AP Psych Unit 1 (Sensation & Perception - Eye) PDF

UNIT 3 Sensation and Perception Why Study Sensation and Perception? Psychologists study sensation and perception to explain how and why externally gathered sensations and perceptions impact behaviors and mental processes Using input from several anatomical structures, the sensa...

UNIT 3 Sensation and Perception Why Study Sensation and Perception? Psychologists study sensation and perception to explain how and why externally gathered sensations and perceptions impact behaviors and mental processes Using input from several anatomical structures, the sensations we perceive process and interpret information about the environment around us and our place within it. This results in perceptions that influence how we think and behave. In this way, sensation and perception provide a bridge between the biological and cognitive perspectives, offering aspects of both for explaining how we think and behave. The ABC’s of Sensation Sensation = the process that occurs when special receptors in the sense organs are activated, allowing various forms of outside stimuli to become neural signals in the brain ○ Sense organs → eyes, ears, nose, skin, and taste buds ○ Transduction = the process of converting outside stimuli, such as light, into neural activity ○ Sensory receptors → specialized forms of neurons, the cells that make up the nervous system Stimulated by different kinds of energy rather than neurotransmitters Ex-receptors in eyes stimulated by light, receptors in ears activated by vibrations, touch receptors stimulated by pressure/temperature, receptors for taste/smell triggered by chemical substances Each receptor type transduces physical info into electrical info in different ways, either depolarizing/hyperpolarizing cell, causing it to fire more/less based on timing/intensity of info detected from the environment ○ In some people, sensory info gets processed unusually Synesthesia = condition in which the signals from the various sensory organs are processed differently; resulting in the sense information being interpreted as more than one sensation Means “joined sensation” Ex: experiencing smells as colors and shapes or sounds, words, and colors as tastes and textures Either signals that come from sensory organs are sent to places of the brain that weren’t originally meant to be or they are processed differently - or people can learn synesthesia like experiences  Ernst Weber did studies trying to determine smallest difference between 2 weights that could be detected ○ Weber’s law of just noticeable difference (JND or the difference threshold) = the smallest difference between two stimuli that is detectable 50 percent of the time M Whatever the difference between stimuli may be, it is always constant ○ Ex: if you sweeten coffee with 5 teaspoons sugar → need 1 more teaspoon to notice difference 50% of the time, % change needed detect JND is 1/5th or 20% Gustav Fechner ○ Expanded on Weber’s work to notice ○ Absolute threshold = the lowest level of stimulation that a person can something consciously detect 50 percent of the time the stimulation is present ne ○ Subliminal stimuli → stimuli below the level of conscious awareness ex that p shes Just strong enough to activate sensory receptors, not strong enough detecting to be consciously aware (picked up by unconscious mind) ○ Subliminal perception → the unconscious processing of sensory information that occurs below the level of conscious awareness (many believe these stimuli act upon unconscious mind, influencing behavior) Signal detection theory = provides a method for assessing the accuracy of judgments or decisions under uncertain conditions; used in perception research and other areas. An individual’s correct “hits” and rejections are compared against their “misses” and “false alarms” a framework for understanding how people detect stimuli in their environment ○ Hit or miss → detection of stimulus ○ False alarm → falsely reporting a stimulus as present ○ correct rejection → reporting that a stimulus isn't there ○ Ex:  When someone walks across the street and hears a car honk, this is a hit. When someone is washing dishes and doesn't hear the phone ring, this is a miss. When someone is sleeping and wakes up thinking they hear the alarm, this is a false alarm. When a family is bird watching and doesn't hear a woodpecker, this is a correct rejection Habituation and Sensory Adaptation Some lower centers of brain filter sensory stimulation and “ignore” or prevent conscious attention to stimuli that don’t change Brain primarily interested in changes in information ○ Ex: people don’t hear noise of air conditioner unless it suddenly cuts off, although they are actually hearing it, not paying attention to it Habituation = tendency of the brain to stop attending to constant, unchanging information backgroundnoise ○ Conscious or unconscious notneedingtobepayingattention ○ No longer requires your attention (not a threat) ○ Habituation, sensory receptors still responding to stimulation, but the lower side centers of brain not sending signals from those receptors