Psychology 100 Exam 2 Question and
Answer | UPDATED ACTUAL | 2026
• Define transduction . CORRECT ANSWER: conversion of an external stimulus into a
neural signal.
specialized cells called sensory receptors convert energy into a neural signal
• Describe the physical properties of waves. Describe how physical properties of light
and sound waves correspond to perceptual experience . CORRECT ANSWER: What
happens when the wave gets short? It means the two peaks gets closer together in the
same amount of time.
For sound, what psychological sensation corresponds to the wavelength of a sound
wave?
Pitch
For light, what psychological sensation corresponds to the wavelength of a light wave?
Color
A loud, low sound such as that of a heavy train passing by would be caused by
soundwaves that are
High amplitude, low frequency
Some insects can see ultraviolet light in ranges that are invisible to humans. Ultraviolet
light is more toward the blue end of the spectrum than visible blue light. Ultraviolet light
is too high frequency for humans to see.
• Describe the concepts from psychophysics: absolute threshold, difference threshold
and Weber's Law . CORRECT ANSWER: Do you think that by doubling the amplitude
of a light wave, you would also double the perceived brightness?
No , because you can already see to a certain brightness
Psychophysics: the study of how our sensations (psychological events) correspond to
physical events in the world
bsolute threshold: the lowest level of stimulus needed for the nervous system to detect
a change 50% of the time.
Sense Thresholds
Vision a candle flame 30 miles away
Hearing a watch ticking 20 feet away
Smell a drop of perfume in a six-room house
Taste a teaspoon of sugar in a gallon of water
Touch a wiring of a fly on your cheek , dropped 1 cm
What is the highest frequency you can hear ?
,As people get older, you stop hearing higher tones
Just Noticeable Difference (JND) : the smallest change in intensity of a stimulus that we
can detect
Weber's law : the strong the stimulus , the bigger the change needed to detect it
Judging whether two stimuli are different (weber's law)
Are these two bags of oranges the same weight ?
Has someone been into this box of chocolates?
Just Noticeable difference (JND)
The smallest detectable difference between two stimuli
Weber's law- amount of stimulus energy required to produce a JND is a constant
fraction of stimulus intensity. (it's all relative)
Sue is taking a hearing test and trying to detect very quiet sounds. One very quiet
sound is so hard to detect that she misses hearing it about 70% of the time . this sound
is
Below her absolute threshold . absolute threshold. The lowest level of a stimulus that a
person can detect 50% of the time.
• Describe detecting a stimulus using the framework of Signal Detection Theory .
CORRECT ANSWER: Signal Detection theory
How stimuli are detected under different conditions
Ex: where is waldo
Signal- what you are trying to detect
Noise- similar stimuli that might compete with the signal and interfere with your ability to
detect the signal
Bird amongst the leaves
Friend in a crowded room full of other people
Sound of the doorbell form the background sound of vacuuming
Single-to-noise ratio
Difficult of detecting the signal depends on the strength of the signal in relation to the
strength of the noise
Loud voice in a quiet room-high signal/low noise- east !
Quiet voice in a loud room-low signal/high noise- hard!
Respond yes
Respond no
Stimulus present
Hit
Miss
Stimulus absent
False alarm
Correct rejection
,You were searching for your lost phone, which has an orange case. When you see a
part of your orange t-shirt peeking out from a pile of clothes, for a moment you think it is
your phone ! you have just experienced a...
False alarm
What if it really was your phone ?
Hit
What will happen if you adjust your response criterion so that you never have any
misses?
It will increase false alarms because if the stimulus is absent then it's a false alarm.
What will happen if you increase your rate of correct rejections?
Your rate of misses will increase because you are saying yes less often. The more
"nos" the more misses.
Real world application of SDT: not just perceptual function
Think of a doctor trying to diagnose cancer.
1. Identify the hits, misses, false alarms, and correct rejections in this case
2. What are some real-world consequences of having liberal (says yes often) vs. a
conservative (says yes rarely) response criterion?
A cold is not serious, but breast cancer is serious, it is known to have a very high false
alarm rate.
An advantage of having a high false alarm rate for detecting breast cancer is because it
• Discuss the role of attention in detecting a stimulus . CORRECT ANSWER: Attention
The input that we receive from the world is overwhelming. In order to process it deeply ,
we must focus on specific parts using attention
Once this array of sensation passes through the attentional filter, only some parts of the
signal are selected
We know that attention is (at least somewhat) like a filter because of effects that show
streams of information popping through the filter
Dichotic listening: play different information through each ear of headphones.
