SightSight

HearingHearing

SmellSmell

TasteTaste

TouchTouch

Vestibular sensesVestibular senses

Actually more than 5 senses Actually more than 5 senses

Basic Five: Basic Five: vision, hearing, vision, hearing, taste, smell and touchtaste, smell and touch

Several skin senses Several skin senses Internal senses: vestibular andInternal senses: vestibular andkinesthetickinesthetic

Working alone,Working alone,write a shortwrite a shortdescription of description of this scene.this scene.Include what Include what is happening is happening and why you and why you think it is think it is happening. Whathappening. Whatsenses are thesenses are thecharacters using?characters using?

Chapter project: You have choices

I hate his I hate his projects. I projects. I wish I could wish I could CHOOSE to CHOOSE to

punch him in punch him in his big nose.his big nose.

I hate I hate SimoncinSimoncini! May i! May

lice lice cover his cover his

ugly ugly body.body.

Why Why did I did I take take this this

stupid stupid course? course?

The initial electrical activity is a The initial electrical activity is a sensationsensation::The initial electrical activity is a The initial electrical activity is a sensationsensation, , a stimulus (colors, a stimulus (colors,

forms, sounds, smells, tastes, etc.)forms, sounds, smells, tastes, etc.)that activates a receptor.that activates a receptor.

Physical change in external or Physical change in external or internal environments triggers internal environments triggers

chemical, electrical and mechanical chemical, electrical and mechanical activity in sense receptors. activity in sense receptors.

Complex processing by nervous Complex processing by nervous systemsystem

Pattern of activity in part of brainPattern of activity in part of brain

The initial electrical activity is a The initial electrical activity is a sensationsensation::

A perception is:A perception is:

++ ==

The initial electrical activity is a The initial electrical activity is a sensationsensation, , a stimulus (colors, a stimulus (colors,

forms, sounds, smells, tastes, etc.)forms, sounds, smells, tastes, etc.)that activates a receptor.that activates a receptor.

A perception is: A perception is: a series of organized a series of organized sensory information that creates sensory information that creates

meaningful stimulimeaningful stimuli..

Each type of sensory receptor takes Each type of sensory receptor takes some sort of external stimulus . . .some sort of external stimulus . . .

. . . and converts it into a chemical-. . . and converts it into a chemical- electrical message that can be electrical message that can be understood by the brain understood by the brain (transduction.)(transduction.)

Transduction:Transduction:sensory processsensory process

that convertsthat convertsphysical energyphysical energyinto the form into the form

of neural of neural messages.messages.

Transduction Transduction (smell example)(smell example)

Step 1:Step 1:Transform one form of Transform one form of energy to another—detectionenergy to another—detectionby a sensory neuron of a by a sensory neuron of a physical stimulusphysical stimulus

Stimulus: food aroma Stimulus: food aroma Nose detects the stimulusNose detects the stimulus(aroma)(aroma)

Transduction Transduction Step 2:Step 2:When the When the appropriateappropriatestimulus stimulus (aroma)(aroma)reaches a sensereaches a senseorgan organ (Niki’s (Niki’s nose),nose), it activates it activatesspecialized specialized neurons called neurons called receptorsreceptors

Transduction Transduction Step 3:Step 3:Receptors convertReceptors convert their their excitationexcitation in intoto a a nerve nerve signal that travels signal that travels along a sensory path-along a sensory path-way to way to specialized specialized sensory processing sensory processing areas of theareas of the brain brain (in all but smell, the (in all but smell, the signal travels by way of the thalamus) signal travels by way of the thalamus)

Transduction Transduction

StimulusStimulus = any aspect of or= any aspect of or change in the environment to change in the environment to which an organism responds.which an organism responds.

Stimuli measured many ways:Stimuli measured many ways:duration, intensity, wavelengthduration, intensity, wavelength

The sensesThe senses

are most responsive to increasesare most responsive to increasesand decreases; to new eventsand decreases; to new eventsrather than ongoing, unchangingrather than ongoing, unchangingstimulationstimulation

The senses adapt, or adjust, to The senses adapt, or adjust, to constant levels of stimulation.constant levels of stimulation.

