Exam 1 Flashcards
Give a one sentence summary of Gestalt psychology
“The whole is greater than the sum of its parts.”
What does “Gestalt” mean?
In German, “form” or “whole”
Major way structuralism differs from Gestalt psychology
structuralism emphasizes the basic elements of perception = reductionist model
What are Gestalt grouping rules? What do they explain?
- A set of rules describing which elements in an image will appear to group together.
- They explain what it is that causes the brain to see something as one whole.
Gestalt ideas that fall under rules for contours
good continuation & occlusion
Define good continuation
two elements will tend to group together if they lie in a similar orientation, or along a similar plane (on the same contour)
Explain good continuation in simpler terms
When something looks like a continuing line, we see it as a whole. The further it gets from being a straight line, the less likely that it’s part of a whole.
Book rewording of good continuation
the tendency of lines of similar orientation to be seen as part of the same contour. Such lines “support” each other = two visual bits of an edge will make it easier to perceive a third colinear segment that lies between them, even if its not visible.
What happens if visible bits/lines form a closed shape? Give ex
The little segments support eeach other even more strongly. Ex/ multiple lines in the shape of a circle
Explain the question behind occlusion.
When we see an unexpected edge pop up in an image, our visual system tries to figure out why
Explain occlusion
When we see an unexpected edge in an image, our visual system assumes it is being occluded by another object, causing us to “create” an image where none may actually exist.
Define texture segmentation
carving an image into regions of common texture properties
Give ex of texture segmentation
in green an blue picture on page 84, the portion of the image with a coarser texture is separated from the rest of the image
List gestalt grouping principles
similarity, proximity, parallelism, symmetry, common region, connectedness
Explain similarity simple way
figures that are similar go together
explain similarity book way
image chunks that are familiar group together
features that similarity can be based off of
color, size, orientaton, form
What doesn’t work well with similarity? Give ex
Combinations of features (color, size, orientation, form)
ex/ trying to make distinctions based on color and shape - left side is orange diamonds/green squares and right side is green diamonds/orange squares
Explain proximity
Items near each other (close in space) are likely to group together
Try to figure out proximity in example 4.10 (a) on p. 84
figure out
Explain parallelism
Parallel contours are likely to belong to the same figure
Explain symmetry
Symmetrical regions are more likely to be seen as a figue
look at examples of occlusion
p. 82 & 83
Explain the principle of common region
Two features will go together if they appear to be part of the same larger region
Explain the principle of common region in simpler terms
Even if??
If there’s some other contour putting two features in the same space, they go together. Common region = enclosed in something
Even if they’re not proximal
Explain connectedness
two items will tend to group together if they’re connected
Explain middle vision
A stage of visual processing that comes AFTER basic features have been extracted from the image and BEFORE object recognition and scene understanding (before you’ve figured out what it is)
middle vision is when what starts. Explain
when the object recognition process starts - we’re unaware that this processing time is happening.
middle vision determines what?
which regions of an image should be grouped together to form objects
a big part of middle vision/detecting objects involves doing what?
finding edges
One of the first things we need to do in order to detect objects is what? Explain what these are
find contours = the outlines that tell us where the edge of an object is
Explain the arrow picture (p. 81) and how it relates to our detection of contours
In some places, the object is darker than the background. In others, it’s lighter. If the changes are continuous, there must be places where the edge of this shape disappears. The occasional lack of an edge doesn’t bother our visual system.
Are computers good at finding edges? explain
Not as good as our human system. Sometime computers leave out edges or detect way too many (p.81)
define illusory contour
a contour that is perceived even though nothing changes from one side of the contour to the other in the image
Explain the gestalt rule of an illusory contour
p. 82 example
Visual system detects an edge even tho there’s none there - visual system superimposes an edge.
Give 2 committee rules for detecting objects
1) honor physics
2) avoid accidents
define ambiguous figure. Example?
one that generates two or more plausible interpretations. Example = necker cube
Ambiguous figures are _______ to the rule. Explain
exceptions - in theory, every image is ambiguous, but the perceptual committees almost always agree on a SINGLE interpretation
Explain the accidental viewpoint
a viewing position that produces some regularity in the visual image that is not present in the real world
the perceptual committees do not ____ on accidental viewpoints. Explain
Bet. Figure 4.7 on p. 81 = very unlikely that that’s 4 worms meeting
Explain the honoring physics aspect of perceptual committees. Give example
figure with arrow - we infer the arrow-shaped object because of our IMPLICIT understanding that solid objects block light. Not rules we have to verbalize - we just know
Define figure-ground assignment
The process of determining that some regions of an object belong to a foreground object (figure) and other regions are part of the background (ground)
List the principles that work in figure-ground assignment
surroundedness, size, symmetry, parallelism, extremal edges, relative motion
Explain surroundedness in F/G assignment
if one region is entirely surrounded by another, then the surrounded region is the figure.
