Hearing Exploring our ability to distinguish, identify, and locate sound. Psychology & Period # Olsen Date Group Names Contents Introduction & Basic information Characteristics of Sound Pitch & frequency Locating sounds Hearing Loss & Deafness Vocabulary Activity: Label the part of the ear Group Activities/ active involvement activities Guess that sound! In the middle Auditory Acuity Two ears are better than one Hearing Quiz Quiz Key Sources Introduction & Basic info Hearing (or audition) is highly adaptive; we can hear a wide range of sounds at varying frequencies, as well as are able to easily detect differences between sounds, such as different voices, instruments, animals, etc. The speed of sound in 750 miles per hour, yet we are also able to detect the direction from which it came from by which ear the sound waves hit first, as well as the intensity of the sound, as the difference may be. When an object makes a noise sound waves travel through the air, and are funneled into your ear canal through your outer ear. The vibrations move into your middle ear hitting your eardrum, causing it to vibrate as the sound waves do. This brings a chain of vibrations continuing first to the hammer, then the anvil, then the stirrup. The stirrup passes the vibrations into the cochlea (a coiled tube in the inner ear) which finally causes the basilar membrane to move changing the vibrations in messages sent to the brain via the auditory nerve, which will make sense of what you are hearing. Characteristics of sounds Pitch and Frequency The strength or amplitude of sound waves determines the loudness. Sound waves also vary in length or frequency. Long waves have low frequency and low pitch, as opposed to short waves with high frequency and high pitch (the tone’s highness or lowness). Place theory presumes that we hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane; the brain can determine a sound’s pitch by the place on the membrane which it receives the neural signals. This is in opposition to Frequency theory, which suggests that the whole basilar membrane vibrates with incoming sound waves, triggering our neural impulses to the brain at this same rate. Locating Sounds Sound travels at 750 miles per hour, although despite this speed our ears are able to detect the difference of which ear receives the sound first, and more intensely with a time difference of just .000027 seconds. With this we are able to detect which direction various sounds are coming from, such as if a horn honks on the right as opposed to the left, or if a phone is ringing, where in the room it is coming from. Locating sound that is equidistant from both ears (such as behind, above, below, or in front of you) are slightly more difficult to distinguish automatically being that the sound waves hit both ears at the same time. Hearing Loss & Deafness The ear’s structure is delicate and vulnerable to damage. Hearing loss is linked to conduction and nerve disorders, and can be caused by prolonged exposure to loud noise and diseases, as well as age related. Problems with the mechanical system, which conducts sound waves to the cochlea causes “conduction hearing loss.” If the eardrum is punctured or if the tiny bones in the middle ear lose the ability to vibrate, the ear will not be able to conduct the necessary vibrations to process the sound waves. Digital hearing aids can be used to improve this. Damage to the cochlea’s hair cell receptors or their associated nerves can cause “sensorineural hearing loss,” this is also called nerve deafness. This can be caused by disease on occasion, but is generally due to genetic causes. The National Center for Health Statistics estimates that 1% of people are born deaf; Cochlear implants can enable hearing in deaf children at times; those who live with hearing loss often face social challenges. Vocabulary Audition: Sense of hearing. Frequency: The number of complete wavelengths that pass a point in a given time. Pitch: A tone’s highness or lowness; depends on frequency. Middle Ear: The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea, semicircular canals, and vestibular sacs. Cochlea: A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses. Place Theory: The hearing theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated. Frequency Theory: The hearing theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch. Conduction hearing loss: Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea. Sensorineural hearing loss: Hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; also called nerve deafness. Cochlea : A spiral-shaped, fluid-filled inner ear structure; it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form. Eardrum: (also called the tympanic membrane) a thin membrane that vibrates when sound waves reach it. Eustachian tube: A tube that connects the middle ear to the back of the nose; it equalizes the pressure between the middle ear and the air outside. When you "pop" your ears as you change altitude (going up a mountain or in an airplane), you are equalizing the air pressure in your middle ear. Hammer : (also called the malleus) a tiny bone that passes vibrations from the eardrum to the anvil. Anvil: (also called the incus) a tiny bone that passes vibrations from the hammer to the stirrup. Stirrup: (also called the stapes) a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the smallest bone in the human body (it is 0.25 to 0.33 cm long). Volley Principle: A theory of frequency; we can achieve a combined frequency above 1000 times per second by firing neural cells in rapid succession. Label as many parts of the ear as you can without looking at the other diagrams. (Tip: coloring the parts may help distinguish them more effectively for labeling and studying purposes. Previous diagram labeled Guess That Sound! Jiggling coins, clinking glasses, clapping hands...think you know what these sound like? The purpose of this game is to test the ability of people to identify several sounds. People should close their eyes or turn away from the "sound maker." Make each sound and see if everyone knows what it is. Example sounds: 1. Shake pennies or other coins 2. Clap hands 3. Clap chalkboard erasers 4. Tap a pencil or pen on a desk 5. Close a book 6. Crumple up paper or foil 7. Stomp on the floor 8. Tear some paper 9. Close a stapler 10. Bounce a ball I am sure that you can think of