DarknessDarkness

Smelly roomsSmelly rooms

Sensory Adaptation Sensory Adaptation

Noisy Noisy streetsstreets

Cold pools

SensationsSensations occur any time one occur any time one stimulus activates a receptor.stimulus activates a receptor.

A combination of sensations plusA combination of sensations plus your past experience=perceptionyour past experience=perception

Absolute thresholdAbsolute threshold --the minimum--the minimum amount of physical energy amount of physical energy required to produce a sensationrequired to produce a sensation

Hi, I’m a typical science teacher and here are some cool facts about absolute threshold.

A candle flame can be seen 30-miles away on a dark, clear nightThe ticking of a watch can be heard 20 feet away under quietconditions.Perfume can be detected whenone drop is put in a three-roomapartment.

The difference thresholdThe difference threshold --the --the minimum amount of physical energy minimum amount of physical energy change required to produce a change required to produce a change in sensation change in sensation

Weber’s Law Weber’s Law --the larger --the larger or stronger a stimulus, or stronger a stimulus, the larger the change the larger the change required for an observer required for an observer to experience a to experience a noticeable difference.noticeable difference. I I / / II = = kk

Fechner’s Law Fechner’s Law Expresses the relationship between Expresses the relationship between actual magnitude of the stimulus and actual magnitude of the stimulus and its perceived magnitude. An increase its perceived magnitude. An increase in physical magnitude of a stimulus in physical magnitude of a stimulus progressively produces smallerprogressively produces smaller increases in perceived magnitudeincreases in perceived magnitudeSS = = kk log log R R (S=sensation, R = stimulus, k (S=sensation, R = stimulus, k = a = a constant that differs for each sensory constant that differs for each sensory modality)modality)

Steven’s Power Law Steven’s Power Law S = k IS = k I

Addresses why Fechner’s law cannot Addresses why Fechner’s law cannot account for some changes in stimulus account for some changes in stimulus detection, and works for a variety of detection, and works for a variety of stimuli (viz. pain and temperature.)stimuli (viz. pain and temperature.)

a

S = sensation; k = a constant, S = sensation; k = a constant, I = stimulus intensityI = stimulus intensitya = a power exponent that depends on the a = a power exponent that depends on the sense being measuredsense being measured

Signal Detection Theory Signal Detection Theory Disputes absolute threshold Disputes absolute threshold

No sharp boundary between stimuli that No sharp boundary between stimuli that you can perceive and stimuli that you cannot you can perceive and stimuli that you cannot perceiveperceive

Detection thresholds involve Detection thresholds involve recognizing some stimulus recognizing some stimulus against a background of against a background of competing stimuli competing stimuli

Signal Detection Theory Signal Detection Theory Processing stimuli Processing stimuli

Pre-attentive process—extracting Pre-attentive process—extracting information automatically and information automatically and simultaneously when presented simultaneously when presented with stimuliwith stimuliAttentive process—considers only one Attentive process—considers only one part of the stimuli presented at a timepart of the stimuli presented at a time

Signal Detection Theory Signal Detection Theory The Stroop Interference Effect The Stroop Interference Effect (Attentive)(Attentive)

Step 1: name the colors in boxes at left rapidlyStep 1: name the colors in boxes at left rapidlyStep 2: read words at right rapidlyStep 2: read words at right rapidlyStep 3: name the colors at right rapidlyStep 3: name the colors at right rapidly

Hi students, I’m Mrs. Science Teacher.

Often times subliminal messages affect our

perceptions of things.

Subliminal: from the Latin words sub (below) and limen (threshold.) Subliminal messages are brief visual or auditory messages presentedbelow the absolute threshold;there is a less than 50% chance they will be perceived.

Very good, foxy lady. Let’s Very good, foxy lady. Let’s start by discussing James start by discussing James

Vicary and his 1957 Vicary and his 1957 experiment.experiment.

