Auditory Perception

Question 1

What is auditory perception?

Answer 1

• Gives us information of sounds
  Where?
  What type of sound?
• Can seem a bit unreliable

Question 2

What is sound?

Answer 2

Soundwaves in air, water or some other conducting medium

Question 3

Frequency

Answer 3

• Gives perception of pitch
• Number of soundwaves/seconds
• Hertz
• Most sounds are in lower frequency

Question 4

Amplitude

Answer 4

• Perception of loudness (heigh of soundwave)
• Decibels
  Increase of 10 dB gives an increase of tenfold

Question 5

Purity

Answer 5

• Perception of timbre
  Quality, how we distinct different instrument from each others

Question 6

Musical tones

Answer 6

Patterns and series of different frequencies
- Irregular frequencies gives noise
- Different sounds has different patterns

Question 7

What are sine waves?

Answer 7

Can be seen as building blocks for more complex sounds
- Different intensity gives different qualities
- Each sound is composed of a fundamental frequency and harmonics at multiple fundamental frequency

Question 8

Fourier’s theorem

Answer 8

With sufficient number of sine waves, any sound can be created

Question 9

Fourier analysis

Answer 9

More complex sounds can be broken down into sine wave tones

Question 10

Phonemes

Answer 10

The basic sounds that compose a language
- Same letter can have a different sounding phoneme - Different physical characteristics
k vs c

Question 11

Phonology

Answer 11

The sounds of language and the rule system for combining them

Question 12

Typology of phonemes

Answer 12

Consonants
1.Placement of articulation
2. Manner of articulation
3. Voicing

Vocals
1. Placement in the mouth
2. Tongue position

Question 13

Speech perception

Answer 13

• Different language sounds differently
• We hear other languages as a long string of sounds, ours is more divided - called categorical perception
• Speech change constantly
  Alot of factors affect speech

Question 14

Coarticulation

Answer 14

More than one sound is articulated at the same time, not one phoneme at a time

Question 15

Problem of invariance - Speech

Answer 15

Same sound can be different
- Still understand speech
Whispering
- Invariant=Never changing
Cool vs Keep
- Both processes involved

Question 16

Motor theory of speech perception

Answer 16

Perceive language by comparing sounds to how you would pronounce it
- Estimating and expectations

Question 17

Sound spectogram

Answer 17

Graphic representation of sounds
- To see how different syllabus can be diferent or similar
- Important for meaning to the words

Question 18

How do we perceive sound?

Answer 18

Sound waves gets translated into nerve impulses and through the auditory nerve, both hemispheres gets the message

1. Outer ear gather the sound waves, starts vibrating
2. Middle ear starts to move due to vibrations
   3- In the inner ear, fluids in the cochlea starts to move, sending nerve impulses to the brain

Question 19

How does coding of intensity work?

Answer 19

1. High amplitude sound waves cause the hair cells to bend more, resulting in higher firing rate within auditory nerve
2. Some hair cells are specialized, only react to high amplitude sound waves

Question 20

When is something too loud for humans?

Answer 20

At 85 dB, for longer periods of exposure
- Vaccum cleaner
- Proximity also matters

Question 21

Conductive hearing loss

Answer 21

Damage to the mechanical system that conducts sound waves to the cochlea
- Outer and middle ear damages
- Capacity to transmit vibrations can be affected

Question 22

Sensorimotor hearing loss

Answer 22

Damage to the chochlea’s receptor cells or the auditory nerve
- Inner ear damages
- Hearing aids cant help
- Due to illness, age, extended or repeated exposure to lound sounds

Question 23

How does coding of pitch work?

Answer 23

There are 2 theories about that
- Frequency Theory (lower frequencies(
- Place Theory (higher frequencies)
Modern take is a combination of both of them

Question 24

Frequency Theory

Answer 24

Perception of pitch depends on the rate of vibration of the basilar membrane
- Firing rate neurons matches the frequency of the sound wave
- Max of 4k Hz
- Neurons has a limited firing rate

Question 25

Place theory

Answer 25

Perception of pitch depends on the portion of the basilar membrane vibrated.
- Certain receptors are sensetive to different sound waves

Question 26

Mismatch detection

Answer 26

Our brain is sensitive for violation of expectations in auditory patterns
- How does the brain react?
- Mismatch Negativity

Question 27

How does different frequencies influence our ability to locate sound?

Answer 27

• Depending on the frequency, we can detect location of sounds differently
  Under 1500 Hz - time is important (ITD)
  Over 4000 Hz - intensity is important (ILD)
  Between 1400 Hz - 4000 Hz = Shit at locating sound locations