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Perception test 1
n/a
59
Psychology
Undergraduate 4
02/26/2012

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Cards

Term
Problem of perception (3)
Definition
1. stimuli are ambiguous (many different stim. can cause same retinal image)
2. brain must make guesses to interpret
3. indirect because it requires information processing
Term
Levels of understanding perception (3 names)
Definition
1. ecological/computational
2.psychological
3. physiological
Term
Ecological/computational
Definition
-level of understanding perception
what is GOAL of perception, and what properties of the stimulus allow the problem to be solved?
ex: moving retinal picture shows we are moving
Term
psychological level
Definition
level of understanding perception
what processes underlie our perception, and what representations they lead to.
Term
physiological level
Definition
level of understanding perception
how the processes and representations are realized by the nervous system
Term
neuropsychology
Definition
studying perceptual deficits in patients with brain damage
Term
fMRI and PET (function)
Definition
examine which parts of the brain are active during a perceptual task by measuring blood flow
Term
electrical potentials (measure)
Definition
examine brain responses to stimuli by measuring electrical responses on scalp
Term
single unit recording
Definition
measure responses of individual cells by recording their electrical signals
Term
neuroimaging
Definition
study perception by imaging brain activity
Term
Neuron (4 parts)
Definition
-cell body (machinery to keep cell functioning)
-dendrites - fibers that RECEIVE info
-axon- fiber to SEND info
-synapse- where neurons meet
Term
how neurons work
Definition
signal through electrical activity controlled by the flow of charged ions across the cell membrane, leading to charge differences.
Term
electric potentials (3 types)
Definition
-resting potential
-graded potential
-action potential
Term
resting potential
Definition
baseline charge difference when cell is at rest
Term
graded potential (def +2 types)
Definition
passive charge difference in response to stimulation
-synaptic potential - due to influence of other neuron
-receptor potential - due to PHYSICAL stimulus (like light absorption)
Term
differences between action and graded potentials (5)
Definition

 

size

 AP

large fixed

GP

small variable

 duration

 brief

 long

 signal

 depolar ONLY

 depolar OR hyperpolar

 location

 axon

 throughout cell

 purpose

 carry fixed signal long distances

 sum togther input from other cells

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Term
synapse (3 traits)
Definition
-connection between neurons mediated by chemical neurotransmitters
-can be excitatory or inhibitory on post-synaptic cell
-receptive fields depend on pattern of synaptic connections to cell
Term
How neurons carry info (3 ways)
Definition
1. size of the response (graded or # of action potentials)
2. pattern of responses
3. pattern of connections
Term
physiological approaches to perception (4)
Definition
-neuropsychology
-neuroimaging
-electrical potentials
-single unit recording
Term
introspection (def, 2 problems, 2 examples)
Definition
-"thinking" about one's own perceptual experience
-subjective, may not reveal underlying processes
-color opponency (red/green), lateral inhibition (Mach bands)
Term
thresholds
Definition
weakest stimuli we can detect or tell apart, high threshold means LOW sensitivity
Term
Problems with Thresholds (4)
Definition
1. limited by noise (not all or none)
2. detection depends on BOTH sensitivity and criterion
3. signal detection theory provides uncertainty
4. criterion-free measures (like forced choice) are more direct
Term
sensory channel (3 traits)
Definition
-"filter" that only responds for certain info (orientation channel only responds to certain tilts)
-can be measured by measuring how TWO stimuli interact
-IF two stim. influence each other, they are encoded by SAME channel
Term
reaction times (def and use)
Definition
measure of the speed of a response
-used to infer type of processing involved
Term
[image]
Definition
[image]
Term
cornea and lens (function)
Definition
focus light to form image on the retina
Term
retina (def and function)
Definition
thin layer of neurons along back of eye that absorb, process and transmit info about the light image
Term
fovea
Definition
small region of retina specialized for finest vision, corresponds to center of gaze
Term
optic disk/ blind spot
Definition
receptor-free "hole" in retina where ganglion axons leave eye
Term
transduction
Definition
convert physical energy into electrical signal
Term
Cones vs Rods (6)
Definition

