Sensation and Perception

Question 1

Sensation & Perception

according to signal detection theory, d’ (d-prime) is a measure of…

Answer 1

sensitivity

Question 2

Sensation & Perception

Theo is not color blind but his wife, Tillie, is red-green color blind. Which of the following best describes the likelihood of their male vs. female biological children being red-green color blind:

a) both their male and female children will be red-green color blind
b) their male children will be red-green color blind, but their female children will not be red-green color blind
c) their female children will be red-green color blind, but their male children will not be red-green color blind
d) neither their male or female children will be red-green color blind

Answer 2

b) their male children will be red-green color blind, but their female children will not be red-green color blind

Question 3

Sensation & Perception

gate control theory most useful for…

Answer 3

identifying ways to relieve pain

Question 4

Sensation & Perception

A psychologist interested in the relationship between the magnitude of physical stimuli and psychological sensations finds that doubling the weight of an object doubles the sensation of heaviness but that doubling the brightness of a light more than doubles the sensation of brightness. This finding is most consistent with…?

Answer 4

Weber-Fechner’s Law
(states that the perceived intensity of a stimulus is proportional to the logarithm of the actual stimulus intensity, meaning that as the stimulus intensity increases, the perceived intensity increase becomes smaller proportionally)

Question 5

Sensation & Perception

Whenever Corky looks at numbers, each number elicits a different color (1 elicits red, 2 elicits blue, etc.). This is referred to as:

Answer 5

synesthesia

Question 6

Sensation & Perception

____ is most responsible for depth perception of objects that are at a close distance.

Answer 6

retinal disparity

Question 7

Sensation & Perception

which theory of color vision is assocaited with afterimages & red/green and blue/yellow colorblindness

Answer 7

opponent-process theory

Question 8

Sensation & Perception

explain the differences between sensation and perception

Answer 8

sensation: the physical detection of stimuli (e.g., feeling warmth on your skin)
perception: how the brain interprets & makes sense of sensory information (e.g., understanding the warmth comes from a hot cup of coffee you’re holding)

sensation is the raw data, perception is the meaning you assign to it

Question 9

Sensation & Perception

explain the difference between bottom-up and top-down processing

Answer 9

bottom-up is data-driven, top-down is concept-driven

bottom-up: begins with incoming sensory information & continues up to the brain where it is perceived, interpreted, & stored

top-down: begins with the brain’s use of pre-existing knowledge & expectations to interpret incoming sensory information

Question 10

Sensation & Perception

explain the physical stimuli for vision; this part of the eye processes visual sensory information

Answer 10

• light waves absorbed by photoreceptors
• the retina

Question 11

Sensation & Perception

list the 2 types of photoreceptors & their function(s)

Answer 11

cones (color): bright light, visual acuity (e.g., sharpness & precise detail), & color

rods: dim light, peripheral vision, & black/white

Question 12

Sensation & Perception

list the 2 theories of color vision

Answer 12

Trichromatic & opponent-process theory

Question 13

Sensation & Perception

Trichromatic Theory vs. Opponent-Process Theory

Answer 13

trichromatic theory explains how colors are detected at the cone level, while opponent-process theory explains how color signals are processed further in the brain

trichromatic: color vision is based on 3 types of cones in the eye, each sensitive to a different primary color (e.g., red, gree, & blue)
opponent-processing: color perception happens through pairs of opposing colors, such as red-green, blue-yellow, & black-white, where stimulating 1 color in a pair inhibits the other color

Question 14

Sensation & Perception

explain negative afterimages according to opponent-process theory

Answer 14

a visual illusion
* when you stare at something, usually a bright object, then close your eyes, you can often see an afterimage but it is a negative of the original image

Question 15

Sensation & Perception

the most common type of color blindness

Answer 15

red/green

Question 16

Sensation & Perception

the etiology of red/green color blindness

gene & chomosomal associations; co-existing physical diseases

Answer 16

genetic mutation
* recessive gene on the X chromosome
* inheriting the single mutated gene is sufficient to cause color blindness

injury/disease
* diabetes
* MS

Question 17

Sensation & Perception

gender differences associated with red/green color blindness

Answer 17

• more common in males (males only have 1 X chromosome, which they inherit from their mothers)
• females only experience color blindness if both inherited X chromosomes are mutated genes

Question 18

Sensation & Perception

the etiology of blue/green color blindness

gene & any associated chromosomes

Answer 18

an autosomal (non-sex) dominant gene

Question 19

Sensation & Perception

gender differences associated with blue/green color blindness

Answer 19

affects males & females equally

Question 20

Sensation & Perception

the ability to perceive depth depends on a combination of what 2 cues

Answer 20

binocular & monocular

Question 21

Sensation & Perception

Explain binocular cues

Answer 21

both eyes
* depth perception of objects that are relatively close
* include retinal disparity & convergence

Question 22

Sensation & Perception

explain retinal disparity

Answer 22

the difference in what each eye sees when looking at an object
(our eyes are in different locations on our face, so each eye has a slightly different viewing angle)
when an object is close, the disparity is greater because the view from each eye is more different

Question 23

Sensation & Perception

explain convergence in association with binocular cues

Answer 23

the tendency of the eyes to turn inward as an object gets closer and vice versa

signals to your brain how close the object is based on the effort your eye muscles need to exert to maintain focus; aka the more your eyes converge, the more effort exerted, the closer the object is

Question 24

Sensation & Perception

explain monocular cues

Answer 24

one eye
* depth perception of objects at a greater distance
* help us judge size, distance, & position of objects
* help us judge the overlap (interposition), linear perspective, texture gradients, and the relative motion of objects (motion parallax)

Question 25

Sensation & Perception

pain is caused when nociceptors (pain receptors) in skin, muscles, joints, & internal organs detect these 3 types of stimuli that are damaging or threatening to damage normal tissue

