4.3: Hearing: The Auditory System

4.3: Hearing: The Auditory System

• Humans are capable of a crude form of echolocation.

• It is possible that blind persons can sometimes detect objects a few feet away from them.
• Ben, who was blind at three years old, learned to make clicking noises that bounced off the surface and let him know where he was.
• He plays video games and rides his skateboard.
• The same parts of the brain associated with visual images in sighted people become active when blind people use their ability to navigate in their environments.

• Although the echolocation explanation can't be ruled out completely, the researchers who studied TN argue that echolocation is not an effective way to detect small objects.
• It's clear that blindsight and echolocation are examples of how subtle signals from neural pathways can impact our sensory experience.

• A person with this condition can tell us the shape and color of an object but can't name it.

• Pick out the different types of perception.

• Sound is a kind of mechanical energy that travels through air.

• The sound waves are created by the vibrating of air.
• We hear sound waves best when they travel through air.
• There can't be sound in a vacuum because there aren't any airborne particles to vibrate.

• Even if nobody can hear it, a falling tree makes a loud noise in the forest.

• When it comes to sensitivity to pitch, age matters.
• Older adults are more sensitive to higher pitch tones.
• Teenagers can hear their cell phones ring while many of their parents or teachers can't because of a ring tone for cell phones.

• Rival hypotheses should not be ruled out.

• Refer to Figure 4.14 for important alternative measured in decibels.

• The inverse of wavelength is sound wave Frequency.
• The height of the cycle is the sound wave amplitude.
• The frequencies for middle C and middle A are different.

• The Audible instruments sound different because of their timbre and the same holds for the human Spectrum.

• The human ear is sensitive to mechanical noise.

• Sense receptors for hearing and vision are the same for transducing light and sound into neural activity.

• The hammer, anvil, and stirrup are the bones in the body.
• The sound waves are transmitted from the eardrum to the sound inner ear by the Audible ossicles.

• The table shows how common sounds rank in potential harm to hearing.

• For sounds between 90 and 100 decibels, no more than 15 minutes of exposure is recommended.

• The level at which hearing damage begins is 85 dB.

• Constant exposure may cause damage.

• It interfered with the telephone conversation.

• The hearing levels are comfortable.

• The inner part of the cochlea is filled with a sense organ made of a thick fluid.
• The base of the hearing cochlea is disturbed by sound waves and they travel to it.

• Hair cells are the tissue that converts acoustic information into hearing action potentials.
• The fluid of the cochlea contains hair cells that protrude into it.

• Each place gets information from a specific place.

• Hair cells located at the base of the basilar are excited by high-pitched tones, whereas hair cells at the top of the basilar are excited by low-pitched tones.

• There are two ways to hear low-pitched tones.
• The simpler way will be discussed first.
• The method works well if the action mal firing rates are close to the limit.