1. Sensation and Perception –Hearing & other senses
The Biological Basis of Behavior: Unit III

2. 4.3 Hearing Sound Pitch Loudness
Caused by changes in air pressure that result from vibration of air molecules.
Pitch
How high or low the sound
Depends of frequency-number of cycles per second (length of wave)
Women’s voices vs. men’s voices
Loudness
Determined by the height, or amplitude, of sound waves.
Measured in decibels

5. The Ear
Shaped to capture sound waves, vibrate with them, and to transmit sound to the brain.
Outer ear captures sound
Eardrum transmits sound to middle ear (Hammer, Anvil, and Stirrup)
Inner ear-Cochlear is the bony tube that contains fluids and “hair cells”.
Auditory nerve carries neural impulses from cochlea to brain.

6. Outer Ear- collects
Middle Ear- amplifies
Inner Ear- transforms

8. Deafness About 2 million Americans are deaf.
May be inherited, or caused by disease, injury, or old age.
Conductive deafness
Damage to the middle ear
Usually the elderly
Hearing aids help
Sensorineural deafness
Can not perceive sounds of certain frequencies
Often neurons (hair cells) in cochlea are destroyed
Damage to auditory nerve
Hearing Aids do not help

9. 4.4 Other Senses Smell & Taste are chemical senses Smell
Dogs vs. Humans (200m vs 10m)
Odors detected by receptor neurons high in each nostril
Messages sent to brain via olfactory nerve
Adapts quickly 1 min-decrease 70% (which sensory concept?)
Combination of receptors = distinct odors

12. Taste
Dogs vs. cats
Four basic qualities
Sweetness, sourness, saltiness, & bitterness
Sensed via receptor neurons on taste buds on the tongue
Sensitivities to different tastes can be inherited. “Taste blind”

16. Skin senses
Touch is a combination of pressure, temperature, & pain
Premature infants grow more quickly and stay healthier if they are touched
Pressure
Receptors located around root of hair cells and beneath the skin
Different body parts are more sensitive to pressure than others

17. Temperature
Temperature neurons just beneath the skin (cold & hot)
Pain
Not all body parts are equally sensitive
Sole of foot vs. neck
Women more sensitive than men
Gate theory-brain can only process certain amount of info. at a time.

20. Body Senses Vestibular sense (balance) Kinesthesis sense(movement)
Tells you whether you are upright without using your eyes
Sensory organs in middle ear monitor motion, position, & gravity (Semicircular Canal)
Kinesthesis sense(movement)
Informs people about the position and motion of their bodies.
Info. fed to brain via sensory organs in joins, tendons, and muscles.