 

 Cones

Rods

 light sensitivity

low

high

 operating range

moderate-bright

dim light

 spatial acuity

high

low

 retinal distrib.

peak in fovea

peak ~20 deg

 # of receptor types

3

1

 color vision

yes

no

Term
receptive field
Definition
area on the retina to which a cell responds
Term
bipolar cell receptive fields (3 traits)
Definition
-center-surround cells, on or off centered
-similar to ganglion cells
-emphasize contrast
Term
lateral inhibition
Definition
inhibition between spatially adjacent cells
Term
Paths of info flow in retina (2)
Definition
1. straight through
receptor -> bipolar->ganglion
2.sideways, via horizontal and amacrine cells
Term
LGN properties (4)
Definition
1. most ganglion cells send their axons to LGN
2.Nasal fibers cross over- CONTRALATERAL
3. 2 layers- magno- and parvocellular
4. center-surround and monocular
Term
Striate cortex (5)
Definition
1. most LGN cells send their axons
2. orientation selectivity
3. inc. selectivity for size
4.BINOCULAR
5. sensitivity to direction of movement
Term
Parallel Pathways (2)
Definition
-parvocellular (color and fine detail)
-magnocellular (motion)
Term
Magnocellular vs Parvocellular (3)
Definition

 

 Magnocellular

Parvocellular

 sens. to color

low

high

 sens. to fine detail

low

high

 sens. to motion and rapid changes

high

low

Term
Receptive field of receptor
Definition
0 + 0
Light must fall at specific point to excite
Term
receptive field of POST receptoral cell
Definition
0 - + - 0
light in center vs surround have OPPOSITE effects
Term
[image]
Definition
receptor-horiz-bipolar circuit
Term
problem of color constancy
Definition
we want to "see" color of OBJECTS, but wavelength reaching eye depends on BOTH object and lighting (emitted vs reflected light)
Term
principle of univariance
Definition
wavelength affects SIZE of response, not FORM of response
MEANS- any single cone can't tell the difference between change in wavelentgh or change in intensity
Term
wavelength rods peak at
Definition
~500 nm
Term
implication of color matching experiments
Definition
one receptor type can match ANY light by varying intensity of ONE primary light, so on for two
Term
Monochromats vs dichromats vs trichromats
Definition
one receptor type (rod vision), two cone types, three cone types
Term
S cones vs M&L cones (3)
Definition

 

 S cones

M&L

 numbers

few

most cones

 function

mainly color

color AND form

 genetics

autosomal

sex-linked

Term
S cones signal _____ but NOT _____
Definition
signal color but NOT LUMINANCE
Term
Trichromacy vs opponency
Definition
-Trichromacy- BASED on color matching
-DEPENDS on receptors
-Opponency BASED on color appearance
DEPENDS on post-receptoral cells
Term
foraging hypothesis
Definition
Third photopigment (M) helps to detect ripe fruit
Term
Hering's Opponent Color theory (3)
Definition
3 opponent channels:
1. red/green
2. Blue/yellow
3. bright/ dark
Term
unique hue
Definition
the idea that a color can be mutually exclusive (ie can't be BOTH red and green)
Term
Hue
Definition
angle a color is from grey
Term
saturation
Definition
how pure a color looks (distance from grey)
Term
Which cells SHOW color opponency?
Definition
post-receptoral ganglions
Term
Pysiological evidence for color opponency (2)
Definition
-response of LGN or ganglion cells to different wavelengths
-different cone types connect to center and surround of RF (gives color and space opponence)
Term
Color spectrum is PHYSICALLY _____, but _____ categorized
Definition
physically continuous, psychologically categorized
Term
language/cultural differences (4)
Definition
1. different languages apply color terms to SIMILAR regions
2. implies color perception is UNIVERSAL
3. universality might result from common physiology
4. weak influence of culture on color perception
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