No controlled research has No controlled research has ever shown that subliminal ever shown that subliminal messages delivered to a messages delivered to a mass audience can mass audience can Influence people’s buying Influence people’s buying habits.habits.

Here is an example of subliminal influences.

She is so hot she sizzles. WOW!

Abbey Road

Sergeant Pepper’s Lonely Heart’s Club Band

Often when television or print ads appear,

they incorporate certain

subliminal advertising techniques

.Name Calling: using negativelabels to discredit a competitor

Glittering generalities: broadstatements that appeal to emotions

Here are some more subliminal advertising

techniques.

Card stacking—slanting facts Plain folks—using folksy language

Transfer: connecting a product with someone or something that is admired

Bandwagon: Appealing to people’s desire to “go with the crowd.”

Now, form into groups and

discuss each of the six subliminal

advertising techniques. Think about examples of each: name

calling, glittering generalities, card

stacking, plain folks, transfer,

and bandwagon. Be prepared to

discuss your results with the

class.

What a foxy

lady!!!

He is sooooo hot!!!

Now you will have a group or

individual activity (your choice) so

you can demonstrate what you have learned in this chapter.

And this activity should be fun

because we

science people always have fun!

Television Commercial Television Commercial 30-60 Seconds30-60 SecondsDialog and actionDialog and actionAppeal to at least 1 senseAppeal to at least 1 senseFactor in use of subliminals—Factor in use of subliminals— Name calling, Glittering generalitiesName calling, Glittering generalities Card stacking, Plain folks, TransferCard stacking, Plain folks, Transfer BandwagonBandwagon

Alternatives: sales poster, song, album Alternatives: sales poster, song, album cover, etc, using the subliminalscover, etc, using the subliminals

Vision Vision

I see I see you!!! And you!!! And you are in you are in a heap of a heap of trouble!!!trouble!!!

Vision Vision

Vision Vision

Blind spot

Lack of receptors at the spot where the optic nerveLack of receptors at the spot where the optic nerve connects to the retinaconnects to the retina

Vision Vision

Most studied of all the senses Most studied of all the senses

Light enters via Light enters via the pupilthe pupil

reaches the lens,reaches the lens,a flexible structurea flexible structure that focuses light that focuses light on the retina on the retina

Vision Vision Retina contains two types of light- Retina contains two types of light- sensitive receptor cells:sensitive receptor cells:

Rods and cones Rods and cones

Those cells change light energy into Those cells change light energy into neuronal impulses, which then travel neuronal impulses, which then travel via the via the optic nerveoptic nerve to the brain. to the brain.

Vision Vision

Cones require more light than rods Cones require more light than rods before they respondbefore they respond

75-150 million rods; 6-7 mil. cones 75-150 million rods; 6-7 mil. cones

Only cones are sensitive to color Only cones are sensitive to color

If all or some cones do not function If all or some cones do not function properly: color deficiency properly: color deficiency

8% Amer. men; 1% Amer. women 8% Amer. men; 1% Amer. women

Vision Vision

Blind spot

We look with our eyes, but see with our brain We look with our eyes, but see with our brain

We look with our eyes, but see with our brain We look with our eyes, but see with our brain

Sensing Colors Sensing Colors

Trichromatic Theory Trichromatic Theory Opponent-Process Opponent-Process Theory Theory

It’s time for an It’s time for an experiment. HOOAH!!!experiment. HOOAH!!!

Rods & cones & peripheral vision

Hearing Hearing

If a tree falls in the forest, and no one is there If a tree falls in the forest, and no one is there to hear it, does it make a sound?to hear it, does it make a sound?

Hearing Hearing Depends on vibrations of the air, Depends on vibrations of the air, called sound waves called sound waves Sound waves Sound waves from the airfrom the air pass pass through various bones and fluids through various bones and fluids to the inner ear to the inner ear

Hearing Hearing

Amplitude is the height of the sound wave,Amplitude is the height of the sound wave,while frequency is a measure of how while frequency is a measure of how frequently the sound waves pass a frequently the sound waves pass a given point.given point.