Figure 4.18 on page 88 - Explain one possible explanation
surroundedness explains why the green region is seen as the figure
Explain size in F/G assignment. Give example
the smaller region is likely to be the figure.
Ex/ the cow is smaller than field in which she stands, letters smaller than the page
Explain symmetry in F/G assignment
a symmetrical region is more likely to be seen as figure
Explain parallelism in F/G assignment
regions with parallel contours tend to be seen as figure
Figure 4.20 on page 89 - Explain one possible explanation
parallelism causes the purple regions to appear figure
Explain extremal edges from the powerpoint
If edges of an object are shaded such that they seem to recede in the distance, they tend to be seen as figure
Explain figure 4.21 upper left figure
the edge of the white disk has shading suggesting that the edge is curving away from the viewer and toward the gray texture = white disk must be closer so it’s figure
Explain figure 4.21 upper right figure
white donut shape has extremal edge cue, so it becomes the figure
Explain relative motion in F/G assignment
If one region moves in front of another, then the closer region is figure
define relatability
the degree to which two line segments appear to be part of the same contour
Explain relatability in detail
lines that can be related by a simple curve (like an elbow or a bend in the road) are more likely to be seen as relatable than something that requires something complex like an S curve
look at relatabiility example
p. 90
define heuristic
mental shortcut
Wordy explanation of global superiority effect example on p. 90 (Fig 4.25)
the big letters interfere with the naming of the little letters more than the little letters interfere with recognition of the big letters
define global superiority effect
the properties of the whole object take precedence over the properties of parts of the object
implicit assumption that the global superiority effect follows
the first goal is to carve the retinal image of large-scale objects
5 goals of middle vision
- bring together what should be brought together
- split asunder that which should be split asunder
- use what you know
- avoid accidents
- seek consensus and avoid ambiguity
Explain “bring together what should be brought together”
gestalt grouping principles, processes that complete contours and objects even when they’re partially hidden behind occluders (relatability, heuristic)
Explain “split asunder what should be split asunder”
edge-finding processes divide regions from each other. F/G separate objects from background
Explain “use what you know”
….. objects are divided into parts on the basis of implicit knowledge of the physics of image formation
Explain “avoid accidents”
avoid interpretations that require the assumptions of highly specific, accidental combinations of features or accidental viewpoints
Explain “seek consensus and avoid ambiguity”
committees ellminate all but one possibility = resolves ambiguity
differences between template and structural descriptions - TYPED
microsoft word
define viewpoint invariance (2)
1) a property of an object that does not change when an observer changes viewpoint
2) a class of theories of object recognition that proposes represenations of objects that do not change when viewpoint changes
define entry-level category
Explain simpler
the label that come to mind most quickly when we identify the object
the first word that comes to mind when we are asked to name objects
define subordinate-level category with example
a more specific term for an object. Ex/ eagle
define superordinate-level category with example
a more general term for an object. Ex/ bird
It takes considerable longer to recognize objects at the ______ level than at the ______ level
subordinate or superordinate
entry-level
when shown an atypical member of a category, people are faster to name the object at a _______ level. Ex/
subordinate (ostrich)
when people become experts at recognizing a certain class of objects, _____ becomes as fast or faster than ______
subordinate-level, entry-level
the processes that recognize a face as a face care little about what?
inversion or distortion of the face
the processes that recognize the face as belonging to a specific individual work poorly on what? very concerned?
on inverted faces. very concerned with the precise configuration of eyes, nose, and mouth
define double dissociation
the phenomenon in which one of two functions, such as hearing and sight, can be damaged without harm to the other, and vice versa
illusory conntours are completed in which part of brain
extrastriate cortex
After extrastriate cortex, processing of object info is split into what?
dorsal and ventral stream
Explain dorsal stream
“where” pathway is concerned with the location and shapes of objects but not their names and functons
Explain ventral stream
“what” pathway is concerned with the names and functions of objects regardless of where they are
what is the inferotemporal cortex. Part of?
part of the cerebral cortex in the lower portion of the temporal lobe important for object recognition
- part of “what” pathway
when IT cortex is lesioned, it leads to?
agnosia
explain concept of grandmother cells
idea that a single neuron could be responsible for recognizing your grandmother
when did the concept of grandmother cells come about
when we figured out that the IT cortex had a semi-specialized function. maybe brain works in even more specialized way.
