Sensation and PerceptionSensation and Perception

Unit 3Unit 3

Chapter 4Chapter 4

Students will explain the processes of sensation and perception and describe the interaction between Students will explain the processes of sensation and perception and describe the interaction between the person and the environment to determine determining perception the person and the environment to determine determining perception

Basic ConceptsBasic Concepts

sensationsensation- stimulation of sense organs- stimulation of sense organs– converted into neural impulsesconverted into neural impulses

perceptionperception- selection, organization, and - selection, organization, and interpretation of sensory inputinterpretation of sensory input– meaningful experiencesmeaningful experiences

psychophysicspsychophysics- study of how - study of how physicalphysical stimuli are translated into stimuli are translated into psychologicalpsychological experiencesexperiences

P.23 Examine the processes of sensation and perception and elaborate on how they interact.P.23 Examine the processes of sensation and perception and elaborate on how they interact.

Thresholds: Looking for LimitsThresholds: Looking for Limits

thresholdsthresholds- dividing point between energy - dividing point between energy levels that do and do not have a levels that do and do not have a detectable effectdetectable effect– absolute thresholdabsolute threshold:: minimumminimum stimulus stimulus

intensity detectedintensity detected– just noticeable differencejust noticeable difference: smallest : smallest differencedifference

in stimulus intensity that a specific sense can in stimulus intensity that a specific sense can detectdetect

P.24 Explain the concepts of threshold P.24 Explain the concepts of threshold and adaptation and adaptation

Examples of Absolute ThresholdsExamples of Absolute Thresholds

Sense Absolute Threshold

VisionVision A candle flame seen at 30 miles on a dark clear nightA candle flame seen at 30 miles on a dark clear night

HearingHearing The tick of a watch under quiet conditions at 20 feetThe tick of a watch under quiet conditions at 20 feet

TasteTaste One teaspoon of sugar in two gallons of waterOne teaspoon of sugar in two gallons of water

SmellSmell One drop of perfume diffused into entire volume of a six One drop of perfume diffused into entire volume of a six room apartmentroom apartment

TouchTouch The wing of a fly falling on your cheek from a distance of 1 The wing of a fly falling on your cheek from a distance of 1 centimetercentimeter

P.24 Explain the concepts of threshold P.24 Explain the concepts of threshold and adaptation and adaptation

Signal Detection TheorySignal Detection Theory

proposes that detection of stimuli involves proposes that detection of stimuli involves decision processes as well as sensory decision processes as well as sensory processes, both influenced by variety of processes, both influenced by variety of factors besides stimulus intensityfactors besides stimulus intensity– expectationsexpectations– level of “noise”level of “noise”

Perception Without AwarenessPerception Without Awareness

subliminal perceptionsubliminal perception- registration of - registration of sensory input without conscious sensory input without conscious awarenessawareness– below thresholdbelow threshold– money, sex, money, sex,

religionreligion

Sensory AdaptationSensory Adaptation

gradual decline in sensitivity to prolonged gradual decline in sensitivity to prolonged stimulationstimulation

continued exposure = adaptation to continued exposure = adaptation to stimulusstimulus

automatic process that keeps people automatic process that keeps people tuned into tuned into changeschanges rather than rather than constantsconstants in their sensory inputin their sensory input

Our Sense of Sight: The Our Sense of Sight: The Visual SystemVisual System

Unit 3Unit 3

P.26 Describe the visual, sensory and P.26 Describe the visual, sensory and auditory sensory systems. auditory sensory systems.

The Stimulus: LightThe Stimulus: Light

lightlight- form of electromagnetic radiation that - form of electromagnetic radiation that travels as a wavetravels as a wave– Varies in both Varies in both amplitude amplitude and and wavelengthwavelength

Amplitude affects perception of brightnessAmplitude affects perception of brightness

Wavelength affects perception of colorWavelength affects perception of color

P.25 List forms of physical energy for which humans and nonhuman animals do and do not have sensory receptors. P.25 List forms of physical energy for which humans and nonhuman animals do and do not have sensory receptors.

The Eye: A Living Optical The Eye: A Living Optical InstrumentInstrument

cornea-cornea- provides 2/3 provides 2/3 of eyes total powerof eyes total power

lens-lens- focuses light focuses light rays on the retinarays on the retina

retinaretina- absorbs light, - absorbs light, processes images, processes images, sends visual info to sends visual info to brainbrain

pupil-pupil- permits light to permits light to pass into eyepass into eye

P.26 Describe the visual, sensory and auditory sensory systems. P.26 Describe the visual, sensory and auditory sensory systems.

Visual Receptors: Visual Receptors: Rods and ConesRods and Cones

RODSRODS

100-125 million rods100-125 million rods

night vision and night vision and peripheral visionperipheral vision

sensitive to dim lightsensitive to dim light

CONESCONES

5-6.4 million cones5-6.4 million cones

daylight vision and daylight vision and color visioncolor vision

visual acuityvisual acuity- - sharpness and sharpness and precise detailprecise detail

P.26 Describe the visual, sensory and P.26 Describe the visual, sensory and auditory sensory systems. auditory sensory systems.

