Theories of visual perception Flashcards
Why is the perception of form and organisation important?
Environment contains hundreds of overlapping objects
Yet perceptual experience is of structured, coherent objects which we can recognise, use and usually name
What are the features of the back of the retina?
List 3 points
- The distribution of receptors are at the back of the retina’
- Receptors are not evenly distributed
- Fovea (where receptors are densely packed), where you see an image of sharp focus and where you see images in colour
Where you see an image of sharp focus and where you see images in colour
This is known as…?
The fovea
Where receptors are densely packed
This is known as…?
The fovea
What can the fovea see?
See an image of sharp focus and images in colour
____ half of the visual field projects onto the right of the brain
a. Right
b. Left
b. Left
Left half of the visual field projects onto the _____ of the brain
a. Right
b. Left
a. Right
_____ half of the visual field projects onto the left of the brain
a. Right
b. Left
a. Right
Right half of the visual field projects onto the ____ of the brain
a. Right
b. Left
b. Left
True or False?
There are even amounts or volumes of the visual cortex devoted to different parts of the visual array
False
There are uneven amounts or volumes of the visual cortex devoted to different parts of the visual array
There are uneven amounts or volumes of the visual cortex devoted to different parts of the visual array
Where is the visual cortex most devoted to?
The fovea
More of the visual cortex is devoted to the fovea where there’s …?
The most amount of receptors
There are uneven amounts or volumes of the visual cortex devoted to different parts of the visual array
Where is the visual cortex least devoted to?
The periphery
True or False?
The retina is curved
True
True or False?
The lens always stays still
False
The lens is constantly moving and being updated
The lens is constantly moving and being updated
How often does this happen?
50 times a second
What moves and updates 50 times a second?
The lens
Interpretation of a sensation is called …?
Perception
What is perception?
Interpretation of a sensation
True or False?
Receptors are evenly distributed
False
Receptors are unevenly distributed
The images we see are…?
List 4 points
- Inverted
- Tiny
- Curved
- Flat
The image we see is inverted, tiny, curved and flat
Why?
To compensate for eye movement, body movement and object movement
To compensate for eye movement, body movement and object movement
We see images…?
Inverted, tiny, curved and flat
True or False?
There are even amounts of cortex devoted to different parts of the visual field
False
There are uneven amounts of cortex devoted to different parts of the visual field
True or False?
There is nothing visual about the cortical representation
True
There is nothing square about the representation of a square
What does this tell us?
There is nothing visual about the cortical representation
What is the homunculus argument /fallacy?
There is a ‘little man’ who lives in our brain and sees and controls everything
The means by which information acquired from the environment via the sense organs is transformed into experiences of objects, events, sounds, tastes, etc.
This is known as…?
Perception
What is perception?
Where information acquired from the environment via the sense organs is transformed into experiences of objects, events, sounds, tastes, etc.
Trying to interpret sensation and come up with some hypothesis about what it is out there in the real world
This is known as…?
Distal stimulus
What is a distal stimulus?
Trying to interpret sensation and come up with some hypothesis about what it is out there in the real world
When distal stimulus causes sensations on the back of the retina
This is known as…?
Proximal stimulus
What is a proximal stimulus?
When distal stimulus causes sensations on the back of the retina
When the brain interprets the proximal stimulus and tries to work out what is it out there in the real world that exists
This is known as…?
Perceptual experience
What is a perceptual experience?
When the brain interprets the proximal stimulus and tries to work out what is it out there in the real world that exists
What is the order of perception/perceptual experience?
List 3 points
- Distal stimulus (stimulus from the environment)
- Proximal stimulus (image you see on the back of the retina)
- Perceptual experience (perception of the world)
Stimulus from the environment
a. Distal stimulus
b. Proximal stimulus
c. Perceptual experience
a. Distal stimulus
Image you see on the back of the retina
a. Distal stimulus
b. Proximal stimulus
c. Perceptual experience
b. Proximal stimulus
Perception of the world
a. Distal stimulus
b. Proximal stimulus
c. Perceptual experience
c. Perceptual experience
Why is perception important?
List 2 reasons
- Our only source of information about world
- All other cognitive systems rely on perception
True or False?
Perception is our only source of information about world
True
True or False?
All other cognitive systems do not neccesarily rely on perception
False
All other cognitive systems rely on perception
What are the sources of energy present in the real world?
List 7
- Light
- Sound
- Vibration
- Heat
- Pressure
- Movement
- Chemicals
What are the sense organs used to transduce the sources of energy present in the real world?