define psychophysics
science of defining the qualitative relationship between physical and psychological events
Rewording of psychophysics definition
connecting physical processes to subjective experience - breaking down things in the mind/subjective experience into something we can measure and explain why
founder of psychophysics. May have began_____
Gustav Fechner. experimental psychology
define just noticeable difference
the smallest detectable difference between two stimuli, or the minimum change in a stiumulus that enables it to be correctly judged as different from a reference stimulus
**smallest change in a stimulus that can be detected**
another term fro JND & what it means
difference threshold - the smallest change in a stimulus that can be detected
who discovered JND
Ernst Weber
experiment that figured out JND
Weber asked ppl to lift one standard weight and one comparison weight that differed from the standard in incremental amounts.
results of Weber’s experiment
- the ability of a subject to detect the difference between the standard and comparison weights depended greatly on the weight of the standard
- *relatively light standard = people were much better at detecting a small difference when they lifted the comparison weight.
- *heavier standard = people needed a bigger difference before they could detect the change
Explain Weber’s Law
Works for?
the JND is a constant ratio of the original stimulus
- the more that you start with, the more of a change it takes for you to notice that its changed
- works for any senses
reowording of Weber’s law
the stronger the original stimulus, the greater the change needs to be for us to detect it
state Fechner’s law
the magnitude of subjective sensation increases proportionally to the log of the stimulus intensity
Fechner’s law allowed for what?
a way to quantify mental/subjective world - able to take something subjective and come up with a mathematical equation to measure it
JND in the real world. 2 things it aims to do
1) downplay negative changes
2) emphasize positive changes
Explain downplaying negative changes with JND and the real world
If you change something just a little bit, we’re probably not gonna notice. Don’t want consumers to know that they’re not getting as much as they were before = change it just enough
Explain emphasizing positive changes with JND and the real world
If you do something good, EVERYONE has to know about it.
- Real cookie crisps look nothing like the picture, but you have to make it be changed just enough that most ppl don’t recognize
- Coca-cola changes their logo just a little bit so that people will still see them as the same, good brand
define absolute threshold
minimum amount of stimulation necessary for a person to detect a stimulus 50% of the time
rewording of absolute threshold
the minimum intensity of a stimulus that can be detected
look over the list of absolute thresholds
p. 13
what is the signal detection theory about?
how people detect a signal in noise
Why is the signal detection theory important?
Because when we’re actually out in the real world, stimuli are never by themselves. There’s never a single sensory thing that has our attention. How do we decide what to attend to?
what’s the signal and what’s the noise?
signal = what we're attending to noise = everything else
With the signal detection theory, how do observers complicate the measurements of thresholds?
bring own biases in - more prepared/motivated/tuned in to hear certain things more than others
Give ex of a situation when we’d want observers to be especially biased toward detecting something
radologist looking at x-rays - want them to be able to detect even the tiniest crack
you’re in the shower and your phone rings, what’s the noise and what’s the signal?
noise - water from shower
signal - phone ring
With signal detection theory, you have to decide if you’re hearing what?
noise alone or signal plus noise
Phone rings in the shower, explain the first step you must do and then explain the 4 possible outcomes
first, set up a criterion level of response that you will call a ring - if the stimulus exceeds that response level, you’ll jump out of shower
1) correct rejection = no when there’s no ring
2) hit = yest when there’s a ring
3) false alarm = jump out of shower when no ring
4) miss = don’t jump out & there is a ring
study the 4 signal detection graphs
p. 15
you’re waiting for an impt phone call that you don’t wanna miss, what do you do? What will this cause?
- look at p. 16 pics
move the criterion level of response (to the left)
- you won’t miss any calls, but you’ll make lots of false alarms
what happens if you shift your criterion to the right?
you won’t make false alarms, but you’ll miss alot of calls
study SDT sensitivity graphs on p. 16
study criterion level graphs on p. 16
Study
what is the receiver operating characteristic curve?
the graphical plot of the hit rate as a function of the false alarm rate
Explain how the ROC graph works
observer can’t tell difference between presence and absence of signal = hit rate and false alarm rate are equal = on diagonal line
- as sensitivity increases, the curve bows upward toward upper left corner
- upper left corner = 100% hits, 0% misses
with SDT, ideally the observer will have what? What does this mean?
the highest sensitivity and highest specificity
- want to respond when there is a threat (hit) and don’t want to respond when there isn’t (false alarm)
Give 2 examples of SDT in real life
1) driving - the sirens are so obnoxious and loud so you don’t have a MISS
2) alarm systems in general - very loud so no one can have a MISS
Give some examples of internal noise
thoughts, feeling, pain, hunger
give a specific personal example of internal noise
death of a loved one = can’t focus on anything else
someone you don’t want to have a lot of internal noise
surgeon - don’t want him to miss something
truck drivers, military
who developed the doctrine of specific nerve energies?
