Chapter 6 Sensation & Perception

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Chapter 6Sensation & Perception

Chapter 6Sensation & Perception

Sensation vs. Perception Sensation

The raw data of experience

Perception Process of

creating meaningful patterns from raw sensory information

-2 can be joined for practical use

-Hearing aids

-Robots

-Flight simulators

Sensing 5 Senses Sight Touch Smell Taste Hearing

Other senses Heat Pressure Pain Balance Movement

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Riddle of separate sensationsSense receptors Specialized cells that convert physical energy

into electrical energy that can be transmitted an impulses to the brain Signals received by the sense organs stimulate

different nerve pathways leading to different areas of the brain.

Ex: Rub your eyes results in visual experience

Synesthesia A rare condition in which stimulation of one

sense also evokes another Ex: See color purple and claim it smells like a

rose

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Absolute threshold The smallest quantity of physical

energy that can be reliably detected by an observer 50% of the time

Absolute thresholds

VisionCandle flame from 30 miles on a clear nightHearingTick of a watch from 20 feet in total quietSmellOne drop of perfume in a 3-room apartmentTouchWing of a bee on the cheek, dropped from 1 cmTasteOne teaspoon of sugar in 2 gallons of water

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Difference threshold The smallest difference in

stimulation that can be reliably detected by an observer when two stimuli are compared

Also called the Just Noticeable Difference (JND)

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Signal-detection theory Sensory Process

Real stimulus causes perception

Example: phone rings and you hear it

Decision Process No stimulus

present, mental error

Example: Waiting for phone call and in shower, think heard phone ring

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Sensory adaptation and deprivationAdaptation The reduction or disappearance of sensory

responsiveness when stimulation is unchanging or repetitious

Prevents us from having to respond continuously to unimportant information

Example: You cannot smell your perfume / cologne a few minutes after spraying

Deprivation The absence of normal levels of sensory

stimulation

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Sensory overload Over-stimulation of the senses

Can use selective attention to reduce sensory overload

Selective attention: the focusing of attention on selected aspects of the environment and the blocking out of others (cocktail party phenomenon)

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What we seeHue Color Names related to

the wavelength of light (ROYGBIV)

Brightness Amount of light emitted

from or reflected by an object

Saturation Complexity of light

waves

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The Parts of the EyeCornea - Protects eye and bends light toward lens

Iris - Controls amount of light into eye

Pupil - Opening through which light reaches the retina

Lens - Focuses on objects by changing shape

Retina - Area where light is focused onto

Blind Spot - Area of retina where there are no receptors

Parts of the Eye



Blind Spot



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Color Vision - Receptor CellsRods Receptors that

respond to light & dark

120 million per eye Used for Night vision

Cones Visual receptors

involved in color vision

8 million per eye Best in daylight Sharpness of vision

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Trichromatic theory

Eye detects 3 primary colors Red, Blue, Green

All other colors derived by combination

Limits does not explain color blindness or after image



Trichromatic Spectrum

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Opponent-process theory Visual system treats pairs of colors as

opposing Red-Green Yellow-Blue Black-White

Only one side may fire at a time Why cannot see reddish-green or yellowish-

blue colors Explains Afterimage and Colorblindness

Afterimage The firing of cone has unused energy

after viewing something steadily

Visual system wants to return to balance Fires in opposite color

Color Blindness It is inherited 8% males & 0.5% females Monchromats - see only black & white Dichromats - typically red / green cannot

be seen

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Vision is not a camera

Most processing is done in the brain Flips the image right side up Fills in holes from blind spot Influenced by one’s experiences &

expectations

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Gestalt Principles Brain’s organization of sensory building blocks into

meaningful units and patterns. Wertheimer, Kohler, Koffka

Gestalt PrinciplesFigure- Ground In any visual image, figures can be

distinguished from the ground on which they appear

Gestalt PrinciplesProximity Things close to one another are grouped

together

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Gestalt principles

Closure The brain tends

to fill in gaps to perceive complete forms

Gestalt Principles

Similarity Things that are

alike are perceived together

ContinuitySeeing continuity in lines that could be interpreted as either continuous or abruptly shifting in direction.

Gestalt Principles Design 3 images in your journal

Each one must use a Gestalt principleFigure-groundProximityClosureSimilarity QuickTime™ and a

decompressorare needed to see this picture.