List 4
- Eyes
- Ears
- Nose
- Skin
Sense organs are used to transduce the sources of energy present in the real world into…?
Electrical signal
What is another term for perception?
Qualia
Qualia is known as…?
Perception
Describe how sources of energy in the real world can be perceived?
List 3 points
- The real world has different sources of energy
- These are transduced by our sense organs, changing from one form of energy to another (to electrical signals)
- The brain tries to perform reverse engineering to work out, what is causing this electrical signal in the real world?
Simply = The brain receives these electric signals and perform perception
What are the 4 theories of visual perception?
- The Gestalt approach to perception
- Gibson’s ecological theory of perception
- Marr’s information processing theory of perception
- The Constructivist approach to perception
These are the 4 theories of visual perception
- The Gestalt approach to perception
- Gibson’s ecological theory of perception
- Marr’s information processing theory of perception
- The Constructivist approach to perception
How do these theories differ? (List 3 points)
- Bottom-up vs. Top-down processing
- Goal of perception
- Methods of study
Who proposed an approach to perception as a theory of visual perception?
Gestalt
Who proposed the ecological theory of perception as a theory of visual perception?
Gibson
Who proposed the information processing theory of perception as a theory of visual perception?
Marr
What does Gestalt psychology propose?
The whole is greater (different) than the sum of its parts
The whole is greater (different) than the sum of its parts
Which psychology proposes this?
Gestalt psychology
Gestalt psychology believes in …?
a. Top-Down Approach
b. Botton-Up Approach
a. Top-Down Approach
What are Gestalt psychologists interested in?
List 2 points
- How we group parts of a stimulus together
- The way we separate figure from ground
(SEGREGATION and GROUPING)
Which type of psychology is interested in:
- How we group parts of a stimulus together
- The way we separate figure from ground
(SEGREGATION and GROUPING)
Gestalt psychology
Rejection or reaction to the idea that you had some mechanistic thing where you started with the input to the retina, and you built up levels of processing to eventually end up at visual processing
What was Gestalt psychology trying to argue based on this approach?
That something was missing from this approach
What do we often do when we are met with ambiguous figures?
We usually change our viewpoint (actively engaging with our environment) if we are looking at something we are unsure about
We usually change our viewpoint (actively engaging with our environment) if we are looking at …?
Ambiguous figures
Name 3 individuals who were part of the Gestalt school
- Max Wertheimer
- Kurt Koffka
- Wolfgang Kohler
Reaction against Structuralism (Edward Titchener (1867-1927)
Which approach does this apply to?
Gestalt approach
Gestalt approach was a reaction against…?
Structuralism (Edward Titchener (1867-1927)
Perception is a combination of individual sensations that can be reduced to …?
Simple individual elements
‘Perception is a combination of individual sensations that can be reduced to simple individual elements.’
What did Gestalt approach argue about this?
Gestault argued that this ignores the relationship between stimuli
Which approach argues that perception ignores the relationship between stimuli?
Gestalt approach
Which approach believes that we don’t see lines and figures but forms and shapes?
Gestalt approach
Gestalt approach believes that we don’t see lines and figures but …?
Forms and shapes
True or False?
Ambiguity generally arises in the real world
False
Ambiguity generally does not arise in the real world
True or False?
We usually see an unstable and ambiguous world
False
We usually see a stable and organised world
Ambiguity generally does not arise in the real world. Rather, we usually see a stable and organised world.
Why?
Because we engage in it and also because we use certain rules to organise what we perceive these innate rules
Gestalt approach was interested in innate rules
This is…?
a. Top down perspective
b. Bottom up perspective
a. Top down perspective
Which approach was interested in innate rules to perception (top down perspective)?
Gestalt approach
Most people see a set of overlapping circles, rather than one circle touching two adjoining shapes that have ‘bites’ taken out of them
Why?
We see objects according to all their elements taken together as a whole
Which approach argues that we see objects according to all their elements taken together as a whole?
Gestalt approach
Which approach sought to isolate principles of perception (innate ‘laws’ which determine way in which objects are perceived)?
Gestalt approach
When you look at a bike, you immediately perceive a bike; you don’t recognise a saddle and then some handle bars and then some wheels
Which approach argues this?
Gestalt approach
Gestalt view argued that: when you look at a bike, you immediately perceive
a. A whole bike
b. A saddle
c. Some handle bars
d. Some wheels
a. A whole bike
What are the 9 Gestalt laws of perceptual organisation?
- Similarity
- Good continuation
- Proximity
- Connectedness
- Closure
- Common Fate
- Familiarity
- Invariance
- Prägnanz – “good figure”
What is the similarity Gestalt law of perceptual organisation?
