Form Perception

Question 1

Gestalt Principles

Answer 1

Laws that describe how we organize visual input (innate from birth)
1. Figure-ground
2. Proximity
3. Closure
4. Similarity
5. Continuity
6. Common fate

Question 2

Figure-Ground

Answer 2

The ability to distinguish an object from its background in a visual scene. (ex. seeing a vase of flowers against a flowery background)

Question 3

Proximity

Answer 3

The tendency to group elements that are close together in space (ex. grouping Xs that are close together in high density rather than far apart ones)

Question 4

Closure

Answer 4

The tendency to fill in gaps in a contour to perceive a whole object (ex. if a pole blocks a truck, you wouldn’t perceive two separate pieces of the truck, but automatically fill in the missing part you can’t see)

Question 5

Similarity

Answer 5

The tendency to group together elements that are physically similar. (ex. grouping columns of Xs and Os, rather than rows of XOs)

Question 6

Continuity

Answer 6

The ability to perceive a simple, continuous form rather than a combination of awkward forms (ex. perceiving an X as two continuous diagonals, rather than two Vs)

Question 7

Common Fate

Answer 7

The tendency to group together elements that change in the same way (ex. grouping a school of fish because they are moving together)

Question 8

Bottom-up processing

Answer 8

Object recognition is guided by the features that are present in the stimulus (ex. recognizing a cow because it has 4 legs, 2 big eyes, 2 long ears, a nose, an udder, and goes “moo”)

Question 9

Top-down processing

Answer 9

Object recognition is guided by your own beliefs/expectations (ex. a B can look like the number 13, but the letters near this symbol influences how you perceive it; if 12 precedes and 14 follows, you will see a 13, but if A precedes and C follows, you will see a B)

Question 10

Bi-directional Activation

Answer 10

Object recognition is guided by both bottom-up (object features) and top-down (expectations) processing

Question 11

Priming

Answer 11

Example of top-down processing, where an experimenter measures how fast a participant can read words that are flashed on a screen. If the experimenter primes the word with the a category, recognition of words in that category will be faster.

Question 12

Theories of object recognition

Answer 12

Geon, template, prototype

Question 13

Geon Theory

Answer 13

Suggests that we have 36 geons stored in memory (cone, sphere, etc) that make it possible to recognize over 150 million objects. (ex. ice cream cone is made of a cone and a sphere)
CONS:
- difficult to imagine the geons used in more complicated objects, such as faces
- can not explain how brain injury can affect recognition for only certain types of objects (ex. recognizing tools, not fruits)

Question 14

Template Theory

Answer 14

Suggest that we find compare exact matches of objects to templates in memory.
EVIDENCE:
- matching objects to a template is deemed familiar, and connections are sent to language areas to name the object
- new template stored for unfamiliar objects
CONS:
- too many stimuli exist to feasibly store in memory

Question 15

Prototype Theory

Answer 15

Suggests that we compare object to our ideal prototype
EVIDENCE:
- does not require an exact match
- explains how we can recognize object we’ve never seen before (ex. new breed of dog)
CONS:
- we are able to recognize specific objects, indicating that we may have more than one prototypes of an object

Question 16

Perceptual Constancies

Answer 16

The ability to perceive an object as unchanging even though the visual image produced by the object is constantly changing.
1. Shape
2. Location
3. Size
4. Brightness
5. Colour

Question 17

Shape Constancy

Answer 17

An object is perceived to have constant shape despite the shape of its retinal image changing with shifts in point of view or change in object position (ex. a door is perceived as rectangular despite its visual change when opening)

Question 18

Location Constancy

Answer 18

An object is perceived the be stationary despite changing location of out retina due to body movements (ex. when driving, we don’t perceive objects, like trees, to be moving)

Question 19

Size Constancy

Answer 19

An object is perceived to be the same size despite the size if it’s retinal image varying with distance. (ex. perceiving depth as your friend walks away, rather than him shrinking in size)

Question 20

Brightness Constancy

Answer 20

An object is perceived to be the same brightness despite reflecting more/less light onto our retinas (ex. mugs have the same brightness, regardless of lamination)

Question 21

Colour Constancy

Answer 21

An object is perceived to have constant colour regardless of different illumination conditions (ex. white dog recognized as white, even under a red light)

Question 22

Müller-Lyer Illusion

Answer 22

Misapplies size constancy and misinterprets depth. Two lines of the same length; line A looks like a corner receding away from you, line B looks like a corner closer to you. Line B is perceived as shorter.