Hearing Hearing

Hammer

Anvil

Stirrup

1. Airborne sound waves must be relayed to the inner ear. 1. Airborne sound waves must be relayed to the inner ear. In this initial transformation, vibrating waves of air enter the In this initial transformation, vibrating waves of air enter the outer ear and strike the eardrum, or tympanic membrane. This outer ear and strike the eardrum, or tympanic membrane. This tightly stretched sheet of tissue transmits the vibrations to tightly stretched sheet of tissue transmits the vibrations to three tiny bones: the hammer, anvil and stirrupthree tiny bones: the hammer, anvil and stirrup

Hearing Hearing

Hammer

Anvil

Stirrup

2. These bones pass vibrations on to the primary organ of 2. These bones pass vibrations on to the primary organ of hearing, the cochlea (in the inner ear)hearing, the cochlea (in the inner ear)bb. The cochlea focuses the vibrations on the basilar membrane. The cochlea focuses the vibrations on the basilar membrane

Hearing Hearing

3. The basilar membrane converts the vibrations into neural 3. The basilar membrane converts the vibrations into neural messages (the swaying of tiny hair cells on the vibrating basilar messages (the swaying of tiny hair cells on the vibrating basilar membrane stimulates sensory nerve endings connected to the membrane stimulates sensory nerve endings connected to the hair cells.) The excited neurons transform the mechanical hair cells.) The excited neurons transform the mechanical vibrations of the basilar membrane into neural activity.vibrations of the basilar membrane into neural activity.

Hearing Hearing

4. Finally, the neural messages travel to the auditory cortex in the 4. Finally, the neural messages travel to the auditory cortex in the brain—neural signals leave the cochlea in a bundle of neurons brain—neural signals leave the cochlea in a bundle of neurons called the auditory nerve. The neurons from the two ears meet called the auditory nerve. The neurons from the two ears meet in the brain stem, which passes the auditory information to in the brain stem, which passes the auditory information to both sides of the brain both sides of the brain

Hearing Hearing

Hearing Hearing

Hammer

Anvil

Stirrup

Hearing Hearing Pitch Pitch 20 cps to 20,000 cps 20 cps to 20,000 cps

Hearing Hearing The inner ear contains tiny, hair-The inner ear contains tiny, hair- like cells that move back & forth like cells that move back & forth

Hair-like cellsHair-like cells change sound change sound vibrations into neuronal signals vibrations into neuronal signals that travel, via the that travel, via the auditory nerveauditory nerve,, to the brain. to the brain.

Perception of loudness depends on Perception of loudness depends on amplitude of vibrations in the air. amplitude of vibrations in the air. That amplitude, or sound-pressure That amplitude, or sound-pressure energy, isenergy, is measured in decibels. measured in decibels.

Hearing Hearing

Softest Softest Sounds Sounds 0 dbls.0 dbls.

Loudest Loudest ear can ear can detect: detect: 140 dbl.140 dbl.

Hearing Hearing Any sound over 110 dbls Any sound over 110 dbls can damage hearing . . . can damage hearing . . .

. . . as can persistent . . . as can persistent sounds as low as 80 dbls sounds as low as 80 dbls

Hearing Hearing Timbre (Timbre (pronounced pronounced tam-bertam-ber):):Timbre (Timbre (pronounced pronounced tam-bertam-ber): “tone ): “tone color” or color” or the complex quality the complex quality of the sound wave.of the sound wave.Example: recognizing Example: recognizing your company your company commander’s voice commander’s voice on the radio.on the radio.

Conduction deafness: Conduction deafness: Conduction deafness: Conduction deafness: conduction of vibrationsconduction of vibrationshas been negatively has been negatively affected affected

Nerve deafness:Nerve deafness:

Damage to auditoryDamage to auditorynerve or one of nerve or one of higher auditory higher auditory processing centersprocessing centers

Hearing Hearing Some hearing loss comes as a result of Some hearing loss comes as a result of age, however.age, however.