Similar things appear to be grouped together
Grouping can occur due to shape, lightness, hue, orientation, size
What is the good continuation Gestalt law of perceptual organisation?
Points that, when connected, result in straight or smoothly curving lines, are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path
What is the proximity Gestalt law of perceptual organisation?
Things that are near to one another appear to be grouped together
What is the connectedness Gestalt law of perceptual organisation?
Things that are physically connected are perceived as a unit
What is the closure Gestalt law of perceptual organisation?
Of several geometrically possible perceptual organisations, a closed figure will be preferred to an open figure
We tend to ‘complete’ a broken figure because of the Strong closure cue for organising what we see
What is the common fate Gestalt law of perceptual organisation?
Things that are moving in the same direction are grouped together
Objects with same orientation are grouped together
What is the familiarity Gestalt law of perceptual organisation?
Things are more likely to form groups if the groups appear familiar or meaningful
What is the invariance Gestalt law of perceptual organisation?
We can recognise objects from different orientations , even when they’re distorted or are presented in different media
Demonstrates active process, having to interpret your sensations
What is the Prägnanz – “good figure” (figure-ground segregation) Gestalt law of perceptual organisation?
We can separate figure from ground
Define Reification
More spatial info than is present
More spatial info than is present
This is known as…?
Reification
What is the major problem in computer vision?
Invariance
We can recognise objects from different orientations , even when they’re distorted or are presented in different media
We can recognise objects from different orientations , even when they’re distorted or are presented in different media
What does this demonstrate?
Active process, having to interpret your sensations
Which Gestalt law of perceptual organisation does this apply to?
Similar things appear to be grouped together
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
a. Similarity
Which Gestalt law of perceptual organisation does this apply to?
Grouping can occur due to shape, lightness, hue, orientation, size
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
a. Similarity
Which Gestalt law of perceptual organisation does this apply to?
Points that, when connected, result in straight or smoothly curving lines, are seen as belonging together, and the lines tend to be seen in such a way as to follow the smoothest path
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
b. Good continuation
Which Gestalt law of perceptual organisation does this apply to?
Things that are near to one another appear to be grouped together
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
c. Proximity
Which Gestalt law of perceptual organisation does this apply to?
Things that are physically connected are perceived as a unit
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
d. Connectedness
Which Gestalt law of perceptual organisation does this apply to?
Of several geometrically possible perceptual organisations, a closed figure will be preferred to an open figure
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
e. Closure
Which Gestalt law of perceptual organisation does this apply to?
We tend to ‘complete’ a broken figure because of the Strong closure cue for organizing what we see
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
e. Closure
Which Gestalt law of perceptual organisation does this apply to?
Things that are moving in the same direction are grouped together
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
f. Common Fate
Which Gestalt law of perceptual organisation does this apply to?
Objects with same orientation are grouped together
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
f. Common Fate
Which Gestalt law of perceptual organisation does this apply to?
Things are more likely to form groups if the groups appear familiar or meaningful
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
g. Familiarity
Which Gestalt law of perceptual organisation does this apply to?
We can recognise objects from different orientations , even when they’re distorted or are presented in different media
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
h. Invariance
Which Gestalt law of perceptual organisation does this apply to?
A major Problem in Computer vision
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
h. Invariance
Which Gestalt law of perceptual organisation does this apply to?
Figure-Ground Segregation
a. Similarity
b. Good continuation
c. Proximity
d. Connectedness
e. Closure
f. Common Fate
g. Familiarity
h. Invariance
i. Prägnanz – “good figure”
i. Prägnanz – “good figure”
What does figure-ground segregation look like in the real world?
Normally in a visual scene, some objects (figures) seem prominent, and other aspects of field recede into the background (ground)
Is this a figure or a ground?
Objects
a. Figure
b. Ground
a. Figure
Is this a figure or a ground?
Background
a. Figure
b. Ground
b. Ground
Is this a figure or a ground?
Lecturer
a. Figure
b. Ground
a. Figure
Is this a figure or a ground?
A room
a. Figure
b. Ground
b. Ground
Why is the Gestalt approach interested in Figure-Ground segregation?
Because it infers top- down process
What are the properties that affect whether the area is seen as a figure or ground (Figure-Ground segregation)?
List 5
- Symmetry
- Convexity
- Area
- Orientation
- Meaning/Importance
Symmetry is one of the properties that affect whether the area is seen as a figure or ground (Figure-Ground segregation)
What does it mean?