Question 23

Ames Room Illusion

Answer 23

Looks like a normal rectangular room, but is actually trapezoidal. Objects in corner A are a greater distance away and perceived as smaller. This illusion manipulates distance to trick size constancy.

Question 24

Ponzo Illusion

Answer 24

Manipulates depth cues to trick size constancy. Horizontal lines A and B are the same length, but A appears closer to the diagonals, so it is perceived as longer)

Question 25

Simple Cells

Answer 25

Responds maximally to a bar of a certain orientation. Receptive field organized in an opponent fashion (on and off fields) (ex. horizontal preferred simple cells: - no stimulus = baseline response - preferred orientation (on field) = strong excitatory response - not preferred orientation (off field) = strong inhibitory response)

Question 26

Complex Cells

Answer 26

Responds maximally to a bar of a certain orientation and direction (ex. 45 degree preferred complex cells: - no stimulus = baseline response - 45 degrees on top and both of retina = strong excitatory response - 60 degrees on middle of retina = weak excitatory response)

Question 27

Hypercomplex Cells

Answer 27

Responds maximally to a bar of a particular orientation and direction of movement, ending at specific points within the receptive field. (ex. upwards horizontal bar preferred complex cells: - moving up horizontally on the ON field only = strong excitatory field - moving up horizontally on the ON field and half the OFF field = weak excitatory response - moving up horizontally on equal shares of the ON and OFF field = weak inhibitory response)

Question 28

Retinotopic mapping

Answer 28

Neighbouring objects in your visual fields are processed by neighbouring areas of your brain.

Question 29

Dorsal stream

Answer 29

The "where" stream that processes the location of objects in the visual scene and how they move; takes information from V1 to parietal cortex which processes spatial information

Question 30

Ventral stream

Answer 30

The "what" stream that processed form and colour of object; takes information from the V1 to the temporal cortex where the feature information comes together. Temporal cortex is arranged in vertical neuronal columns perpendicular to the cortex with 6 layers, each layer responding to a different feature of that category. (ex. a cortical column that best responds to apples will have a layer for red apples and another layer for green apples)

Question 31

Face-tracking studies

Answer 31

Studies that tracked where an infant looks when they are shown a face. Younger infants focus of outer contours (chin, hair, etc) whereas older infants focuses on inner features (eyes, nose, mouth, etc)

Question 32

Kitten Study

Answer 32

Kittens were raised in a cylinder with vertical stripes, and failed to develop feature detectors for horizontal lines

Question 33

Cataract Study

Answer 33

Cataracts diffuse light from passing through a cloudy lens, resulting in the complete inability to perceive objects. Surgery replaces the cloudy lens with an artificial one; increased visual impairment in those who had their surgeries later after the critical period.

Question 34

Primary Visual Cortex damage

Answer 34

Vision loss in specific regions of the visual field, but able to recognize objects in the intact areas. ("keyhole" vision)

Question 35

Extrastriate Cortex damage

Answer 35

Visual field remains intact but difficulty with object recognition (called visual agnosia)

Question 36

Object Agnosia

Answer 36

The inability to perceive objects. Unable to identify objects regardless of their good visual acuity, but could name objects by touch (ex. man with object agnosia would see a glove, and could describe it, but would not be able to name it until he has touched it)

Question 37

Prosopagnosia

Answer 37

The inability to recognize faces, caused by a damaged right fusiform gyrus. They can identify objects and facial features but are unable to place name to a face. They rely on other cues like voice/smell to recognize people. They can identify categories, but not specific examples (ex. recognizing a dog, but not that it's their own)