Part 2 - Sensation and Perception - CH 5 B

Color vision Trichromatic theory of color vision: - all colors can be produced by combining red, green + bive • applies to the retina where color vision is controlled by 3 typesos cones Oponent- process Theory: • Color is coded in opponent pairs a black/white Layellow/bive La realgreen • some cells are excited by one of the apporent Colors and are inhibited by the other applies to cells afier the rehna * both theones are true but for aifferent parts of visual system * Support for Opponent-process theory when stanng @ a colored stimulus, the color painings of the opponent process theory lead to a negative afterimage Afterimage: Connuaton of a visval sensation after removal of stimulus Depth Perception deptn perception: our ability to perceive spatial relationships in 3D Ladept cues of a visual scene are wed to establish our sense of depin Depen cues: Binocular cues - cue that relies on the use of born eyes Binocular disparity - slighty different views of the world that each eye receives Monocular cues - cue that relies on only one eye -illnear perspechue - wren 2 parraiter lines seem to converge → Interposition: tuepartial overlap of dojects Soundl Frequency wavelengin is directy related to frequency frequency: number of waves that pass a given pantin a given time penod L expressed in hertz (Hz) long wavelengins = low frequency Snort Wavelengins = high frequencies soundwaves Frequenc frequency of soundwaves = pitch high frequency = hign-pitcred sound •ION frequency = low-pitched sound audible range of sound frequencies for humans is between 20-2000 Hz Amplitude + Decibers amplitude of soundwaves : loudness • higher amplitude = louder sounds • lower amplitude - quieter sounas loudness is measured in decibers CaB) a conversation = 60dB a rock concerts 20aB heanng damage: 80- 130dB threshola for pain= BOdB Auditory Transduction I. sound waves travel through auditory canal and hit tympanic membrane causing It to vibrate 2. Vibration causes 3 ossicles to more (presses stapes into te oval window of tre cochlea 3. thefluid inside cochlea begins to mave stimulating the hair cells (sensory receptors far sound) which become activated 4. the hair cells generate neural impulses that travel along the auditory nerve to tue brain 5. aualtory into is sent to interior calcults, ten the medial Malamus 7 finally to the auditory correx in tve temporal lone for processione nucleus of the ear is divided into 3 parts: l. outer- pinna + tympanic membrane 2. middle - tethree ossicles: makeus, incus + stapes 3. inner- cochlea + basilar membrane Pitch Perception Temporal Theory : - frequency is coded by the activity level of a sensory neuron - problem-frequency of action potentials cannot account for tue entire range that we are alde to hear (there is a point @ which a cell cannot fire any faster) Place Trean: different portions of the basilar membrane are sensitive to sounds of different frequencies - the base responds to high frequencies + the tip responas to lan frequencies * Both #reories explain different aspeas of pitch perfection * Sound Localization • localizing sound involves the use of 2 cues: 1. Monaural Cues: - one ear each ear interacts wi incoming sound aues diffarently 2. Binaural Cues: - 2 ears • provide infamation on the location of sound alang a horizantal axis -relies on differences in pattems of vibration - interaural level difference: sound coming from one side of the body is more intense @ the closest ear bc of the attenuation of the soundwave as it passes through the head interaural timing difference: Small difference in the ime @ when a given sand wave arnues @ each ear Hearing Loss Deafness: the partial or complere mabality to near Congenital deafness: deafness from birth conductiue neanng loss: associaled wi a failure in tue vibration of the eardrum andfor monement of the ossicles can be ofien dealt win using reanng aids whion amplify incoming sound waves to mare vibration of the eararum i movement of the assicies more likely to occur can be caused by age, geretic preaispastian or enuronmental effects Sensorineural hearing loss: failure to transmit neural signais from tue cochlea to the brain Locan be causea by Meniere's alsease which can result in degeneration of inner ear Structures The vestibular sense Vestioular sense: contributes to our aility to maintai balance + bady posture La major organs located next to cochlea in tue inner car horgans are fluid filled + contain hair Cells which respond to head movement + grautational forces •the maculae are specialized for sensing linear arceleration, such as when grauty acts on the tiling head, or if the nead stars moung in a Straight line difference in inertia between hair cell stereoclia + the otolithic membrane in which they are embedded leads to a shearing force trat causer the stereocilia to bend in the direction of that linear acceleration Proprioception + Kinesthesia • vestibular system also collects info important for controlling movement + reflexes that move parts of our bodies to compensale for changes in body position bath proprice phan + kinestresia interact iul information providea by tue vestibular system proprioception: perception of body position Kinesesia: . perception of the body's mouerent through space • trus information travels to bram via the spinal column - info from the brain is sent to sensory organs of the proprioceptive + Knostratic SyStems Gestar Principles of Porcaption Gestalt Psycholagy field of psyandlagy barea an idea that tre lunde is differant from tue sum ofits parts brain creates a perception that is more inan simay tue sum of availaole sensory inputs the brain does this in predictable ways which gestalt porchologists translated into principles by munion me organize sensory information Principles Include: - figure-grand relationship -proximity "Simianty - continuty -Closure