Symmetrical areas are usually viewed as figures
Convexity is one of the properties that affect whether area seen as figure or ground are (Figure-Ground segregation)
What does it mean?
Convex shapes are usually viewed as figures
Area is one of the properties that affect whether the area is seen as a figure or ground (Figure-Ground segregation)
What does it mean?
Stimuli with a comparatively smaller area are usually viewed as figures
Orientation is one of the properties that affect whether the area is seen as a figure or ground (Figure-Ground segregation)
What does it mean?
Vertical and horizontal orientations are usually viewed as figures
Meaning/Importance is one of the properties that affect whether the area is seen as a figure or ground (Figure-Ground segregation)
What does it mean?
Meaningful objects are more likely to be viewed as figures
This implies attention (top-down)
Which Figure-Ground segregation property does this apply to?
Symmetrical areas are usually viewed as figures
a. Symmetry
b. Convexity
c. Area
d. Orientation
e. Meaning/Importance
a. Symmetry
Which Figure-Ground segregation property does this apply to?
Convex shapes are usually viewed as figures
a. Symmetry
b. Convexity
c. Area
d. Orientation
e. Meaning/Importance
b. Convexity
Which Figure-Ground segregation property does this apply to?
Stimuli with a comparatively smaller area are usually viewed as figures
a. Symmetry
b. Convexity
c. Area
d. Orientation
e. Meaning/Importance
c. Area
Which Figure-Ground segregation property does this apply to?
Vertical and horizontal orientations are usually viewed as figures
a. Symmetry
b. Convexity
c. Area
d. Orientation
e. Meaning/Importance
d. Orientation
Which Figure-Ground segregation property does this apply to?
Meaningful objects are more likely to be viewed as figures
a. Symmetry
b. Convexity
c. Area
d. Orientation
e. Meaning/Importance
e. Meaning/Importance
Meaningful objects are more likely to be viewed as figures
What does this imply?
This implies attention (top-down)
What are the 5 problems with the Gestalt approach?
- Underplay the parallel processing and unconscious processing that the brain does
- Explanation of how some of their laws worked was wrong
- Their laws provide a description of how things work rather than an explanation
- Their laws are ill defined – Prägnanz – what is the simplest and most stable shape?
- Stating the obvious
What did Gibson’s ecological theory of perception believe about perception?
Perception is ‘direct’
According to Gibson’s ecological theory of perception, rich information received are …?
Sufficient for interaction with environment
What did Gibson’s ecological theory of perception believe about complex cognitive processes?
Complex cognitive processes are unnecessary
What were the 2 main arguments of Gibson’s ecological theory of perception?
- Bottom Up approach
- Ecological
According to Gibson’s ecological theory of perception, perception involves a bottom-up approach
What did they argue? (List 3 points)
- Perception is ‘direct’
- Rich information received sufficient for interaction with environment
- Complex cognitive processes unnecessary
Believes motion and moving around is a major component of visual perception
Who believed this?
Gibson
Gibson believes motion and moving around is a major component of visual perception
How did he study perception?
Studied in natural environments, not the lab (no 2D displays)
How did Gibson’s ideas evolved?
List 4 points
- As a child his father took him on train rides
- Intrigued by the way the world flowed and expanded towards him, and contracted and flowed away behind him – Optic Flow
- In later life applied this to pilot training
- Notice it is active, movement of the observer provides additional stream of information
Define optic flow
When the world flows and expands towards you, and contracts and flows away behind you
When the world flows and expands towards you, and contracts and flows away behind you
This is known as…?
Optic flow
What is Ambient Optic Array?
Information coming into your eye
What are the 2 characteristics of Ambient Optic Array?
- Structure of light reflected by textured surfaces
- Changes due to observer movement (as you move around, the image on the back of the retina changes)
- Structure of light reflected by textured surfaces
- Changes due to observer movement (as you move around, the image on the back of the retina changes)
These are characteristics of…?
