Sensa&on(and(Percep&on(

Sensa&on:(your(window(to(the(world((

Percep&on:(interpre&ng(what(comes(in(your(window.((

Bo:om;Up(Processing(

•  Also(called(feature(analysis.(

•  We(use(the(features(on(the(object(itself(to(build(a(percep&on.(

•  Takes(longer(that(top;down(but(is(more(accurate.(

(

Click(to(see(an(example(of(bo:om(–up(processing.((

Top;Down(Processing(

•  We(perceive(by(filling(the(gaps(in(what(we(sense.(

•  I(_ant(ch_co_ate(ic_(cr_am.(

•  Based(on(our(experiences(and(schemas.(

•  If(you(see(many(old(men(in(glasses,(you(are(more(apt(to(process(a(picture(of(an(old(man((even(when(you(may(be(in(error).(

6(

Psychophysics8A$study$of$the$relationship$between$physical$

characteristics$of$stimuli$and$our$psychological$experience$with$them.8

8

Physical$World8 Psychological$World8

Light8 Brightness8

Sound8 Volume8

Pressure8 Weight8

Sugar8 Sweet8

Signal(Detec&on(theory(

•  Absolute(thresholds(are(not(really(absolute.(

•  Things(like(mo&va&on(or(physical(state(can(effect(what(we(sense.(

•  False(Posi&ves(•  False(Nega&ves(

If(a(baby(whimpers(in(the(night,(mom(is(up(and(listening.((Other(noises(don’t(even(phase(mom.((

10(

Thresholds8

Absolute$Threshold:$Minimum$stimulation$needed$to$detect$a$particular$stimulus$50%$of$the$time.8Prop

ortio

n$of$�Yes�$Respo

nses8

0.00$$$$$$$$$$$$$$$$$0.50$$$$$$$$$$$$$$$$1.008

$$$$$$$$$$$$$0$$$$$$$$$$$$5$$$$$$$$$$$$10$$$$$$$$$$$15$$$$$$$$$$20$$$$$$$$$$258$$$$$$$$$$$$$$$$$$$$$$$$$$$Stimulus$Intensity$(lumens)8

11(

Subliminal$Threshold8

Subliminal$Threshold:$When$stimuli$are$below$

one’s$absolute$threshold$for$conscious$awareness.8

Kurt Scholz/ Superstock

13(

Difference$Threshold8

Difference$Threshold:$Minimum$difference$between$two$stimuli$required$for$detection$50%$of$the$time,$also$called$just$noticeable$difference$

(JND).(Difference8Threshold8

Tell$when$you$(observer)$detect$a$difference$in$the$light.7

No8

Observer�s Response

No8 Yes8

Weber�s(Law(

•  Computes(the(Just(No&ceable(Difference.(

•  The(change(needed(is(propor&onal(to(the(original(intensity(of(the(s&mulus.(

•  The(more(intense(the(s&mulus(the(more(change(is(needed(to(no&ce(the(difference.(

•  8%(for(vision.(

Sensory(Adapta&on(

•  Decreased(responsiveness(to(s&muli(due(to(constant(s&mula&on.(

Do(you(feel(your(underwear(all(day?(

Cocktail;party(phenomenon(

•  The(cocktail%party%effect(describes(the(ability(to(focus(one's(listening(a:en&on(on(a(single(talker(among(a(mixture(of(conversa&ons(and(background(noises,(ignoring(other(conversa&ons.(

•  Form(of(selecBve%aCenBon.(

Ina;entional$Blindness !Ina@entional$blindness$refers$to$the$inability$to$see$an$object$or$a$person$in$our$midst.$

Simmons$&$Chabris$(1999)$showed$that$half$of$the$observers$failed$to$see$the$gorillaVsuited$assistant$in$a$ball$passing$game.$8

Dan

iel S

imon

s, U

nive

rsity

of I

llino

is

Transduc&on(

•  Transforming(signals(into(neural(impulses.(

•  Informa&on(goes(from(the(senses(to(the(thalamus(,(then(to(the(various(areas(in(the(brain.(

Remember(Ethan(in(Sky(High.((He(changes(his(body(to(slime.((Solid(form(to(liquid(form.(((Change(from(one(form(of(energy(to(another.((Click(the(picture(to(watch(power(placement.((

Phase(One:(Gathering(Light(

•  The(height(of(a(wave(gives(us(its(intensity((brightness).((•  The(length(of(the(wave(gives(us(its(hue((color).(•  ROY(G(BIV(•  The(longer(the(wave(the(more(red.(•  The(shorter(the(wavelength(the(more(violet.((