Mosquito Ring Tone (Teen Buzz) Mosquito Ring Tone (Teen Buzz) Presbycusis: Presbycusis: aging earaging ear; ; starting around starting around age 20, theage 20, the human ear loses its ability human ear loses its ability to hear tones in the highest human-range to hear tones in the highest human-range frequencies frequencies (18-20 kHz) and as one (18-20 kHz) and as one ages it becomes more difficult to detect ages it becomes more difficult to detect those soundsthose sounds

Balance Balance Regulated by the Regulated by the vestibular system inside the inner ear. inside the inner ear.

Three semicircular Three semicircular canals containing fluid canals containing fluid Over stimulation can Over stimulation can cause dizziness or cause dizziness or motion sickness motion sickness

Hey Hottie! How about a vestibular experiment

?

OK, you gorgeous hunk of a woman.

Hearing Hearing

Hammer

Anvil

Stirrup

Balance Balance Regulated by the Regulated by the vestibular system inside the inner ear. inside the inner ear.

Three semicircular Three semicircular canals containing fluid canals containing fluid Over stimulation can Over stimulation can cause dizziness or cause dizziness or motion sickness motion sickness Meniere’s SyndromeLabyrinthitis

Body Sensations Body Sensations

Kinesthesis—sense of movement —sense of movement and body and body positions positions Cooperates with the vestibular and visual Cooperates with the vestibular and visual senses to maintain posture and balance senses to maintain posture and balance Sensation of kinesthesis comes from Sensation of kinesthesis comes from receptors in/near muscles, etc. receptors in/near muscles, etc.

Smell and Taste Smell and Taste

The chemical senses: The chemical senses: their receptors their receptors are sensitive to chemical molecules are sensitive to chemical molecules rather than to light energy or sound rather than to light energy or sound waves waves Smell: molecules, via vapors, make Smell: molecules, via vapors, make contact with a special membrane in contact with a special membrane in upper nasal passages—the olfactory upper nasal passages—the olfactory bulb--where smell receptors are located, bulb--where smell receptors are located, and sent directly to the limbic system.and sent directly to the limbic system.

You may recall that we used You may recall that we used smell to describe Transductionsmell to describe Transduction

Step 1:Step 1:Transform one form of Transform one form of energy to another—detectionenergy to another—detectionby a sensory neuron of a by a sensory neuron of a physical stimulusphysical stimulus

Stimulus: food aroma Stimulus: food aroma Nose detects the stimulusNose detects the stimulus(aroma)(aroma)

Transduction Transduction Step 2:Step 2:When the When the appropriateappropriatestimulus stimulus (aroma)(aroma)reaches a sensereaches a senseorgan organ (Niki’s (Niki’s nose),nose), it activates it activatesspecialized specialized neurons called neurons called receptorsreceptors

Transduction Transduction Step 3:Step 3:Receptors convert their Receptors convert their excitation into a nerve excitation into a nerve signal that travels signal that travels along a sensory path-along a sensory path-way, via the Thalamus,way, via the Thalamus,to specialized sensoryto specialized sensoryprocessing areas of processing areas of the brainthe brain

Transduction Transduction

Smell and Taste Smell and Taste Those receptors send messages Those receptors send messages about smells via the about smells via the olfactory olfactory nervenerve to the brain. to the brain.

Taste: appropriate Taste: appropriate chemicals must chemicals must stimulate receptors in stimulate receptors in the taste buds of your tongue the taste buds of your tongue

Smell Disorders Smell Disorders Anosmia: Anosmia: Anosmia: loss of the sense of smell Anosmia: loss of the sense of smell

Hyposmia: Hyposmia: Hyposmia: decreased ability to Hyposmia: decreased ability to smellsmellPhantosmiaPhantosmiaPhantosmia: phantom odors, mostly Phantosmia: phantom odors, mostly

unpleasant (rotting flesh, smoke, etc.)unpleasant (rotting flesh, smoke, etc.)

