Sensation and Perception: Hearing

Sound

Sound comes in waves.

The waves are produced by vibration.

Sound is vibration

Ex. Clap your hands causes the air to vibrate.

Psychological Dimension

Examine how sensation influences our PERCEPTION

Sound

The Nature of Sound

Loudness: The dimension of auditory experience related to the intensity of a pressure wave. The amplitude of the sound wave determines loudness.

Loudness is measured in decibels (dB). The absolute threshold for hearing is 0 dB.

Subway train at 20 feet is 100 db

Prolonged exposure above 70 db produces hearing loss.

Decibels

Pain threshold is 120-130 decibels

Fireworks: 145-15 decibels

Gunfire: 145-155 decibels

The call of the blue whale reaches levels up to 188 decibels.

1 ton TNT bomb: decibel count of 210.

Tunguska Meteor :300-315 decibel

Sound

The Nature of Sound

Pitch: the dimension of auditory experience related to the frequency of a pressure wave. Pitch is expressed as hertz (Hz)---the # of waves that reach the ear each second.

Middle C on the piano represents a sound of 256 Hz

Sound

The Nature of Sound

Timbre: The dimension of auditory sensation that reflects the complexity of a sound wave.

unique quality of an instrument’s sound; its “voice.”Timbre is what makes a note played on a flute sound entirely different if played on an oboe

Psychological Dimension

Loudness:

Pitch:

Timbre:

Structure of the Auditory System

Auditory canal: the opening through which sound waves travel.

Eardrum

Eardrum: transfers sound vibration form the air.

Ossicles

Ossicles: three tiny bones that transfer sound waves from the ear drum.

Cochlea

Cochlea the main organ of hearing; snail-shaped, bony, fluid-filled structure in the inner ear where sound waves are changed to neural impulses.

Cochlea is divided by the Basilar membrane

Thin strip of tissue located in the cochlea.

Cilia

B.M. contains the hair cells(cilia), the receptor cells for hearing. They are NOT real HAIR!!

Deafness

1. Conduction deafness: damage to the middle ear, eardrum may be punctured, three little bones are damaged. Hearing aids help.

Deafness

2. Nerve deafness: damage to the hair cells of the inner ear or damage to the auditory nerve. Exposure to loud sounds, disease, and aging. Cochlear implants are helpful

Mental Imagery

Mental representation of objects or events that are not physically present.

Includes visual “pictures”

Includes images for our other senses

Ex. We can easily create a mental representation for the taste and texture of a chocolate milk shake

We can manipulate visual images.

What role does our hemispheres play in mental imagery?

Mental pictures…doodling and drawing. Processing spatial stimuli, this is processed primarily on the right side of the brain

Lyrics…processed primarily on the left side of the brain

Write down what you are thinking…words and fine motor skills are processed primarily on the left side of the brain.

Demo

Brain determines the origins of sounds by timing.

Example: sound originates from the left of the head, those sound waves reach the left ear first and then bounce off of objects to the right of the head and then back to the right ear. COOL