Sensation & perception 6-8%



sensation & perception 6-8%

people:

gustav fechner – fechner’s law

david hubel & torsten wiesel – vision nobel

prize, feature detectors

ernst weber – weber’s law

torsten wiesel – sensory deprivation (seeing) long term effects

sensory transduction (stimuli signals transformed into neural impulses),

sensory adaptation (decreased responsiveness), sensory habituation (how fouced we are about them), cocktail-party phenomenon (involuntarily pay attention), sensation (activation of senses like eyes & ears), perception (understanding sensations)

vision (dominant sense) –

light intensity = how bright appears

light wavelength = hue we see (longer than we can see are infrared, microwaves, radio waves; shorter are ultraviolet & x-rays) – longest to shortest – roy g. biv; objects color appearance b/c reflect that wavelength

eye – cornea (protects & helps focus the light), pupil (muscles are iris – dilate to let more light in), accomodation (process of focusing light), lens (curved & flexible to focus), image is flipped upside down and inverted & then projected on retina (screen on back of eye)

transduction – (translate incoming stimuli into neural signals – other senses as well) happens when light activates neurons in retina including cones (activated by color, more in center of retina) & rods (black & white, more 20 to 1, peripheral, night vision), fovea centralis (lots of cones, focus spot), next bipolar cells activated, then ganglion

cells fire, axons of ganglion cells = optic nerve – send impulses to thalamus part called the lateral geniculate nucleus (lgn) – then sent to visual cortex in occipital lobe, blind spot (optic nerve leaves retina – no rods or cones) optic nerve – 2 parts to diff hemispheres, optic chiasm (where nerves cross each other)

inside brain – impulses activate feature detectors (groups of neurons in visual cortex that respond to diff types of visual images) ex: vertical lines/curves/motion, visual impairment

theories of color

trichromatic -(cones detect blue, red, green),

opponent-process theory – red/green, blue/yellow, black/white sensory receptors in

pairs – if one is stimulated, its pair is inhibited from firing – explains dichromatic color blindness, monochromatic color blindness (only gray), afterimages

hearing – sound waves & transduction

amplitude – height of wave (loudness – decibels)

frequency – length of wave (pitch –

megahertz), high-pitched = high freq = waves densely packed together

ear parts – pinna (outer ear), ear canal/auditory canal, eardrum/tympanic membrane, ossicles bones (hammer/malleus, anvil/incus, stirrup/stapes), oval window, cochlea (snail shell w/fluid), basilar membrane (floor of cochlea), lined w/hair cells (connected to organ of corti – neurons activated by hair cells movement), fluid moves = hair cells move = transduction, impulses to brain via auditory nerve

pitch theories

place theory – hair cells respond to diff freq

of sound based on where located in cochlea (upper tones)

frequency theory – lower tones – rate at

which cells fire – hair cells fire at diff rate (freq) in the cochlea

deafness

conduction deafness (problem conduction sound to cochlea)

nerve/sensorineural deafness – hair cells damaged (by loud noise) – don’t regenerate

touch – some nerve endings respond to pressure, others temp, nerve ending concentrated in certain areas, if touch or temp receptors stimulated sharply then pain receptors will also fire

gate-control theory – pain messages high priority so nerve “gates” swing wide open and shut for low priority messages – allow you to focus on message, endorphins (brain pain killers) & opiates (morphine) also swing gate shut

chemical senses (taste & smell)

taste/gustation – chemicals in food absorbed by taste buds on tongue (located on papillae – bumps on tongue), types – sweet, salty, sour, bitter, & maybe umami, some taste buds respond more intensely to specific taste and more weakly to others, more densly packed taste buds = more chemicals absorbed = more intense tasting food, food flavor = combination of taste & smell

smell/olfaction – chemicals emitted by substances

nose, nostril, mucous membrane, absorbed by olfactory receptor cells, olfactory bulb straight to limbic system of brain (amygdala and hippocampus – emotion and memory = powerful trigger for memories), anosmia (burnt out receptors), pheromones (natural chemicals), context driven

body position senses

vestibular senses – how body is oriented in space by 3 semicircular canals filled w/fluid in inner ear (provide feedback on body orientation), if fluid moves so much brain receives confusing signals = dizziness & nausea

kinesthetic sense – feedback on position and orientation of specific body parts (arm, leg), receptors in muscles and joints send info to brain

perception –

psychophysics (study interaction b/w sensations receive and experience of them)

absolute threshold – smallest amount of stimulus we can detect

subliminal stimuli (below absolute threshold) – most messaging not scientifically supported

difference threshold/just noticeable difference (smallestamount of change needed in a stimulus before we detect a change)

weber’s law (computes jnd) – change needed is proportional to the original intensity of stimulus)

weber’s constants differ for senses – hearing 5%, vision 8%

perceutual theories

signal detection theory – takes into account how

motivated we are to detect certain stimuli & what expect to perceive (factors caled response criteria/receiver operating characteristics), false positive – think perceive stimulus that is not there

