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

2. 4.3 Hearing Sound 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

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

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

9. 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

10. 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

13. Taste Dogs vs. cats Four basic qualities Sweetness, sourness, saltiness, & bitterness 5 th -unami “yummy” in Japanese Sensed via receptor neurons on taste buds on the tongue Sensitivities to different tastes can be inherited. “Taste blind”

17. 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

18. 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.

21. Body Senses Vestibular sense (balance) 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.