Dysosmia: Dysosmia: things smell differently than Dysosmia: things smell differently than they should they should

Smell and Taste Smell and Taste Taste is actually produced by smell Taste is actually produced by smell

Smell and Taste Smell and Taste

Sensations of warmth, cold and Sensations of warmth, cold and pressure . . .pressure . . .

. . . affect taste . . . affect taste Cold chili; hot soda pop; soggy chips Cold chili; hot soda pop; soggy chips

It’s time for another It’s time for another experiment! experiment!

Taste controlled by smell

Smell and Taste Smell and Taste

Four primary sensory Four primary sensory experiences experiences make up taste:make up taste:

Sour, Sour, salty, salty, bitter bitter and and sweet sweet

Old theory re: smell: six qualities Old theory re: smell: six qualities Flowery, fruity, spicy, resinous, Flowery, fruity, spicy, resinous, putrid, and burned putrid, and burned Several smell theories, no conclusionsSeveral smell theories, no conclusions

Recent research: Recent research: umami (Asian)(Asian)

It’s time for another It’s time for another experiment. HOOAH!!!experiment. HOOAH!!!

The taste buds

Bitter SourSweetSalty

Sour

The Skin Senses The Skin Senses Receptors in the skin provide Receptors in the skin provide the the brain with four kinds of brain with four kinds of information information about the environment: about the environment: Pressure, warmth, cold, and Pressure, warmth, cold, and pain pain

The Skin Senses The Skin Senses Connected to the somatosensory cortex,Connected to the somatosensory cortex, located in the parietal lobeslocated in the parietal lobes

The Skin Senses The Skin Senses Level of sensitivity varies on body Level of sensitivity varies on body

Fingertips—densely populated Fingertips—densely populated with receptors: highly with receptors: highly sensitive—sensitive—1010 times more so times more so than on backs or calvesthan on backs or calves

Back of calf—relatively few Back of calf—relatively few receptors: less sensitive receptors: less sensitive

It’s time for another It’s time for another experiment! experiment!

Skin receptors—differences in density based on body parts

The Skin Senses The Skin Senses Phantom limbPhantom limb

The Skin Senses The Skin Senses Pressure sensations can Pressure sensations can serve as protectionserve as protection

Some skin Some skin receptors are receptors are particularly sensitive particularly sensitive to hot or cold stimuli.to hot or cold stimuli.Warm water on warm vs. cold day Warm water on warm vs. cold day

The Skin Senses The Skin Senses Stimuli such as scratches, punctures,Stimuli such as scratches, punctures, severe pressure, heat, and cold can severe pressure, heat, and cold can produce pain. produce pain.

Pain is an emergency Pain is an emergency system that demands system that demands immediate action. immediate action. It It makes it possible to makes it possible to prevent damage to your bodyprevent damage to your body..

The Skin Senses The Skin Senses Gate-Control Theory Gate-Control Theory

Neurons with Myelin on axons,Neurons with Myelin on axons,faster messages—most sensory images to brain faster messages—most sensory images to brain

The Skin Senses The Skin Senses Gate-Control Theory Gate-Control Theory Second route, smaller, Second route, smaller, slow fibers, without Myelinslow fibers, without Myelinsheaths on axons, send sheaths on axons, send messages more slowly.messages more slowly.Competing messages Competing messages from fast fibers can block from fast fibers can block pain messages in slow pain messages in slow fibers—can close a spinalfibers—can close a spinalgategate

The Skin Senses The Skin Senses Gate-Control Theory Gate-Control Theory

When you hit your finger with When you hit your finger with a hammer, you automatically a hammer, you automatically make use of the “gate” by make use of the “gate” by vigorously shaking your handvigorously shaking your handto generate fast fiber signals to generate fast fiber signals that block the pain. The that block the pain. The “gate,”“gate,” itself, probably itself, probably operates in a operates in a brain stem region called the brain stem region called the periaqueductal gray (PAG).periaqueductal gray (PAG).