Energy v. Chemical senses

Energy%Senses% Chemical%Senses%

Vision Our(most(dominant(sense.(

%Visual%Capture%

Phase(Two:(Gejng(the(light(in(the(eye(

25(

Parts$of$the$eye81.  Cornea:$Transparent$tissue$where$light$enters$

the$eye.82.  Iris:$Muscle$that$expands$and$contracts$to$

change$the$size$of$the$opening$(pupil)$for$light.83.  Lens:$Focuses$the$light$rays$on$the$retina.84.  Retina:$Contains$sensory$receptors$that$process$

visual$information$and$sends$it$to$the$brain.8

26(

The$Lens8Lens:$$Transparent$structure$behind$the$

pupil$that$changes$shape$to$focus$images$on$the$

retina.88

Accommodation:$The$process$by$which$the$eye�s$lens$changes$

shape$to$help$focus$near$or$far$objects$on$the$

retina.8

27(

The$Lens8Nearsightedness:$A$condition$in$which$

nearby$objects$are$seen$more$clearly$than$distant$objects.8

8Farsightedness:$A$condition$in$which$faraway$objects$are$

seen$more$clearly$than$near$objects.$8

28(

Retina8

Retina:$The$lightVsensitive$inner$

surface$of$the$eye,$containing$receptor$rods$and$cones$in$

addition$to$layers$of$other$neurons$

(bipolar,$ganglion$cells)$that$process$visual$information.8

29(

Optic$Nerve,$Blind$Spot$&$Fovea8

http://www.bergen.org

Optic$nerve:$Carries$neural$impulses$from$the$eye$to$the$brain.$Blind$Spot:$Point$where$the$optic$nerve$leaves$the$eye$because$there$are$no$receptor$cells$located$there.$$This$creates$a$blind$spot.$Fovea:$Central$point$in$the$retina$around$which$the$eye�s$cones$cluster.8

30(

Test$your$Blind$Spot8

Use$your$textbook.$Close$your$left$eye,$and$fixate$your$right$eye$on$the$black$dot.$Move$the$page$towards$your$eye$and$away$from$your$eye.$At$

some$point$the$car$on$the$right$will$disappear$due$to$a$blind$spot.8

Phase(Three:(Transduc&on(

Transduc&on(Con&nued(

•  Order(is(Rods/Cones(to(Bipolar(to(Ganglion(to(Op&c(Nerve.(

•  Sends(info(to(thalamus;(area(called(lateral%geniculate%nucleus%(LGN).(

•  Then(sent(to(cerebral(cortexes.(

•  Where(the(op&c(nerves(cross(is(called(the(opBc%chiasm.(

34(

Visual$Information$Processing8

Optic$nerves$connect$to$the$thalamus$in$the$middle$of$the$brain,$and$the$thalamus$connects$to$

the$visual$cortex.8

35(

Feature$Detection8

Nerve$cells$in$the$visual$cortex$respond$to$specific$features,$such$as$edges,$angles,$and$

movement.8

Ros

s Kin

naird

/ Alls

port/

Get

ty Im

ages

36(

Visual$Information$Processing8

Processing$of$several$aspects$of$the$stimulus$simultaneously$is$called$parallel$processing.$The$brain$divides$a$visual$scene$into$subdivisions$such$

as$color,$depth,$form$and$movement$etc.8

Color(Vision(

Two Major Theories

Trichroma&c(Theory(

Three(types(of(cones:(•  Red(•  Blue(•  Green(•  These(three(types(of(cones(can(make(millions(of(combina&ons(of(colors.(

•  Does(not(explain(anerimages(or(color(blindness(well.(

39(

Color$Blindness8

Ishihara$Test8

Genetic$disorder$in$which$people$are$blind$to$green$or$red$colors.$$This$supports$the$

Trichromatic$theory.8

40(

Opponent$Colors8

Gaze$at$the$middle$of$the$flag$for$about$308Seconds.$When$it$disappears,$stare$at$the$dot$and$report8

whether$or$not$you$see$Britainks$flag.8

41(

Color$Constancy8

Color$of$an$object$remains$the$same$under$different$illuminations.$However,$when$context$changes$the$color$of$an$object$may$look$different.8

R. B

eau Lotto at University C

ollege, London

Constancy(

•  Objects(change(in(our(eyes(constantly(as(we(or(they(move….but(we(are(able(to(maintain(content(percep&on(