more sounds to make. You could also have people take turns making sounds and asking the others to guess the noise. Materials: Items to create sounds with (see examples above or create your own). In the Middle! Let's get a little more scientific here (hear?). Blindfold one person and have him sit in the middle of the class. Have the other people form a large circle around the blindfolded person. Point to one of the people in the circle and have him say the seated person's name. The seated person must then try point in the direction of the voice and identify the name of the person who said his name. Try this experiment with the seated person using both ears and then again with one ear closed. How accurate can the center person identify the caller and where the call came from? Are two ears better than one? Materials: Chair for center subject Blindfold This game will demonstrate the ability to locate by which ear the sound waves hit first, and the intensity which the make contact with the ear. Auditory Acuity You hear the ringing of the phone in the middle of the night, but you just can't find it. You can hear it, but you can't see it. Where is that thing? Just how good is the ability to find things using only the sense of hearing? Blindfold a person. Have him cover one ear. Take a watch or stopwatch that "ticks". An electric watch will not work. Ask the student to tell you when he hears some "ticking". Approach the blindfolded person from several different angles and record the distance when the subject says "I can hear the ticking". Keep track of the angles and the distances. Repeat the same experiment with the student's other ear closed. Then do it again with both of his ears opened. Questions and Comparisons: 1. The distances for the different ears. 2. Both ears vs. one ear. 3. The best and worst angles for detection. 4. Your ear's performance vs. your partner's ear's performance. Materials: Two Ears are better than one: Sound Localization To show the importance of two ears, try this one. Make an X on the floor with tape or chalk or erasable marker. Measure distances in a straight line in increments of 5 ft (1.5 m) from the X and label each of these points with the distance it is from the X (5 ft, 10 ft, 15 ft, etc.) Now for the test. Place a blindfolded subject on the X. Now, you stand on one of the points away from the X. Say the subject's name. The subject must now tell you which line you are standing on. Try it when the subject uses one and both ears. Make it harder with shorter distances from the X. Are 2 ears better than one in judging distance? Materials: tape OR chalk OR marker For most people, it will be easier to judge distance using two ears. Our brains use the loudness of sounds and the differences in time for sounds to reach each ear to make accurate determinations of sound locations. Hearing Quiz 1. What is the measuring unit for sound energy? A. Frequency C. Audition B. Decibels D. Liters 2. Place theory is associated with which membrane? A. Cochlea’s C. Cell B. Hearing D. Sensory 3. True or False: Hearing loss caused by damage to the mechanical system is sensorineural hearing loss? A. True B. False 4. Long waves have _________ frequency and _______ pitch. A. High, low C. Low, low B. Middle, middle D. Low, high 5. The middle ear contains which three tiny bones? A. Hammer, anvil, stirrup C. Tibia, femur, anvil B. Fore bone, middle bone, outer bone D. None of the above 6. Audition is _________. A. A tone’s highness or lowness. C. Projection of actions and voice. B. The rate nerve impulses that travel D. What links pitch and area. up the auditory nerve. 7. What is used to restore hearing for people with nerve deafness? A. Headphones C. Hearing transplant B. Nothing D. Cochlear implant 8. The National Center for Health Statistics estimates that ______ percent of people are born deaf. A. 25% C. 17% B. 7% D. 1% 9. Individuals cannot fire neurons faster than 1000 times/ second. A. True B. False Select 2 to discuss 10. Discuss the volley principle and explain how it works. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 11. Explain the reasoning/ rational behind Helen Keller’s statement that she “found deafness to be a much greater handicap than blindness… Blindness cuts people off from things. Deafness cuts people off from people”. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 12. Why do older people suffer hearing loss of high frequencies? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ Hearing Quiz Key 13. What is the measuring unit for sound energy? C. Frequency C. Audition D. Decibels D. Liters 14. Place theory is associated with which membrane? C. Cochlea’s C. Cell D. Hearing D. Sensory 15. True or False: Hearing loss caused by damage to the mechanical system is sensorineural hearing loss? B. True B. False 16. Long waves have _________ frequency and _______ pitch. C. High, low C. Low, low D. Middle, middle D. Low, high 17. The middle ear contains which three tiny bones? C. Hammer, anvil, stirrup C. Tibia, femur, anvil D. Fore bone, middle bone, outer bone D. None of the above 18. Audition is _________. C. A tone’s highness or lowness. C. Projection of actions and voice. D. The rate nerve impulses that travel D. What links pitch and area. up the auditory nerve. 19. What is used to restore hearing for people with nerve deafness? C. Headphones C. Hearing transplant D. Nothing D. Cochlear implant 20. The National Center for Health Statistics estimates that ______ percent of people are born deaf. C. 25% C. 17% D. 7% D. 1% 21. Individuals cannot fire neurons faster than 1000 times/ second. B. True B. False 22. Discuss the volley principle and explain how it works. The volley principle is like soldiers who alternate firing so that some can shoot while others reload, aq group of neural cells that can alternate firing. By firing in rapid succession, they can achieve a combined frequency above 1000 times per second. 23. Explain the reasoning/ rational behind Helen Keller’s statement that she “found deafness to be a much greater handicap than blindness… Blindness cuts people off from things. Deafness cuts people off from people”. __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 24. Why do older people suffer hearing loss of high frequencies? People suffer hearing loss for high frequencies because of nerve degeneration near the beginning of the basilar membrane.