Chapter 3: Sensation

Psychology-Chapter3 Sensation activation of the sense organs (physical response) perception how stimuli are interpreted ( psychological response) "Sortingout" analysis", "Integration of stimuli" Shmulus any PA ssing source of physical energy that produces a response in a sense organ Stimuli vary In type and intensity psychophasics Study of the relationship between the actual physical aspects of a stimulus and our psychological expenence of that stimulus >absolute treshold the lowest intensity of a stimulus that an rganism can detect holse background stimulation that interferes with the perception of other Stimuli $ refers not just to auditory stimuli, but also to unnanted stimulithat interfere t other senses difference treshold the smallest level of added or reduced stimulation required to sense that a change in stimulation has occurred. also called "Just noticeable difference": Webers law? Estates that a just noticeable difference IS a constant proportion of the intensity of an Initial stimulus (rather than a constant zamt (ex: if the room was loud to begin the stimulus needs to be londto be noticed) Sensory) Adaptation an adjustment in sensory coparity after prolonged exposure to unchanging stimuli (our brain mentally turns V the volume of the Stimulation) Wision vision StartST light (the physical energy that stimulates the eye) light is measured in wavelenghts visual Spectrum range of wavelenghts that is visible to the humaneye restructure corneat Transparent, protective mindow a) thefrontof the eye

eyestructure cornea-pupil-lers-retina? The curnature of the comea "bends"or "tetrack" lightas H passes through, playinga innoing role infocusing theight more happy comea pupil /pupadark hole inthecenter of the Iris. Iris: illf is the coloreed part of the eye, which ranges from light blue -darkbrown) pupil dilates & constructs dimmer lighting = dilation brighter environment constriction small pupil-grantyincreases the range or distances at whichobjects are in focus mdc open PUPII range IV relatively small, details are harder to discern PUPIL lens Tens: directing behind the pupil lens acts to bend therays of 1191 ht sothat they are property focused on the rear of the eye. Accommod ation Jens focuses 11 light by changing its own thick flatter when looking adistant sb, cets rounder -Etoser objects (asthe image travels throllan the lens, it reverses lens retina itself The image going to the Retina (ultimate destination in the eye) refina is upsidedown.) the part of the eye that converts electromagnetic energy of light to electrical impulses for transmission to the brain. has 42 kinds of light sensitive receptors cells in the retina. 1 rods 2cones are thin cone shaped Cylindrical respon sible for thighly sensitive Sharp focus and to light color perception night vision particularly in bright light. penitieral nsion - -10 cated in the fovea dimly lit situations largely insens thre To color and Sharp details

psychology continued (Ch-3) dark adaptation- adjusting to dim light after being in bright 110ht adaptation depends on rate of change in chemical compositi on of frods cones cones adapt -fewmins rods - 20-30 mins light adaptation adjusting to bnght 11 ght after being in dim light takes only a minute or so. Rods contain rhodopsin (complex reddish purple protein whose composition changes chemically when energized by light) rods and conesisend information to Bipolar cells ,and bipo lar cells send information to theganglion cells Ganglion cells summanze into, which is sent through back of the eyeball and sent tothe brain through ganglion ax ons called 0 Ptic nerve optic chlasm Optic herresi- each eye meet at a point roughly between the two eyes-where the optic neme splits does 0 go from the optic here to brain OPTIC nerve- optic chiasm brain ganglion some ganglion activated message ( darkness has reached surrounding) the area) cellst one of the initial sites oncethe brain. celle by light in center others activated by light in the center (darkness in Surrounding maxamize the detection of vanations in light and darkness visual cortex vitimate processing of visual images takes placehere. most complex kind of processing ocars Feature detectors specialized neurons that are activated only by nsual Stimuli having certain features such as a particular shape) pattern ex:particular lines of particular width, shape, moving, Stationary stimuli >brain cysems process different things one may process shapes colors ,movement, location, depth etc. prosopagnosia- Inability to recognizerfaces Humans T normal color visioncan distingish Upto million diff color S.

eyestructure cornea pupil lens retina 7%men - colorblind 04% nomen Color blind colorblind-ore the morid dull lack contrast mostcommon-read green -seenas yellow some PPI cant differentiate yellow blue -rare cases. some people perceive 0 color atall trichmmatic Theory of color vision theory propossed by Thomas young & extended by Hermann von Helmholtz inthe 180015 theory suggest there is zircones in the reting \ one responsive to blue violet Icone - responsive to green Unchromatic processes work w/m the I cone - responsive to yellow fred retina itself) 7 perception of color influenced by therelative strenght wl which each of the 3 kinds of cones IS activated. ex: (Seeblue sky , blue-violet cones are activated others less active) after magel-looking D an image for about a min and then looking D a Tspecific White sheet of paper the colors colors change opponent proceestreory receptor cells are polinked in Pairs, working in opposition to each Other proposed by Enald Henng (19thcentury) It blue-yellow pairing 2 red-green Pairing 3 black-white paining (opponent mechanisms operate both in the retina and at later Stages of neuronal processing) canexplainattermage Hearing gother senses sense of motion and balance resides inthe ear. (along Theaning) outer ear acts as a reverse megaphone to bring sounds to inside of car sound locallzan on process by which we I denting The direction from which a sound IS coming. Sound movement of Fair molecules brought by a source of vibration

