ch 11 sensation and perception psyc 320 takashi yamauchi © takashi yamauchi (dept. of psychology,...
TRANSCRIPT
Ch 1 1
Sensation and Perception
psyc 320
Takashi Yamauchi© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)
Ch 1 2
Sensation & Perception
• Ch. 1: Introduction to perception
• Main topics– Perceptual processes– How to study perception– How to measure perception
Ch 1 3
• Sensation & Perception
• How is this course different from other psychology courses?
–learn sensation & perception
–Some very basic form of mind (sensing & perceiving)
–Deal with fundamental principles of psychology
Ch 1 4
Questions:
• What is perception?
Perception is about perceiving.
What is perceiving?
What do we do when we perceive?
We see, smell, hear, feel, taste, …
Ch 1 5
What tools do we have for perceiving?• Eyes, ears, nose, tongue, skin,
– eyes see,
– ears hear,
– nose smell,
– tongue taste,
– skin feel (temperature)
– skin feel (touch)
Ch 1 6
What do eyes, a nose, ears, a tongue, and skin do?
• Eye:
• Ear:
• Nose:
• Tongue:
• Skin:
Ch 1 7
What does the eye do?
• Eye:
– detecting light
Seeing,
yes but what is seeing?
What is light?
electromagnetic energy
Ch 1 8
What is electromagnetic energy?
• Electro + magnetic + energy = electromagnetic energy
• Electromagnetic energy is a stream of photons.– www.wikipedia.org
Ch 1 9
What are photons?
• They are massless particles each traveling in a wave-like pattern and moving at the speed of light.
• The smallest (quantum) unit of light/electromagnetic energy.
• It is the carrier of electromagnetic radiation of all wavelengths– such as gamma rays, X-rays, ultraviolet light, visible
light, infrared light, microwaves, and radio waves.
Ch 1 10
So what is “seeing”?
• Detecting some form of the movement of photons (electromagnetic radiation).
Ch 1 11
What does the ear do?
Hears sound
What is sound?
the vibration of air.
What is the vibration of air?Where do they come from?
Air moves when something else moves
Ch 1 12
What does the nose do?
• Nose: is for smelling
–Where does smelling come from?
–Smelling is a “sensation caused by odorant molecules dissolved in air.” (wikipedia.org)
Ch 1 13
Odorant molecules? What are they?
• Odorant (aroma compound) chemical compound (e.g., H2O; a
chemical substance of two or more different chemical elements.)
• Where do they come from?– Organic compounds foods, flowers, – Inorganic compounds ammonia,…
Ch 1 14
Taste
• How do we get that?– From our tongues.
• Where do we get that?– From foods we eat.– From specific chemicals.
Ch 1 15
What does the skin do?
• Detect temperature:
• What is temperature?• It is about how hot or cold something is.
• How does something get hot or cold?• Temperature is the result of the motion of particles
which make up a substance. • Temperature increases as the energy of this motion
increases. (wikipedia)
Ch 1 16
What does the skin do?
feels touching
It responds to mechanical stimulation or pressure
Ch 1 17
So, what is perception?
• Perception is a system that tells us about an environment.
Ch 1 18
Eye, ear, nose, tongue & skin
• They are sensors.
• They are detecting some kind of changes in an environment.
Ch 1 19
So, studying perception we need to study
• How the eye works,
• How the ear works,
• How the nose works,
• How the tongue works, and
• How the skin works
• Is that all?
Ch 1 20
What tools do we have for perceiving?
• Eyes, ears, nose, tongue, skin, – Eyes see, ears hear, nose smell, – tongue taste, skin feel
• Are these all?• NO!
Brain (not Bryan)
Ch 1 21
The brain is the locus of perception
• the study of perception entails the study of the brain and behavior.
Ch 1 22
A quick demonstration
• Tell me what you see.
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Ch 1 24
ch 10 25
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Ch 1 27
(A)
(B)
(A)
(B)
Ch 1 28
Visual Illusions
• Why does this happen?
• Tell me what these illusions teach us.
Ch 1 29
What is perception?
• Perception involves:– Detecting the information in the environment.– Sending the information to the brain, and
interpreting it.
• Perception is about– Detecting and interpreting
Ch 1 30
Let’s have some break.
• Listen to music
• See a painting
Ch 1 31
Paul Klee: Golden fish
Ch 1 32Paul Klee: Ad Parnassum
Ch 1 33Anselm Kiefer: Nuremberg
Ch 1 34
Henri Rousseau: The Dream
Ch 1 35
What’s going on?
• Perception is about detecting, but also more than detecting.
Ch 1 36
What’s going on when we see the pictures?
• When we listen to beautiful music, we often see a picture.
• When we see a beautiful picture, we hear music. How come?
Ch 1 37
How come?–Different types of physical information (air vibration, light energy) are translated into a common language in the brain– neural information
Environmental Stimuli (e.g., light energy)
Transduction
Neural Processing
Perception
Ch 1 38
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Ch 1 40
Key points:• Perception is about finding out what is going on in
an environment.