false negative – no perceiving stimulus that is present

top-down processing – perceive by filling in gaps in what we sense (use background knowledge to help)

schemata (mental representations of how expect the world to be) create perceptual set (predispostion of perceiving something in certain way) – backmasking (70s b/c expected bad messages); makes you vulnerable to illusions

bottom-up processing/feature analysis – use only features of the object itself to build a complete perception – put characteristics together to get perception of object – automatic process – feature detectors in visual cortex – longer but more accurate

culture & experience influence perception – perceptual set, context effects

role of attention

rules of visual perception & optical illusions

figure-ground relationship – figure vs

background

gestalt rules – perceive images as groups not isolated elements

proximity – close = group

similarity – similar = group

continuity – continuous form = group

closure – fill in gaps = group

constancy

size (closer = bigger but know same object)

shape (diff angles/diff view but know same

object)

brightness – see as being constant color even as light reflects off object diff

perceived motion

stroboscopic effect – flip books – series of pics

phi phenomenon – lights turning on/off see motion

autokinetic effect – spot on light on wall in dark room – stare at – appears to move

depth cues & depth perception

eleanor gibson & visual cliff experiment

monocular cues – linear perspective, relative size cue, interposition cue (blocks other object = must be closer), texture gradient, shadowing

binocular cues – binocular

disparity/retinal disparity (closer object more disparity b/w images from each eye), convergence (closer to face – eyes move towards each other to keep focus)

muller-lyer illusion – lines w/arrows

esp (6th sense) – no scientific proof – telepathy, clairvoyance, precognition, psychokinesis

states of consciousness 2-4%

people:

william james –

sigmumd freud

ernest hilgard

dualism vs monism (mind & body)

consciousness – awareness about

ourselves and environment – diff states not on/off , states (daydreaming, dreaming, awake, hypnosis, hallucination, meditation

freud & levels – conscious, pre, un

evidence that there are levels -- mere exposure effect, priming, blind sight

levels--conscious level, nonconscious level (heart, digestion, breathing), preconscious level (not thinking about but could be/preconscious memory), subconscious level (priming & mere exposure effect), unconscious level (psychoanalytics believe in this)

sleep – one of the states of consciousness (not unconscious), circadian rhythm (24hr metobolic &thought pattern) & sleep cycle (use eeg to examine)

sleep stages

sleep onset – falling asleep

drowsy but awake – alpha waves (mild hallucinations)

stage 1 – fall asleep

1 & 2 – theta waves (high freq, low amplitude)

stage 2 – sleep spindles (short burst of rapid brain waves)

3 & 4 – delta sleep (slow wave) – deeper & less aware of environment, important for replenishing body’s chemicals, growth, & immune

go backwards thru 3 , 2, 1

rem –intense brain activity like when awake, paradoxcal sleep, dreams (but any stage), memory, rem rebound

90 minute stages 4 to 7 times /night, close to morning less time in 3 & 4, babies more rem

sleep disorders

insomnia (10%), caffeine problem

narcolepsy (suddenly fall into rem sleep)

sleep apnea – stop breathing wake up slightly and don’t know it, overweight men

night terrors – children, stage 4 sleep

sleep walking – somnambulism – kids

dreams

freud – manifest vs latent content

activation-synthesis theory – brain

intepreting what is happening physiologically during rem

information-processing theory – dealing w/daily

stress and info during rem

hypnosis

posthypnotic amnesia—forget hypnotized

events

posthypnotic suggestions

hypnotic suggestibility --

role theory – act out role

state theory – altered state of consciousness (pain control)

dissociation theory – ernest hilgard – voluntarily divided consciousness & hidden observer level monitors what is happening – hand in ice (no pain) but lift finger if any part of them felt pain

psychotherapy

drugs – psycchoactive drugs – chemicals change chemistry of brain

agonists – mimic neurotransmitters

antagonists – block neurotransmitters

reuptake inhibitors

drug dependence

tolerance – drug takes place of natural neurotransmitter

addiction

withdrawal & symptoms

stimulants (caffeine, cocaine, amphetamines,

nicotine) – speed up processes include. ans (hr, breathing), leads to euphoria (concaine), side effects – disturbed sleep, reduce appetite, anxiety, heart problems)

depressants – slow down (alcohol, barbiturates,

anxiolytics/tranquilizers/antianxiety drugs) valium, alcohol – inhibits judgement, cerebellum (motor coordination)

hallucinogens (psychodelics) – sensory

hallucinations, identity loss, vivid fantasies (lsd, peyote, mushrooms, marijuana), remain in body for weeks – add a little – more profound effect – reverse tolerance

opiates – morphine, heroin, methadone, codeine,

opium (poppy plant), agonists for endorphins – painkillers & mood elevators, drowsiness & euphoria, very addictive b/c rapid brain chemistry change

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