ear farther away from the source. The ILD is largest at 90 and -90 degrees, and it is nonexistent at 0 degrees (directly in front) and 180 degrees (directly behind). Between these two extremes, the ILD generally correlates with the angle of the sound source, but because of the irregular shape of the head, the correlation is not quite as precise at it is with ITDs. Although the general relationship between ILD and sound source angle is almost identical to the relationship between ITD and angle, there is an important difference between the two cues: the head blocks high-frequency much more effectively than it does low-frequency sounds. This is because long wavelengths of low-frequency sounds “bend around” the head in much the same way that a large ocean wave crashes over piling near the shore. This is interesting to me, because I am deaf in one ear so I have to use this phenomenon to locate the direction of sounds. When I don't know where a sound is coming from, I have to turn my head until I find the direction that the sound is most intense.

The second concept that I found interesting was the medial superior olive (MSO) located in the brain. This lateralized part of the brain receives input from both ears and is responsible for interpreting and perceiving interaural time differences. The medial superior olive is the first place in the auditory system where inputs from both ears converge. Researchers have located MSO neurons in this area of the brain whose firing rates increase in response to time differences in inputs from the two ears. This was interesting to me, because I did not realize there are neurons in the brain that only fire when receiving inputs from both ears. Since I am deaf in one ear, I wonder if I still have these neurons or if they go away after a period of not using them.

The third thing I found interesting was the inverse-square law. This principle states that as distance from a source increases, intensity initially decreases much faster than distance increases, such that the decrease in intensity is equal to the increase in distance squared. This general law also applies to optics and other forms of energy. The effectiveness of relative intensity decreases substantially as distance increases. When sound sources are close to the listener, a small difference in distance can produce a relatively large intensity difference. Listeners are fairly good at using intensity differences to determine distance when sounds are presented within 1 meter of the head, but listeners tend to consistently underestimate the distance to sound sources farther away, and the amount of underestimation is larger for greater distances. Intensity works best as a distance cue when the sound source or the listener is moving. In a manner akin to motion parallax in the perception of visual depth, sounds that are farther away do not seem to change direction in relation to the listener as much as nearer sounds do. I found this interesting, because I have always been intrigued by how quickly sound seems to drop off at such small distance changes when closer but not when further away.

Strangely, the thing I found least interesting was the mathematical part of the third thing I found to be most interesting. I am always fascinated by the ways the world and how we perceive it can be explained through math; I am just rarely ever interested in the actual mathematical formulas.

Everything in the chapter about sound location will help me better understand sensation and perception. Since I have such difficulty tracing the origin of sounds with only one good ear, I have to read about the different ways normal people experience the perception of sound location. These are not things that I can ever experience personally.

This chapter built on previous chapters, because it went into more depth about the ways we perceive sound. The previous chapter focused more heavily on the anatomy, while this one focused more heavily on different ways we may perceive the same sound because of things like distance or direction.

I would like to know more about sound location in general, since, as I have stated far too many times already, I am unable to locate sounds on my own, so I would like to find out ways to better cope with my disability. This whole class would be worth it if all I learned was a better way to tell the direction of sound.

I spent pretty much the entire reading thinking about how I wish I could tell which direction sound came from.

Terms: Interaural Level Difference, Intensity, Sound Source, Pressure Wave, Localization, Frequency, Wavelength, Medial Superior Olive, Inverse-Square Law, Motion Parallax

1a) What did you find interesting?
i thought this chapter was pretty well put together, i had several interesting topics that i was interested in, the one that i really found interesting is the Directional Transfer Function. (DTF)

1b) Why was it interesting to you?
DTF is the measure that describes how the pinna, ear canal, head and torso change intensity of sounds with different locations, this interests me because sometimes when you hear sounds, it kind of echo and stuff, i want to know if the direction of that particular sound matters, and if DTF have anything to do with it, also, how come sounds echos from particular places instead of all places.

2a) What did you find interesting?
Another topic that i found interesting as well was the Inverse Square Law, this states that basically the further a sound is at, the lower the intensity of it is.

2b) Why was it interesting to you?
i thought this was interesting because of how some people can hear individuals who choose to speak quietly or speak under their breath, also when you're with friends and want to listen to music, some people prefer their music to be low, some people prefer to be medium and most people (Especially teenagers and adolescence) like their music to be pretty high. i want to know if this law can explain some of those factors furthermore.

3a) What did you find interesting?
Third thing that i found interesting as well was the Lateral Superior Olive (LSO) which is a relay station in the brain stem where inputs from both ears contribute to detection of the interarural level difference.

3b) Why was it interesting to you?
i'm interested in this as well because i'm curious on how people can take in different sounds at the same time, or the process of hearing a word, going into your hearing process and eventually making it all the way up to your brain and have your brain understand it right away from there on out, you just know how to respond sometimes without critically thinking about it, you just have a quick respond to something, i want to know how that process works, and how we get to be sometimes so good at answering questions briefly without taking alot of time thinking about it.

4a) What one (1) thing did you find the least interesting?
this chapter was actually decent, it didn't really have many boring, or misunderstood sections, but i will have to say, Fundamental frequency was probably my least interesting chapter

4b) Why wasn't it interesting to you?
it wasn't interesting to me because the way it was example, i didnt quiet get how it was explain or the actual purpose of it, if they would've elaborated more on it, then i probably would've had a better understanding of what its actually about.