Information reported only from the attended ear.
Right ear: the theory of relativity
Left ear: it was a dark stormy night
The cocktail party effect: happens when important information pops out in a
conversation that you are not attending (ex. Your name)
Inattentional blindness occurs when unattended stimuli are ignored as if they weren't
there
When you don't see something that is there. Ex: a killer on the left side of the room and
you come in and sit down and face away from them.
Change blindness is a version of this that occurs when you fail to detect obvious
changes in your environment
When you don't detect something in the environment that has changed . (ex: the gorilla
going between the people passing the balls and people do not see it)
Change blindness demo
People can also fail to notice rather large change in their visual world
, Spot the difference
The tree
The pillars ar taller
Big bush in the back
Attention
Ear-allows us to focus on some sensory information, and emphasize other information ,
making it easier to detect what we are interested in
Eye- change blindness and inattentional blindness- show that we are not actually able
to attend to all that much at once
• Distinguish between top-down and bottom-up processing. Apply these concepts to
new examples . CORRECT ANSWER: Bottom-Up processing: Construing a
representation from parts and basic features
Top-down processing: processing influenced by previous experience knowledge
Image: Top-Down Processing
The dog, when you take away the line you can still see the dog.
Image: Top-Down Processing
"It was a sunny day and the children were going to the park" at first it sounds blurry and
then you can understand it.
Sensation and Perception
Another way to think about it...
Sensation: is a bottom up process
Perception: includes top-down processing as well, which can change what we report
about sensations.
Recap
Bottom-up
Constructing a representation from parts and basic features starts with the raw data
construct meaning for that
A demonstration of top-down processing
Perceptual sets= sets formed when our expectations influence our perceptions.
• Describe the basic anatomy of the visual system . CORRECT ANSWER: Sclera: the
white part!
Pupil: circular hole where light enters
Iris: colored portion of the eye that controls pupil size (letting in more or less light)
Cornea: curved, transparent layer covering the iris and pupil that helps focus light
Life pro tip: take out your contacts , lest you irritate your cornea!
Lens: oval shaped disc that bends light
Accommodation: changing of the lens' shape to focus on near/far objects
Answer | UPDATED ACTUAL | 2026
• Define transduction . CORRECT ANSWER: conversion of an external stimulus into a
neural signal.
specialized cells called sensory receptors convert energy into a neural signal
• Describe the physical properties of waves. Describe how physical properties of light
and sound waves correspond to perceptual experience . CORRECT ANSWER: What
happens when the wave gets short? It means the two peaks gets closer together in the
same amount of time.
For sound, what psychological sensation corresponds to the wavelength of a sound
wave?
Pitch
For light, what psychological sensation corresponds to the wavelength of a light wave?
Color
A loud, low sound such as that of a heavy train passing by would be caused by
soundwaves that are
High amplitude, low frequency
Some insects can see ultraviolet light in ranges that are invisible to humans. Ultraviolet
light is more toward the blue end of the spectrum than visible blue light. Ultraviolet light
is too high frequency for humans to see.
• Describe the concepts from psychophysics: absolute threshold, difference threshold
and Weber's Law . CORRECT ANSWER: Do you think that by doubling the amplitude
of a light wave, you would also double the perceived brightness?
No , because you can already see to a certain brightness
Psychophysics: the study of how our sensations (psychological events) correspond to
physical events in the world
bsolute threshold: the lowest level of stimulus needed for the nervous system to detect
a change 50% of the time.
Sense Thresholds
Vision a candle flame 30 miles away
Hearing a watch ticking 20 feet away
Smell a drop of perfume in a six-room house
Taste a teaspoon of sugar in a gallon of water
Touch a wiring of a fly on your cheek , dropped 1 cm
What is the highest frequency you can hear ?
,As people get older, you stop hearing higher tones
Just Noticeable Difference (JND) : the smallest change in intensity of a stimulus that we
can detect
Weber's law : the strong the stimulus , the bigger the change needed to detect it
Judging whether two stimuli are different (weber's law)
Are these two bags of oranges the same weight ?
Has someone been into this box of chocolates?
Just Noticeable difference (JND)
The smallest detectable difference between two stimuli
Weber's law- amount of stimulus energy required to produce a JND is a constant
fraction of stimulus intensity. (it's all relative)
Sue is taking a hearing test and trying to detect very quiet sounds. One very quiet
sound is so hard to detect that she misses hearing it about 70% of the time . this sound
is
Below her absolute threshold . absolute threshold. The lowest level of a stimulus that a
person can detect 50% of the time.