Visual DeficienciesVisual Deficiencies

NearsightednessNearsightedness

close objects seen close objects seen clearly but distant clearly but distant objects appear blurryobjects appear blurry

light falls short of light falls short of retinaretina

eyeball is too longeyeball is too long

FarsightednessFarsightedness

distant objects seen distant objects seen clearly but close clearly but close objects appear blurryobjects appear blurry

light falls behind light falls behind retinaretina

eyeball is too shorteyeball is too short

P.26 Describe the visual, sensory and auditory sensory systemsP.26 Describe the visual, sensory and auditory sensory systems. .

Visual AdaptationVisual Adaptation

Dark AdaptationDark Adaptation

process by which the process by which the eyes become more eyes become more sensitive to light in sensitive to light in low illuminationlow illumination

Complete in 30 Complete in 30 minutesminutes

Light AdaptationLight Adaptation

process whereby process whereby eyes become less eyes become less sensitive to light in sensitive to light in high illuminationhigh illumination

Improves visual acuityImproves visual acuity

Viewing the World in ColorViewing the World in Color

trichromatic theorytrichromatic theory- human eye has three - human eye has three types of receptors with differing types of receptors with differing sensitivities to different light wavelengthssensitivities to different light wavelengths– red, green and bluered, green and blue– ““color mixing” allows for all colorscolor mixing” allows for all colors

afterimageafterimage- visual image that persists after - visual image that persists after a stimulus is removeda stimulus is removed– color will be complement of original colorcolor will be complement of original color

https://www.youtube.com/watch?v=dxqsBk7Wn-Yhttps://www.youtube.com/watch?v=dxqsBk7Wn-Y

Perceiving Forms, Patterns, Perceiving Forms, Patterns, and Objectsand Objects

Unit 3Unit 3

Perceptions are SubjectivePerceptions are Subjective

same visual input can result in radically same visual input can result in radically different perceptionsdifferent perceptions

perceptual setperceptual set- readiness to perceive a - readiness to perceive a stimulus is a particular waystimulus is a particular way

inattentional blindnessinattentional blindness- involves failure to - involves failure to see visible objects or events because see visible objects or events because attention is focused elsewhereattention is focused elsewhere

Looking at the Whole Picture: Looking at the Whole Picture: Gestalt PrinciplesGestalt Principles

Figure and GroundFigure and Ground

figurefigure is thing being is thing being looked at, while looked at, while groundground is background is background against which it against which it standsstands

figures appear closer, figures appear closer, stand out and have stand out and have more substancemore substance

P.28 Explain Gestalt’s principles of P.28 Explain Gestalt’s principles of perception. perception.

P.28 Explain Gestalt’s principles of P.28 Explain Gestalt’s principles of perception. perception.

Gestalt PrinciplesGestalt Principles

ProximityProximity

things that are near things that are near one another seem to one another seem to belong togetherbelong together

P.28 Explain Gestalt’s principles of perception. P.28 Explain Gestalt’s principles of perception.

Gestalt PrinciplesGestalt Principles

ClosureClosure

group elements to group elements to create completenesscreate completeness

fill in gapsfill in gaps

P.28 Explain Gestalt’s principles of P.28 Explain Gestalt’s principles of perception. perception.

Gestalt PrinciplesGestalt Principles

SimilaritySimilarity

tendency to group tendency to group stimuli that are similarstimuli that are similar

same characteristicssame characteristics

P.28 Explain Gestalt’s principles of P.28 Explain Gestalt’s principles of perception. perception.

Gestalt PrinciplesGestalt Principles

SimplicitySimplicity

Tendency to group Tendency to group elements that elements that combine to form a combine to form a good figuregood figure

Organize forms in Organize forms in simplest way possiblesimplest way possible

P.28 Explain Gestalt’s principles of P.28 Explain Gestalt’s principles of perception. perception.

Gestalt PrinciplesGestalt Principles

ContinuityContinuity

follows in direction ledfollows in direction led

connect points that connect points that result in straight or result in straight or gently curved lines gently curved lines that create “smooth” that create “smooth” pathspaths

P.28 Explain Gestalt’s principles of P.28 Explain Gestalt’s principles of perception. perception.

Perceiving Depth of DistancePerceiving Depth of Distance

Binocular CuesBinocular Cuesclues about distance based on clues about distance based on differing views of the differing views of the two eyestwo eyes

retinal disparityretinal disparity- images - images projected to different locations projected to different locations on right and left retinason right and left retinas

convergenceconvergence- sensing the - sensing the eyes converging toward each eyes converging toward each other as they focus on closer other as they focus on closer objectsobjects

Monocular CuesMonocular Cuesclues about distance based on clues about distance based on the image in either eye the image in either eye alonealone

motion parallaxmotion parallax- images - images projected at different distances projected at different distances moving across retina at moving across retina at different ratesdifferent rates

pictorial depth cuespictorial depth cues- -

clues about distanceclues about distance

given in a flat picturegiven in a flat picture

depth perceptiondepth perception- interpretation of visual cues - interpretation of visual cues that indicate how near or far away objects arethat indicate how near or far away objects are

P.29 Describe binocular and monocular depth cues. P.29 Describe binocular and monocular depth cues.

