I. Sensation and perception chapter 6. Sensation [p186] The detection of physical energy emitted or reflected by physical objects Occurs when energy.

I. Sensation and perceptionI. Sensation and perception

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Sensation Sensation [p186][p186]

The detection of The detection of physical energyphysical energy emitted or emitted or reflected by physical objectsreflected by physical objects

Occurs when energy in the external Occurs when energy in the external environment or the body stimulates receptors environment or the body stimulates receptors in the in the sense organs (eyes, ears, nose, skin, sense organs (eyes, ears, nose, skin, tongue)tongue)

Sense receptorsSense receptors are specialized cells that are specialized cells that convert physical energy into electrical energy convert physical energy into electrical energy that can be transmitted as nerve impulses to that can be transmitted as nerve impulses to the brainthe brain

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Perception Perception [p186][p186]

The process by which the brain The process by which the brain organizes and interprets sensory organizes and interprets sensory informationinformation

II. Measuring the sensesII. Measuring the senses

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PsychophysicsPsychophysics

The study of the relationship between the The study of the relationship between the physical characteristics of stimuli (such as physical characteristics of stimuli (such as their intensity) and our psychological their intensity) and our psychological experience of them experience of them [p187][p187]

How close does a candle flame have to be to see it?How close does a candle flame have to be to see it?How close does a watch have to be to hear it?How close does a watch have to be to hear it?

How much sugar to taste it?How much sugar to taste it?How much perfume to smell it?How much perfume to smell it?How much pressure to feel it?How much pressure to feel it?

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Absolute thresholds Absolute thresholds [pp187-188][pp187-188]

The smallest quantity of physical energy that can be The smallest quantity of physical energy that can be reliably detected by an observer (reliable=50% of the reliably detected by an observer (reliable=50% of the time)time)

VisionVisionA single candle flame from 30 miles on a clear nightA single candle flame from 30 miles on a clear night

HearingHearingThe tick of a watch from 20 feet in total quietThe tick of a watch from 20 feet in total quiet

SmellSmellOne drop of perfume in a 6-room apartmentOne drop of perfume in a 6-room apartment

TouchTouchThe wing of a bee on the cheek, dropped from 1 cmThe wing of a bee on the cheek, dropped from 1 cm

TasteTasteOne teaspoon of sugar in 2 gallons of waterOne teaspoon of sugar in 2 gallons of water

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NoiseNoise

A term given to competing and irrelevant A term given to competing and irrelevant stimuli stimuli

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Physical conditionPhysical condition

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Sensory adaptation Sensory adaptation [p190][p190]

The reduction or disappearance of The reduction or disappearance of sensory responsiveness when sensory responsiveness when stimulation is unchanging or stimulation is unchanging or repetitiousrepetitious

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Sensory deprivationSensory deprivation[p190][p190]

The absence of normal levels of The absence of normal levels of sensory stimulationsensory stimulation

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Selective attentionSelective attention

The focusing of attention on selected The focusing of attention on selected aspects of the environment and the aspects of the environment and the blocking out of others blocking out of others [p190][p190]

““The cocktail party effect”The cocktail party effect”

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The Stroop EffectThe Stroop Effect

DemonstratesDemonstrates

1. a failure of selective attention1. a failure of selective attention

2. a difficulty with ignoring or 2. a difficulty with ignoring or blocking out very familiar stimuli. blocking out very familiar stimuli.

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III. VisionIII. Vision

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Light waves Light waves [p191][p191]

The physical energy needed to see.The physical energy needed to see.

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The eye The eye [p192][p192]

CorneaCorneaProtects eye and bends light Protects eye and bends light toward lenstoward lens

LensLensFocuses on objects by changing Focuses on objects by changing shape (accommodation)shape (accommodation)

IrisIrisControls amount of light that gets Controls amount of light that gets into eyeinto eye

PupilPupilAperture through which light Aperture through which light reaches the retinareaches the retina

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The eye The eye [pp192-193][pp192-193]

RetinaRetinaNeural tissue lining the back Neural tissue lining the back of the eyeball’s interior of the eyeball’s interior containing the receptors for containing the receptors for visionvision

RodsRodsVisual receptors that respond Visual receptors that respond to dim lightto dim light

ConesConesVisual receptors involved in Visual receptors involved in color visioncolor vision

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Visual information Visual information processingprocessingThe The optic nerveoptic nerve carries neural impulses carries neural impulses from the eye to the visual areas of the from the eye to the visual areas of the brain brain [p193][p193]

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IV. HearingIV. Hearing

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Sound waves Sound waves [p203][p203]

The physical energy needed to hearThe physical energy needed to hear

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The ear The ear [pp203-205][pp203-205]

Outer ear:Outer ear: pinna pinna and and external external auditory canalauditory canal

Middle ear:Middle ear: eardrum eardrum and and middle ear middle ear bonesbones

Inner ear:Inner ear: cochlea cochlea

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Auditory processing Auditory processing [p204][p204]

The The auditory nerveauditory nerve carries neural impulses carries neural impulses from the ear to the brain’s auditory areas.from the ear to the brain’s auditory areas.

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V. TouchV. Touch

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Sensitivity to touchSensitivity to touch[p209][p209]

PressurePressure TemperatureTemperature PainPain warns us warns us

that damage to that damage to our bodies is our bodies is occurringoccurring

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Gate-control theory of painGate-control theory of pain

Experience of pain Experience of pain depends in part on depends in part on whether the pain whether the pain gets past a gets past a neurological neurological “gate” in the “gate” in the spinal cord. spinal cord. [p209][p209]

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Gate-control theory revised Gate-control theory revised [p210][p210]

The matrix of The matrix of neurons in the neurons in the brain is capable of brain is capable of generating pain generating pain (and other (and other sensations) in the sensations) in the absence of signals absence of signals from sensory from sensory nerves.nerves.