Ambient Optic Array
Bottom Up approach
a. Gibson’s Ecological Theory
b. Gestalt approach
a. Gibson’s Ecological Theory
Top-down approach
a. Gibson’s Ecological Theory
b. Gestalt approach
b. Gestalt approach
Sufficient information in the retinal array
a. Gibson’s Ecological Theory
b. Gestalt approach
a. Gibson’s Ecological Theory
Perception is ‘direct’ – not different from sensation
a. Gibson’s Ecological Theory
b. Gestalt approach
a. Gibson’s Ecological Theory
Retinal image provides rich information sufficient for interaction
a. Gibson’s Ecological Theory
b. Gestalt approach
a. Gibson’s Ecological Theory
Complex cognitive processes unnecessary
a. Gibson’s Ecological Theory
b. Gestalt approach
a. Gibson’s Ecological Theory
Ecological – study in natural environments not labs – and allow movement
a. Gibson’s Ecological Theory
b. Gestalt approach
a. Gibson’s Ecological Theory
Underplay the parallel processing and unconscious processing that the brain does
a. Gibson’s Ecological Theory
b. Gestalt approach
b. Gestalt approach
Their laws provide a description of how things work rather than an explanation
a. Gibson’s Ecological Theory
b. Gestalt approach
b. Gestalt approach
Their laws are ill defined – Prägnanz – what is the simplest and most stable shape?
a. Gibson’s Ecological Theory
b. Gestalt approach
b. Gestalt approach
Stating the obvious
a. Gibson’s Ecological Theory
b. Gestalt approach
b. Gestalt approach
What are invariants?
Unambiguous information about environment
It can be directly perceived
– e.g.(1) Horizon ratio relation
Unambiguous information about environment
It can be directly perceived
– e.g.(1) Horizon ratio relation
This is known as…?
Invariants
Proportion of object above
horizon is constant with changes in distance but not size
This is known as…?
Horizon ratio
Proportion of object above
horizon is constant with changes in _____ but not_____
- distance
- size
Proportion of object ____
horizon is constant with changes in distance but not size
a. Below
b. Above
b. Above
The proportion of the object above and below the horizon line is constant for objects of the same size standing on the same ground
This is known as…?
Horizon ratio
The proportion of the object above and below the horizon line is constant for objects of …?
The same size standing on the same ground
If we have regular objects that were receding away from us, their proportion of their overall height that’s above the environment is…?
The same, regardless of the distance
What are the 2 types of invariants?
- Horizon ratio relation
- Texture gradients
What are texture gradients?
Texture changes depending on its orientation and its distance from you
Texture changes depending on its orientation and its distance from you
This is known as…?
Texture gradients
Changes in texture in the optic array tell us about _____, ______ and ______
- distance
- orientation
- curvature of surfaces
The finer the gradient, the _______ the objects are
a. Further away
b. Closer
a. Further away
The courser the gradient, the ________ the objects are
a. Further away
b. Closer
b. Closer
The _____ the gradient, the further away the objects are
a. courser
b. finer
b. finer
The _____ the gradient, the closer the objects are
a. courser
b. finer
a. courser
Texture becomes smaller/finer as distance increases
This is known as…?
Texture gradient
Texture becomes smaller/finer as distance __
a. increases
b. decreases
c. does not change
a. increases
Describe Gibson & Bridgeman’s (1987) findings on invariants
List 2 points
- Participants could correctly identify objects, state their colour, identify the lighting conditions and the objects spatial orientations just from black and white photos of object surfaces
- The average subject identified about two- thirds of the photographs correctly
True or False?
Participants could not correctly identify objects, state their colour, identify the lighting conditions and the objects spatial orientations from black and white photos of object surfaces
False
Participants could correctly identify objects, state their colour, identify the lighting conditions and the objects spatial orientations just from black and white photos of object surfaces
Describe Gibson & Bridgeman’s (1987) study on invariants
List 5 points
- “What substance or material is this composed of?” (free response)
- “Is it gaseous, liquid, or solid?” (3 choices)
- (If answer was “solid” on number 2) “Could you bend, deform, or change this surface with your finger?”
(2 choices) - “Is the surface planar (flat, smooth) or uneven?” (2 choices)
- “Does everything in the picture have the same pigmentation (colored or black-white substance)?” (2 choices) “Is the lighting diffuse, or does most of it come from one direction?” (2 choices)
(If answer was “directional” on number 6) “What direc- tion is the light coming from?” (8 choices: the 4 edges and 4 corners of the photographs)
“On the box below, circle the edge or corner of the pic-
ture which seems closest to you. If all parts seem equally close, circle the whole box.” (9 choices: 4 edges, 4 corners, or the whole photograph)
True or False?
Motion is not important to perceive invariant information
False
Motion is very important/ necessary in order to perceive invariant information
Motion very important/ necessary in order to perceive invariant information
Why?
In a static scene everything is invariant, so it is useful to introduce motion to highlight the invariant properties
In a static scene everything is _____
Invariant
In a static scene everything is invariant
How can we highlight the invariant properties?
Introduce motion
What are the 2 types of motion?
- Motion due to observer movements
- Motion due to object movement
What type of motion/movement did Gibson’s ecological theory of perception focus on?