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Depth and distance perceptionBinocular cues Visual cues that require the use of both eyes Convergence

Turning inward of the eyes, which occurs when they focus on a nearby object

Retinal disparity The slight difference in lateral separation

between two objects as seen by the right and left eyes

Binocular Vision



Visual Field



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Depth and distance perceptionMonocular cues Visual cues that can be used by one eye Light & Shadow Interposition Motion Paralax Relative Size Relative Clarity Texture Gradient Linear Perspective

Constancy - the accurate perception of objects as stable or unchanging despite appearances

Shape Constancy Shapes don’t change

Size Constancy Ability to retain the size of

an object regardless of where it is located

Constancy

Color Ability to perceive an object as the same color

regardless of the environment Brightness

The brain causes rods and cones to compensate for changes in brightness

Location Constancy Ability to keep an object in the

environment steady If we are in motion, the environment

must be steady, if the environment is in motion, we must be steady

Perceptual Illusions

Occurs because of misleading clues in the stimulus giving rise to false perceptions

The Müller-Lyer illusion

Journal Activity

1) Draw 2 lines to split your paper into fourths

2) Look at the image below with your right eye. (close/cover the left)

3) In the upper half of the paper, draw what you see with your right eye (line up the center line of the picture with the one on your paper)

4) Repeat with the left eye and the bottom half of the paper.

Audition

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What we hearLoudness The dimension of auditory experience related

to the intensity of a pressure wave (decibels)Pitch The dimension of auditory experience related

to the frequency of a pressure waveTimbre The dimension of auditory experience related

to the complexity of a pressure wave

Decibel Levels 10 - just above audible 60 - normal conversation 70 - disrupt sleep 120 - thunder / rock concert 130 - threshold of pain 180 - space shuttle launch

Pitch Different species and ages can hear

different tones

Kilohertz

Mosquito Buzz

http://www.freemosquitoringtones.org/

Timbre

Different instruments/tones are more pleasing to different people

Most pleasing chord is the 5th of any note

Some chords are more pleasing, and so songs using them may become more popular



4 Chords - The Axis of Awesome

Don’t Stop Believin’ - Journey James Blunt – Beautiful

Black Eyed Peas – Where is the love)

Alphaville - Forever youngJason Mraz – I’m yours

Mika - Happy endingAlex Lloyd - Amazing

The Calling - Wherever you will go

Elton John - Can You Feel The Love Tonight

Maroon 5 - She Will Be Loved

4 ChordsJohn Denver - Take Me Home, Country RoadsRakim – Stay A WhileLady Gaga – PaparazziU2 - With or Without YouCrowded House - Fall At Your FeetKasey Chambers - Am I Not Pretty EnoughThe Beatles - Let it BeMichael Jackson – Man in the Mirror Red Hot Chili Peppers - Under The BridgeDaryl Braithwaite - The horsesBob Marley - No Woman No CryMarcy Playground - Sex and Candy

4 ChordsMen At Work - Land Down Under"Banjo" Paterson - WALTZING MATILDAJack Johnson – Taylor Spice Girls – 2 Become 1 A ha - Take on meGreen Day - When I Come AroundEagle-Eye Cherry - Save TonightToto - AfricaBeyonce - If I were a boyThe Offspring - Self EsteemThe Offspring - You’re gonna go far kidCranberries – ZombieOneRepublic – Apologize

4 ChordsLady Gaga - Poker face

Aqua - Barbie girl)Pink - You and your hand

Tim Minchin - Canvas bags

MGMT - Kids

Andrea Bocelli - Time to say Goodbye

Auld Lang Syne

Five for fighting - Superman

Axis of awesome - Birdplane

Missy Higgins - Scar

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An ear on the world

The Parts of the Ear

Outer Ear Catches sound waves Travels to eardrumMiddle Ear Eardrum causes hammer, anvil, &

stirrup to vibrate

The Parts of the Ear

Inner Ear Stirrup is attached to cochlea passing

along vibration Cochlea is snail shaped structure filled

with fluid and cilia (tiny hair receptor cells)

Study Guide

Retina Cornea Iris Pupil Blind spot Rods and cones Afterimage Color blindness Absolute Threshold Just Noticeable

Difference

-Sensory Deprivation

-Adaptation

-Trichomatic System

-Selective Attention

-Signal Detection Theory

-Loudness

-Pitch

-Timbre

-Binocular vs Monocular

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Auditory localization Sounds from

different directions are not identical as they arrive at left and right ears. Loudness Timing Phase

The brain calculates a sound’s location by using these differences.