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Neural processing of touch, Neural processing of touch, temperature, pain informationtemperature, pain information

Occurs in Occurs in somatosensory somatosensory cortex of parietal cortex of parietal lobeslobes

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VI. TasteVI. Taste

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Taste Taste [pp205-206][pp205-206]

The detection of chemicals that have been The detection of chemicals that have been dissolved in saliva.dissolved in saliva.Each Each papillapapilla contains about 200 taste buds. contains about 200 taste buds.Each Each taste budtaste bud contains 50-100 contains 50-100 receptorsreceptors..

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Five tastes Five tastes [p206][p206]

Five basic tastesFive basic tastesSalty, sour, bitter, sweet, umamiSalty, sour, bitter, sweet, umami

Different people have different tastes Different people have different tastes based on:based on:GeneticsGeneticsCultureCultureLearningLearningFood attractivenessFood attractiveness

Information from the taste receptors is carried by Information from the taste receptors is carried by cranial nerves to the parietal lobes.cranial nerves to the parietal lobes.

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VII. SmellVII. Smell

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Smell Smell [p207][p207]

Airborne chemical molecules enter the nose Airborne chemical molecules enter the nose and circulate through the nasal cavity.and circulate through the nasal cavity.Vapors can also enter through the mouth and pass into nasal Vapors can also enter through the mouth and pass into nasal cavity.cavity.

Receptors on the roof of the nasal cavity Receptors on the roof of the nasal cavity detect these molecules and relay information detect these molecules and relay information to the frontal lobes.to the frontal lobes.

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VIII. Body position and VIII. Body position and movementmovement

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The environment withinThe environment within[pp210-211][pp210-211]

KinesthesisKinesthesisThe sense of body position The sense of body position and movement of body partsand movement of body parts

EquilibriumEquilibriumThe sense of balanceThe sense of balance

Semicircular canalsSemicircular canalsSense organs in the inner ear, Sense organs in the inner ear, which contribute to which contribute to equilibrium by responding to equilibrium by responding to rotation of the headrotation of the head

Neural processingNeural processingOccurs in frontal and parietal Occurs in frontal and parietal lobeslobes

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IX. Perceptual OrganizationIX. Perceptual Organization

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Form perceptionForm perception[p197][p197]

Allows us to differentiate objects Allows us to differentiate objects we seewe see

GestaltGestalt=organized whole=organized whole

Gestalt principlesGestalt principles describe the describe the brain’s organization of sensory brain’s organization of sensory building blocks into meaningful building blocks into meaningful units and patternsunits and patterns

Figure-groundFigure-ground is the Gestalt is the Gestalt principle by which we organize principle by which we organize perceptual fields into forms that perceptual fields into forms that stand out (figure) and those that stand out (figure) and those that are left over (ground)are left over (ground)

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Ambiguous figure-ground Ambiguous figure-ground relationshipsrelationships

Gestalt principlesGestalt principles[pp197-198][pp197-198]

ProximityProximityThings close to one another are grouped togetherThings close to one another are grouped together

ClosureClosureThe brain tends to fill in gaps to perceive complete formsThe brain tends to fill in gaps to perceive complete forms

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Gestalt principlesGestalt principles

SimilaritySimilarityThings that are alike are perceived Things that are alike are perceived together together [p198][p198]

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Depth perception Depth perception [p199][p199]

Allows us to judge Allows us to judge distancedistance

Binocular cuesBinocular cuesVisual cues that require Visual cues that require the use of both eyesthe use of both eyes

Retinal disparityRetinal disparityThe slight difference in The slight difference in what the right and left what the right and left eyes seeeyes see

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Monocular cues Monocular cues [p199][p199]

Visual cues that can be used byVisual cues that can be used byone eyeone eye

Sometimes called Sometimes called pictorial cuespictorial cues

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Relative size Relative size [p199][p199]

When viewing 2 When viewing 2 objects that are objects that are similar in size, similar in size, the smaller the smaller image will be image will be perceived as perceived as being farther being farther awayaway

Linear perspective Linear perspective [p199][p199]

Parallel lines that Parallel lines that converge converge indicate depthindicate depth

Overlap (interposition) Overlap (interposition) [p198][p198]

An object An object partially covering partially covering another object is another object is perceived as perceived as closercloser

Perceptual constancies Perceptual constancies [p200][p200]

The perception of objects as stable The perception of objects as stable or unchanged despite changes in the or unchanged despite changes in the sensory patterns they producesensory patterns they produceShape constancyShape constancy

Location constancyLocation constancy

Size constancySize constancy

Brightness constancyBrightness constancy

Color constancyColor constancy

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Visual illusions Visual illusions [pp200-202][pp200-202]

Occur when two objects produce the Occur when two objects produce the same retinal image but are perceived same retinal image but are perceived as different imagesas different images

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Psychological and cultural Psychological and cultural influences influences [pp213-214][pp213-214]We are more likely to perceive something We are more likely to perceive something when we need it.when we need it.

What we believe can affect what we What we believe can affect what we perceive.perceive.

Emotions, such as fear, can influence Emotions, such as fear, can influence perceptions of sensory information.perceptions of sensory information.

Expectations based on previous Expectations based on previous experiences can influence perception.experiences can influence perception.

All are influenced by culture.All are influenced by culture.

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