Chapter 4 © South-Western | Cengage Learning A Discovery Experience PSYCHOLOGY Slide 1 Sensation CHAPTER 4 LESSONS 4.1 4.1Basic Principles of Sensation

Chapter 4

© South-Western | Cengage Learning

A Discovery ExperiencePSYCHOLOGY

Slide 1

SensationSensation

CHAPTER 4CHAPTER 4CHAPTER 4CHAPTER 4

LESSONSLESSONS

4.14.1 Basic Principles of Sensation

4.24.2 Vision

4.34.3 Hearing and Your Other Senses

LESSONSLESSONS

4.14.1 Basic Principles of Sensation

4.24.2 Vision

4.34.3 Hearing and Your Other Senses



Chapter 4 Slide 2

LESSON 4.1LESSON 4.1

Basic Principles of SensationBasic Principles of Sensation

OBJECTIVESOBJECTIVESExplain the concepts of sensory thresholds and

compare the different theories.Describe sensory adaptation.

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Slide 3

Sensory ThresholdsSensory Thresholds

Sensation is the process that detects stimuli from your body and environment.

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Slide 4

Table 4-1Table 4-1

The Stimuli and Sensory Receptors for The Stimuli and Sensory Receptors for Each Primary SenseEach Primary Sense

Sense Stimulus Sensory Receptors

Vision Light waves Light-sensitive rods and cones in the retina of the eye

Hearing Sound waves Pressure-sensitive hair cells in the cochlea of the inner ear

Taste Molecules dissolved in fluid on the tongue

Taste cells in the taste buds of the tongue

Smell Molecules dissolved in fluid in the nose

Sensitive ends of olfactory (smell) neurons

Touch Pressure on the skin Sensitive ends of touch neurons

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Slide 5

Absolute ThresholdAbsolute Threshold

Psychophysics is the study of how physical stimuli are translated into psychological experience.

Absolute threshold is the weakest amount of a given stimulus that a person can detect half of the time.

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Slide 6

Table 4-2Table 4-2

Examples Of Absolute ThresholdsExamples Of Absolute Thresholds

Stimulus Absolute Threshold

Vision A candle seen at 30 miles on a dark, clear night

Hearing The tick of a watch at 20 feet under quiet conditions

Taste One teaspoon of sugar in 2 gallons of water

Smell One drop of perfume diffused into a three-room apartment

Touch The wing of a fly falling on your cheek from a distance of 0.5 inch

Source: Adapted from Galanter, 1962.

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Signal-Detection TheorySignal-Detection Theory

Signal-detection theory states that detecting a stimulus is influenced by a person’s decision-making strategy.

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Slide 8

Difference ThresholdDifference Threshold

Difference threshold is the smallest difference between two stimuli that can be detected half of the time.

Weber’s law is the principle that to be noticed as different, two stimuli must differ by a constant minimum percentage rather than by a constant amount.

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Slide 9

Sensory AdaptationSensory Adaptation

Sensory adaptation is the tendency for sensory receptors to decrease in response to stimuli that continue at the same level.



Chapter 4 Slide 10


VisionVision

OBJECTIVES Identify and illustrate the structures of the eye

that are responsible for vision.Describe the way the brain perceives color.

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Figure 4-1Figure 4-1

The Electromagnetic SpectrumThe Electromagnetic Spectrum

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Structures of the Human EyeStructures of the Human EyeThe pupil is an opening in the iris that allows light to

enter the eye.The iris is a ring of muscles that range in color from

light blue to dark brown.The lens is a clear, elastic, disc-shaped structure that

refocuses light.The retina is the light-sensitive surface at the back of

the eye.The optic nerve carries information from the retina to

the brain.The blind spot is the area on the retina where the

optic nerve leaves the eye and that contains no receptor cells.

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Slide 13


Major Structures Of The Human EyeMajor Structures Of The Human Eye

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Slide 14

VideoVideo

Anatomy of the Eye (Virtual Reality)Anatomy of the Eye (Virtual Reality)

Videos are located on the Instructor’s Resource CD in the Videos folder.

Filename: AnatomyEyeVRRunning time: variable

This video is activated by moving the mouse over the video screen to explore the anatomy of the eye.

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Slide 15


How Light Travels through the EyeHow Light Travels through the Eye

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Slide 16

VideosVideos

Transmission of Light through the EyeTransmission of Light through the Eye

Videos are located on the Instructor’s Resource CD in the Videos folder.

Filename: LightThroughEyeRunning time: 28 seconds

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Slide 17

Color VisionColor VisionAll the colors you see are red, blue, and

green, or a mixture of these three.The color is in your visual system.An object appears as a particular color

because it absorbs or reflects certain wavelengths of light.

Colors are created by the cones in your eye responding to wavelengths and sending neural signals to your brain, which then creates the colors you see.

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Slide 18

Color BlindnessColor Blindness

Color blindness is a deficiency in the ability to distinguish among colors.

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Slide 19


Test for Color BlindnessTest for Color Blindness



Chapter 4 Slide 20


Hearing and Your Other SensesHearing and Your Other Senses

OBJECTIVESExplain and illustrate the human auditory

system and the structure of the ear.Describe the senses of smell, taste, touch, and

body position and movement.

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Slide 21

The Auditory SystemThe Auditory System

The auditory system controls your sense of hearing.

Hearing begins with sound waves—vibrations in air, water, or solid material.

The number of sound waves that pass through a given point in one second is called the sound’s frequency.

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Slide 22

The Auditory System—PitchThe Auditory System—Pitch

When your sensory system experiences the physical sensation of frequency, you also have the psychological experience of pitch. High-pitched sounds are high frequenciesLow-pitched sounds are low frequencies.

