Sensation and Perception –Hearing & other senses

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 • 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 • 5th-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.