to cortex estimatin Sensory Adaptation = tendency of sensory receptor cells to become less responsive to a stimulus that is unchanging ○ Unconscious started stiffation ○ Ex: smelling garbage in kitchen when you first walk in and then it fades ○ Ex: first put food in mouth, tastes strong, fades as we eat more ○ Sensory adaptation different because receptor cells themselves become less Terrase responsive to unchanging stimuli, and receptors no longer send signals to brain The Science of Seeing What is light? Vision: Crash Course Anatomy & Physiology #18 Light is made up of both waves and particles Albert Einstein first proposed light is actually tiny “packets” of waves ○ Wave packets called photons → have specific wavelengths associated with them (distance from one wave peak to the next) 3 psychological properties of light ○ Brightness → determined by amplitude of the wave-how high/low wave is Higher wave-brighter, low waves appear dimmer ○ Color (hue) → determined by length of wave (measured in nanometers)  Long waves found at red end of visible spectrum (portion of whole spectrum of light visible to human eye), shorter waves found at blue end Red, green, blue ○ Saturation → purity of color people perceive Highly saturated red, contain only red wavelengths, less-saturated red contain mixture Mixing colors can lessen saturation of original color Structure of the EYE Light enters eye directly from source (sun) or indirectly by reflecting off object ○ To see clearly, single point of light from source or reflected from an object must travel through structures of eye and end up on retina as single point ○ Light bends as it passes through substances of different densities → refraction Example-look at straw through glass of water, appears broken/bent=optical illusion Surface of eye covered in clear membrane → cornea ○ Protects the eye + focuses/bends most of the light coming into the eye ○ Fixed curvature (convex), like a camera w/ no option to adjust focus ○ Cornea can be surgically improved by changing shape of cornea, helps focus (LASIK) Next layer is a clear, watery fluid → aqueous humor ○ Continually replenished/supplies nourishment to eye Light from visual image then enters interior of eye through hole → pupil ○ Black part of eye / opening that the iris creates Pupil is in a round muscle called the iris (colored part) ○ Iris can change size of pupil allowing more/less light, helps focus the image, I like squinting (dilating and constricting) ○ Responds to light in environment Behind the iris, suspended by muscles, is a clear structure → lens ○ Flexible lens finishes focusing process begun by cornea ○ Can change its curvature to focus images Visual accommodation = the change in the thickness of the lens as the eye focuses on objects that are far away or close ○ From thick to thin (round to flat) ○ Thin for far away and thick for close up ○ Variation in thickness allows lens to project sharp image to retina ○ Presbyopia → as we age lose ability for lens to change/becomes less flexible -harder to see things up close (need bifocals or reading glasses) Presbyopia  ○ Myopia → nearsightedness: eye shape (eyeball too long, cornea or lens too round) causes focal point to fall short of retina - can’t see far, 30% americans ○ Hyperopia → farsightedness (eyeball too short, cornea not round enough, too flat), light focus point is beyond/behind the retina - can’t see close up - 10% americans ○ Astigmatism → cornea or lens of the eye has an abnormal curvature (blurry vision at all distances) Once past the lens, light passes through large, open space filled with clear, jelly-like I fluid → vitreous humor ○ Like aqueous humor, nourishes eye and give it shape Transduction of Light 2-Minute Neuroscience: The Retina Final stop for light → retina, light sensitive (photosensitive) area at back of eye containing 3 layers ○ Rods/Cones (photoreceptors) → respond to various wavelengths of light ○ Bipolar cells ○ Ganglion cells Retina responsible absorbing/processing light info rods/cones business end ○ Part that actually receives photons of light, turns them into neural signals for brain Sends them first to bipolar cells → A type of interneuron; called bipolar or “two-ended” because they have a single dendrite at one end L and a single axon on the other end then bipolar cells sent to retinal ganglion cells (axons form optic nerve) Cones = Visual sensory receptors found at the back of the retina, responsible for color vision and sharpness of vision ○ 6 million each eye, 50,000 have private line to optic nerve ○ Receptors for visual acuity, or fine detail ○ Located all over retina, but heavily concentrated in very center (no rods) → called fovea ○ Work best in bright light, responsible for color vision Rods = Visual sensory receptors found at the back of the retina, responsible for non-color sensitivity to low levels of light ○ 100 million each eye, found all over retina except fovea ○ Concentrated in periphery, responsible for peripheral vision ○ Detect shapes and movements ○ Sensitive to changes brightness (especially dim light/night vision), but not to variety of