•  Shape(Constancy(•  Size(Constancy(•  Brightness(Constancy(

Opponent;Process(theory(

The(sensory(receptors(come(in(pairs.(

•  Red/Green(•  Yellow/Blue(•  Black/White(

•  If(one(color(is(s&mulated,(the(other(is(inhibited.(

Hearing(

Our auditory sense (audition)

We(hear(sound(WAVES(

•  The(height(of(the(wave(gives(us(the(amplitude(of(the(sound.(

•  The(frequency(of(the(wave(gives(us(the(pitch(if(the(sound.(

The(Ear(

Transduc&on(in(the(ear(•  Sound(waves(hit(the(eardrum(then(

anvil%then(hammer(then(sBrrup(then(oval%window.(

•  Everything(is(just(vibra&ng.(•  Then(the(cochlea(vibrates.(•  The(cochlea(is(lined(with(mucus(

called(basilar%membrane.(•  In(basilar%membrane%there(are(hair(

cells.(•  When(hair(cells(vibrate(they(turn(

vibra&ons(into(neural(impulses(which(are(called(organ%of%CorB.(

•  Sent(then(to(thalamus(up(auditory(nerve.(

It(is(all(about(the(vibra&ons!!!(

Pitch(Theories(

Place(Theory(and(Frequency(Theory(

Place(Theory(

•  Different(hairs(vibrate(in(the(cochlea(when(they(different(pitches.(

•  So(some(hairs(vibrate(when(they(hear(high(and(other(vibrate(when(they(hear(low(pitches.(

Frequency(Theory(

•  All(the(hairs(vibrate(but(at(different(speeds.(

(

(

Deafness(

ConducBon%Deafness%•  Something(goes(wrong(with(

the(sound(and(the(vibra&on(on(the(way(to(the(cochlea.(

•  You(can(replace(the(bones(or(get(a(hearing(aid(to(help.(

Nerve%(sensorineural)%Deafness%•  The(hair(cells(in(the(cochlea(

get(damaged.(

•  Loud(noises(can(cause(this(type(of(deafness.(

•  NO(WAY(to(replace(the(hairs.(

•  Cochlea(implant(is(possible.(

53(

Hearing$Deficits8

Older$people$tend$to$hear$low$frequencies$well$but$suffer$hearing$loss$when$listening$for$high$frequencies.8

54(

Deaf$Culture8

Cochlear$implants$are$electronic$devices$that$enable$the$brain$to$hear$sounds.$8

Cochlear Implant Deaf Musician

EG Im

ages/ J.S. Wilson ©

Wolfgang G

stottner. (2004) American

Scientist, Vol. 92, Num

ber 5. (p. 437)

56(

Biopsychosocial$Influences8

Touch(Gate%Control%Theory%of%Pain%•  pain(messages(start(from(nerves(associated(with(the(damaged(&ssue(and(flow(along(the(peripheral(nerves(to(the(spinal(cord(and(on(up(to(the(brain.(

•  before(they(can(reach(the(brain(these(pain(messages(encounter(“nerve(gates”(in(the(spinal(cord(that(open(or(close(depending(upon(a(number(of(factors(

Taste(

•  We(have(bumps(on(our(tongue(called(papillae.(

•  Taste(buds(are(located(on(the(papillae((they(are(actually(all(over(the(mouth).(

•  Sweet,(salty,(sour(and(bi:er.(

59(

Taste8

Traditionally,$taste$sensations$consisted$of$sweet,$salty,$sour,$and$bi@er$tastes.$Recently,$receptors$for$a$fifth$taste$have$been$discovered$called$�Umami�.3

Sweet Sour Salty Bitter Umami (Fresh

Chicken)

Smell$and$Memories8

The$brain$region$for$smell$(in$red)$is$closely$connected$with$the$

brain$regions$involved$with$memory$(limbic$system).$That$is$why$strong$memories$are$

made$through$the$sense$of$smell.8

Sensory$Interaction8

When$one$sense$affects$another$sense,$sensory$interaction$takes$place.$So,$the$taste$of$strawberry$

interacts$with$its$smell$and$its$texture$on$the$tongue$to$produce$flavor.3

Ves&bular(Sense(

•  Tells(us(where(our(body(is(oriented(in(space.(

•  Our(sense(of(balance.(•  Located(in(our(semicircular(canals(in(our(ears.(

Kinesthe&c(Sense(

•  Tells(us(where(our(body(parts(are.(

•  Receptors(located(in(our(muscles(and(joints.(

Without(the(kinesthe&c(sense(you(could(not(touch(the(bu:on(to(make(copies(of(your(bu:ocks.(