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Gustation (taste)Taste buds Collections of taste-receptor cells No buds on center of tongue 5 tastes - salty, sour, bitter, sweet, umami

Tastes of FlavorDifferent people have different tastes and/or

flavor based on: Genetics Culture Learning Food attractiveness Texture Temperature

Tasters Supertasters

Tasters

Nontasters

To taste… Determine your 5 favorite foods and 5 least

favorite foods Explain why you like each one

Interview 1 family member and 1 friend and have them do the same

Bring in an example of 1 of these foods Only if possible - you will not be graded on

whether or not you bring anything in

Should be a tiny taste of the food

New Tastes Using a spoon (if necessary) try a small

sample of the foods present.

On a half-sheet of paper, describe what you are tasting in terms of sour, bitter, sweet, umami and salty.

Tastes around the world Grab 1-3 partners and pick up one of the

packets describing a different culture’s food.

1) Make a list of foods that were eaten Include beverages and spices

2) Would you eat any of these foods?

3) What American/modern foods are similar to the ones you read about?

Olfaction (smell)

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Smell: the sense of scents Airborne chemical molecules enter the nose

and move through the nasal cavity. Receptors on the roof of the nasal cavity

detect these molecules.

The Sense of Scents We discriminate among odors, but

familiar scents are hard to identify (adaptation)

Women more acute sense of smell Anosmia

Complete loss of ability to smell

Why Smell? The part of the brain that processes smells is

actually right there where the emotions

odors were important for the survival of the species

Smell and Culture Fashions in odor change with the times. In the

17th Century, say the authors, the best-loved perfumes were spices, resins and incense-like aromatics. They suspect that a lovely court lady, deliciously spiced for her time, might be rushed to the nearest exit by moderns. They also suggest that expensive modern perfumes (containing synthetics and animal sex lures) might have caused a similar reaction at the court of Louis XIV.

Fashions in smell vary with geography, too. The authors point out that Chinese gourmets, rebuked for liking "rotten eggs," can point with horror to the "rotten milk" (cheese) that Westerners find so delicious.

Most Preferred Scents

Cutaneous (touch)

4 Ways to Respond Pressure/touch Warm Cold Pain All intensities can be influenced by

personal expectations

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Gate-control theory of pain

Experience of pain depends in part on whether the pain gets past a neurological “gate” in the spinal cord.

Identifying Items

Describe what you are feeling within each bag Texture Feeling on skin Soft/hard Rough/smooth Etc

What points on the human body are the most sensitive?

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Gate-control theory revised The brain is capable

of generating pain even without signals from nerves.

Phantom Limb Placebo Effect

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The environment within

Kinesthesis The sense of body position and

movement of body partsEquilibrium The sense of balance Inner ear contributes to equilibrium

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Depth Perception: Visual cliff

Visual illusion of a cliff Babies show

increased attention over deep side at age 2 months, but aren’t afraid until about the age they can crawl.

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Psychological & Cultural Influences We are more likely to perceive something

when we need it and disregard when we don’t (inattentional blindness)

What we believe Emotions, such as fear Expectations based on previous experiences Perceptual set: a habitual way of perceiving,

based on expectations All are influenced by culture.

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Subliminal Perception Notion we may respond to stimuli below

our level of awareness 2/3 of American believe it is used and

works on some level Only prove in highly controlled labs

Subliminal Messages Humans can be “primed” to look for

specific traits based upon what may have flashed across the screen

Humans that are “shown” a face, will prefer it over one they have not seen

Unconscious Messages Hoax in the 1950’s at movie theaters

EAT POPCORN DRINK COKE

Would work best if subjects were reminded to be THIRSTY

Tapes to play while sleeping

Not always effective, the subjects must be primed in order for the effect to take place Therefore not useful in advertising

Hidden Messages Advertisers use their money’s worth in

ads Some may place “hidden” messages within

an image or commercial to influence the audience

The AIDS epidemiccontinues to focus on thethe established risk groups.

Find the hidden image



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Extrasensory perception (ESP)

The ability to perceive something without ordinary sensory information

Has not been scientifically demonstrated Clairvoyance Telepathy Precognition Psycho kinesis

Testing… Psychic Tests

Read Your Mind

20 questions

http://www.psychics.co.uk/psychictests/index.html

http://www.bellaonline.com/code/psychic/

http://20q.nadafy.com/20Q.aspx

Seeing is Believing We can convince ourselves that we we

have seen is true Based on sensation rather than truth Eg: UFOs

Things that scare us

Study Guide Gustation

Taste buds 5 flavors What affects taste/flavor Super/non tasters

Olfaction Closest to emotions

Cutaneous 4 responses Gate-control theory and Phantom Limb

Kinethesis and Equilibrium Subliminal Messaging and Perception ESP

Chapter 6 Sensation & Perception

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