Motion due to observer movements
Gibson’s ecological theory of perception focussed on motion due to observer movements
Why? List 2 points
- It generates large changes in the ambient optic array
- Gibson was interested in what these changes can tell us about the environment
Define motion parallax
Things far away move more slowly than things nearby
Things far away move more slowly than things nearby
This is known as…?
Motion parallax
According to motion parallax, speed of movement tells us about …?
The distance to object from us
According to motion parallax, ______ tells us about distance to object
Speed of movement
Observer movement generates large changes in ambient optic array
This is known as…?
Motion parallax
Observer movement generates large changes in _____
Ambient optic array
______ generates large changes in ambient optic array
Observer movement
As an observer moves relative to a 3-D scene, nearby objects appear to move rapidly whereas far objects appear to move slowly
This is an example of…?
Motion parallax
As an observer moves relative to a 3-D scene, nearby objects appear to ____
a. Move rapidly
b. Move slowly
c. Freeze
d. Blink
a. Move rapidly
As an observer moves relative to a 3-D scene, far objects appear to _____
a. Move rapidly
b. Move slowly
c. Freeze
d. Blink
b. Move slowly
Monocular cue to depth is known as…?
Motion parallax
What does motion parallax depend on?
List 2 things
- Relative direction
- Amount of motion
Things closest to you go by very quickly and those that are furthest away go very slowly when you’re on a moving train
This is known as…?
Motion parallax
Motion Parallax is used more by …?
Animals that don’t have much binocular overlap
How can we increase motion parallax cue?
List 2 ways
- Head bob
- Orthogonal running
What is optical Flow (expansion)?
Combination of parallax and retinal size
Combination of parallax and retinal size
This is known as…?
Optical Flow (expansion)
Horizontal lines are painted on the road, becoming
closer together as driver approach junctions
These markings are often seen on the exit roads from motorways and serve to create the illusion of increasing speed, which causes the driver to slow down before joining a non- motorway road
This is an example of…?
Optic flow
Describe a practical implication of Gibson’s Optic Flow Ideas
List 2 points
- Horizontal lines are painted on the road, becoming closer together as driver approach junctions
- These markings are often seen on the exit roads from motorways and serve to create the illusion of increasing speed, which causes the driver to slow down before joining a non- motorway road
Optic flow is a very strong cue for ____ and _____
- Speed
- Orientation
By moving, we are introducing more ____
Information in terms of the visual system
How can we introduce more information in terms of the visual system?
By moving
Define affordance
Opportunity for action
What the surface/ object offers the animal
Opportunity for action
What the surface/ object offers the animal
This is known as…?
Affordance
If you’re trying to design an object, you may try and emphasise what that object affords
e.g. what are you able to do with it, can it be grasped, eaten, sat upon?
This is known as…?
Affordance
What does affordance tell us about perception?
Memory and experience not necessary to perceive things (bottom-up)
Which approach highlighted important information in retinal image for perceiving depth and distance?
Gibson’s ecological theory of
perception
Which approach claims that perception is “direct” - no role for cognition in perception?
Gibson’s ecological theory of
perception
Which approach emphasised importance of action as goal of perception?
Gibson’s ecological theory of
perception
What are the 3 criticisms of Gibson’s ecological theory of
perception?
- Vague? = How is this information picked up?
- Ignores top-down = i.e. experience and memory
- Ignores neuroscience
What are the 4 stages of image analysis according to Marr’s information processing approach to perception?
- Grey level description
- Primal sketch (Raw and Full)
- 21⁄2D sketch
- 3D object-centred description
- Grey level description
- Primal sketch (Raw and Full)
- 21⁄2D sketch
- 3D object-centred description
These are the 4 stages of image analysis according to…?
Marr’s information processing approach to perception
Marr’s information processing approach to perception emphasised a …
a. Bottom-up approach
b. Top-down approach
a. Bottom-up
Bottom-up but emphasised computational nature of perception
a. Gestalt
b. Gibson
c. Marr
c. Marr
Marr’s information processing approach to perception is bottom-up but emphasised …?
Computational nature of perception
Which stage of image analysis does this apply to?
Representation of objects independent of observer
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
d. 3D object-centred description
Which stage of image analysis does this apply to?
Measuring intensity of light at. each point in image
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
a. Grey level description
Which stage of image analysis does this apply to?
Representation of contrast change (blobs, edges, bars etc) over range of spatial frequencies)
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
b. Primal sketch (Raw and Full)
Which stage of image analysis does this apply to?
