Sensation and Sensation and PerceptionPerception

Chapter 4Chapter 4

Sensation and Sensation and PerceptionPerception

ThEcOwgAvecOlaThEcOwgAvecOla ““The Cow Gave Cola”The Cow Gave Cola”

.rat eht saw tac ehT.rat eht saw tac ehT ““The cat saw the rat” or “the cat was The cat saw the rat” or “the cat was

the rat”the rat”

I cdnuolt bleveiee taht I cloud aulacity I cdnuolt bleveiee taht I cloud aulacity uesdnatnrd waht I was rdanieg. The uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervy lteter by huamn mnid deos not raed ervy lteter by istlef, but the wrod as a wlohe. Azanmig istlef, but the wrod as a wlohe. Azanmig huh? yaeh, and I awlyas tghuhot slpeling huh? yaeh, and I awlyas tghuhot slpeling was ipmorantt! was ipmorantt!

Spps y wrt n ntrstng stry.  Spps t Spps y wrt n ntrstng stry.  Spps t ws th bst stry y hd vr wrttn.  Nw tk ws th bst stry y hd vr wrttn.  Nw tk tht splndd stry nd rs ll th vwls.  rs tht splndd stry nd rs ll th vwls.  rs thm ll ntl th stry mks n sns bcs, thm ll ntl th stry mks n sns bcs, wll, wht s  wrd wtht  vwl?   spps wll, wht s  wrd wtht  vwl?   spps thr r sm wrds wth n vwl.  Th wrd thr r sm wrds wth n vwl.  Th wrd “my” fr nstnc hs n vwl, bt sn’t “my” fr nstnc hs n vwl, bt sn’t thr  syng, “nd smtms y?”   stry thr  syng, “nd smtms y?”   stry wtht vwls wld b cnfsng, prplxng, wtht vwls wld b cnfsng, prplxng, cmpltly bfflng.  Wld y b bl t rd cmpltly bfflng.  Wld y b bl t rd t?  Wld y b bl t cmprhnd wht th t?  Wld y b bl t cmprhnd wht th stry ws syng?stry ws syng?

Sensation and Sensation and PerceptionPerception

Sensation- the process of receiving Sensation- the process of receiving information from the environmentinformation from the environment

Perception- the process of organizing Perception- the process of organizing sensory information and making it sensory information and making it meaningfulmeaningful

Absolute Threshold- the level of sensory Absolute Threshold- the level of sensory stimulation needed for sensation (and stimulation needed for sensation (and thus perception) to occurthus perception) to occur Ex. A dim light in a well light room is barely Ex. A dim light in a well light room is barely

visible, yet highly visible in a dark roomvisible, yet highly visible in a dark room Ex. Slight ding is barely audible in a noisy Ex. Slight ding is barely audible in a noisy

room, yet highly audible in a quiet roomroom, yet highly audible in a quiet room

Sensation and Sensation and PerceptionPerception

Subliminal Perception (Subliminal Subliminal Perception (Subliminal Messages)- stimulation that is below our Messages)- stimulation that is below our threshold and takes place below our level threshold and takes place below our level of consciousnessof consciousness

Watch clips Watch clips

of moviesof movies

Does subliminal Does subliminal

advertising work?advertising work?0

25

50

75

100

Low Absolutethreshold

Medium

Intensity of stimulus

Percentageof correctdetections

Subliminal stimuli

Sensation and Sensation and PerceptionPerception

Weber’s Law- to perceive a Weber’s Law- to perceive a difference between 2 stimuli, they difference between 2 stimuli, they must differ by constant proportionmust differ by constant proportion

Sensory Adaptation- diminished Sensory Adaptation- diminished sensitivity with constant stimulationsensitivity with constant stimulation Ex. Smell when you walk in a restaurantEx. Smell when you walk in a restaurant Ex. Light in a movie theaterEx. Light in a movie theater

Whorff HypothesisWhorff Hypothesis Show list of colors and label the colorsShow list of colors and label the colors

List as many words for “love” as you canList as many words for “love” as you can List as many words for “snow” as you canList as many words for “snow” as you can

Whorff Hypothesis- the more words a culture Whorff Hypothesis- the more words a culture has for something, the more they perceive ithas for something, the more they perceive it

Ex. Teenagers can think of many words for loveEx. Teenagers can think of many words for love

Ex. Eskimos have many words– we have only a Ex. Eskimos have many words– we have only a fewfew

Sensation- VisionSensation- Vision

Vision- sense of seeing

White Light- light as it originates (off the sun or off a bulb) before it is broken into different frequencies

Vision contVision cont

Vision contVision cont

Cornea- clear outer covering of the eyeCornea- clear outer covering of the eye Pupil- adjustable opening in the eyePupil- adjustable opening in the eye

black circleblack circle Gets larger in darkness to allow more light Gets larger in darkness to allow more light

in, and smaller in brightness to keep light in, and smaller in brightness to keep light outout