The Skin Senses The Skin Senses Controlling pain Controlling pain

Hypnosis Hypnosis

Placebos Placebos

AcupunctureAcupuncture

Acupuncture works because the needles, like placebos,Acupuncture works because the needles, like placebos,trigger the release of pain-killing endorphins. Although trigger the release of pain-killing endorphins. Although we do not know precisely how the triggering mechanismwe do not know precisely how the triggering mechanismworks, controlled studies do show that acupuncture works, controlled studies do show that acupuncture patients exhibit elevated endorphin levels.patients exhibit elevated endorphin levels.

The Skin Senses The Skin Senses

The Placebo EffectThe Placebo EffectExpectation of pain Expectation of pain relief is enough to causerelief is enough to causethe brain to release the brain to release painkilling endorphins painkilling endorphins

The episode of M*A*S*H entitled The episode of M*A*S*H entitled ““Major Topper,” March 27, 1978 Major Topper,” March 27, 1978

People People do not merely have sensory do not merely have sensory experiences; weexperiences; we perceive objects. perceive objects.

Brain receives information from the Brain receives information from the senses and interprets it into meaningfulsenses and interprets it into meaningful experiences—unconsciously. experiences—unconsciously.

Process of Process of perceptionperception

Feature Detectors Feature Detectors in the cerebral cortexin the cerebral cortexcells specialize in cells specialize in extracting certain extracting certain features of a features of a stimulus—our brainsstimulus—our brainshave specialized have specialized groups of cells dedicated to the detection groups of cells dedicated to the detection of specific stimulus features of specific stimulus features (length, (length, slant, color, boundary)slant, color, boundary)

The binding problemThe binding problemProcess used by the brain to bind Process used by the brain to bind (combine) results of many sensory (combine) results of many sensory operations into a single precept.operations into a single precept.

People’s facesPeople’s faces

Bottom-up and Top-down ProcessingBottom-up and Top-down ProcessingPerception: take sensory data into the Perception: take sensory data into the system through receptors and sends system through receptors and sends it upward to the cortexit upward to the cortex

Bottom-up: perceptual analysis that Bottom-up: perceptual analysis that emphasizes characteristics of the emphasizes characteristics of the stimulus, rather than our concepts and stimulus, rather than our concepts and expectationsexpectations

Bottom-up and Top-down ProcessingBottom-up and Top-down ProcessingTop-down: perceivers goals, past Top-down: perceivers goals, past experience, knowledge, expectations,experience, knowledge, expectations, memory, motivations, or cultural back-memory, motivations, or cultural back- ground in the interpretation of an object ground in the interpretation of an object or eventor event

Perceptual Constancy Perceptual Constancy Ability to recognize the same object Ability to recognize the same object as remaining constant under different as remaining constant under different conditions conditions

Sometimes our

perceptions can be

incorrect. Those

situations are called illusions.

Illusions are created

when perceptual cues are

distorted so that our brains cannot

correctly interpret

space, size and depth

cues. Many illusions

are optical illusions.

To demonstrate, we shall now

observe some optical illusions from the Internet.

Here are some more.

Brain continuously trying to build Brain continuously trying to build “ “wholes” wholes” out of the confusion of out of the confusion of stimuli that bombards the sensesstimuli that bombards the senses..

The “whole” experience The “whole” experience that comesthat comes from from organizing bits and organizing bits and pieces of information pieces of information into meaningful objects into meaningful objects and patterns is called and patterns is called GestaltGestalt..

Types of Perception Types of Perception

Figure-ground perception—ability to Figure-ground perception—ability to properly discriminate between properly discriminate between figure and groundfigure and ground

The fact that we can perceive a The fact that we can perceive a single pattern in more than one way single pattern in more than one way shows that shows that we are not passive we are not passive receivers of stimulireceivers of stimuli

Often perceptions are not based Often perceptions are not based entirely on current sensory entirely on current sensory information information

Hear a barking dog in Hear a barking dog in the distance. . . assumethe distance. . . assumeit is a dog.it is a dog.

Perceptual influence: Perceptual influence: phenomenon of filling in phenomenon of filling in gaps in what senses tell us.gaps in what senses tell us.

