Download CHAPTER 4 Sensation

CHAPTER 4
Sensation
LESSONS
4.1 Basic Principles of Sensation
4.2 Vision
4.3 Hearing and Your Other Senses
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 1
LESSON 4.1
Basic Principles of Sensation
OBJECTIVES
 Explain the concepts of sensory thresholds and
compare the different theories.
 Describe sensory adaptation.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 2
Sensory Thresholds
Sensation is the process that detects
stimuli from your body and environment.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 3
Table 4-1
The Stimuli and Sensory Receptors for
Each 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 Taste cells in the taste buds of the
in fluid on the tongue 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
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 4
Absolute Threshold
Absolute threshold is the weakest
amount of a given stimulus that a person
can detect half of the time.
Present at different intensities
Determine lowest level detectable 50
percent of the time
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 5
Table 4-2
Examples 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 threeroom apartment
Touch
The wing of a fly falling on your cheek from
a distance of 0.5 inch
Source: Adapted from Galanter, 1962.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 6
Signal-Detection Theory
Signal-detection theory states that
detecting a stimulus is influenced by a
person’s decision-making strategy.
Also influenced by:
Expectations
Rewards and costs
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 7
Difference Threshold
Difference threshold is the smallest
difference between two stimuli that can
be detected half of the time.
Changes in strength and intensity
Ex: 1lb vs 2lb and 100lb vs 101lb
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 8
Sensory Adaptation
Sensory adaptation is the tendency for
sensory receptors to decrease in
response to stimuli that continue at the
same level.
Ex: Get used to a smell right beside you
Remove it for about 10 minutes,
put it back, just as strong as the
beginning
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 9
LESSON 4.2
Vision
OBJECTIVES
 Identify and illustrate the structures of the eye
that are responsible for vision.
 Describe the way the brain perceives color.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 10
Figure 4-1
The Electromagnetic Spectrum
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 11
Structures of the Human Eye
 The 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.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 12
Figure 4-2
Major Structures of the Human Eye
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 13
Figure 4-3
How Light Travels through the Eye
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 14
Color Vision
 All 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.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 15
Color Blindness
Color blindness is a deficiency in the
ability to distinguish among colors.
1 in 50
90% are males
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 16
Figure 4-4
Test for Color Blindness
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 17
LESSON 4.3
Hearing and Your Other Senses
OBJECTIVES
 Explain and illustrate the human auditory
system and the structure of the ear.
 Describe the senses of smell, taste, touch, and
body position and movement.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 18
The Auditory System
The auditory system controls your sense
of hearing.
Hearing begins with sound waves—
vibrations in air, water, or solid material.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 19
The Auditory System—Amplitude
Loudness of sound is 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.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 20
Table 4-3
Decibel 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
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 21
The 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.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 22
Figure 4-5
The Human Ear
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 23
New Science
Sensory Crossovers
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 24
Smell
 The olfactory nerve transmits neural
impulses containing smell information from
the nose to the brain.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 25
Figure 4-6
The Olfactory System
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 26
Taste
 Taste buds are sensory receptor organs that
contain the receptor cells for taste.
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 27
Taste 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)
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 28
The Skin Senses
Skin is your largest sensory organ.
The sense of touch is actually a
combination of three skin senses:
Pressure
Temperature
Pain
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 29
Chapter 4
Clicker Questions
1. Which refers to nerve cells firing less
frequently after high levels of stimulation?
a. critical thinking
b. environmental threshold
c. absolute threshold
d. sensory adaptation
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 30
Chapter 4
Clicker Questions
2. The major contribution of the signal-detection
theory was the establishment of specific
absolute thresholds for all senses.
a. True
b. False
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 31
Chapter 4
Clicker Questions
3. Which is a ring of muscles that range in color
from light blue to dark brown?
a. pupil
b. iris
c. lens
d. retina
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 32
Chapter 4
Clicker Questions
4. Loudness of a sound corresponds to the
height of a sound wave called
a. amplitude
b. pitch
c. frequency
d. timbre
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 33
Chapter 4
Clicker Questions
5. What is the term for the senses that detect
body position and movement?
a. olfactory
b. proprioceptive
c. sensorineural
d. auditory
PSYCHOLOGY
A Discovery Experience
© 2011 South-Western | Cengage Learning
Chapter 4 Slide 34