• Perceptual organs (eyes, ears, nose, skin, a tongue) are basically detectors (sensors)
• Perception requires transforming physical information (e.g., light) into neural information.
• Perception also involves “interpretation,” which is carried out by the brain.
Ch 1 41
Studying perception
• How perceptual detectors work.
• How physical information is transformed (e.g., light) into neural information.
• How neural information is processed in the brain.
• How neural information is interpreted and triggers a specific form of perception.
Ch 1 42
How come?–Different types of physical information (air vibration, light energy) are transformed into a common neural language in the brain– neural information
Environmental Stimuli (e.g., light energy)
Transduction
Neural Processing
Perception
Ch 1 43
Demonstration (attention & perception)
• An interaction between
– attention and perception
– cognition and perception
• Tell me what you see.
Ch 1 44
• Tired
• Old
• Sick
• Dark
• Slow
• Heavy
• Hospital
• ugly
• death
Ch 1 45
• Beautiful
• Young
• Fresh
• Fast
• Energy
• Juicy
• Clean
• cheerful
• Vigorous
Ch 1 47
Ch 1 48
Ch 1 49
Demonstration (knowledge and perception)
Ch 1 50
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Ch 1 52
Ch 1 53
Ch 1 54
Ch 1 55
What did you see?
• What does this tell?
Ch 1 56
Perceptual process
• Perception is the end result of complex processes.
Ch 1 57
Why study perception?
• If the doors of perception were to be cleaned, man would see everything as it truly is…..Infinite.
– William Blake
Ch 1 58
How to approach the study of perception
• Levels of analysis– Psychophysical level of analysis
– Physiological level of analysis
Ch 1 59
Measuring Perception
• Psychophysical level of analysis– Description
• Phenomenological method• E.g., Let a person describe what they see
– Recognition– Detection
Ch 1 60
• Detection– Absolute threshold
• is the smallest amount of stimulus energy necessary to detect a stimulus.
E.g., eye exam
– Difference threshold• is the smallest difference between two
stimuli that a person can detect.
Ch 1 61
Ch 1 62
Demonstration
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Ch 1 67
Demonstration: Measuring weight
• DL (difference threshold) gets larger as the standard stimulus gets larger.
Ch 1 68
Ch 1 69
Demonstration
• Color, line, length
Ch 1 70
The impact of standard stimuli
• DL (difference threshold) gets larger as the standard stimulus gets larger.
• Weber’s lawDL/S=K
• DL: difference threshold• S: standard stimulus• K: constant
Ch 1 71
Weber’s law
Ch 1 72
Question:
• With a standard stimulus 1 kg, John’s difference threshold was 0.25kg. With a standard stimulus 10kg, what would be John’s difference threshold?
Ch 1 73
Question:
• With a standard stimulus 1 kg, John’s difference threshold was 0.25kg. With a standard stimulus 10kg, what would be John’s difference threshold?
DL/S=K
•DL: ?
•S: 10
•K:
DL/S=K
•DL: 0.25
•S: 1
•K: 0.25
Ch 1 74
Magnitude estimation
• Assign a value to a standard stimulus
• The subject estimates the value of a target stimulus.
Ch 1 75
Magnitude estimationStandard: == 10
Target: == ?
Standard: == 100
Target: == ?
Ch 1 76
Standard: == 100
Target: == ?
Ch 1 77
Standard: == 100
Target: == ?
Ch 1 78
Steven’s power law
• S is the physical magnitude of a target that you are estimating.
• P is your estimation• K is some value (constant)• n is some value
nKSP
Ch 1 79
Magnitude estimation
Ch 1 80
Ch 1 81
Steven’s power law nKSP
• S is the physical magnitude of a target that you are estimating.
• P is your estimation
• K is some value (constant)
• n is some value
Ch 1 82
Experiment (you are estimating the length of lines)
Ch 1 83
Standard = 100 Target = ?
Ch 1 84
Target Your estimations0 0
10 4620 5830 6740 7450 7960 8470 8980 9390 96100 100110 103120 106130 109140 112150 114160 117170 119180 121190 124200 126210 128
Estimating the length of stimuli
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Physical magnitudes
Yo
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P: your estimation
S: stimulus intensity
n: some value =0.33
K: some value (constant) = 21.5
nKSP P = S raised to the n-th power
Ch 1 85
Experiment (you are estimating the intensity of electric shock)
Standard = 100
Target = ?
Ch 1 86
Estimating the intensity of electric shock
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Physcial magnitude
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P: your estimation
S: stimulus intensity
n: some value =1.5
K: some value (constant) = 0.1
nKSP
Ch 1 87
020406080
100120140160180200220240260280300320
0 50 100 150 200 250
Physical magnitudes
You
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timat
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Estimating electric shock
Estimating the length of lines
Ch 1 88
Steven’s power law nKSP • S is the physical
magnitude of a target that you are estimating.
• P is your estimation
• K is some value (constant)
• n is some value
Ch 1 89
Threshold
• Absolute threshold
• Difference threshold
Ch 1 90
Difference threshold
• Weber’s law
• Stevens’s law