wavelength, only see black/white/shade of gray ○ Many rods connected to a single bipolar cell → if one rod is stimulated, brain perceives that whole region of rods is stimulated ○ Visual acuity (sharpness) low, things seen in low levels light look fuzzy/grayis  Blind Spot = area in the retina where the axons of the retinal ganglion cells exit the eye to form the optic nerve, insensitive to light ○ If you stare at one spot long enough, objects that slowly cross visual field at one point disappear briefly bc there is a “hole” in the retina-the place where all axons of those ganglion cells leave retina to become optic nerve, the optic disk ○ No rods/cones here https://www.youtube.com/watch?v=zjTCbL2wbRk The Visual Pathway Light entering eye separated left/right visual fields ○ Light from right visual field falls on left side of each eye’s retina, and vice versa Light travels in straight line through cornea + lens, resulting image projected upside down/reversed left to right as compared to visual fields ○ Brain compensates for this Info from left visual field (falling on right side each retina) goes to right visual cortex, while info from right visual field (falling on left side each retina) goes to left visual cortex ○ Why? Retinas are divided in half axons from temporal halves project to visual cortex on same side of brain axons from nasal halves cross over to visual cortex on opposite side of brian Optic chiasm is point of cross over Rods work well in low levels of light, they allow eyes adapt to low light ○ Daylight into a dark movie theater Dark adaptation = The recovery of the eye’s sensitivity to visual stimuli in darkness after exposure to bright lights (daylight to dark) ○ Pupils? dialate ○ Bright lights from car on highway, temporarily see less, then rods readapt to dark ○ Process slows as we age-harder to see at night-night blindness ○ Caused by increased retinal sensitivity in the rods ○ Rhodopsin is light-sensitive pigment in the rods that helps them deal with low-light conditions ○ Takes about 30 min Light adaptation = The recovery of the eye’s sensitivity to visual stimuli in light after exposure to darkness (dark to light) pupils constrict cones take over to pickup color information  ○ The cones have to adapt to the increased level of light ○ Few seconds Cones accomplish light adaptation much faster than rods to dark adaptation atsigyf.EE 1 Ferren Trichromatic (three colors) Theory = theory of color vision that proposes three types of cones: red, blue, green ○ 3 primary colors of light ○ Earliest theory why we can only see colors within visible spectrum ○ 3 cone types in retina work together to perceive a range of colors blue+red=purple, red+green=yellow, black and white produced by rods Theory is we see color based on by comparing responses from 3 kinds of cones, each of which is more sensitive to a short, medium, long wavelength of light Different shades of colors correspond to different amounts of light received by each of these three types of cones Cones fire message to brain’s vision centers Each is sensitive to short, medium, long wavelength of light Color we see depends on mix of strengths of cone types that are firing The combination of cones and the rate at which they fire at determine the color that will be seen ○ This theory focuses on what happens in the eye rather than the brain Opponent-Process Theory = theory of color vision that proposes visual neurons (or groups of neurons) are stimulated by light of one color and inhibited by light of another color ○ Four primary colors: red, green, blue, yellow  ○ The colors are arranged in pairs, with each member of the pair as opponents Red or green - blue or yellow - black or white (without color/detect Iii light dark changes) ○ If one member of a pair is strongly stimulated, the other member is inhibited and cannot be working, so there are no reddish-greens or bluish-yellows ○ Afterimages = Images that occur when a visual sensation persists for a brief time even after the original stimulus is removed Can't be explained by trichromatic theory When you stare at a red object for a long time and then look at a white surface, you will see a green afterimage because the red-sensitive cells are fatigued, causing the green cells to fire more readily. ○ This theory focuses on what happens in the brain rather than the eye Both theories play a part in color vision → explain color vision on different levels J ○ Trichromatic theory → raw stimuli, the actual detection of various wavelengths of light ○ Opponent-process theory → afterimages and other aspects of visual perception that occur after the initial detection of light from our environment Tri-chromatic vs. Color Opponent processing – Introduction to Sensation and Perception Color Blindness Inability to perceive color differences → defective cones in the retina of the eye Color-deficient vision is a better term because people have two types of cones working and can see many colors Caused by lack of short, medium, or long wavelength cones in the fovea Genetic condition → recessive trait ○ Achromatopsia/monochromatic vision → people have