Sensation and Perception Flashcards
Sensation & Perception
according to signal detection theory, d’ (d-prime) is a measure of…
sensitivity
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
b) their male children will be red-green color blind, but their female children will not be red-green color blind
Sensation & Perception
gate control theory most useful for…
identifying ways to relieve pain
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…?
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)
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:
synesthesia
Sensation & Perception
____ is most responsible for depth perception of objects that are at a close distance.
retinal disparity
Sensation & Perception
which theory of color vision is assocaited with afterimages & red/green and blue/yellow colorblindness
opponent-process theory
Sensation & Perception
explain the differences between sensation and perception
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
Sensation & Perception
explain the difference between bottom-up and top-down processing
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
Sensation & Perception
explain the physical stimuli for vision; this part of the eye processes visual sensory information
- light waves absorbed by photoreceptors
- the retina
Sensation & Perception
list the 2 types of photoreceptors & their function(s)
cones (color): bright light, visual acuity (e.g., sharpness & precise detail), & color
rods: dim light, peripheral vision, & black/white
Sensation & Perception
list the 2 theories of color vision
Trichromatic & opponent-process theory
Sensation & Perception
Trichromatic Theory vs. Opponent-Process Theory
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
Sensation & Perception
explain negative afterimages according to opponent-process theory
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
Sensation & Perception
the most common type of color blindness
red/green
Sensation & Perception
the etiology of red/green color blindness
gene & chomosomal associations; co-existing physical diseases
genetic mutation
* recessive gene on the X chromosome
* inheriting the single mutated gene is sufficient to cause color blindness
injury/disease
* diabetes
* MS
Sensation & Perception
gender differences associated with red/green color blindness
- 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
Sensation & Perception
the etiology of blue/green color blindness
gene & any associated chromosomes
an autosomal (non-sex) dominant gene
Sensation & Perception
gender differences associated with blue/green color blindness
affects males & females equally
Sensation & Perception
the ability to perceive depth depends on a combination of what 2 cues
binocular & monocular
Sensation & Perception
Explain binocular cues
both eyes
* depth perception of objects that are relatively close
* include retinal disparity & convergence
Sensation & Perception
explain retinal disparity
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
Sensation & Perception
explain convergence in association with binocular cues
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
Sensation & Perception
explain monocular cues
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)
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
thermal, mechanical, or chemical stimuli
Sensation & Perception
explain Gate Control Theory
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)
Sensation & Perception
list a few ways to relieve pain according to Gate Control Theory
- applying heat or cold to affected area of the body
- guided imagery
- hypnosis
- distraction (e.g., watching a movie, playing a game)
Sensation & Perception
this is a neurological condition that causes people to experience multiple senses simultaneously
synesthesia (occurs when your brain routes sensory information through multiple sense that are not normally related)
Sensation & Perception
list & describe the most common type of synesthesia
**grapheme-color **synesthesia
* associating letters, numbers, or words with specific colors
Sensation & Perception
the etiology of synesthesia
- 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
Sensation & Perception
define psychophysics
the study of the relationship between the physical stimuli and psychological sensations
Sensation & Perception
list the 4 theories of psychophysics
- Weber’s Law
- Fechner’s Law (aka Fechner-Weber’s Law)
- Steven’s Power Law
- Signal Detection Theory
Sensation & Perception
Weber’s Law
1. assumptions
2. key points
3. example
- 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 - the just noticeable difference (JND) for a stimulus is a constant proportion, regardless of the intensity of the original stimulus
- 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
Sensation & Perception
Fechner’s Law
1. assumptions
2. key points
3. example
- (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) - JND grows to an increasingly greater degree with each linear increment in intensity
- 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
Sensation & Perception
differentiate, in simple terms, between Weber’s Law & Weber-Fechner’s Law
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
Sensation & Perception
which is more accurate:
a) Weber’s Law
b) Fechner’s Law
c) Steven’s Power Law
c) Steven’s Power Law
Sensation & Perception
Steven’s Power Law
1. assumptions
2. key points
3. example
- there is an exponential relationship between psychological sensation and the perceived magnitude of a physical stimulus and the exponent varies for different stimuli
- perceived intensity varies based on the sensory modality (e.g., vision, hearing, touch)
- example: how our eyes & ears make things feel bigger or smaller than they really are (e.g., overstimulation)
Sensation & Perception
the research that Steven’s Power Law is based on the method of…
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
Sensation & Perception
Signal Detection Theory (SDT)
1. assumptions
2. key points
3. example
- 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 - 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)
- 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)
Sensation & Perception
define sensitivity and decision criterion according to Signal Detection Theory & give an example
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