MHAS HAS Hammer, Ahull Shrup (M15) canal 7 eardrum- middle- oval mandow (innerear that cochlie hair cells here 1). poptic optu Chican 1 auditory canal tubelike passage that leads to cardnum brain 2 reardrum part of the car that vibrates when sound waves hit (if smiddle ear -tinychamber containing 3 bones Chammer, anvil, strong) that transmit vibrations to the oval window oval window thin membrane leading to the inner ear force of sound waves become amplified on the oral window m addle ear acts as 9 tiny amplifier inner ear portion of the ar that changes soundv I bration into of form in whichtn ey can be transmitte ed to the beth cochlea colled tube that looks like asnall and IS filled f fluid that work n/m the Vibrates in response to sounds basilar membraner. structure that seperates the cochica into Upper lower chamber of basilar membrane covered t shair cells hair cells bend by vibrations entering cochler, and the cells send a neural messg to the brain you Da the Frequency #of ware cycles that occur in a second & frequencies =few wave cy cles second ing in opposition each other pitch characteristic that makes sounds seem "high" or 11/0n" lowest frequency humans can hear 20cycles second amplitude wave patterns that allow US to distinguish between loud and les of Sof sounds Decibels rango of sounds sounds higher than Rodecibels painful to human ear Hyperactists person acutely sensitireto sounds that others find tolerable (ex doorbells ,emmblingpaper= forthem) Qure if car place theory of hearing VS frequency theory hearing different areas of basilav membrane entire basilar membrane acts as I are speciall 299 to respond to diff sound microphone ibratingas a whole frequencies nearestoral window Afraquency Incarest cochtea frequency in response to sound

L and R car process Sound differently R ear reacts more tospeed. tas L ear reacts to more music Echolocation use of sound wares and echoes toddermine where objects are. tr a (usedby Bats PPI T impaired vision) n vestibular system responds to the pull of granty and allows usto maintain our balance, even whensfanding in abus in Stop-go traffic main structure formed by the semicircular canals of the inner ear which consist of 3 tubes Containing fruid that sloshes through them when the head mores Signaling rotational or angular movement to the brain pull on our bodle essensed by the Otholiths: tiny motion-sensitive crystals in the semiarauga canals When we more crystals shift, contacting the hair cells in the Semicirallar canal. SMELL olfaction sense of smell allows US to detection than 19,000 seperate smells women have better Senseof Smell than men. sense of smell sparked when the molecules eneter the nasal passage & meet ottactory cells the receptor neurons of the nose. morethan \ 000 type of receptors have been Identified on those cells response of olfactory cells are then transmitted to bran, rherethey are combined into recognition of a particular smell TASTEL gustation sense of taste involves receptor cells that respond to 4 basic stimulus Qualities 1 sweet 2 Sour 5th category exists: (savong) 3 Salty umami : involves food that contain amino + bitter auds wehave roughly 10,000 taste buds (distributed accross the tounge and other parts of mounth

taste buds war out - replaced every 10days ors supertasters vs. nontasters highly sensitive to taste may see out relatin truce as many receptors as father goods ton "hontasters". may be prone to mainly female make up 15% of the us population RSDS) reflex sympathetic dystrophy syndrome disease characterized by constant, intense pain that ic out of proportion to any injury (small shmulus, ex gentle breez, touch of a feather) can produce agong skin senses touch pressure, temperature pain. chronic pain affects 116million Americans pain can be outcome of cell injury when a cell is damaged, substance that transmits pain messages to the brain regardless of the source of damage, It releases a chemical called gate control theory of Pam sparticular name receptors in the spina 1 cord lead to specific areas of the brain related to pain when receptors are activated b/c of Injury /problem T a part of the body, a "gate" to the brain IS open causing usto feel pain mother set of receptors, can, when stimulated close the 11gatell gate" pain can be shut by 2 ways I other impulses can overwhelm the neme Dathways nonpainful stimuli competes with and displaces the neural mssg of pain. lex: robbing the skin around an injury listening to music) competing Stimuli can Overpower the painful ones. 2 neural gate can be shut by psychological factors rt an individuals cument emotions, inter pretation of events, previous experience managing pain medication Hypnosis surgery nemelbram stimulation Biofeedback relaxation restructuring light therapy techniques

textune gradient provides info about distance, ex-looking at morederalls are perceived as closer picture ppl intront hne more spentry Sensony compling features Them ppl in theback 1 synesthesia perceptual phenomenon in which stimulation of one sensory system (such as hanning) involuntarily leads a person to - genetically inherited expenence an additional sensongresponse in a diff Sensory system such as vision) multimodal perception brain collects the information from the Individual Sensory systems and Integrates coordinates H. perceptual organization figure object being perceived. ground background or Spaces within the object perception constructive process by which me go beyond the Stimuli that are presented to us and attempt to construct a meaningful situation Gestalt laws of organization senes of pnnciples that focus on the ways we organize bits and pieces of information into meaningful wholes closure similanty DOD >proximity DAA >simplicity K focuses on function meaning of stimulus topdom processing perception IS guided by higher level knowledge, work expenence expectations and morivan ons- "see bigger Y leture, then break it " Simutaneously perception is affected by our expectations Bottom-up processing consists of the progres of recognizing and Processing information from indindual components of a Stimuli and moving the pereption of the whole b Smaller features then putting it together (xxpurete) *focuses on what the stimulus is depth perception-ability to view the world in 3 dimonsons and to persure distance. binducar disparity difference in the images seen by the L and eye. bd frerence from these images helps vs determine distance * one Hemlar retinal dispartly oneclose is larger both objects same 3 netinal dispanty distance is minor