Iris- colored circular muscle that opens Iris- colored circular muscle that opens and closes the pupiland closes the pupil

Lens- behind pupil to change shape and Lens- behind pupil to change shape and focus the image in the retinafocus the image in the retina

Vision contVision cont

Retina- inner surface in the back of the Retina- inner surface in the back of the eye which contain million of receptorseye which contain million of receptors

Rods- visual receptor for black and white Rods- visual receptor for black and white Cones- visual receptors for colorCones- visual receptors for color Page 95 in the book Fire TruckPage 95 in the book Fire Truck Fovea- central part of the retina where Fovea- central part of the retina where

cones exist and images are projectedcones exist and images are projected Optic Nerve- carries visual information Optic Nerve- carries visual information

to the brain for interpretationto the brain for interpretation

Vision contVision cont

Blind Spot- portion of the retina Blind Spot- portion of the retina where the optic nerve exits the eye, where the optic nerve exits the eye, and there are no rods and conesand there are no rods and cones

Put hand over one eye, place other Put hand over one eye, place other hand straight out at arms length and hand straight out at arms length and one finger up, move hand SLOWLY one finger up, move hand SLOWLY outward, finger will “disappear”outward, finger will “disappear”

Page 94 in the bookPage 94 in the book

Vision contVision cont

Vision contVision cont NearsightedneNearsightedne

ss- see nearby ss- see nearby objects more objects more clearlyclearly

FarsightednesFarsightedness- see faraway s- see faraway objects more objects more clearlyclearly

Color Color Blindness- Blindness- inability to inability to perceive perceive certain colors certain colors such as red such as red and greenand green

Color blind Color blind test page 96test page 96

Vision contVision cont Afterimage- image that remains after Afterimage- image that remains after

stimulation of the retina has endedstimulation of the retina has ended Cones not used fire to bring the visual Cones not used fire to bring the visual

system back in balancesystem back in balance

Another afterimage activity on page 97

VisionVision

Opponent Processing Theory- Opponent Processing Theory- opposing retinal processes enable opposing retinal processes enable color visioncolor vision

Red – GreenRed – Green Blue – YellowBlue – Yellow Black – WhiteBlack – White

Sensation- HearingSensation- Hearing

Audition- sense of hearingAudition- sense of hearing Pitch- how high or low a sound isPitch- how high or low a sound is

Depends on the frequency- how many Depends on the frequency- how many times the wave passes through a pointtimes the wave passes through a point

Timbre- the complexity of a soundTimbre- the complexity of a sound Intensity- how loud a sound isIntensity- how loud a sound is Decibels- measure of sounds Decibels- measure of sounds

intensity (loudness)intensity (loudness)

HearinHearing g

contcont

Hearing contHearing cont Eardrum- piece of skin stretched tightly over Eardrum- piece of skin stretched tightly over

the entrance to the earthe entrance to the ear Like a real drumLike a real drum Sound waves hit the ear drum and vibrate, causing Sound waves hit the ear drum and vibrate, causing

connected bones to vibrateconnected bones to vibrate Cochlea- snail shaped part of the ear filled with Cochlea- snail shaped part of the ear filled with

liquid and small hairsliquid and small hairs Cilia- hair cells in the cochlea that receive Cilia- hair cells in the cochlea that receive

different frequenciesdifferent frequencies Like strings on a musical instrumentLike strings on a musical instrument

Auditory Nerve- bundle of nerves that carry Auditory Nerve- bundle of nerves that carry sound from the ear to the brainsound from the ear to the brain

Sensation- TouchSensation- Touch

Cutaneous Receptors- nerve receptors in Cutaneous Receptors- nerve receptors in the skin which respond to pressure, the skin which respond to pressure, temperature, and paintemperature, and pain

3 Sensations of touch:3 Sensations of touch: PressurePressure TemperatureTemperature PainPain

Sensation- SmellSensation- Smell

Olfaction- the sense of smellOlfaction- the sense of smell Olfactory bulbs- units that receive Olfactory bulbs- units that receive

odor molecules and communicate odor molecules and communicate their nature to the braintheir nature to the brain

Pheromones- odor chemicals that Pheromones- odor chemicals that communicate a messagecommunicate a message

Smell cont

Receptor cells inolfactory membrane

Nasal passage

Olfactorybulb

Olfactorynerve

Smell contSmell cont

Women

Men

10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99Age Group

4

3

2

0

Numberof correct

answers

Women and young adults have best sense of smell

Sensation- TasteSensation- Taste Taste Receptors- chemical receptors on Taste Receptors- chemical receptors on

the tongue that decode molecules of food the tongue that decode molecules of food or drink to identify themor drink to identify them

4 Sensations of Taste:4 Sensations of Taste: SaltSalt SweetSweet SourSour BitterBitter

SensationsSensations

Sensory Interaction- principle that Sensory Interaction- principle that one sense may influence anotherone sense may influence another Ex smell and taste regarding foodEx smell and taste regarding food