PSYCH261 Lecture : Biological Psychology 10th Edition Chapter 7
16 Oct 2011
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Humans have spec. sensory specializations eg. sense of taste: bitterness, for poison. Various sense systems have specializations, but also commonality b/w systems. Auditory systems well adapted to detect/interpret useful info. Sound wave: periodic compression of air, water, other media. Amplitude: aka: intensity, loudness; determined by vertical extent of sound wave. Frequency: hz (compression/sec); pitch: aspect of perception; ^ frequency -> ^pitch. Avg able to hear 15hz-20,000hz; kids can hear higher frequency. Outer ear: pinna -> auditory canal->tympanic membrane (eardrum) in middle ear. T. m. transmit vibrations to 3 bones (malleus, incus, & stapes); vibrate->oval window. >set fluid in cochlea in motion->displace hair cells (auditory receptors) Frequency: basilar membrane vibrates in sync w/ sound -> action potentials @ same frequency. Place theory: basilar membrane has spec. area w/ spec. frequency; activates hair cells @ only 1 place. Combo: frequency theory for low-frequency sound: place theory for high frequency. Volley principle: auditory nerve as a whole creates volleys of impulses for <4000hz.