Perception is Perception is learned behaviorlearned behavior Takes babies 7-8 months to learn Takes babies 7-8 months to learn to recognize different people.to recognize different people.

Gestalt: German term meaning Gestalt: German term meaning pattern or configurationpattern or configuration

Scientists try to identify principles Scientists try to identify principles brain uses in constructing brain uses in constructing perceptions perceptions

Five principles: Five principles: similarity,similarity, proximity, proximity, continuity, simplicity, and closurecontinuity, simplicity, and closure

Similarity: when similar and dissimilar objects are mingled, we see the similar objects as groups

HomeHometeam team in red in red

uniformsuniformsVisiting Visiting team in team in white white

uniforms uniforms

x o x o x x o x o x x o x o x x o x o x x o x o xx o x o xx o x o x x o x o x x o x o x x o x o x

Proximity: perceive a number of similar objects as groups or sets

Proximity: perceive a number of similar objects as groups or sets

Do you see a lawn or individual blades of grass?

Do you see pine treesor individual needles?

Example: in music we do not hear Example: in music we do not hear individual notes as much as we hear individual notes as much as we hear melodies (notes in proximity to one melodies (notes in proximity to one another) another)

Continuity: we tend to see continuous patterns, not disrupted ones

Baseball venue rather than various shapes (diamond infield, square bases,etc.)

Following a sound of a Following a sound of a particular voice or particular voice or instrument when many instrument when many other sounds are other sounds are occurring is due to occurring is due to similarity and continuity similarity and continuity

Law of common fate: we tend to group Law of common fate: we tend to group similar objects together that share a similar objects together that share a common motion or destinationcommon motion or destination

Runners vs. spectators Runners vs. spectators

Simplicity: we see the simplest patterns possible; the law ofPragnanz

Closure: when we see a familiar pattern or shape with some missing parts, we fill in the gaps.

Abird

in thethe hand

Gestalt principles Gestalt principles of organizationof organization help tohelp to explain how we group our explain how we group our sensations and fill gaps in order to sensations and fill gaps in order to make sense of our world.make sense of our world.

Vision Vision Two eyes Two eyes two imagestwo images

Images differ on each retina Images differ on each retina

Combination of 2 images into one Combination of 2 images into one is called binocular fusion is called binocular fusion

Retinal disparityRetinal disparity

Hey-yo! Let’s do Hey-yo! Let’s do another experiment—another experiment—

this one is about this one is about retinal disparity.retinal disparity.

Pen or pencil Hold 12-inches in front of face. Both eyes, then left eye closed, then right eye closed. What happens?

Pilots’ Monocular Cues Pilots’ Monocular Cues

Relative sizeRelative size Light and shadow Light and shadow InterpositionInterposition Relative motionRelative motion Atmospheric perspective Atmospheric perspective

von Helmholtz Theoryvon Helmholtz Theory

Theory of learning-based inference Theory of learning-based inference People use prior learning to interpretPeople use prior learning to interpret new sensory informationnew sensory informationBased on learning, people make Based on learning, people make inferences (guesses or predictions) about what inferences (guesses or predictions) about what sensations meansensations meanOur perceptual interpretations are, in effect, Our perceptual interpretations are, in effect, hypotheses about our sensationshypotheses about our sensations

Extrasensory Perception (ESP)Receiving information about the world through other than the normal senses.

                                                  

                       Paranormal experience—a sensebeyond the basic 5 senses.

Experienced with thoughts, not body sensations—therefore very controversial

Major types of ESP:Telepathy—ability to read another’s

thoughtsClairvoyance—ability to “see” events or objects happening somewhere elsePrecognition—ability to see the future

Major types of ESP (continued)Retrocognition—ability to see

into the distant past

Mediumship—the ability to channel dead spirits

Psychometry—ability to read information about a person or place by touching a physical object

Parapsychology:“Father:” J. B. Rhine

Zener Card Experiments—deck of 25 cards, each withone of 5 patterns