process of taking in stimuli from the environment
Post on 27-Dec-2015
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SENSATIONProcess of taking in stimuli from the
environment
Smallest amount of stimulus that can detected at least half the time
Vision:1 candle flame,30 miles away on a dark night
Hearing: tick of watch at 20 feetTaste:1 teaspoon of sugar in 2 gallons of waterSmell:1 drop of perfume in a 3-room apartmentTouch: wing of bee, on your cheek from 1 cm.
ABSOLUTE THRESHOLD:
WOULD YOU NOTICE ONE CANDLE 30 MILES AWAY ON A DARK NIGHT?
http://commons.wikimedia.org/wiki/File:Einzelne_Kerze.JPG
Signal Detection Theory:No absolute thresholds, because it is affected by other factors like attention, expectations, motivations, emotions
Smallest difference between 2 stimuli that a person can detect at least 50% of the time
Just-noticeable difference (jnd)
Weber’s Law: the difference threshold increases in proportion to the original stimuli
Vision: 8%8 more candles to 100 candles to notice that
it’s brighter
DIFFERENCE THRESHOLD:
Decreasing sensitivity to unchanging stimuli-can focus attention on what’s important-lose delicious smell at the coffee shop after a while
http://commons.wikimedia.org/wiki/File:HK_Central_Mid-Level_Caine_Road_Starbucks_Coffee_Shop.JPG
SENSORY ADAPTATION:
Converting environmental stimuli into neural impulses
-senses gather energy/chemicals from environment
-must be converted into electrochemical energy so that neurons can carry the information to the brain to be processed
TRANSDUCTION:
Vision-light waves
Hearing-sound waves
Touch-pressure, temperature, pain
ENERGY SENSES:
-light waves
Most important sense for humans-rely
on it the most
http://commons.wikimedia.org/wiki/File:Cranach,_Lucas_d.J._-_Lucretia_-_Detail_face.JPG
Visual capture: tendency for vision to dominate other senses
VISION:
PROCESS OF VISION:
http://commons.wikimedia.org/wiki/File:Anatomy_and_physiology_of_animals_How_light_travels_from_the_object_to_the_retina_of_the_eye.jpg
THE EYE:
http://upload.wikimedia.org/wikipedia/commons/2/27/Retinal_anatomy.jpg
LIGHT IS REFLECTED OFF OF
OBJECTS AND ENTERS THE EYE
IT PASSES THROUGH THE PROTECTIVE
COVERING OF THE CORNEA
IT ENTERS THROUGH THE PUPIL (BLACK
OPENING) WHICH IS CONTROLLED BY
THE IRIS (COLORED MUSCLE)
LIGHT IS FOCUSED (ACCOMODATION) ON THE RETINA BY
THE LENS ACCORDING TO
DISTANCE
RETINA RECEIVES THE LIGHT UPSIDE
DOWN AND INVERTED
TRANSDUCTION OCCURS IN THE
RETINA
Photoreceptors: cells sensitive to light 3 Layers in retina:1.-Rods: black/white/nighttime vision-in
peripheral vision -Cones: color vision, best acuity,
concentrated in fovea (center of retina)2. Bipolar cells: activate 3rd layer3. Ganglion cells: connect to optic nerve=Transduction (light to neural impulse)
RETINA:
Optic nerve carries
messages into the brain-where leaves the brain
is blind spot
Optic chiasm: half of each optic
nerve goes to the opposite hemisphere
Thalamus: routes the visual information to
the visual cortex in the occipital
lobe
http://commons.wikimedia.org/wiki/File:Constudeyepath.gif
ROY G BIV- VISIBLE SPECTRUM-determined by light’s wavelength
Theories:1.Trichromatic theory: 3 types of
photoreceptors: red, green, blue2. Opponent-process theory: colors come in
opposite pairs (afterimages, colorblindness)
COLOR VISION:
http://commons.wikimedia.org/wiki/File:Spectrummasthead.jpg
HEARING (Audition):
-sound wavesPitch=frequency of wavesLoudness=amplitude of waves
http://commons.wikimedia.org/wiki/File:HumanEar.jpg
Outer ear
collects and
amplifies
sounds
Tympanic membra
ne (eardrum) vibrates with the sound waves
Ossicles (3 bones in middle
ear) vibrate
and activate the Oval Window
Oval window vibrates
the cochlea (transduction happens
here)
Hair cells inside
cochlea activate the
auditory nerve which
carries messages to the thalamus
Thalamus sends
message to auditory cortex in
the occipital
lobe
Conduction deafness: loss of hearing due to inability to carry sound to inner ear (punctured eardrum, ossicles)-hearing aid
Sensorineural deafness: loss of hearing due to damage in the cochlea or auditory nerve-cochlear implant
DEAFNESS:
-sensitive to tactile sensations: pressure, warmth, cold, pain
-all other sensations are combination of these 4
-transductionhappens in skin receptors locatedall over the body
TOUCH (SOMATOSENSATION):
http://commons.wikimedia.org/wiki/File:LeftHand_2.png
Parietal lobe Sensitivity of body part=larger section of
cortex-is also inverted, top
controls the bottom of the body
SOMATOSENSORY CORTEX:
http://commons.wikimedia.org/wiki/File:Sensory_Homunculus.png
-associated with substance P-natural pain killers are endorphins-adaptive=causing damage, stop it
Gate-control theory: theory to explain pain-must go through gate in spinal cord-only most important pains go through-scratch=no longer itch
PAIN:
TASTE (GUSTATION): tastebud receptors-5 tastes: sweet, salty, sour, bitter, umami-supertasters: most tastebuds
SMELL (OLFACTION): receptors in nostril-only sense to not travel to thalamus 1st
-goes to limbic system=memory and emotion
Sensory interaction: work together to create sensation
CHEMICAL SENSES:
Kinesthesis: body position sense-know where body parts are and movements
Vestibular sense: sense of balance-in inner ear-semicircular canals
BODY SENSES:
http://upload.wikimedia.org/wikipedia/commons/2/23/Balance_beam_GMM.jpg
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