Percep&on(

The(process(of(organizing(and(interpre&ng(informa&on,(enabling(us(to(recognize(meaningful(

objects(and(events.(

(

Perceptual$Organization8

When$vision$competes$with$our$other$senses,$vision$usually$wins$–$a$phenomena$called$visual$

capture.88

How$do$we$form$meaningful$perceptions$from$sensory$information?8

8We$organize$it.$Gestalt$psychologists$showed$that$

a$figure$formed$a$�whole�$different$than$its$surroundings.8

Gestalt(Psychology(•  Gestalt(psychologists(focused(on(how(we(

GROUP(objects(together.(

•  We(innately(look(at(things(in(groups(and(not(as(isolated(elements.(

•  Proximity((group(objects(that(are(close(together(as(being(part(of(same(group)(

•  Similarity((objects(similar(in(appearance(are(perceived(as(being(part(of(same(group)(

•  ConBnuity((objects(that(form(a(con&nuous(form(are(perceived(as(same(group)(

•  Closure%(like(top;down(processing…we(fill(gaps(in(if(we(can(recognize(it)(

Grouping8

After$distinguishing$the$figure$from$the$ground,$our$perception$needs$to$organize$the$figure$into$

a$meaningful$form$using$grouping$rules.8

Grouping$&$Reality8

Although$grouping$principles$usually$help$us$construct$reality,$they$may$occasionally$lead$us$astray.8

Both photos by W

alter Wick. R

eprinted from G

AM

ES M

agazine. .© 1983 PC

S Gam

es Limited Partnership

Figure(Ground(Rela&onship(

Our(first(perceptual(decision(is(what(is(the(image(is(the(figure(and(what(is(the(background.(

Depth(Cues(•  Eleanor(Gibson(and(her(Visual%Cliff%Experiment.(

•  If(you(are(old(enough(to(crawl,(you(are(old(enough(to(see(depth(percep&on.(

•  We(see(depth(by(using(two(cues(that(researchers(have(put(in(two(categories:((

•  Monocular(Cues(

•  Binocular(Cues((

Binocular(Cues(

•  We(need(both(of(our(eyes(to(use(these(cues.(

•  ReBnal%Disparity%(as(an(object(comes(closer(to(us,(the(differences(in(images(between(our(eyes(becomes(greater.(

•  Convergence((as(an(object(comes(closer(our(eyes(have(to(come(together(to(keep(focused(on(the(object).(

Binocular$Cues8

Retinal$disparity:$Images$from$the$two$eyes$differ.$Try$looking$at$your$two$index$fingers$when$pointing$them$towards$each$other$half$an$inch$apart$and$about$5$inches$

directly$in$front$of$your$eyes.$You$will$see$a$“finger$sausage”$as$shown$in$the$inset.8

Binocular$Cues8

Convergence:$Neuromuscular$cues.$When$two$eyes$move$inward$(towards$the$nose)$to$see$near$objects$and$outward$(away$from$the$nose)$to$see$

faraway$objects.8

Monocular$Cues8

Relative$Size:$If$two$objects$are$similar$in$size,$we$perceive$the$one$that$casts$a$smaller$retinal$image$

to$be$farther$away.8

Monocular$Cues8

Interposition:$Objects$that$occlude$(block)$other$objects$tend$to$be$perceived$as$closer.8

Rene M

agritte, The Blank Signature, oil on canvas, N

ational Gallery of A

rt, Washington. C

ollection of M

r. and Mrs. Paul M

ellon. Photo by Richard C

arafelli.

Monocular$Cues8

Relative$Clarity:$Because$light$from$distant$objects$passes$through$more$light$than$closer$objects,$we$perceive$hazy$objects$to$be$farther$away$than$those$objects$that$appear$sharp$and$clear.8

Monocular$Cues8

Texture$Gradient:$Indistinct$(fine)$texture$signals$an$increasing$distance.8

© Eric Lessing/ A

rt Resource, N

Y

Monocular$Cues8

Relative$Height:$We$perceive$objects$that$are$higher$in$our$field$of$vision$to$be$farther$away$than$those$that$are$lower.8

Image courtesy of Shaun P. Vecera, Ph. D

., adapted from

stimuli that appered in Vecrera et al., 2002

Monocular$Cues8

Relative$motion:$Objects$closer$to$a$fixation$point$move$faster$and$in$opposing$direction$to$those$

objects$that$are$farther$away$from$a$fixation$point,$moving$slower$and$in$the$same$direction.$8

Monocular$Cues8

Linear$Perspective:$Parallel$lines,$such$as$railroad$tracks,$appear$to$converge$in$the$distance.$The$

more$the$lines$converge,$the$greater$their$perceived$distance.8 ©

The New

Yorker Collection, 2002, Jack Ziegler

from cartoonbank.com

. All rights reserved.