Representation of orientation, depth, colour relative to the observer
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
c. 21⁄2D sketch
Which stage of image analysis does this apply to?
Black and white representation of the retinal image and examining that for abrupt changes in contrast (where edges in objects are)
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
a. Grey level description
Which stage of image analysis does this apply to?
The intensity of light is measured at each point on the retina
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
a. Grey level description
Which stage of image analysis does this apply to?
Produced by activation of retinal photoreceptors
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
a. Grey level description
What is grey level description?
List 2 points
- The intensity of light is measured at each point on the retina
- Produced by activation of retinal photoreceptors
Which stage of image analysis does this apply to?
Goal: Identify object edges
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
b. Primal sketch (Raw and Full)
What is the goal of raw primal sketch?
Identify object edges
What is the process of raw primal sketch?
List 3 points
- Gaussian blurring
- Identify intensity changes
- Assign primitives
One of the processes of raw primal sketch is Gaussian blurring
What happens in this process?
Blur images to different degrees
One of the processes of raw primal sketch is identify intensity changes
What happens in this process?
Those present at more than 2 levels of blurring
One of the processes of raw primal sketch is assign primitives
What happens in this process?
4 types of intensity change:
1. Edge-segment
2. Bar
3. Termination
4. Blob
Which raw primal sketch process does this apply to?
Blur images to
different degrees
a. Gaussian blurring
b. Identify intensity changes
c. Assign primitives
a. Gaussian blurring
Which raw primal sketch process does this apply to?
Those present at more than 2 levels of blurring
a. Gaussian blurring
b. Identify intensity changes
c. Assign primitives
b. Identify intensity changes
Which raw primal sketch process does this apply to?
4 types of intensity change:
1. Edge-segment
2. Bar
3. Termination
4. Blob
a. Gaussian blurring
b. Identify intensity changes
c. Assign primitives
c. Assign primitives
How can we assign primitives? List 4 ways
- Edge-segment
- Bar
- Termination
- Blob
What are the 4 types of intensity change?
- Edge-segment
- Bar
- Termination
- Blob
Which stage of image analysis does this apply to?
Goal: Identify object outline
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
b. Primal sketch (Raw and Full)
What are the 2 types of primal sketch
- Raw
- Full
What is the goal of full primal sketch?
Identify object outline
What is the process of full primal sketch?
List 2 points
- Group primitives together and assign place token
- Place tokens can be grouped to form higher-order place tokens
– Grouping based on clustering (like Gestalt proximity) and curvilinear aggregation (like Gestalt good continuation)
Place tokens can be grouped to form higher-order place tokens
What are the 2 ways we can group tokens?
- Grouping based on clustering (like Gestalt proximity)
- Grouping based on curvilinear aggregation (like Gestalt good continuation)
Which stage of image analysis does this apply to?
Primal Sketch combined with depth cues, colour, motion
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
c. 21⁄2D sketch
What is 2 1/2 D sketch?
Primal Sketch combined with depth cues, colour, motion
Why is 2 1/2 D sketch not 3D?
Because it is observer- orientated
(unseen parts of scene and objects)
Which stage of image analysis does this apply to?
2 1/2 sketch analyzed for 3D volume primitives (cylinders, cones, cubes etc)
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
d. 3D object-centred description
What is 3D representation?
2 1/2 sketch analyzed for 3D volume primitives (cylinders, cones, cubes etc)
Produces 3D representation that is independent of observer
Which stage of image analysis does this apply to?
Produces 3D representation that is independent of observer
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
d. 3D object-centred description
Which stage of image analysis does this apply to?
Conscious experience of vision
a. Grey level description
b. Primal sketch (Raw and Full)
c. 21⁄2D sketch
d. 3D object-centred description
d. 3D object-centred description
What is the importance of the Computational Approach?
List 2
- An algorithm/ rule/ system is more likely to be understood by understanding the problem that has to be solved, rather than the examining the mechanism (and hardware) in which it is embodied (AI arguments)
- To understand perception (purely) by studying neurons is like trying to understand bird flight by studying only feathers
An algorithm/ rule/ system is more likely to be understood by understanding the problem that has to be solved, rather than …?
The examining the mechanism (and hardware) in which it is embodied (AI arguments)
An algorithm/ rule/ system is more likely to be understood by …?
Understanding the problem that has to be solved
Trying to understand perception (purely) by studying neurons is like trying to understand bird flight by studying …?
Only feathers
- Bottom-up approach
- Computational
- Biologically plausible
Which approach to perception is this?
Marr’s information processing approach to perception
What is the main criticism of Marr’s information processing approach to perception?