cones, but they are not functioning correctly as the result of one or more genetic mutations Very rare Everything looks the same to the brain -all things in shades of gray Complete loss of color perception  ○ Dichromatic vision → have one cone not functioning properly See the world with combinations of two cones/colors ability to distinguish between fine shades of color is reduced 3 Kinds of color blindness How COLOR VISION Works (Types of Color Blindness, Genetics & Disease) ○ Protanopia → red cones not working properly Confuse reds and greens, see world in blue, yellow and shades of gray ○ Deuteranopia → deficient functioning of green cone cells Confuse reds and greens, see world in blue, yellow and shades of gray ○ Tritanopia → lack of blue cone cells See world in primarily reds, greens, and shades of gray Sex-linked inheritance ○ The gene for color-deficient vision is recessive ○ Men have greater chance of getting it (8%) ○ Women need to inherit 2 recessive genes, one from each parent (less than 1%) ○ Man only needs to inherit one on X chromosome from mother Ishihara Test (color blindness test)  UNIT 1 Sensation The Hearing Sense: If a tree falls in a forest, does it make a sound? Audition → biological process which our ears process sound waves Sound waves are vibrations of molecules in air that surround us ○ Travel much slower than light waves Wavelengths interpreted by brain as frequency or pitch (high/medium/low) Amplitude interpreted as loudness (soft/loud a sound is) ○ How much pressure is being forced through the air (measured by decibels) Timbre interpreted as richness in tone of sound A person hears limited frequencies ○ Measured in Hertz = cycles or waves per second, a measure of frequency ○ Human limits 20-20,000Hz ○ To hear higher/lower frequencies music, need to increase amplitude or loudness/volume ○ Animals can perceive sound differently than humans ○ Dog whistle, undetectable by human ears Structure of the Ear Outer Ear ○ Pinna = the visible, external part of the ear - concentrates/funneling the soundwaves from outside the structure Also entrance to the auditory canal ○ Auditory Canal (ear canal) = short tunnel that runs from the pinna to the eardrum (tympanic membrane)  When sound waves hit eardrum, they cause 3 tiny bones (auditory ossicles) in middle ear vibrate Middle Ear ○ Hammer (malleus), anvil (incus), stirrup (stapes), each named for shape Collectively referred to as ossicles 3 smallest bones in body, vibration of 3 amplifies vibrations from eardrum Stirrup (last bone in the chain) causes the membrane (oval window- part of cochlea) covering the opening of inner ear to vibrate Inner Ear (where stapes meets oval window) ○ Cochlea = snail shaped structure of the inner ear that is filled with fluid When the oval window vibrates, it causes the fluid in the cochlea to vibrate. Fluid surrounds the basilar membrane Basilar membrane contains organ of Corti which contains receptor cells for hearing Basilar membrane vibrates causes organ of Corti vibrate, hair cells on organ of Corti (auditory receptors for sound)(transduction of vibrations to nerve impulses), send neural message through auditory nerve + into brain, passes through thalamus to temporal lobe’s auditory cortex, which interprets sound Auditory Nerve = bundle of axons from the hair cells in the inner ear Perceiving Pitch Pitch = Psychological experience of sound that corresponds to the frequency of the sound waves; higher frequencies are perceived as higher pitches ○ How high or low a sound is Place theory = Theory of pitch that states that different pitches are experienced by the stimulation of hair cells in different locations on the organ of Corti ○ Pitch depends on where the hair cells that are stimulated are located Frequency theory = Theory of pitch that states that pitch is related to the speed of vibrations in the basilar membrane ○ Frequency coding → basilar membrane vibrates at that frequency with nerve impulses that correspond to that pitch ○ In this theory, all of the auditory neurons are firing at the same time Frequency theory works for low pitches + place theory works moderate/high pitches Volley Principle = Theory of pitch that states that frequencies from about 400 Hertz to 4,000 Hertz cause the hair cells (auditory neurons) to fire in a volley pattern, or take turns in firing ○ Groups of neurons work together to produce a combined pattern of neural firing that corresponds to the higher pitch of the sound wave ○ Explains higher pitched sounds Sound localization → determining where a sound originates based on loudness and timing of when ear receives the sound (louder/close) Types of Hearing Impairments Hearing impairment-used to refer to difficulties in hearing ○ Partially hearing impaired/totally hearing impaired Conduction deafness → problems with mechanics of outer or middle ear ○ Sound vibrations can’t be passed from eardrum to cochlea ○ Cause may be a damaged eardrum or damage to the bones in the middle ear ○ Can be treatable, hearing aids can restore hearing Common for older people Sensorineural deafness/Nerve deafness→damage to the inner ear (cochlea