Monocular$Cues8

Light$and$Shadow:$Nearby$objects$reflect$more$light$into$our$eyes$than$more$distant$objects.$Given$two$identical$objects,$the$dimmer$one$appears$to$be$farther$away.8

From �Perceiving Shape From

Shading� by V

ilayaur S. R

amachandran. ©

1988 by Scientific Am

erican, Inc. A

ll rights reserved.

Apparent$Motion8

Phi$Phenomenon:$When$lights$flash$at$a$certain$speed$they$tend$to$present$illusions$of$motion.$Neon$signs$use$this$principle$to$create$motion$

perception.8

Two lights flashing one after the other. One light jumping from one point to another: Illusion of motion.

Perceptual$Constancy8

Perceiving$objects$as$unchanging$even$as$illumination$and$retinal$images$change.$Perceptual$constancies$include$constancies$of$shape$and$size.8

Shape$Constancy8

Size$Constancy8

Stable$size$perception$amid$changing$size$of$the$stimuli.8

Size$Constancy8

SizeVDistance$Relationship8

The$distant$monster$(below,$left)$and$the$top$red$bar$(below,$right)$appear$bigger$because$of$

distance$cues.8

From Shepard, 1990

Alan C

hoisnet/ The Image B

ank

SizeVDistance$Relationship8

Both$girls$in$the$room$are$of$similar$height.$However,$we$perceive$them$to$be$of$different$heights$as$they$stand$in$the$two$corners$of$the$

room.

Both photos from S. Schwartzenberg/ The Exploratorium

Ames$Room8

The$Ames$room$is$designed$to$demonstrate$the$sizeVdistance$illusion.8

Perceived(Mo&on(

•  Stroboscopic(effect((flip(book(effect)(

•  Phi(phenomenon((

•  Autokine&c(Effect((if(people(stare(at(a(white(spotlight(in(a(dark(room,(it(appears(to(move.)(

Monocular(Cues(

•  You(really(only(need(one(eye(to(use(these((used(in(art(classes(to(show(depth).(

•  Linear(Perspec&ve(•  Interposi&on(•  Rela&ve(size(•  Texture(gradient(•  Shadowing(

Perceptual$Adaptation8

Visual$ability$to$adjust$to$an$artificially$

displaced$visual$field,$e.g.,$prism$glasses.8

Courtesy of H

ubert Dolezal

Perceptual$Set8

A$mental$predisposition$to$perceive$one$thing$and$not$another.$What$you$see$in$the$center$picture$is$influenced$by$flanking$pictures.8

From Shepard, 1990.

(a)$Loch$ness$monster$or$a$tree$trunk;$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$(b)$Flying$saucers$or$clouds?8

Perceptual$Set8

Other$examples$of$perceptual$set.8

Frank Searle, photo Adam

s/ Corbis-Sygm

a

Dick R

uhl

Childrenks$schemas$represent$reality$as$well$as$their$abilities$to$represent$what$they$see.8

Schemas8

Schemas$are$concepts$that$organize$and$interpret$unfamiliar$information.8

Courtesy of A

nna Elizabeth Voskuil

Claims$of$ESP8

1.  Telepathy:$MindVtoVmind$communication.$One$person$sending$thoughts$and$the$other$receiving$them.$8

2.  Clairvoyance:$Perception$of$remote$events,$such$as$sensing$a$friend’s$house$on$fire.8

3.  Precognition:$Perceiving$future$events,$such$as$a$political$leader’s$death.8

Premonitions$or$Pretensions?8

Can$psychics$see$the$future?$Can$psychics$aid$police$in$identifying$locations$of$dead$bodies?$What$about$psychic$predictions$of$the$famous$

Nostradamus?88

The$answers$to$these$questions$are$NO!$Nostradamus�$predictions$are$�retrofi@ed�$to$events$that$took$place$after$his$predictions.8

Pu@ing$ESP$to$Experimental$Test8In$an$experiment$with$28,000$individuals,$

Wiseman$a@empted$to$prove$whether$or$not$one$can$psychically$influence$or$predict$a$coin$toss.$

People$were$able$to$correctly$influence$or$predict$a$coin$toss$49.8%$of$the$time.8