• Describe detecting a stimulus using the framework of Signal Detection Theory .
CORRECT ANSWER: Signal Detection theory
How stimuli are detected under different conditions
Ex: where is waldo
Signal- what you are trying to detect
Noise- similar stimuli that might compete with the signal and interfere with your ability to
detect the signal
Bird amongst the leaves
Friend in a crowded room full of other people
Sound of the doorbell form the background sound of vacuuming
Single-to-noise ratio
Difficult of detecting the signal depends on the strength of the signal in relation to the
strength of the noise
Loud voice in a quiet room-high signal/low noise- east !
Quiet voice in a loud room-low signal/high noise- hard!
Respond yes
Respond no
Stimulus present
Hit
Miss
Stimulus absent
False alarm
Correct rejection
,You were searching for your lost phone, which has an orange case. When you see a
part of your orange t-shirt peeking out from a pile of clothes, for a moment you think it is
your phone ! you have just experienced a...
False alarm
What if it really was your phone ?
Hit
What will happen if you adjust your response criterion so that you never have any
misses?
It will increase false alarms because if the stimulus is absent then it's a false alarm.
What will happen if you increase your rate of correct rejections?
Your rate of misses will increase because you are saying yes less often. The more
"nos" the more misses.
Real world application of SDT: not just perceptual function
Think of a doctor trying to diagnose cancer.
1. Identify the hits, misses, false alarms, and correct rejections in this case
2. What are some real-world consequences of having liberal (says yes often) vs. a
conservative (says yes rarely) response criterion?
A cold is not serious, but breast cancer is serious, it is known to have a very high false
alarm rate.
An advantage of having a high false alarm rate for detecting breast cancer is because it
• Discuss the role of attention in detecting a stimulus . CORRECT ANSWER: Attention
The input that we receive from the world is overwhelming. In order to process it deeply ,
we must focus on specific parts using attention
Once this array of sensation passes through the attentional filter, only some parts of the
signal are selected
We know that attention is (at least somewhat) like a filter because of effects that show
streams of information popping through the filter
Dichotic listening: play different information through each ear of headphones.
Information reported only from the attended ear.
Right ear: the theory of relativity
Left ear: it was a dark stormy night
The cocktail party effect: happens when important information pops out in a
conversation that you are not attending (ex. Your name)
Inattentional blindness occurs when unattended stimuli are ignored as if they weren't
there
When you don't see something that is there. Ex: a killer on the left side of the room and
you come in and sit down and face away from them.
Change blindness is a version of this that occurs when you fail to detect obvious
changes in your environment
When you don't detect something in the environment that has changed . (ex: the gorilla
going between the people passing the balls and people do not see it)
Change blindness demo
People can also fail to notice rather large change in their visual world
, Spot the difference
The tree
The pillars ar taller
Big bush in the back
Attention
Ear-allows us to focus on some sensory information, and emphasize other information ,
making it easier to detect what we are interested in
Eye- change blindness and inattentional blindness- show that we are not actually able
to attend to all that much at once
• Distinguish between top-down and bottom-up processing. Apply these concepts to
new examples . CORRECT ANSWER: Bottom-Up processing: Construing a
representation from parts and basic features
Top-down processing: processing influenced by previous experience knowledge
Image: Top-Down Processing
The dog, when you take away the line you can still see the dog.
Image: Top-Down Processing
"It was a sunny day and the children were going to the park" at first it sounds blurry and
then you can understand it.
Sensation and Perception
Another way to think about it...
Sensation: is a bottom up process
Perception: includes top-down processing as well, which can change what we report
about sensations.
Recap
Bottom-up
Constructing a representation from parts and basic features starts with the raw data
construct meaning for that
A demonstration of top-down processing
Perceptual sets= sets formed when our expectations influence our perceptions.
• Describe the basic anatomy of the visual system . CORRECT ANSWER: Sclera: the
white part!
Pupil: circular hole where light enters
Iris: colored portion of the eye that controls pupil size (letting in more or less light)
Cornea: curved, transparent layer covering the iris and pupil that helps focus light
Life pro tip: take out your contacts , lest you irritate your cornea!
Lens: oval shaped disc that bends light
Accommodation: changing of the lens' shape to focus on near/far objects