5) What did you read in the chapter that you think will be most useful to in understanding Sensation / Perception?
i thought this chapter and the taste bud chapter were pretty cool and helpful in perception generally. i think that Timbre is pretty useful, and it's being able to tell two sounds with the same loudness and pitch that are in fact quiet the same, basically is like listening to two different songs that have completely different messages and different beats but the loudness of them are the same, it's being able to tell that those two songs might be at the same rate in loudness, but they are in fact different in many other factors.

6) How, in what ways, does this chapter relate (build on) to the previous chapters?
the last chapter was basically talking about what sounds are, what we interpret sounds, the functioning of hearing, different hearing illness/challenges. where in this chapter, we are being taught about how we receive sounds, which and where sounds go or come from, the process of knowing the different levels or waves, and processing sounds into our brains so it makes sense.

7a) What topic would you like to learn more about?
i think i want to learn more about the Interarual Time Difference (ITD) which is the difference in time between a sound arriving at one ear versus the other.

7b) Why?
i want to learn more about it because i want to know how some people can go deaf in one ear but not the other, if your brain is functioning correctly at all times without any problem, how could your hearing be imbalance, and because it also seems interesting and would really want know more about it.

8) What ideas related to what you were reading (what did you think about) did you have while reading the chapter?
When i was reading this chapter, i thought about people who make music, like DJs, MCs etc, i was thinking if they knew all these things about sounds/hearing and such, and i thought as if i was one of those people, i would learn everything there is to learn about hearing and sounds so that i can be as successful as i want to be in music because i would know away to sometimes manipulate some beats and do what i can for people to receive my message in many ways, for example, i think the Artist, (DRAKE) knows alot about sounds/hearing and such because no matter what songs he puts out, no matter how he deliver them, his message is always receive with no confusions .

9) TERMS: Interaural Time Difference , Sound, Hear, hearing system, Auditory system, Timbre, Lateral Superior Olive (LSO) Inverse Square Law. Directional Transfer Function, Fundamental Frequency.

1a & b) What did you find interesting? Why? The first item in this chapter I found interesting was the section on interaural time differences (ITD). This is defined as the sound difference in time between a sound arriving at one ear versus the other. If the source of the sound is to the right ear, the sound will reach the right ear first. This can also be used to locate the angle of a sound source, which is called azimuth. I found it interesting because I like knowing the mechanics behind the information I learn.

2a & b) What did you find interesting? Why? The second item in this chapter I found interesting was auditory localization, or sound localization. This chapter opens with an example when we are outside in the dark and hear something such as an owl hooting, most of the time we can locate the owl without even seeing it, we can simply piece together the information to its’ location. The book explains that the theory of auditory localization is very different from visual object localization. Seeing the owl it would be very simple to know if it was to your left or right; but not being able to see it and only determining its location by its sound is another story. I find this interesting because it is a system that we use very often, even without us knowing it. We hear sirens, bells, yells, etc. coming from somewhere when we are walking to class or just out and about; we need to quickly locate them even if they weren't yet in our visual field.

3a & b) What did you find interesting? Why? The third item in this chapter I found interesting was the structures of the ears (inside/outside) and the brain are not the only factors in determining how one perceive the location of the sound, the size and shape of the head and torso are also important factors in determining which frequencies reach the ear easiest. Furthermore, the intensity of each frequency varies according to the direction of the sound, and those varieties are cues (for us) to locate the where the sound comes from.

4a & b) What one (1) thing did you find the least interesting? Why? The one part of the chapter I found least interesting, or at least more complicated to read was the inverse square law. The book defines it as a law that states the intensity has an initial decrease which is much faster than the distance increasing. The formula that is stated in the book is, the increase of distance squared is equal to the decrease in intensity. I did not find this interesting because it is a formula! I have never been much for formulas of any kind. I’m confused by them a lot more easily!

5) What did you read in the chapter that you think will be most useful to in understanding Sensation/Perception? The section about complex sounds will be the most useful in understanding Perception/Sensation because understanding the different complex sounds helps with the identification of other types of frequency. Knowing the differences between ITD and cone of confusion and how that fits in with complex sounds will be crucial as well. Most of us take for granted our auditory system; I think knowing about all the aspects of the next FEW chapters will help us accomplish that.

6) How, in what ways, does this chapter relate (build on) to the previous chapters? This chapter builds on previous chapters because it goes into more details on the internal functions of the ear. It talks about how we measure sound sources and what sense we make of it. It talks about the different levels of intensity and how we measure intensity. This chapter, and I’m sure the next one too, will just keep giving us more details from the previous chapter, “painting” a better picture for us.

7a & b) What topic would you like to learn more about? Why? I would like to learn more about the section that covered when sounds become familiar. It was very interesting to read we can become familiar with a sound and then recognize it in a split second when we hear it after our initial exposure. I want to learn about how/why this occurs and what parts of the brain are active when we actively remember a sound. I would like to know if there are any fMRI’s that have taken this information, or what other devices are out there that measure this.

8) What ideas related to what you were reading (what did you think about) did you have while reading the chapter? While reading this chapter, I was mostly thinking about how I have never really thought about how I am able to listen where a sound is coming from. As I am writing this in my sunroom, the windows open, I can hear traffic. It is very hard to tell which way a car is traveling because it bounces off so many objects. I would like to more about how someone can predict where that sound is derived from. Just like a gunshot in the woods, usually that person has no clue where it came from, why? It has always been something that I have thought about no mater the topic of study but I had seem to think about it much more during this chapter and throughout this assignment.

TERMS: interaural time differences (ITD), azimuth, auditory localization, sound localization, visual object localization, inverse square law, frequency, auditory system, intensity, perception, sensation