Johannes Muller
Explain the doctrine of specific nerve energies
1) we are aware of our surroundings only as a result of our nerve activity
2) what matters is WHAT nerves are stimulated, not HOW
Give examples of doctrine of specific nerve energies
we see because the optic nerve leading form the eye to the brain is stimulated, but it doesn’t matter if it was light or something else that stimulated the nerve
Give an example of doctrine of specific nerve energies YOURSELF
1) close eyes, press gently on outside corner of one eye through the lid.
2) you’ll see a spot of light toward the inside of your visual field by your nose
3) no stimulation by light but your brain interprets the input from your optic nerve as something visual
get hit on the back of the head - explain with doctrine of SNE
see lights cuz vision part of brain was hit/stimulated in such a way that tell you there are lights.
- it doesn’t matter that there’s actually nothing there
who developed the neuron doctrine? How?
Santiago Ramon y Cajal
He was the first to use microscopic staining methods - injected stains into pieces of brain
what is the neuron doctrine?
the functional unit of the brain is the neuron
What’s important about the neuron doctrine?
Answer the question, What makes up the nervous system? How does this one organ give us such a rich sensory experience?
- it constitutes the basis for us to understand how the nervous system is organized
What is wave-particle duality?
light acts as both a wave and a particle
Double slit experiment - Who did it? What did it involve? What did he find out?
Richard Feynman
- shot light through a double slit, if it was matter = should see 2 lines on screen. If wave = interference pattern, range of bands
- confirmed to us that light behaves as a wave!!!
Explain Eninstein’s Photoelectric Effect experiment and results
Have a sheet of metal and shoot light off of it
- we would expect that waves with greater energy/amplitude would cause more particles to go off
- red and blue light of same intesnity should have the same effect
- this DIDN’T happen = particles must have different levels of energy
= light behaves as a particle
3 layers of the eye
- Sclera (outer)
- Choroid (middle)
- Retina (inner)
sclera - what is it and function?
white of eye
maintain shape
what is the cornea? what does it do?
clear tissue at surface of sclera - covers front surface of eye - very thin transparent film with no blood vessels
funciton: allows light to transmit through the eye cuz it has no blood vessels
choroid location? What lies in choroid layer?
between sclera and retina
- iris, pupil, lens
what is the pupil?
dark circular opening at center of IRIS where light enters eye
dark to bright light, what happens to pupil? what else happens?
constricts, you sneeze
What is the iris?
colored part of the eye
Iris function
Give ex/
adaptation: regulates amt of eye entering eye by expanding and contracting the pupil
- walk into a bright room from a dark room = pupils constrict
what does the lens do? What specific function is this? What’s significant about this?
refracts (bends) light
accommodation: allows you to see things close or far away by changing shape
it’s the only refractive structure that can alter refractive power (humors and cornea can’t)
What are humors? function?
fluid filled chambers, refract light
Vitreous humor size, location, and structure?
size = larger section location = toward the back of eye structure = filled with colorless gelatinous mass
Aqueous humor size, location, and structure?
size = smaller section location = in front structure = filled with watery substance
What is the retina composed of? explain how they are arranged
very sensitive cells called photoreceptors (rods and cones) that are interconnected by a complex mesh of neurons
what is the fovea? what’s it responsible for?
most sensitive part of the retina and contains mostly cones.
- sharp vision
What’s the optic nerve? Explain issue with this
bundle of nerves that run into brain to form this cranial nerve impt for vision
- blind spot = spot on retina with no photoreceptors, where the optic nerve is exiting your eye
List the 5 different types of cells in the retina under their subcategories and with their subcategories under them
3 “Main” Types
1) Photoreceptors - rods and cones
2) Bipolar - diffuse (rod pathway) and midget (cone)
3) Ganglion - M (rod pathway) and P (cone)
2 Lateral Types
1) horizotal (run between photoreceptors & bipolar)
2) Amacrine (run between bipolar & ganglion)
Rods and cones transmit info to? which transmits info to?
bipolar cells
ganglion cells
what do horizontal and amicrine cells do?
connect things across a layer rather than going fone layer to the next = integration across layers
What is lateral inhibition?
Reword this?
Give an example
- the process by which our visual system enhances contrasts by inhibiting neurons surrounding an excited neuron
- when a visual field is excited (more active than normal), it inhibits the neurons close to it (makes them less active than normal)
- this creates more contrast
Ex/ have headphones on and when loud noise happens, your earphones automatically shut off = contrast, causes silence to cells around it
What is the primary function of the Zonules of Zinn?
to change the shape of the lens by relaxing and contracting
A good description of convergence?
one cell branches out and connects to many others