or hair cells), the auditory nerve, or auditory processing areas of the brain. ○ Most common type of permanent hearing loss ○ Hair cells can be abnormal at birth, infection or trauma → once dead can no longer function or be replaced ○ 90% preventable ○ Exposure to excessive loud sounds and headphone/earbud style ○ Hearing aids usually can’t help because damage is to the nerves or brain Normal hearing aids are sound amplifiers ○ Cochlear implants → an “electrode array” is surgically placed within the  cochlea and an external device is placed behind the pinna to collect and process sounds and transmit the signals to the cochlear implant, which stimulate the auditory nerve.. Brain processes the electrode info as sound Chemical Senses (Taste and Smell) Sense of taste and smell very closely related (chemoreception) ○ 90% of what we deem taste is really smell ○ Without input from nose, only 4 or 5 kinds of taste sensors in mouth Food preferences or aversions form very early in life Taste one of earliest developed senses Developing babies exposed to substances mother inhales or digests, impart flavor to amniotic fluid which baby ingests After birth, exposure to different tastes/smells may affect food choices/nutritional status, picking certain foods over others for long time Taste Buds Taste buds = taste receptor cells, special neurons in mouth responsible for sense of taste (gustation) Most taste buds tongue, few on roof of mouth, cheeks, under tongue, throat Amount tastebuds indicates how sensitive person is various tastes ○ Some have 500, others 20xs that- “supertasters” (detect all levels of taste) Very picky abt amount of specific spices in food + much more sensitive to chemicals, like hot peppers There are medium and non tasters too Bumps seen on tongue → papillae → taste buds line inside walls of papillae Each taste bud has 20 receptors, work like receptor sites on neurons ○ Receive molecules various substances fit into receptor like key into lock ○ Taste called chemical sense, works w/ food molecules same way neural receptors work w/ neurotransmitters ○ Molecules (dissolved in saliva) fit into receptors, signal is fired to brain which interprets sensation ○ Taste receptors get big workout, replaced every 10 →14 days ○ Tongue is burned, damaged cells no longer work, over time get replaced, taste sense comes back Our taste buds die and grow back about every two weeks. Around 40 years of age, this process slows down, so while the buds continue to die off, fewer grow back. Fewer taste buds means blander taste, and a different combination of activated cells when we experience a food. The 6 Tastes Sweet, salty, sour, bitter, umami( brothy, meaty, savory flavor), and oleogustus (fatty) ○ Umami → glutamate → found in certain foods but also breast milk ○ Oleogustus → unpleasant/gag fat ○ Most sensitive to bitter and least to sweet ○ Sweet →energy (glucose) ○ Salt → brain requires sodium to function properly ○ Sour → toxic/poison All taste sensations processed all over tongue Taste info sent to thalamus then gustatory cortex taste sensations work together along with sense smell and texture, temperature, and “heat” of foods, produce thousands taste sensations, further affected by culture, personal expectations, past learning experiences Sense of Smell Olfaction = Sense of smell → chemical, like taste Outer part of nose is like pinna/ear canal → collect sensory info, pass to brain Upper nasal cavity (mucus cavity) transduces odors to signals brain can understand ○ Areas olfactory receptor cells about inch square each cavity (10 million olfactory receptors) ○ Receptor sites on hair cells send signals to brain when stimulated by molecules of substances in air moving past them Olfactory receptor cells have cilia (little hairs), that project into cavity ○ Like taste buds, receptor sites on these hair cells send signals to brain when stimulated ○ Die off every 5-8 weeks and are replaced, at least 1,000 receptors When a person sniffs, that moves molecules of smell into nose and into nasal cavities Vision/hearing/taste/touch signals all pass through THALAMUS + then on to different parts of the cortex ○ Sense of smell processed special place in brain → olfactory bulbs = Two bulb like projections of the brain located just above the sinus cavity and just below the frontal lobes that receive information from the olfactory receptor cells Located right on top sinus cavity, each side brain, directly beneath frontal lobes Olfactory receptors send neural signals directly to bulbs to higher cortical areas, primary olfactory cortex, orbitofrontal cortex, amygdala Pheromones = airborne chemical signals that animals can perceive The Other Senses Somesthetic Senses = The body senses consisting of the skin senses, the kinesthetic sense (movement), and the vestibular senses (balance) ○ Soma = “body” + esthetic = “feeling” ○ Each system provides info for the brain to form a cohesive understanding of bodily interactions and spatial orientation Skin senses → touch, pressure, temperature, pain ○ Skin is a huge organ-20 square feet in size ○ Receives and transmits info from outside