Answer 25

thermal, mechanical, or chemical stimuli

Question 26

Sensation & Perception

explain Gate Control Theory

Answer 26

a mechanism in the spinal cord that controls whether pain signals are sent to the brain
* open gate: pain signals pass through the brain & pain is perceived (activity in small fibers)
* closed gate: pain signals are blocked & no pain is felt by the (activity in large fibers)

Question 27

Sensation & Perception

list a few ways to relieve pain according to Gate Control Theory

Answer 27

• applying heat or cold to affected area of the body
• guided imagery
• hypnosis
• distraction (e.g., watching a movie, playing a game)

Question 28

Sensation & Perception

this is a neurological condition that causes people to experience multiple senses simultaneously

Answer 28

synesthesia (occurs when your brain routes sensory information through multiple sense that are not normally related)

Question 29

Sensation & Perception

list & describe the most common type of synesthesia

Answer 29

**grapheme-color **synesthesia
* associating letters, numbers, or words with specific colors

Question 30

Sensation & Perception

the etiology of synesthesia

Answer 30

• may have a genetic component
• may be due to brain structure: some evidence suggests it’s due to more connections across different brain areas responsible for senses

Question 31

Sensation & Perception

define psychophysics

Answer 31

the study of the relationship between the physical stimuli and psychological sensations

Question 32

Sensation & Perception

list the 4 theories of psychophysics

Answer 32

• Weber’s Law
• Fechner’s Law (aka Fechner-Weber’s Law)
• Steven’s Power Law
• Signal Detection Theory

Question 33

Sensation & Perception

Weber’s Law
1. assumptions
2. key points
3. example

Answer 33

1. the smallest noticable difference in a stimulus (e.g., brightness, weight) is a constant proportion of the original stimulus intensity (e.g., the stronger the original stimulus, the larger the change needs to be for someone to detect a difference)
   only applies to some stimuli & only intensities in the mid-range
2. the just noticeable difference (JND) for a stimulus is a constant proportion, regardless of the intensity of the original stimulus
3. example: if you’re holding a 10 lb. weight, adding a 1 lb. weight might be noticeable, but adding a 1 lb. weight to a 100 lb. weight might not be noticeable.

to notice a change (JND), the difference must be a certain percentage of the original stimulus, not a fixed amount

Question 34

Sensation & Perception

Fechner’s Law
1. assumptions
2. key points
3. example

Answer 34

1. (builds on Weber’s Law) there is a logarithmic relationship between psychological sensation and the magnitude of a physical stimulus
   (simple terms: the magnitude of a stimulus must be increased geometrically if the magnitude of sensation is to increase arithmetically)
2. JND grows to an increasingly greater degree with each linear increment in intensity
3. example: Think of picking up blocks. If you’re holding one block and get another block, you really notice it! But if you’re holding lots and lots of blocks, getting one more block doesn’t feel very different.

• more accurate than Weber’s Law for stimuli at extreme intensities

Question 35

Sensation & Perception

differentiate, in simple terms, between Weber’s Law & Weber-Fechner’s Law

Answer 35

Weber’s Law: you need bigger changes when things are already big
Weber-Fechner’s Law: builds on Weber’s Law by establishing a mathematical/logarithmic equation that helps us understand how we experience these changes

Question 36

Sensation & Perception

which is more accurate:
a) Weber’s Law
b) Fechner’s Law
c) Steven’s Power Law

Answer 36

c) Steven’s Power Law

Question 37

Sensation & Perception

Steven’s Power Law
1. assumptions
2. key points
3. example

Answer 37

1. there is an exponential relationship between psychological sensation and the perceived magnitude of a physical stimulus and the exponent varies for different stimuli
2. perceived intensity varies based on the sensory modality (e.g., vision, hearing, touch)
3. example: how our eyes & ears make things feel bigger or smaller than they really are (e.g., overstimulation)

Question 38

Sensation & Perception

the research that Steven’s Power Law is based on the method of…

Answer 38

magnitude estimation
* required participants to assign numbers to stimuli based on the sensations they elicited

e.g., if a subject assigned a 3 to one weight and believed the next weight was 2x as heavy, they would then assign a 6 to the second weight

Question 39

Sensation & Perception

Signal Detection Theory (SDT)
1. assumptions
2. key points
3. example

Answer 39

1. assumptions:
   perception of a stimulus (signal) is the outcome of both sensory and decision-making processes
   the decision-making process is always accompanied by some degree of uncertainty, which is caused by the presence of background noise (e.g., random neural activity in the perceiver’s perceptual system, the perceiver’s levels of motivation & fatige, distractions in the environment)
   decision-making is affected by a perceiver’s sensitivity to decision criterion
2. hit (the stimulus is present and the person says it is present), false alarm (the stimulus is not present but the person says it is present), miss (the stimulus is present but the person says it is not present), or correct rejection (the stimulus is not present and the preson says it is not present)
3. example: *deciding if you really saw a puppy or not. hit (see a puppy that’s really there), falst alarm (think you see a puppy but it’s just a stuffed toy), miss (miss seeing a real puppy), correct rejection (correctly see there’s no puppy when there isn’t one)

Question 40

Sensation & Perception

define sensitivity and decision criterion according to Signal Detection Theory & give an example

Answer 40

sensitivity: the perceiever’s ability to distinguish between the stimulus & noise
decision criterion: (aka decision bias or response bias) the perceiever’s willingness or tendency to say that a stimulus is present in ambiguous situations

the greater a perceiver’s sensivity, the greater the potential for accuracy in perceiving a stimulus

example: if 2 people have the same level of sensitivity but differ in terms of willingness to say that a stimulus is present, they will likely make different decisions about the presence of weak stimuli that are accompanied by background noise