Phi PhenomenonPhi Phenomenon

• illusion of movement created by illusion of movement created by presenting visual stimuli in rapid presenting visual stimuli in rapid successionsuccession

• our perceptions fill in the gaps to perceive our perceptions fill in the gaps to perceive motionmotion

Stroboscopic PhotographyStroboscopic Photography

Our Sense of Hearing: Our Sense of Hearing: The Auditory SystemThe Auditory System

The Stimulus: SoundThe Stimulus: Sound

sound waves are vibrations of molecules sound waves are vibrations of molecules that travel through physical mediumthat travel through physical medium– wavelengthwavelength described in terms of frequency described in terms of frequency

cycles per second, hertz (Hz)cycles per second, hertz (Hz)

– amplitudeamplitude described in terms of loudness described in terms of loudnessmeasured in decibels (dB)measured in decibels (dB)

Sensory Processing in the EarSensory Processing in the Ear

external earexternal ear– vibration of air vibration of air

moleculesmolecules

middle earmiddle ear– vibration of movable vibration of movable

bonesbones

inner earinner ear– waves in a fluidwaves in a fluid

https://www.youtube.com/watch?v=flIAxGsV1q0

The human earThe human ear

pinnapinna- sound - sound collecting bonecollecting bone

hammer, anvil, hammer, anvil, stirrupstirrup- amplify tiny - amplify tiny changes in air changes in air pressurepressure

cochleacochlea- contains - contains receptors for hearingreceptors for hearing

Our Chemical Senses: Our Chemical Senses: Taste and SmellTaste and Smell

https://www.youtube.com/watch?v=EJud8MKrvBEhttps://www.youtube.com/watch?v=EJud8MKrvBE

Taste: The Gustatory SystemTaste: The Gustatory System

Chemical substances that are solubleChemical substances that are soluble

Receptors are clusters of taste cells on Receptors are clusters of taste cells on taste budstaste buds– short life of 10 daysshort life of 10 days– perception depend on patterns from receptorsperception depend on patterns from receptors

Four primary tastesFour primary tastes– sweet, sour, salty, bittersweet, sour, salty, bitter

https://www.youtube.com/watch?v=kyrIxAXZISchttps://www.youtube.com/watch?v=kyrIxAXZISc

Smell: The Olfactory SystemSmell: The Olfactory System

chemical substances-volatile ones that chemical substances-volatile ones that evaporate and spread throughout the airevaporate and spread throughout the air– dissolved in fluid, mucus in the nosedissolved in fluid, mucus in the nose

olfactory ciliaolfactory cilia- hairlike structures in upper - hairlike structures in upper portion of nasal passagesportion of nasal passages– short life (30-60 days)short life (30-60 days)

Sensory adaptation = 4 minutesSensory adaptation = 4 minutes

Our Sense of TouchOur Sense of Touch

conversion of physical sensation into a conversion of physical sensation into a psychological experiencepsychological experience

mechanical, thermal and chemical energymechanical, thermal and chemical energy– pressure of touch in warmth, cold and painpressure of touch in warmth, cold and pain

P.27 Describe other sensory systems, including olfaction and gustation, and identify skin senses, kinesthesis, and vestibular P.27 Describe other sensory systems, including olfaction and gustation, and identify skin senses, kinesthesis, and vestibular sense.sense.

Puzzles in Pain PerceptionPuzzles in Pain Perception

Pain PathwaysPain Pathways1.1. Fast- registers Fast- registers

localized pain and localized pain and relays it to cortex in relays it to cortex in fraction of a secondfraction of a second

2.2. Slow- conveys Slow- conveys longer lasting, longer lasting, aching or burning aching or burning pain that comes pain that comes after initial injuryafter initial injury

Gate Control TheoryGate Control TheoryIncoming pain Incoming pain sensations must pass sensations must pass through “gate” in through “gate” in spinal cord that can spinal cord that can be closed, blocking be closed, blocking ascending pain ascending pain signalssignalsCognitive and Cognitive and emotional processes emotional processes block pain signalsblock pain signals

https://www.youtube.com/watch?v=1mHIv5ToMTMhttps://www.youtube.com/watch?v=1mHIv5ToMTM

Our Other SystemsOur Other Systems

KinestheticKinesthetic

monitors positions of monitors positions of various body partsvarious body parts

receptors located in joints receptors located in joints and musclesand muscles

VestibularVestibular

responds to gravity and responds to gravity and keeps you informed keeps you informed about you body’s about you body’s location in spacelocation in space

provides the sense of provides the sense of balance and equilibriumbalance and equilibrium

receptors located within receptors located within semicircular canals of semicircular canals of earear

P.27 Describe other sensory systems, including olfaction and gustation, and identify skin senses, kinesthesis, and P.27 Describe other sensory systems, including olfaction and gustation, and identify skin senses, kinesthesis, and vestibular sense.vestibular sense.