ch 11 sensation and perception psyc 615 takashi yamauchi © takashi yamauchi (dept. of psychology,...
TRANSCRIPT
Ch 1 1
Sensation and Perception
Psyc 615
Takashi Yamauchi© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)
Ch 1 2
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 3
What do eyes, a nose, ears, a tongue, and skin do?
• Eye:
• Ear:
• Nose:
• Tongue:
• Skin:
Ch 1 4
What does the eye do?
• Eye:
– detecting light
Seeing,
yes but what is seeing?
What is light?
electromagnetic energy
Ch 1 5
What is electromagnetic energy?
• Electro + magnetic + energy = electromagnetic energy
• Electromagnetic energy is a stream of photons.
Ch 1 6
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 7
So what is “seeing”?
• Detecting the movement of photons (electromagnetic radiation).
Ch 1 8
What does the ear do?
Hears a 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 9
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.” (Wikipeida.org)
Ch 1 10
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 11
Taste
• How do we get that?– From our tongues.
• Where do we get that?– From foods we eat.– From specific chemicals.
Ch 1 12
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 goes up or down due to the motion of
particles. • Temperature increases as the energy of this motion
increases. (wikipedia)
Ch 1 13
What does the skin do?
feels touching
It responds to mechanical stimulation or pressure
Ch 1 14
So, what is perception?
• Perception is a system that tells us about an environment.
Ch 1 15
Eye, ear, nose, tongue & skin
• They are sensors.
• They are detecting some kind of changes in an environment.
Ch 1 16
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 17
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 18
The brain is the locus of perception
• To study perception, we have to study of the brain and behavior.
Ch 1 19
A quick demonstration
• Tell me what you see.
Ch 1 20
Ch 1 21
Ch 1 22
(A)
(B)
(A)
(B)
Ch 1 23
Visual Illusions
• Why does this happen?
• Tell me what these illusions teach us.
Ch 1 24
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 25
Let’s have some break.
• Listen to music
• See a painting
Ch 1 26Paul Klee: Ad Parnassum
Ch 1 27Anselm Kiefer: Nuremberg
Ch 1 28
Henri Rousseau: The Dream
Ch 1 29
What’s going on?
• Perception is about detecting, but also more than detecting.
Ch 1 30
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 31
Ch 1 32
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 33
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 (psychological state).
Ch 1 34
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 35
Demonstration (attention & perception)
• An interaction between
– attention and perception
– cognition and perception
• Tell me what you see.
Ch 1 36
Demonstration (knowledge and perception)
Ch 1 37
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Ch 1 41
Ch 1 42
What did you see?
• What does this tell?
Ch 1 43
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 44
Measuring Perception
• Psychophysical level of analysis– Description
• Phenomenological method• E.g., Let a person describe what they see
– Recognition– Detection
Ch 1 45
• 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 46
Demonstration
Ch 1 47
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Ch 1 49
Ch 1 50
Ch 1 51
Demonstration: Measuring weight
• DL (difference threshold) gets larger as the standard stimulus gets larger.
Ch 1 52
Ch 1 53
Demonstration
• Color, line, length
Ch 1 54
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 55
Weber’s law
Ch 1 56
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 57
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 58
Magnitude estimation
• Assign a value to a standard stimulus
• The subject estimate the value of a target stimulus.
Ch 1 59
Magnitude estimationStandard: == 10
Target: == ?
Standard: == 100
Target: == ?
Ch 1 60
Standard: == 100
Target: == ?
Ch 1 61
Standard: == 100
Target: == ?
Ch 1 62
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 63
Magnitude estimation
Ch 1 64
Ch 1 65
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 66
Experiment (you are estimating the length of lines)
Ch 1 67
Standard = 100 Target = ?
Ch 1 68
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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estim
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P: your estimation
S: stimulus intensity
n: some value =0.33
K: some value (constant) = 21.5
nKSP
Ch 1 69
Experiment (you are estimating the intensity of electric shock)
Standard = 100
Target = ?
Ch 1 70
Estimating the intensity of electric shock
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Physcial magnitude
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Target Your estimations0 0
10 320 930 1640 2550 3560 4670 5980 7290 85100 100110 115120 131130 148140 166150 184160 202170 222180 241190 262200 283210 304
P: your estimation
S: stimulus intensity
n: some value =1.5
K: some value (constant) = 0.1
nKSP
Ch 1 71
020406080
100120140160180200220240260280300320
0 50 100 150 200 250
Physical magnitudes
You
r es
timat
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Estimating electric shock
Estimating the length of lines
Ch 1 72
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 73
Threshold
• Absolute threshold
• Difference threshold
Ch 1 74
Difference threshold
• Weber’s law
• Stevens’s law