Retinal image not always sufficient to allow reconstruction…role of memory and experience?
Retinal image not always sufficient to allow reconstruction…role of memory and experience?
Which approach to perception does this criticism apply to?
Marr’s information processing approach to perception
What is the constructivist approach to perception?
- Retinal image does not provide sufficient information
- Perception depends upon stored knowledge (memory) and experience
Retinal image does not provide sufficient information
Which approach to perception does this apply to?
The constructivist approach to perception
Perception depends upon stored knowledge (memory) and experience
Which approach to perception does this apply to?
The constructivist approach to perception
Who proposed the idea of unconscious inference?
Helmholtz
Who is the main guy behind the constructivist approach to perception?
Helmholtz
What 2 things did Helmholtz propose for the constructivist approach to perception?
- Unconscious inference
- Likelihood principle
What is unconscious inference?
Involuntary, pre-rational and reflex-like mechanism which is part of the formation of visual impressions
Involuntary, pre-rational and reflex-like mechanism which is part of the formation of visual impressions
This is known as…?
Unconscious Inference
What are the 2 types of fixed unconscious neural processing?
- Illusions: impervious to experience
- Naïve optics (e.g. movement of sun in the sky)
True or False?
Interpretation is so hardwired into your brain that knowledge of the world around you does not help much
e.g. you see this illusion as a distorted square, even though you know that it is just an illusion
True
- Illusions: impervious to experience
- Naïve optics (e.g. movement of sun in the sky)
These are the 2 types of…?
Fixed unconscious neural processing
Define the Titchner Illusion
Brain over emphasizes size differences in grouping and separating objects
Brain over emphasizes size differences in grouping and separating objects
This is known as…?
Titchner Illusion
Who proposed the idea of likelihood principle?
Helmholtz
Who proposed a generation of ‘Perceptual hypotheses’?
Richard Gregory
What is the generation of ‘Perceptual hypotheses’?
Many illusions explained by stored knowledge leading to inaccurate perceptual hypotheses
Many illusions explained by stored knowledge leading to inaccurate perceptual hypotheses
This is known as…?
Generation of ‘Perceptual hypotheses’?
Who was the founder member of Experimental Psychology Society?
Richard Gregory
The hollow mask illusion explained by our stored knowledge gives the impression that faces are …?
Convex
Why do we see faces as being convex in the hollow mask illusion?
Because of our stored knowledge that faces are convex
Which approach to perception highlighted the importance of both bottom-up and top- down processing?
The constructivist approach to perception
Which approach to perception was criticised for being vague?
The constructivist approach to perception
What are the 3 main differences between the Gestalt approach, Gibson theory, Marr theory and the constructivist approach?
- Bottom-up vs. Top-down
- Goal of perception
- Methods of study
What are the 2 limitations of the Gestalt approach, Gibson theory, Marr theory and the constructivist approach?
- Different interests and focus
- Poor neuroscience until relatively recently
Select that apply
Bottom up approach only
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
c. Marr
Select that apply
Top-down approach
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
d. Constructivist
Select that apply
Both bottom up and top down approach
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
d. Constructivist
Select that apply
Goal: Reconstruction
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
c. Marr
d. Constructivist
Select that apply
Goal: Action
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Select that apply
Methods: Some Experimental/ Lab
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
Select that apply
Methods: Experimental/ Outside lab
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Select that apply
Methods: Computational
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
c. Marr
Select that apply
Methods: Experimental/ Lab
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
d. Constructivist
Select that apply
Key aspect: Perceptual Hypotheses and stored knowledge
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
d. Constructivist
Select that apply
Key aspect: Perception as a computational, information processing problem
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
c. Marr
Select that apply
Key aspect: Direct Perception for action
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Select that apply
Key aspect: Sum more than parts, laws of perceptual organisation
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
Select that apply
Criticism: Vague: how are hypotheses generated?
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
d. Constructivist
Select that apply
Criticism: No role for top down
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
c. Marr
Select that apply
Criticism: Vague: how information picked up and processed
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Select that apply
Criticism: Descriptive rather than explanatory
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
Laws of perceptual
organisation
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
a. Gestalt
Ecological approach
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Ambient optic array
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Invariants
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
Affordance
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
b. Gibson
- Grey-level description
– Primal sketch
– 2 1⁄2 D sketch
– 3D object-centred description
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
c. Marr
Unconscious inference
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
d. Constructivist
Perceptual hypotheses
a. Gestalt
b. Gibson
c. Marr
d. Constructivist
d. Constructivist