world to CNS (thalamus to the somatosensory cortex in parietal lobe) ○ Special receptors for touch, pressure, temperature, pain Structures within the skin and brain process and/or transduce touch stimuli. The sensation of “hot” is produced by the activation of warm and cold receptors in the skin. Type of skin receptors ○ Pacinian (puh-see-nee-ian) corpuscles → just beneath skin, respond to changes in deep pressure & vibrations Nerves endings wrap around end hair follicles (tweeze eyebrows, someone pulls your hair) Sensitive to both pain/touch ○ Free nerve endings just beneath uppermost layer skin respond changes temp/pressure/pain ○ Pain nerve fibers/pressure receptors → in internal organs how we have stomach ache/intestinal pain, full bladder Different types of pain  ○ Visceral Pain → Receptors detect pain (and pressure) in organs ○ Somatic Pain → Pain sensations in skin/muscles/tendons/joints carried on large nerve fibers Body’s warning system something is being, or about to be, damaged Tends to be sharp and fast 2nd type of somatic pain carried on small nerve fibers, kind of reminder system, slower, more general ache/throb (keeps from further injury) Ex: hit your thumb with hammer, first pain is intense/sharp/fast, later it becomes bruise, ache, reminds you to take it easy on it Pain: Gate Control Theory ○ The more neurons fire in response to a pain stimulus, the more intense the pain ○ pain signals must pass through the same neural “gate” located in spinal cord Activity of gate can close by non-pain signals coming into spinal cord from body/brain If gate is closed by one pain message, other messages may not be able to pass through (ex: scratch v. itch) (override the pain w/competing sensory signal) Gate not physical structure, represents relative balance in neural activity of cells in spinal cord Stimulation of pain receptors releases neurotransmitter and neuromodulator → substance P (peptide)(carries pain message) Releases into spinal cord activates other neurons send messages through spinal gates (opened by pain signal) From spinal cord, message goes to brain, activating cells thalamus, somatosensory cortex, frontal lobes, limbic system Brain then interprets pain info, sends signals either to open spinal gates further (causes greater experience pain) or closes them (dampening pain) ○ anxiety/fear/helplessness intensify pain ○ laughter/distraction/sense of control/mental state about the pain can diminish it ○ Body can release endorphins → natural version of morphine Inhibit transmission pain signals in brain, inhibit release of substance P in spinal cord ○ Current research shows women feel pain more intensely than men Pain Disorders  ○ Congenital analgesia and Congenital insensitivity to pain with anhidrosis (inability to sweat normally) → people born without ability to feel pain Kids reckless behavior, prone to infection They fear nothing ○ Phantom limb pain → 50-80% amputees experience sensations-burning, shooting pains, pins/needles due to amputation of limb Once believed psychological problem, now believed caused by traumatic injury to nerves during amputation Maladaptive neuroplasticity or reorganization of some parts of the somatosensory cortex After amputation, the brain continues to receive signals from limb nerves - now misinterpreted as pain Body Movements and Position Kinesthesia = the awareness of body movements ○ Special receptors in muscles/tendons/joints provide information about body movement and the movement and location of arms/legs in relation to one another → create mental map of position ○ No visual feedback ○ Coordinated movement and spatial awareness Proprioception = Awareness of where the body and body parts are located in relation to each other in space and to the ground ○ When you close eyes + lift hand over head, you know where hand is bc these special receptors (proprioceptors) tell you about joint movement or muscles stretching/contracting Vestibular Sense = The awareness of the balance, position, and movement of the head and body through space in relation to gravity’s pull ○ Structures for this sense located in inner ear ○ Otolith organs → tiny sacs found just above cochlea Movement acts as stimulus, sacs contain gelatin-like fluid with tiny crystals suspended, tells person they’re moving forward/backward/sideways/up/down Basically how the cochlea works just with movement as stimulus rather than sound Vertigo ○ Semicircular canals → 3 somewhat circular tubes filled with fluid will stimulate hairlike receptors when rotated Just like X/Y/Z axes in math, body has similar structure (planes) When you spin, fluid in horizontal canal is still rotating, makes you feel dizzy Can influence balance ○ Disagreement in what eyes say + body says causes motion sickness Sensory conflict theory = An explanation of motion sickness in which the information from the eyes conflicts with the information from the vestibular senses, resulting in dizziness , nausea, and other physical discomfort Disorientation Fixating on point helps reach equilibrium back Repeated exposure can environment causing motion sickness can help alleviate