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Slide 23

The Auditory System—AmplitudeThe Auditory System—Amplitude

Loudness of sound is a psychological experience that corresponds to the height of a sound wave, called amplitude.Amplitude is measured in decibels (dB).The greater the amplitude, the higher the

decibels, and the louder the sound.

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Slide 24

Table 4-3Table 4-3

Decibel Level of Some Common SoundsDecibel Level of Some Common Sounds

Decibels Source Exposure Danger

180 Space shuttle launch Hearing loss certain within 150 feet of launch pad

140 Jet aircraft motor Any exposure dangerous

120 Sandblaster, thunderclap Immediate danger

100 Heavy auto traffic, lawn mower

2 hours

60 Normal conversation No danger

40 Quiet office No danger

30 Quiet library No danger

20 Soft whisper No danger

0 Minimal detectable sound No danger

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Slide 25

The EarThe Ear

The ear is divided into three major parts:The outer ear is the part you see. The eardrum is a thin, flexible membrane

that vibrates in sequence with sound waves.

The cochlea is the coiled, fluid-filled tube in the inner ear that contains hair-like auditory receptors.

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Slide 26


The Human EarThe Human Ear

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Slide 27

Hearing LossHearing Loss

There are two types of hearing loss: Conduction hearing lossSensorineural hearing loss

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Slide 28

Conduction Hearing Loss Conduction Hearing Loss

Occurs when there are physical problems sending sound waves through the outer or middle ear

Often involves a punctured eardrum or damage to any of the bones in the middle ear

Hearing aids Common treatment for conduction hearingTiny instruments worn just inside the outer earChange sound waves into amplified vibrations and

send them to the inner ear

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Slide 29

Sensorineural Hearing Loss Sensorineural Hearing Loss More common than conductive hearing lossInvolves nerve problems in the inner earOften occurs because hair cells in the cochlea

are damaged either by disease, injury, or aging

Cochlear implantOnly means of restoring hearingMiniature electronic device surgically placed into

cochleaChanges sound waves into electrical signalsBest candidates—young children born with hearing

loss

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Slide 30

SmellSmellOlfactory nerve transmits neural impulses

containing smell information from the nose to the brain.The stimuli for smell are airborne molecules. These molecules enter your nasal passages and

reach tiny receptor cells at the top of the nasal cavity.

These receptor cells then transmit neural impulses containing smell information through the olfactory nerve to the brain.

Once your brain has processed these neural signals, you experience the aroma or odor.

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Slide 31


The Olfactory SystemThe Olfactory System

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Slide 32

TasteTaste

Taste buds are sensory receptor organs that contain the receptor cells for taste.

Taste occurs when receptor cells in your mouth and throat trigger neural impulses to the brain.

About 50 to 150 of these receptor cells are contained in each of the 10,000 taste buds that are located mainly on the tongue.

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Slide 33

Taste SensationsTaste Sensations

Four most familiar taste sensations:Sweetness (mostly sugars)Sourness (mostly acids)Saltiness (mostly salts)Bitterness (mainly chemicals that have no food

value or are toxic)

Most taste experiences are complex and result from the combined effects of receptor cells in the mouth and nose, which produce the different flavors you experience.

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Slide 34


The Tongue Map MythThe Tongue Map Myth

Myth: Different areas of the tongue are more sensitive to one of the four primary tastes.

Fact: All your taste buds detect all taste qualities.

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Slide 35

The Skin SensesThe Skin Senses

Skin defines boundaries with the environment.

Skin is your largest sensory organ.The sense of touch is actually a

combination of three skin senses: PressureTemperaturePain

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Slide 36

PressurePressure

The stimulus for pressure is physical pressure on the skin.

The entire body is sensitive to pressure.Some areas have more receptors so

are more sensitive.

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Slide 37

TemperatureTemperature

Temperature sensations depend on which type of receptor is stimulated.

Whether more warm or cold receptors are stimulated depends on the difference between your skin temperature and the temperature you are feeling.

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Slide 38

PainPainPain serves as a warning system that signals

danger and the risk of injury. Pain can also force people to cope

appropriately with an injury.The most widely accepted theory of pain is

gate-control theory.Gate-control theory describes how pain

signals open a neurological “pain gate” in the spinal cord and how other touch signals close the gate.

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Slide 39

Body Position and MovementBody Position and Movement

Kinesthetic sense provides information about the movement and location of different parts of your body.

Vestibular sense provides information on the position of your body by sensing gravity and motion.

Equilibrium is another name for vestibular sense.

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Slide 40

Chapter 4Chapter 4 Clicker QuestionsClicker Questions

1.1. Which refers to nerve cells firing less frequently after high levels of stimulation?

a.a. critical thinking

b.b. environmental threshold

c.c. absolute threshold

d.d. sensory adaptation

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Slide 41


2.2. The major contribution of the signal-detection theory was the establishment of specific absolute thresholds for all senses.

a.a. True

b.b. False

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Slide 42


3.3. Which is a ring of muscles that range in color from light blue to dark brown?

a.a. pupil

b.b. iris

c.c. lens

d.d. retina

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Slide 43


4.4. Loudness of a sound corresponds to the height of a sound wave called

a.a. amplitude

b.b. pitch

c.c. frequency

d.d. timbre

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Slide 44


5.5. What is the term for the senses that detect body position and movement?

a.a. olfactory

b.b. proprioceptive

c.c. sensorineural

d.d. auditory

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Chapter 4 © South-Western | Cengage Learning A Discovery Experience PSYCHOLOGY Slide 1 Sensation CHAPTER 4 LESSONS 4.1 4.1Basic Principles of Sensation